path: root/SOURCES/linux-surface.patch

From ec6fa26f04034a252e606d4cdc8097282c59ab18 Mon Sep 17 00:00:00 2001
From: Tsuchiya Yuto <kitakar@gmail.com>
Date: Sun, 18 Oct 2020 16:42:44 +0900
Subject: [PATCH] (surface3-oemb) add DMI matches for Surface 3 with broken DMI
 table

On some Surface 3, the DMI table gets corrupted for unknown reasons
and breaks existing DMI matching used for device-specific quirks.

This commit adds the (broken) DMI data into dmi_system_id tables used
for quirks so that each driver can enable quirks even on the affected
systems.

On affected systems, DMI data will look like this:
    $ grep . /sys/devices/virtual/dmi/id/{bios_vendor,board_name,board_vendor,\
    chassis_vendor,product_name,sys_vendor}
    /sys/devices/virtual/dmi/id/bios_vendor:American Megatrends Inc.
    /sys/devices/virtual/dmi/id/board_name:OEMB
    /sys/devices/virtual/dmi/id/board_vendor:OEMB
    /sys/devices/virtual/dmi/id/chassis_vendor:OEMB
    /sys/devices/virtual/dmi/id/product_name:OEMB
    /sys/devices/virtual/dmi/id/sys_vendor:OEMB

Expected:
    $ grep . /sys/devices/virtual/dmi/id/{bios_vendor,board_name,board_vendor,\
    chassis_vendor,product_name,sys_vendor}
    /sys/devices/virtual/dmi/id/bios_vendor:American Megatrends Inc.
    /sys/devices/virtual/dmi/id/board_name:Surface 3
    /sys/devices/virtual/dmi/id/board_vendor:Microsoft Corporation
    /sys/devices/virtual/dmi/id/chassis_vendor:Microsoft Corporation
    /sys/devices/virtual/dmi/id/product_name:Surface 3
    /sys/devices/virtual/dmi/id/sys_vendor:Microsoft Corporation

Signed-off-by: Tsuchiya Yuto <kitakar@gmail.com>
Patchset: surface3-oemb
---
 drivers/platform/surface/surface3-wmi.c           | 7 +++++++
 sound/soc/codecs/rt5645.c                         | 9 +++++++++
 sound/soc/intel/common/soc-acpi-intel-cht-match.c | 8 ++++++++
 3 files changed, 24 insertions(+)

diff --git a/drivers/platform/surface/surface3-wmi.c b/drivers/platform/surface/surface3-wmi.c
index 09ac9cfc40d8..c626109cf445 100644
--- a/drivers/platform/surface/surface3-wmi.c
+++ b/drivers/platform/surface/surface3-wmi.c
@@ -37,6 +37,13 @@ static const struct dmi_system_id surface3_dmi_table[] = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
 		},
 	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
+			DMI_MATCH(DMI_SYS_VENDOR, "OEMB"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "OEMB"),
+		},
+	},
 #endif
 	{ }
 };
diff --git a/sound/soc/codecs/rt5645.c b/sound/soc/codecs/rt5645.c
index 197c56047947..9893e9c3cdf7 100644
--- a/sound/soc/codecs/rt5645.c
+++ b/sound/soc/codecs/rt5645.c
@@ -3718,6 +3718,15 @@ static const struct dmi_system_id dmi_platform_data[] = {
 		},
 		.driver_data = (void *)&intel_braswell_platform_data,
 	},
+	{
+		.ident = "Microsoft Surface 3",
+		.matches = {
+			DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
+			DMI_MATCH(DMI_SYS_VENDOR, "OEMB"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "OEMB"),
+		},
+		.driver_data = (void *)&intel_braswell_platform_data,
+	},
 	{
 		/*
 		 * Match for the GPDwin which unfortunately uses somewhat
diff --git a/sound/soc/intel/common/soc-acpi-intel-cht-match.c b/sound/soc/intel/common/soc-acpi-intel-cht-match.c
index c60a5e8e7bc9..e947133a2c36 100644
--- a/sound/soc/intel/common/soc-acpi-intel-cht-match.c
+++ b/sound/soc/intel/common/soc-acpi-intel-cht-match.c
@@ -27,6 +27,14 @@ static const struct dmi_system_id cht_table[] = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
 		},
 	},
+	{
+		.callback = cht_surface_quirk_cb,
+		.matches = {
+			DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
+			DMI_MATCH(DMI_SYS_VENDOR, "OEMB"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "OEMB"),
+		},
+	},
 	{ }
 };
 
-- 
2.36.0

From 1395350fc7351ab5a75541dd444b9321ab51642a Mon Sep 17 00:00:00 2001
From: Tsuchiya Yuto <kitakar@gmail.com>
Date: Tue, 29 Sep 2020 17:32:22 +0900
Subject: [PATCH] mwifiex: pcie: add reset_wsid quirk for Surface 3

This commit adds reset_wsid quirk and uses this quirk for Surface 3 on
card reset.

To reset mwifiex on Surface 3, it seems that calling the _DSM method
exists in \_SB.WSID [1] device is required.

On Surface 3, calling the _DSM method removes/re-probes the card by
itself. So, need to place the reset function before performing FLR and
skip performing any other reset-related works.

Note that Surface Pro 3 also has the WSID device [2], but it seems to need
more work. This commit only supports Surface 3 yet.

[1] https://github.com/linux-surface/acpidumps/blob/05cba925f3a515f222acb5b3551a032ddde958fe/surface_3/dsdt.dsl#L11947-L12011
[2] https://github.com/linux-surface/acpidumps/blob/05cba925f3a515f222acb5b3551a032ddde958fe/surface_pro_3/dsdt.dsl#L12164-L12216

Signed-off-by: Tsuchiya Yuto <kitakar@gmail.com>
Patchset: mwifiex
---
 drivers/net/wireless/marvell/mwifiex/pcie.c   | 10 +++
 .../wireless/marvell/mwifiex/pcie_quirks.c    | 83 +++++++++++++++++++
 .../wireless/marvell/mwifiex/pcie_quirks.h    |  6 ++
 3 files changed, 99 insertions(+)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index d5fb29400bad..033648526f16 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -2993,6 +2993,16 @@ static void mwifiex_pcie_card_reset_work(struct mwifiex_adapter *adapter)
 {
 	struct pcie_service_card *card = adapter->card;
 
+	/* On Surface 3, reset_wsid method removes then re-probes card by
+	 * itself. So, need to place it here and skip performing any other
+	 * reset-related works.
+	 */
+	if (card->quirks & QUIRK_FW_RST_WSID_S3) {
+		mwifiex_pcie_reset_wsid_quirk(card->dev);
+		/* skip performing any other reset-related works */
+		return;
+	}
+
 	/* We can't afford to wait here; remove() might be waiting on us. If we
 	 * can't grab the device lock, maybe we'll get another chance later.
 	 */
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
index 0234cf3c2974..563dd0d5ac79 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
@@ -15,10 +15,21 @@
  * this warranty disclaimer.
  */
 
+#include <linux/acpi.h>
 #include <linux/dmi.h>
 
 #include "pcie_quirks.h"
 
+/* For reset_wsid quirk */
+#define ACPI_WSID_PATH		"\\_SB.WSID"
+#define WSID_REV		0x0
+#define WSID_FUNC_WIFI_PWR_OFF	0x1
+#define WSID_FUNC_WIFI_PWR_ON	0x2
+/* WSID _DSM UUID: "534ea3bf-fcc2-4e7a-908f-a13978f0c7ef" */
+static const guid_t wsid_dsm_guid =
+	GUID_INIT(0x534ea3bf, 0xfcc2, 0x4e7a,
+		  0x90, 0x8f, 0xa1, 0x39, 0x78, 0xf0, 0xc7, 0xef);
+
 /* quirk table based on DMI matching */
 static const struct dmi_system_id mwifiex_quirk_table[] = {
 	{
@@ -87,6 +98,14 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 		},
 		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
 	},
+	{
+		.ident = "Surface 3",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
+		},
+		.driver_data = (void *)QUIRK_FW_RST_WSID_S3,
+	},
 	{}
 };
 
@@ -103,6 +122,9 @@ void mwifiex_initialize_quirks(struct pcie_service_card *card)
 		dev_info(&pdev->dev, "no quirks enabled\n");
 	if (card->quirks & QUIRK_FW_RST_D3COLD)
 		dev_info(&pdev->dev, "quirk reset_d3cold enabled\n");
+	if (card->quirks & QUIRK_FW_RST_WSID_S3)
+		dev_info(&pdev->dev,
+			 "quirk reset_wsid for Surface 3 enabled\n");
 }
 
 static void mwifiex_pcie_set_power_d3cold(struct pci_dev *pdev)
@@ -159,3 +181,64 @@ int mwifiex_pcie_reset_d3cold_quirk(struct pci_dev *pdev)
 
 	return 0;
 }
+
+int mwifiex_pcie_reset_wsid_quirk(struct pci_dev *pdev)
+{
+	acpi_handle handle;
+	union acpi_object *obj;
+	acpi_status status;
+
+	dev_info(&pdev->dev, "Using reset_wsid quirk to perform FW reset\n");
+
+	status = acpi_get_handle(NULL, ACPI_WSID_PATH, &handle);
+	if (ACPI_FAILURE(status)) {
+		dev_err(&pdev->dev, "No ACPI handle for path %s\n",
+			ACPI_WSID_PATH);
+		return -ENODEV;
+	}
+
+	if (!acpi_has_method(handle, "_DSM")) {
+		dev_err(&pdev->dev, "_DSM method not found\n");
+		return -ENODEV;
+	}
+
+	if (!acpi_check_dsm(handle, &wsid_dsm_guid,
+			    WSID_REV, WSID_FUNC_WIFI_PWR_OFF)) {
+		dev_err(&pdev->dev,
+			"_DSM method doesn't support wifi power off func\n");
+		return -ENODEV;
+	}
+
+	if (!acpi_check_dsm(handle, &wsid_dsm_guid,
+			    WSID_REV, WSID_FUNC_WIFI_PWR_ON)) {
+		dev_err(&pdev->dev,
+			"_DSM method doesn't support wifi power on func\n");
+		return -ENODEV;
+	}
+
+	/* card will be removed immediately after this call on Surface 3 */
+	dev_info(&pdev->dev, "turning wifi off...\n");
+	obj = acpi_evaluate_dsm(handle, &wsid_dsm_guid,
+				WSID_REV, WSID_FUNC_WIFI_PWR_OFF,
+				NULL);
+	if (!obj) {
+		dev_err(&pdev->dev,
+			"device _DSM execution failed for turning wifi off\n");
+		return -EIO;
+	}
+	ACPI_FREE(obj);
+
+	/* card will be re-probed immediately after this call on Surface 3 */
+	dev_info(&pdev->dev, "turning wifi on...\n");
+	obj = acpi_evaluate_dsm(handle, &wsid_dsm_guid,
+				WSID_REV, WSID_FUNC_WIFI_PWR_ON,
+				NULL);
+	if (!obj) {
+		dev_err(&pdev->dev,
+			"device _DSM execution failed for turning wifi on\n");
+		return -EIO;
+	}
+	ACPI_FREE(obj);
+
+	return 0;
+}
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
index 8ec4176d698f..25370c5a4f59 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
@@ -19,5 +19,11 @@
 
 #define QUIRK_FW_RST_D3COLD	BIT(0)
 
+/* Surface 3 and Surface Pro 3 have the same _DSM method but need to
+ * be handled differently. Currently, only S3 is supported.
+ */
+#define QUIRK_FW_RST_WSID_S3	BIT(1)
+
 void mwifiex_initialize_quirks(struct pcie_service_card *card);
 int mwifiex_pcie_reset_d3cold_quirk(struct pci_dev *pdev);
+int mwifiex_pcie_reset_wsid_quirk(struct pci_dev *pdev);
-- 
2.36.0

From 312dfdce8be446cbe3fc1fb49754057218e2c7bd Mon Sep 17 00:00:00 2001
From: Tsuchiya Yuto <kitakar@gmail.com>
Date: Wed, 30 Sep 2020 18:08:24 +0900
Subject: [PATCH] mwifiex: pcie: (OEMB) add quirk for Surface 3 with broken DMI
 table

(made referring to http://git.osdn.net/view?p=android-x86/kernel.git;a=commitdiff;h=18e2e857c57633b25b3b4120f212224a108cd883)

On some Surface 3, the DMI table gets corrupted for unknown reasons
and breaks existing DMI matching used for device-specific quirks.

This commit adds the (broken) DMI info for the affected Surface 3.

On affected systems, DMI info will look like this:
    $ grep . /sys/devices/virtual/dmi/id/{bios_vendor,board_name,board_vendor,\
    chassis_vendor,product_name,sys_vendor}
    /sys/devices/virtual/dmi/id/bios_vendor:American Megatrends Inc.
    /sys/devices/virtual/dmi/id/board_name:OEMB
    /sys/devices/virtual/dmi/id/board_vendor:OEMB
    /sys/devices/virtual/dmi/id/chassis_vendor:OEMB
    /sys/devices/virtual/dmi/id/product_name:OEMB
    /sys/devices/virtual/dmi/id/sys_vendor:OEMB

Expected:
    $ grep . /sys/devices/virtual/dmi/id/{bios_vendor,board_name,board_vendor,\
    chassis_vendor,product_name,sys_vendor}
    /sys/devices/virtual/dmi/id/bios_vendor:American Megatrends Inc.
    /sys/devices/virtual/dmi/id/board_name:Surface 3
    /sys/devices/virtual/dmi/id/board_vendor:Microsoft Corporation
    /sys/devices/virtual/dmi/id/chassis_vendor:Microsoft Corporation
    /sys/devices/virtual/dmi/id/product_name:Surface 3
    /sys/devices/virtual/dmi/id/sys_vendor:Microsoft Corporation

Signed-off-by: Tsuchiya Yuto <kitakar@gmail.com>
Patchset: mwifiex
---
 drivers/net/wireless/marvell/mwifiex/pcie_quirks.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
index 563dd0d5ac79..32e2f000e57b 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
@@ -106,6 +106,15 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 		},
 		.driver_data = (void *)QUIRK_FW_RST_WSID_S3,
 	},
+	{
+		.ident = "Surface 3",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "OEMB"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "OEMB"),
+		},
+		.driver_data = (void *)QUIRK_FW_RST_WSID_S3,
+	},
 	{}
 };
 
-- 
2.36.0

From 91a301f7fd782acf695910c618edcb98c062ed99 Mon Sep 17 00:00:00 2001
From: Tsuchiya Yuto <kitakar@gmail.com>
Date: Sun, 4 Oct 2020 00:11:49 +0900
Subject: [PATCH] mwifiex: pcie: disable bridge_d3 for Surface gen4+

Currently, mwifiex fw will crash after suspend on recent kernel series.
On Windows, it seems that the root port of wifi will never enter D3 state
(stay on D0 state). And on Linux, disabling the D3 state for the
bridge fixes fw crashing after suspend.

This commit disables the D3 state of root port on driver initialization
and fixes fw crashing after suspend.

Signed-off-by: Tsuchiya Yuto <kitakar@gmail.com>
Patchset: mwifiex
---
 drivers/net/wireless/marvell/mwifiex/pcie.c   |  7 +++++
 .../wireless/marvell/mwifiex/pcie_quirks.c    | 27 +++++++++++++------
 .../wireless/marvell/mwifiex/pcie_quirks.h    |  1 +
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index 033648526f16..ca6bcbe4794c 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -380,6 +380,7 @@ static int mwifiex_pcie_probe(struct pci_dev *pdev,
 					const struct pci_device_id *ent)
 {
 	struct pcie_service_card *card;
+	struct pci_dev *parent_pdev = pci_upstream_bridge(pdev);
 	int ret;
 
 	pr_debug("info: vendor=0x%4.04X device=0x%4.04X rev=%d\n",
@@ -421,6 +422,12 @@ static int mwifiex_pcie_probe(struct pci_dev *pdev,
 		return -1;
 	}
 
+	/* disable bridge_d3 for Surface gen4+ devices to fix fw crashing
+	 * after suspend
+	 */
+	if (card->quirks & QUIRK_NO_BRIDGE_D3)
+		parent_pdev->bridge_d3 = false;
+
 	return 0;
 }
 
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
index 32e2f000e57b..356401bab59c 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
@@ -38,7 +38,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Pro 4"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface Pro 5",
@@ -47,7 +48,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_SKU, "Surface_Pro_1796"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface Pro 5 (LTE)",
@@ -56,7 +58,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_SKU, "Surface_Pro_1807"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface Pro 6",
@@ -64,7 +67,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Pro 6"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface Book 1",
@@ -72,7 +76,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Book"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface Book 2",
@@ -80,7 +85,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Book 2"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface Laptop 1",
@@ -88,7 +94,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Laptop"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface Laptop 2",
@@ -96,7 +103,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Laptop 2"),
 		},
-		.driver_data = (void *)QUIRK_FW_RST_D3COLD,
+		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
+					QUIRK_NO_BRIDGE_D3),
 	},
 	{
 		.ident = "Surface 3",
@@ -134,6 +142,9 @@ void mwifiex_initialize_quirks(struct pcie_service_card *card)
 	if (card->quirks & QUIRK_FW_RST_WSID_S3)
 		dev_info(&pdev->dev,
 			 "quirk reset_wsid for Surface 3 enabled\n");
+	if (card->quirks & QUIRK_NO_BRIDGE_D3)
+		dev_info(&pdev->dev,
+			 "quirk no_brigde_d3 enabled\n");
 }
 
 static void mwifiex_pcie_set_power_d3cold(struct pci_dev *pdev)
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
index 25370c5a4f59..a1de111ad1db 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
@@ -23,6 +23,7 @@
  * be handled differently. Currently, only S3 is supported.
  */
 #define QUIRK_FW_RST_WSID_S3	BIT(1)
+#define QUIRK_NO_BRIDGE_D3	BIT(2)
 
 void mwifiex_initialize_quirks(struct pcie_service_card *card);
 int mwifiex_pcie_reset_d3cold_quirk(struct pci_dev *pdev);
-- 
2.36.0

From 1febd99bd24be85092ba5ddbf04cac8d9deab2c0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>
Date: Tue, 3 Nov 2020 13:28:04 +0100
Subject: [PATCH] mwifiex: Add quirk resetting the PCI bridge on MS Surface
 devices

The most recent firmware of the 88W8897 card reports a hardcoded LTR
value to the system during initialization, probably as an (unsuccessful)
attempt of the developers to fix firmware crashes. This LTR value
prevents most of the Microsoft Surface devices from entering deep
powersaving states (either platform C-State 10 or S0ix state), because
the exit latency of that state would be higher than what the card can
tolerate.

Turns out the card works just the same (including the firmware crashes)
no matter if that hardcoded LTR value is reported or not, so it's kind
of useless and only prevents us from saving power.

To get rid of those hardcoded LTR reports, it's possible to reset the
PCI bridge device after initializing the cards firmware. I'm not exactly
sure why that works, maybe the power management subsystem of the PCH
resets its stored LTR values when doing a function level reset of the
bridge device. Doing the reset once after starting the wifi firmware
works very well, probably because the firmware only reports that LTR
value a single time during firmware startup.

Patchset: mwifiex
---
 drivers/net/wireless/marvell/mwifiex/pcie.c   | 12 +++++++++
 .../wireless/marvell/mwifiex/pcie_quirks.c    | 26 +++++++++++++------
 .../wireless/marvell/mwifiex/pcie_quirks.h    |  1 +
 3 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index ca6bcbe4794c..24bcd22a2618 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -1781,9 +1781,21 @@ mwifiex_pcie_send_boot_cmd(struct mwifiex_adapter *adapter, struct sk_buff *skb)
 static int mwifiex_pcie_init_fw_port(struct mwifiex_adapter *adapter)
 {
 	struct pcie_service_card *card = adapter->card;
+	struct pci_dev *pdev = card->dev;
+	struct pci_dev *parent_pdev = pci_upstream_bridge(pdev);
 	const struct mwifiex_pcie_card_reg *reg = card->pcie.reg;
 	int tx_wrap = card->txbd_wrptr & reg->tx_wrap_mask;
 
+	/* Trigger a function level reset of the PCI bridge device, this makes
+	 * the firmware of PCIe 88W8897 cards stop reporting a fixed LTR value
+	 * that prevents the system from entering package C10 and S0ix powersaving
+	 * states.
+	 * We need to do it here because it must happen after firmware
+	 * initialization and this function is called after that is done.
+	 */
+	if (card->quirks & QUIRK_DO_FLR_ON_BRIDGE)
+		pci_reset_function(parent_pdev);
+
 	/* Write the RX ring read pointer in to reg->rx_rdptr */
 	if (mwifiex_write_reg(adapter, reg->rx_rdptr, card->rxbd_rdptr |
 			      tx_wrap)) {
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
index 356401bab59c..6437f067d07a 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.c
@@ -39,7 +39,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Pro 4"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface Pro 5",
@@ -49,7 +50,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_SKU, "Surface_Pro_1796"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface Pro 5 (LTE)",
@@ -59,7 +61,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_SKU, "Surface_Pro_1807"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface Pro 6",
@@ -68,7 +71,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Pro 6"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface Book 1",
@@ -77,7 +81,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Book"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface Book 2",
@@ -86,7 +91,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Book 2"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface Laptop 1",
@@ -95,7 +101,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Laptop"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface Laptop 2",
@@ -104,7 +111,8 @@ static const struct dmi_system_id mwifiex_quirk_table[] = {
 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Laptop 2"),
 		},
 		.driver_data = (void *)(QUIRK_FW_RST_D3COLD |
-					QUIRK_NO_BRIDGE_D3),
+					QUIRK_NO_BRIDGE_D3 |
+					QUIRK_DO_FLR_ON_BRIDGE),
 	},
 	{
 		.ident = "Surface 3",
@@ -145,6 +153,8 @@ void mwifiex_initialize_quirks(struct pcie_service_card *card)
 	if (card->quirks & QUIRK_NO_BRIDGE_D3)
 		dev_info(&pdev->dev,
 			 "quirk no_brigde_d3 enabled\n");
+	if (card->quirks & QUIRK_DO_FLR_ON_BRIDGE)
+		dev_info(&pdev->dev, "quirk do_flr_on_bridge enabled\n");
 }
 
 static void mwifiex_pcie_set_power_d3cold(struct pci_dev *pdev)
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
index a1de111ad1db..0e429779bb04 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
+++ b/drivers/net/wireless/marvell/mwifiex/pcie_quirks.h
@@ -24,6 +24,7 @@
  */
 #define QUIRK_FW_RST_WSID_S3	BIT(1)
 #define QUIRK_NO_BRIDGE_D3	BIT(2)
+#define QUIRK_DO_FLR_ON_BRIDGE	BIT(3)
 
 void mwifiex_initialize_quirks(struct pcie_service_card *card);
 int mwifiex_pcie_reset_d3cold_quirk(struct pci_dev *pdev);
-- 
2.36.0

From 8c6862539a41224f764f06e5f0c7284770edc3f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>
Date: Thu, 25 Mar 2021 11:33:02 +0100
Subject: [PATCH] Bluetooth: btusb: Lower passive lescan interval on Marvell
 88W8897

The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version)
is used in a lot of Microsoft Surface devices, and all those devices
suffer from very low 2.4GHz wifi connection speeds while bluetooth is
enabled. The reason for that is that the default passive scanning
interval for Bluetooth Low Energy devices is quite high in Linux
(interval of 60 msec and scan window of 30 msec, see hci_core.c), and
the Marvell chip is known for its bad bt+wifi coexisting performance.

So decrease that passive scan interval and make the scan window shorter
on this particular device to allow for spending more time transmitting
wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and
the new scan window is 6.25 msec (0xa * 0,625 msec).

This change has a very large impact on the 2.4GHz wifi speeds and gets
it up to performance comparable with the Windows driver, which seems to
apply a similar quirk.

The interval and window length were tested and found to work very well
with a lot of Bluetooth Low Energy devices, including the Surface Pen, a
Bluetooth Speaker and two modern Bluetooth headphones. All devices were
discovered immediately after turning them on. Even lower values were
also tested, but they introduced longer delays until devices get
discovered.

Patchset: mwifiex
---
 drivers/bluetooth/btusb.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 42234d5f602d..72202a744564 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -63,6 +63,7 @@ static struct usb_driver btusb_driver;
 #define BTUSB_INTEL_BROKEN_SHUTDOWN_LED	0x2000000
 #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000
 #define BTUSB_INTEL_NO_WBS_SUPPORT	0x8000000
+#define BTUSB_LOWER_LESCAN_INTERVAL	0x10000000
 
 static const struct usb_device_id btusb_table[] = {
 	/* Generic Bluetooth USB device */
@@ -377,6 +378,7 @@ static const struct usb_device_id blacklist_table[] = {
 	{ USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL },
 	{ USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL },
 	{ USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL },
+	{ USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL },
 
 	/* Intel Bluetooth devices */
 	{ USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED },
@@ -3751,6 +3753,19 @@ static int btusb_probe(struct usb_interface *intf,
 	if (id->driver_info & BTUSB_MARVELL)
 		hdev->set_bdaddr = btusb_set_bdaddr_marvell;
 
+	/* The Marvell 88W8897 combined wifi and bluetooth card is known for
+	 * very bad bt+wifi coexisting performance.
+	 *
+	 * Decrease the passive BT Low Energy scan interval a bit
+	 * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter
+	 * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly
+	 * higher wifi throughput while passively scanning for BT LE devices.
+	 */
+	if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) {
+		hdev->le_scan_interval = 0x0190;
+		hdev->le_scan_window = 0x000a;
+	}
+
 	if (IS_ENABLED(CONFIG_BT_HCIBTUSB_MTK) &&
 	    (id->driver_info & BTUSB_MEDIATEK)) {
 		hdev->setup = btusb_mtk_setup;
-- 
2.36.0

From 921b3bdd8d6d963f5ea108a699ef6f70a3709acd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>
Date: Tue, 10 Nov 2020 12:49:56 +0100
Subject: [PATCH] mwifiex: Use non-posted PCI register writes

On the 88W8897 card it's very important the TX ring write pointer is
updated correctly to its new value before setting the TX ready
interrupt, otherwise the firmware appears to crash (probably because
it's trying to DMA-read from the wrong place).

Since PCI uses "posted writes" when writing to a register, it's not
guaranteed that a write will happen immediately. That means the pointer
might be outdated when setting the TX ready interrupt, leading to
firmware crashes especially when ASPM L1 and L1 substates are enabled
(because of the higher link latency, the write will probably take
longer).

So fix those firmware crashes by always forcing non-posted writes. We do
that by simply reading back the register after writing it, just as a lot
of other drivers do.

There are two reproducers that are fixed with this patch:

1) During rx/tx traffic and with ASPM L1 substates enabled (the enabled
substates are platform dependent), the firmware crashes and eventually a
command timeout appears in the logs. That crash is fixed by using a
non-posted write in mwifiex_pcie_send_data().

2) When sending lots of commands to the card, waking it up from sleep in
very quick intervals, the firmware eventually crashes. That crash
appears to be fixed by some other non-posted write included here.

Patchset: mwifiex
---
 drivers/net/wireless/marvell/mwifiex/pcie.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index 24bcd22a2618..b4ad0113a035 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -238,6 +238,12 @@ static int mwifiex_write_reg(struct mwifiex_adapter *adapter, int reg, u32 data)
 
 	iowrite32(data, card->pci_mmap1 + reg);
 
+	/* Do a read-back, which makes the write non-posted, ensuring the
+	 * completion before returning.
+	 * The firmware of the 88W8897 card is buggy and this avoids crashes.
+	 */
+	ioread32(card->pci_mmap1 + reg);
+
 	return 0;
 }
 
-- 
2.36.0

From 1e8468a42b52eb369a70003f99dde7b16846c5e2 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sat, 27 Feb 2021 00:45:52 +0100
Subject: [PATCH] ath10k: Add module parameters to override board files

Some Surface devices, specifically the Surface Go and AMD version of the
Surface Laptop 3 (wich both come with QCA6174 WiFi chips), work better
with a different board file, as it seems that the firmeware included
upstream is buggy.

As it is generally not a good idea to randomly overwrite files, let
alone doing so via packages, we add module parameters to override those
file names in the driver. This allows us to package/deploy the override
via a modprobe.d config.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: ath10k
---
 drivers/net/wireless/ath/ath10k/core.c | 58 ++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 8f5b8eb368fa..80c1bac732bc 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -36,6 +36,9 @@ static bool skip_otp;
 static bool rawmode;
 static bool fw_diag_log;
 
+static char *override_board = "";
+static char *override_board2 = "";
+
 unsigned long ath10k_coredump_mask = BIT(ATH10K_FW_CRASH_DUMP_REGISTERS) |
 				     BIT(ATH10K_FW_CRASH_DUMP_CE_DATA);
 
@@ -48,6 +51,9 @@ module_param(rawmode, bool, 0644);
 module_param(fw_diag_log, bool, 0644);
 module_param_named(coredump_mask, ath10k_coredump_mask, ulong, 0444);
 
+module_param(override_board, charp, 0644);
+module_param(override_board2, charp, 0644);
+
 MODULE_PARM_DESC(debug_mask, "Debugging mask");
 MODULE_PARM_DESC(uart_print, "Uart target debugging");
 MODULE_PARM_DESC(skip_otp, "Skip otp failure for calibration in testmode");
@@ -56,6 +62,9 @@ MODULE_PARM_DESC(rawmode, "Use raw 802.11 frame datapath");
 MODULE_PARM_DESC(coredump_mask, "Bitfield of what to include in firmware crash file");
 MODULE_PARM_DESC(fw_diag_log, "Diag based fw log debugging");
 
+MODULE_PARM_DESC(override_board, "Override for board.bin file");
+MODULE_PARM_DESC(override_board2, "Override for board-2.bin file");
+
 static const struct ath10k_hw_params ath10k_hw_params_list[] = {
 	{
 		.id = QCA988X_HW_2_0_VERSION,
@@ -844,6 +853,42 @@ static int ath10k_init_configure_target(struct ath10k *ar)
 	return 0;
 }
 
+static const char *ath10k_override_board_fw_file(struct ath10k *ar,
+						 const char *file)
+{
+	if (strcmp(file, "board.bin") == 0) {
+		if (strcmp(override_board, "") == 0)
+			return file;
+
+		if (strcmp(override_board, "none") == 0) {
+			dev_info(ar->dev, "firmware override: pretending 'board.bin' does not exist\n");
+			return NULL;
+		}
+
+		dev_info(ar->dev, "firmware override: replacing 'board.bin' with '%s'\n",
+			 override_board);
+
+		return override_board;
+	}
+
+	if (strcmp(file, "board-2.bin") == 0) {
+		if (strcmp(override_board2, "") == 0)
+			return file;
+
+		if (strcmp(override_board2, "none") == 0) {
+			dev_info(ar->dev, "firmware override: pretending 'board-2.bin' does not exist\n");
+			return NULL;
+		}
+
+		dev_info(ar->dev, "firmware override: replacing 'board-2.bin' with '%s'\n",
+			 override_board2);
+
+		return override_board2;
+	}
+
+	return file;
+}
+
 static const struct firmware *ath10k_fetch_fw_file(struct ath10k *ar,
 						   const char *dir,
 						   const char *file)
@@ -858,6 +903,19 @@ static const struct firmware *ath10k_fetch_fw_file(struct ath10k *ar,
 	if (dir == NULL)
 		dir = ".";
 
+	/* HACK: Override board.bin and board-2.bin files if specified.
+	 *
+	 * Some Surface devices perform better with a different board
+	 * configuration. To this end, one would need to replace the board.bin
+	 * file with the modified config and remove the board-2.bin file.
+	 * Unfortunately, that's not a solution that we can easily package. So
+	 * we add module options to perform these overrides here.
+	 */
+
+	file = ath10k_override_board_fw_file(ar, file);
+	if (!file)
+		return ERR_PTR(-ENOENT);
+
 	snprintf(filename, sizeof(filename), "%s/%s", dir, file);
 	ret = firmware_request_nowarn(&fw, filename, ar->dev);
 	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot fw request '%s': %d\n",
-- 
2.36.0

From 5f96f9f986f4177c1072baa7f3ab5f134cf20415 Mon Sep 17 00:00:00 2001
From: Dorian Stoll <dorian.stoll@tmsp.io>
Date: Thu, 30 Jul 2020 13:21:53 +0200
Subject: [PATCH] misc: mei: Add missing IPTS device IDs

Patchset: ipts
---
 drivers/misc/mei/hw-me-regs.h | 1 +
 drivers/misc/mei/pci-me.c     | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/misc/mei/hw-me-regs.h b/drivers/misc/mei/hw-me-regs.h
index 64ce3f830262..c208a1e3a7c1 100644
--- a/drivers/misc/mei/hw-me-regs.h
+++ b/drivers/misc/mei/hw-me-regs.h
@@ -92,6 +92,7 @@
 #define MEI_DEV_ID_CDF        0x18D3  /* Cedar Fork */
 
 #define MEI_DEV_ID_ICP_LP     0x34E0  /* Ice Lake Point LP */
+#define MEI_DEV_ID_ICP_LP_3   0x34E4  /* Ice Lake Point LP 3 (iTouch) */
 #define MEI_DEV_ID_ICP_N      0x38E0  /* Ice Lake Point N */
 
 #define MEI_DEV_ID_JSP_N      0x4DE0  /* Jasper Lake Point N */
diff --git a/drivers/misc/mei/pci-me.c b/drivers/misc/mei/pci-me.c
index a738253dbd05..4e1c3fe09e53 100644
--- a/drivers/misc/mei/pci-me.c
+++ b/drivers/misc/mei/pci-me.c
@@ -96,6 +96,7 @@ static const struct pci_device_id mei_me_pci_tbl[] = {
 	{MEI_PCI_DEVICE(MEI_DEV_ID_CMP_H_3, MEI_ME_PCH8_ITOUCH_CFG)},
 
 	{MEI_PCI_DEVICE(MEI_DEV_ID_ICP_LP, MEI_ME_PCH12_CFG)},
+	{MEI_PCI_DEVICE(MEI_DEV_ID_ICP_LP_3, MEI_ME_PCH12_CFG)},
 	{MEI_PCI_DEVICE(MEI_DEV_ID_ICP_N, MEI_ME_PCH12_CFG)},
 
 	{MEI_PCI_DEVICE(MEI_DEV_ID_TGP_LP, MEI_ME_PCH15_CFG)},
-- 
2.36.0

From fce727fc65f22335a65f82446d045da06cae42c6 Mon Sep 17 00:00:00 2001
From: Dorian Stoll <dorian.stoll@tmsp.io>
Date: Thu, 6 Aug 2020 11:20:41 +0200
Subject: [PATCH] misc: Add support for Intel Precise Touch & Stylus

Based on linux-surface/intel-precise-touch@3f362c

Signed-off-by: Dorian Stoll <dorian.stoll@tmsp.io>
Patchset: ipts
---
 drivers/misc/Kconfig          |   1 +
 drivers/misc/Makefile         |   1 +
 drivers/misc/ipts/Kconfig     |  17 ++
 drivers/misc/ipts/Makefile    |  12 ++
 drivers/misc/ipts/context.h   |  47 +++++
 drivers/misc/ipts/control.c   | 113 +++++++++++
 drivers/misc/ipts/control.h   |  24 +++
 drivers/misc/ipts/mei.c       | 125 ++++++++++++
 drivers/misc/ipts/protocol.h  | 347 ++++++++++++++++++++++++++++++++++
 drivers/misc/ipts/receiver.c  | 224 ++++++++++++++++++++++
 drivers/misc/ipts/receiver.h  |  16 ++
 drivers/misc/ipts/resources.c | 128 +++++++++++++
 drivers/misc/ipts/resources.h |  17 ++
 drivers/misc/ipts/uapi.c      | 208 ++++++++++++++++++++
 drivers/misc/ipts/uapi.h      |  47 +++++
 15 files changed, 1327 insertions(+)
 create mode 100644 drivers/misc/ipts/Kconfig
 create mode 100644 drivers/misc/ipts/Makefile
 create mode 100644 drivers/misc/ipts/context.h
 create mode 100644 drivers/misc/ipts/control.c
 create mode 100644 drivers/misc/ipts/control.h
 create mode 100644 drivers/misc/ipts/mei.c
 create mode 100644 drivers/misc/ipts/protocol.h
 create mode 100644 drivers/misc/ipts/receiver.c
 create mode 100644 drivers/misc/ipts/receiver.h
 create mode 100644 drivers/misc/ipts/resources.c
 create mode 100644 drivers/misc/ipts/resources.h
 create mode 100644 drivers/misc/ipts/uapi.c
 create mode 100644 drivers/misc/ipts/uapi.h

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 0f5a49fc7c9e..12b081bc875a 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -487,4 +487,5 @@ source "drivers/misc/cardreader/Kconfig"
 source "drivers/misc/habanalabs/Kconfig"
 source "drivers/misc/uacce/Kconfig"
 source "drivers/misc/pvpanic/Kconfig"
+source "drivers/misc/ipts/Kconfig"
 endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index a086197af544..972cae33ba36 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_UACCE)		+= uacce/
 obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o
 obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
 obj-$(CONFIG_HI6421V600_IRQ)	+= hi6421v600-irq.o
+obj-$(CONFIG_MISC_IPTS)		+= ipts/
diff --git a/drivers/misc/ipts/Kconfig b/drivers/misc/ipts/Kconfig
new file mode 100644
index 000000000000..83e2a930c396
--- /dev/null
+++ b/drivers/misc/ipts/Kconfig
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+config MISC_IPTS
+	tristate "Intel Precise Touch & Stylus"
+	depends on INTEL_MEI
+	help
+	  Say Y here if your system has a touchscreen using Intels
+	  Precise Touch & Stylus (IPTS) technology.
+
+	  If unsure say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ipts.
+
+	  Building this driver alone will not give you a working touchscreen.
+	  It only exposed a userspace API that can be used by a daemon to
+	  receive and process data from the touchscreen hardware.
diff --git a/drivers/misc/ipts/Makefile b/drivers/misc/ipts/Makefile
new file mode 100644
index 000000000000..8f58b9adbc94
--- /dev/null
+++ b/drivers/misc/ipts/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Makefile for the IPTS touchscreen driver
+#
+
+obj-$(CONFIG_MISC_IPTS) += ipts.o
+ipts-objs := control.o
+ipts-objs += mei.o
+ipts-objs += receiver.o
+ipts-objs += resources.o
+ipts-objs += uapi.o
+
diff --git a/drivers/misc/ipts/context.h b/drivers/misc/ipts/context.h
new file mode 100644
index 000000000000..f4b06a2d3f72
--- /dev/null
+++ b/drivers/misc/ipts/context.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_CONTEXT_H_
+#define _IPTS_CONTEXT_H_
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/types.h>
+
+#include "protocol.h"
+
+enum ipts_host_status {
+	IPTS_HOST_STATUS_STARTING,
+	IPTS_HOST_STATUS_STARTED,
+	IPTS_HOST_STATUS_STOPPING,
+	IPTS_HOST_STATUS_STOPPED,
+};
+
+struct ipts_buffer_info {
+	u8 *address;
+	dma_addr_t dma_address;
+};
+
+struct ipts_context {
+	struct mei_cl_device *cldev;
+	struct device *dev;
+
+	bool restart;
+	enum ipts_host_status status;
+	struct ipts_get_device_info_rsp device_info;
+
+	struct ipts_buffer_info data[IPTS_BUFFERS];
+	struct ipts_buffer_info doorbell;
+
+	struct ipts_buffer_info feedback[IPTS_BUFFERS];
+	struct ipts_buffer_info workqueue;
+	struct ipts_buffer_info host2me;
+};
+
+#endif /* _IPTS_CONTEXT_H_ */
diff --git a/drivers/misc/ipts/control.c b/drivers/misc/ipts/control.c
new file mode 100644
index 000000000000..a1d1f97a13d7
--- /dev/null
+++ b/drivers/misc/ipts/control.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/mei_cl_bus.h>
+
+#include "context.h"
+#include "protocol.h"
+#include "resources.h"
+#include "uapi.h"
+
+int ipts_control_send(struct ipts_context *ipts, u32 code, void *payload,
+		      size_t size)
+{
+	int ret;
+	struct ipts_command cmd;
+
+	memset(&cmd, 0, sizeof(struct ipts_command));
+	cmd.code = code;
+
+	if (payload && size > 0)
+		memcpy(&cmd.payload, payload, size);
+
+	ret = mei_cldev_send(ipts->cldev, (u8 *)&cmd, sizeof(cmd.code) + size);
+	if (ret >= 0)
+		return 0;
+
+	/*
+	 * During shutdown the device might get pulled away from below our feet.
+	 * Dont log an error in this case, because it will confuse people.
+	 */
+	if (ret != -ENODEV || ipts->status != IPTS_HOST_STATUS_STOPPING)
+		dev_err(ipts->dev, "Error while sending: 0x%X:%d\n", code, ret);
+
+	return ret;
+}
+
+int ipts_control_send_feedback(struct ipts_context *ipts, u32 buffer)
+{
+	struct ipts_feedback_cmd cmd;
+
+	memset(&cmd, 0, sizeof(struct ipts_feedback_cmd));
+	cmd.buffer = buffer;
+
+	return ipts_control_send(ipts, IPTS_CMD_FEEDBACK, &cmd,
+				 sizeof(struct ipts_feedback_cmd));
+}
+
+int ipts_control_set_feature(struct ipts_context *ipts, u8 report, u8 value)
+{
+	struct ipts_feedback_buffer *feedback;
+
+	memset(ipts->host2me.address, 0, ipts->device_info.feedback_size);
+	feedback = (struct ipts_feedback_buffer *)ipts->host2me.address;
+
+	feedback->cmd_type = IPTS_FEEDBACK_CMD_TYPE_NONE;
+	feedback->data_type = IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES;
+	feedback->buffer = IPTS_HOST2ME_BUFFER;
+	feedback->size = 2;
+	feedback->payload[0] = report;
+	feedback->payload[1] = value;
+
+	return ipts_control_send_feedback(ipts, IPTS_HOST2ME_BUFFER);
+}
+
+int ipts_control_start(struct ipts_context *ipts)
+{
+	if (ipts->status != IPTS_HOST_STATUS_STOPPED)
+		return -EBUSY;
+
+	dev_info(ipts->dev, "Starting IPTS\n");
+	ipts->status = IPTS_HOST_STATUS_STARTING;
+	ipts->restart = false;
+
+	ipts_uapi_link(ipts);
+	return ipts_control_send(ipts, IPTS_CMD_GET_DEVICE_INFO, NULL, 0);
+}
+
+int ipts_control_stop(struct ipts_context *ipts)
+{
+	int ret;
+
+	if (ipts->status == IPTS_HOST_STATUS_STOPPING)
+		return -EBUSY;
+
+	if (ipts->status == IPTS_HOST_STATUS_STOPPED)
+		return -EBUSY;
+
+	dev_info(ipts->dev, "Stopping IPTS\n");
+	ipts->status = IPTS_HOST_STATUS_STOPPING;
+
+	ipts_uapi_unlink();
+	ipts_resources_free(ipts);
+
+	ret = ipts_control_send_feedback(ipts, 0);
+	if (ret == -ENODEV)
+		ipts->status = IPTS_HOST_STATUS_STOPPED;
+
+	return ret;
+}
+
+int ipts_control_restart(struct ipts_context *ipts)
+{
+	if (ipts->restart)
+		return -EBUSY;
+
+	ipts->restart = true;
+	return ipts_control_stop(ipts);
+}
diff --git a/drivers/misc/ipts/control.h b/drivers/misc/ipts/control.h
new file mode 100644
index 000000000000..2c44e9e0e99f
--- /dev/null
+++ b/drivers/misc/ipts/control.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_CONTROL_H_
+#define _IPTS_CONTROL_H_
+
+#include <linux/types.h>
+
+#include "context.h"
+
+int ipts_control_send(struct ipts_context *ipts, u32 cmd, void *payload,
+		      size_t size);
+int ipts_control_send_feedback(struct ipts_context *ipts, u32 buffer);
+int ipts_control_set_feature(struct ipts_context *ipts, u8 report, u8 value);
+int ipts_control_start(struct ipts_context *ipts);
+int ipts_control_restart(struct ipts_context *ipts);
+int ipts_control_stop(struct ipts_context *ipts);
+
+#endif /* _IPTS_CONTROL_H_ */
diff --git a/drivers/misc/ipts/mei.c b/drivers/misc/ipts/mei.c
new file mode 100644
index 000000000000..59ecf13e00d2
--- /dev/null
+++ b/drivers/misc/ipts/mei.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "context.h"
+#include "control.h"
+#include "protocol.h"
+#include "receiver.h"
+#include "uapi.h"
+
+static int ipts_mei_set_dma_mask(struct mei_cl_device *cldev)
+{
+	int ret;
+
+	ret = dma_coerce_mask_and_coherent(&cldev->dev, DMA_BIT_MASK(64));
+	if (!ret)
+		return 0;
+
+	return dma_coerce_mask_and_coherent(&cldev->dev, DMA_BIT_MASK(32));
+}
+
+static int ipts_mei_probe(struct mei_cl_device *cldev,
+			  const struct mei_cl_device_id *id)
+{
+	int ret;
+	struct ipts_context *ipts;
+
+	if (ipts_mei_set_dma_mask(cldev)) {
+		dev_err(&cldev->dev, "Failed to set DMA mask for IPTS\n");
+		return -EFAULT;
+	}
+
+	ret = mei_cldev_enable(cldev);
+	if (ret) {
+		dev_err(&cldev->dev, "Failed to enable MEI device: %d\n", ret);
+		return ret;
+	}
+
+	ipts = kzalloc(sizeof(*ipts), GFP_KERNEL);
+	if (!ipts) {
+		mei_cldev_disable(cldev);
+		return -ENOMEM;
+	}
+
+	ipts->cldev = cldev;
+	ipts->dev = &cldev->dev;
+	ipts->status = IPTS_HOST_STATUS_STOPPED;
+
+	mei_cldev_set_drvdata(cldev, ipts);
+	mei_cldev_register_rx_cb(cldev, ipts_receiver_callback);
+
+	return ipts_control_start(ipts);
+}
+
+static void ipts_mei_remove(struct mei_cl_device *cldev)
+{
+	int i;
+	struct ipts_context *ipts = mei_cldev_get_drvdata(cldev);
+
+	ipts_control_stop(ipts);
+
+	for (i = 0; i < 20; i++) {
+		if (ipts->status == IPTS_HOST_STATUS_STOPPED)
+			break;
+
+		msleep(25);
+	}
+
+	mei_cldev_disable(cldev);
+	kfree(ipts);
+}
+
+static struct mei_cl_device_id ipts_mei_device_id_table[] = {
+	{ "", IPTS_MEI_UUID, MEI_CL_VERSION_ANY },
+	{},
+};
+MODULE_DEVICE_TABLE(mei, ipts_mei_device_id_table);
+
+static struct mei_cl_driver ipts_mei_driver = {
+	.id_table = ipts_mei_device_id_table,
+	.name = "ipts",
+	.probe = ipts_mei_probe,
+	.remove = ipts_mei_remove,
+};
+
+static int __init ipts_mei_init(void)
+{
+	int ret;
+
+	ret = ipts_uapi_init();
+	if (ret)
+		return ret;
+
+	ret = mei_cldev_driver_register(&ipts_mei_driver);
+	if (ret) {
+		ipts_uapi_free();
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit ipts_mei_exit(void)
+{
+	mei_cldev_driver_unregister(&ipts_mei_driver);
+	ipts_uapi_free();
+}
+
+MODULE_DESCRIPTION("IPTS touchscreen driver");
+MODULE_AUTHOR("Dorian Stoll <dorian.stoll@tmsp.io>");
+MODULE_LICENSE("GPL");
+
+module_init(ipts_mei_init);
+module_exit(ipts_mei_exit);
diff --git a/drivers/misc/ipts/protocol.h b/drivers/misc/ipts/protocol.h
new file mode 100644
index 000000000000..c3458904a94d
--- /dev/null
+++ b/drivers/misc/ipts/protocol.h
@@ -0,0 +1,347 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_PROTOCOL_H_
+#define _IPTS_PROTOCOL_H_
+
+#include <linux/types.h>
+
+/*
+ * The MEI client ID for IPTS functionality.
+ */
+#define IPTS_MEI_UUID                                                          \
+	UUID_LE(0x3e8d0870, 0x271a, 0x4208, 0x8e, 0xb5, 0x9a, 0xcb, 0x94,      \
+		0x02, 0xae, 0x04)
+
+/*
+ * Queries the device for vendor specific information.
+ *
+ * The command must not contain any payload.
+ * The response will contain struct ipts_get_device_info_rsp as payload.
+ */
+#define IPTS_CMD_GET_DEVICE_INFO 0x00000001
+#define IPTS_RSP_GET_DEVICE_INFO 0x80000001
+
+/*
+ * Sets the mode that IPTS will operate in.
+ *
+ * The command must contain struct ipts_set_mode_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_SET_MODE 0x00000002
+#define IPTS_RSP_SET_MODE 0x80000002
+
+/*
+ * Configures the memory buffers that the ME will use
+ * for passing data to the host.
+ *
+ * The command must contain struct ipts_set_mem_window_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_SET_MEM_WINDOW 0x00000003
+#define IPTS_RSP_SET_MEM_WINDOW 0x80000003
+
+/*
+ * Signals that the host is ready to receive data to the ME.
+ *
+ * The command must not contain any payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_READY_FOR_DATA 0x00000005
+#define IPTS_RSP_READY_FOR_DATA 0x80000005
+
+/*
+ * Signals that a buffer can be refilled to the ME.
+ *
+ * The command must contain struct ipts_feedback_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_FEEDBACK 0x00000006
+#define IPTS_RSP_FEEDBACK 0x80000006
+
+/*
+ * Resets the data flow from the ME to the hosts and
+ * clears the buffers that were set with SET_MEM_WINDOW.
+ *
+ * The command must not contain any payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_CLEAR_MEM_WINDOW 0x00000007
+#define IPTS_RSP_CLEAR_MEM_WINDOW 0x80000007
+
+/*
+ * Instructs the ME to reset the touch sensor.
+ *
+ * The command must contain struct ipts_reset_sensor_cmd as payload.
+ * The response will not contain any payload.
+ */
+#define IPTS_CMD_RESET_SENSOR 0x0000000B
+#define IPTS_RSP_RESET_SENSOR 0x8000000B
+
+/**
+ * enum ipts_status - Possible status codes returned by IPTS commands.
+ * @IPTS_STATUS_SUCCESS:                 Operation completed successfully.
+ * @IPTS_STATUS_INVALID_PARAMS:          Command contained a payload with invalid parameters.
+ * @IPTS_STATUS_ACCESS_DENIED:           ME could not validate buffer addresses supplied by host.
+ * @IPTS_STATUS_CMD_SIZE_ERROR:          Command contains an invalid payload.
+ * @IPTS_STATUS_NOT_READY:               Buffer addresses have not been set.
+ * @IPTS_STATUS_REQUEST_OUTSTANDING:     There is an outstanding command of the same type.
+ *                                       The host must wait for a response before sending another
+ *                                       command of the same type.
+ * @IPTS_STATUS_NO_SENSOR_FOUND:         No sensor could be found. Either no sensor is connected, it
+ *                                       has not been initialized yet, or the system is improperly
+ *                                       configured.
+ * @IPTS_STATUS_OUT_OF_MEMORY:           Not enough free memory for requested operation.
+ * @IPTS_STATUS_INTERNAL_ERROR:          An unexpected error occurred.
+ * @IPTS_STATUS_SENSOR_DISABLED:         The sensor has been disabled and must be reinitialized.
+ * @IPTS_STATUS_COMPAT_CHECK_FAIL:       Compatibility revision check between sensor and ME failed.
+ *                                       The host can ignore this error and attempt to continue.
+ * @IPTS_STATUS_SENSOR_EXPECTED_RESET:   The sensor went through a reset initiated by ME or host.
+ * @IPTS_STATUS_SENSOR_UNEXPECTED_RESET: The sensor went through an unexpected reset.
+ * @IPTS_STATUS_RESET_FAILED:            Requested sensor reset failed to complete.
+ * @IPTS_STATUS_TIMEOUT:                 The operation timed out.
+ * @IPTS_STATUS_TEST_MODE_FAIL:          Test mode pattern did not match expected values.
+ * @IPTS_STATUS_SENSOR_FAIL_FATAL:       The sensor reported a fatal error during reset sequence.
+ *                                       Further progress is not possible.
+ * @IPTS_STATUS_SENSOR_FAIL_NONFATAL:    The sensor reported a fatal error during reset sequence.
+ *                                       The host can attempt to continue.
+ * @IPTS_STATUS_INVALID_DEVICE_CAPS:     The device reported invalid capabilities.
+ * @IPTS_STATUS_QUIESCE_IO_IN_PROGRESS:  Command cannot be completed until Quiesce IO is done.
+ */
+enum ipts_status {
+	IPTS_STATUS_SUCCESS = 0,
+	IPTS_STATUS_INVALID_PARAMS = 1,
+	IPTS_STATUS_ACCESS_DENIED = 2,
+	IPTS_STATUS_CMD_SIZE_ERROR = 3,
+	IPTS_STATUS_NOT_READY = 4,
+	IPTS_STATUS_REQUEST_OUTSTANDING = 5,
+	IPTS_STATUS_NO_SENSOR_FOUND = 6,
+	IPTS_STATUS_OUT_OF_MEMORY = 7,
+	IPTS_STATUS_INTERNAL_ERROR = 8,
+	IPTS_STATUS_SENSOR_DISABLED = 9,
+	IPTS_STATUS_COMPAT_CHECK_FAIL = 10,
+	IPTS_STATUS_SENSOR_EXPECTED_RESET = 11,
+	IPTS_STATUS_SENSOR_UNEXPECTED_RESET = 12,
+	IPTS_STATUS_RESET_FAILED = 13,
+	IPTS_STATUS_TIMEOUT = 14,
+	IPTS_STATUS_TEST_MODE_FAIL = 15,
+	IPTS_STATUS_SENSOR_FAIL_FATAL = 16,
+	IPTS_STATUS_SENSOR_FAIL_NONFATAL = 17,
+	IPTS_STATUS_INVALID_DEVICE_CAPS = 18,
+	IPTS_STATUS_QUIESCE_IO_IN_PROGRESS = 19,
+};
+
+/*
+ * The amount of buffers that is used for IPTS
+ */
+#define IPTS_BUFFERS 16
+
+/*
+ * The special buffer ID that is used for direct host2me feedback.
+ */
+#define IPTS_HOST2ME_BUFFER IPTS_BUFFERS
+
+/**
+ * enum ipts_mode - Operation mode for IPTS hardware
+ * @IPTS_MODE_SINGLETOUCH: Fallback that supports only one finger and no stylus.
+ *                         The data is received as a HID report with ID 64.
+ * @IPTS_MODE_MULTITOUCH:  The "proper" operation mode for IPTS. It will return
+ *                         stylus data as well as capacitive heatmap touch data.
+ *                         This data needs to be processed in userspace.
+ */
+enum ipts_mode {
+	IPTS_MODE_SINGLETOUCH = 0,
+	IPTS_MODE_MULTITOUCH = 1,
+};
+
+/**
+ * struct ipts_set_mode_cmd - Payload for the SET_MODE command.
+ * @mode: The mode that IPTS should operate in.
+ */
+struct ipts_set_mode_cmd {
+	enum ipts_mode mode;
+	u8 reserved[12];
+} __packed;
+
+#define IPTS_WORKQUEUE_SIZE	 8192
+#define IPTS_WORKQUEUE_ITEM_SIZE 16
+
+/**
+ * struct ipts_set_mem_window_cmd - Payload for the SET_MEM_WINDOW command.
+ * @data_buffer_addr_lower:     Lower 32 bits of the data buffer addresses.
+ * @data_buffer_addr_upper:     Upper 32 bits of the data buffer addresses.
+ * @workqueue_addr_lower:       Lower 32 bits of the workqueue buffer address.
+ * @workqueue_addr_upper:       Upper 32 bits of the workqueue buffer address.
+ * @doorbell_addr_lower:        Lower 32 bits of the doorbell buffer address.
+ * @doorbell_addr_upper:        Upper 32 bits of the doorbell buffer address.
+ * @feedback_buffer_addr_lower: Lower 32 bits of the feedback buffer addresses.
+ * @feedback_buffer_addr_upper: Upper 32 bits of the feedback buffer addresses.
+ * @host2me_addr_lower:         Lower 32 bits of the host2me buffer address.
+ * @host2me_addr_upper:         Upper 32 bits of the host2me buffer address.
+ * @workqueue_item_size:        Magic value. (IPTS_WORKQUEUE_ITEM_SIZE)
+ * @workqueue_size:             Magic value. (IPTS_WORKQUEUE_SIZE)
+ *
+ * The data buffers are buffers that get filled with touch data by the ME.
+ * The doorbell buffer is a u32 that gets incremented by the ME once a data
+ * buffer has been filled with new data.
+ *
+ * The other buffers are required for using GuC submission with binary
+ * firmware. Since support for GuC submission has been dropped from i915,
+ * they are not used anymore, but they need to be allocated and passed,
+ * otherwise the hardware will refuse to start.
+ */
+struct ipts_set_mem_window_cmd {
+	u32 data_buffer_addr_lower[IPTS_BUFFERS];
+	u32 data_buffer_addr_upper[IPTS_BUFFERS];
+	u32 workqueue_addr_lower;
+	u32 workqueue_addr_upper;
+	u32 doorbell_addr_lower;
+	u32 doorbell_addr_upper;
+	u32 feedback_buffer_addr_lower[IPTS_BUFFERS];
+	u32 feedback_buffer_addr_upper[IPTS_BUFFERS];
+	u32 host2me_addr_lower;
+	u32 host2me_addr_upper;
+	u32 host2me_size;
+	u8 reserved1;
+	u8 workqueue_item_size;
+	u16 workqueue_size;
+	u8 reserved[32];
+} __packed;
+
+/**
+ * struct ipts_feedback_cmd - Payload for the FEEDBACK command.
+ * @buffer: The buffer that the ME should refill.
+ */
+struct ipts_feedback_cmd {
+	u32 buffer;
+	u8 reserved[12];
+} __packed;
+
+/**
+ * enum ipts_feedback_cmd_type - Commands that can be executed on the sensor through feedback.
+ */
+enum ipts_feedback_cmd_type {
+	IPTS_FEEDBACK_CMD_TYPE_NONE = 0,
+	IPTS_FEEDBACK_CMD_TYPE_SOFT_RESET = 1,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_ARMED = 2,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_SENSING = 3,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_SLEEP = 4,
+	IPTS_FEEDBACK_CMD_TYPE_GOTO_DOZE = 5,
+	IPTS_FEEDBACK_CMD_TYPE_HARD_RESET = 6,
+};
+
+/**
+ * enum ipts_feedback_data_type - Describes the data that a feedback buffer contains.
+ * @IPTS_FEEDBACK_DATA_TYPE_VENDOR:        The buffer contains vendor specific feedback.
+ * @IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES:  The buffer contains a HID set features command.
+ * @IPTS_FEEDBACK_DATA_TYPE_GET_FEATURES:  The buffer contains a HID get features command.
+ * @IPTS_FEEDBACK_DATA_TYPE_OUTPUT_REPORT: The buffer contains a HID output report.
+ * @IPTS_FEEDBACK_DATA_TYPE_STORE_DATA:    The buffer contains calibration data for the sensor.
+ */
+enum ipts_feedback_data_type {
+	IPTS_FEEDBACK_DATA_TYPE_VENDOR = 0,
+	IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES = 1,
+	IPTS_FEEDBACK_DATA_TYPE_GET_FEATURES = 2,
+	IPTS_FEEDBACK_DATA_TYPE_OUTPUT_REPORT = 3,
+	IPTS_FEEDBACK_DATA_TYPE_STORE_DATA = 4,
+};
+
+/**
+ * struct ipts_feedback_buffer - The contents of an IPTS feedback buffer.
+ * @cmd_type: A command that should be executed on the sensor.
+ * @size: The size of the payload to be written.
+ * @buffer: The ID of the buffer that contains this feedback data.
+ * @protocol: The protocol version of the EDS.
+ * @data_type: The type of payload that the buffer contains.
+ * @spi_offset: The offset at which to write the payload data.
+ * @payload: Payload for the feedback command, or 0 if no payload is sent.
+ */
+struct ipts_feedback_buffer {
+	enum ipts_feedback_cmd_type cmd_type;
+	u32 size;
+	u32 buffer;
+	u32 protocol;
+	enum ipts_feedback_data_type data_type;
+	u32 spi_offset;
+	u8 reserved[40];
+	u8 payload[];
+} __packed;
+
+/**
+ * enum ipts_reset_type - Possible ways of resetting the touch sensor
+ * @IPTS_RESET_TYPE_HARD: Perform hardware reset using GPIO pin.
+ * @IPTS_RESET_TYPE_SOFT: Perform software reset using SPI interface.
+ */
+enum ipts_reset_type {
+	IPTS_RESET_TYPE_HARD = 0,
+	IPTS_RESET_TYPE_SOFT = 1,
+};
+
+/**
+ * struct ipts_reset_sensor_cmd - Payload for the RESET_SENSOR command.
+ * @type: What type of reset should be performed.
+ */
+struct ipts_reset_sensor_cmd {
+	enum ipts_reset_type type;
+	u8 reserved[4];
+} __packed;
+
+/**
+ * struct ipts_command - A message sent from the host to the ME.
+ * @code:    The message code describing the command. (see IPTS_CMD_*)
+ * @payload: Payload for the command, or 0 if no payload is required.
+ */
+struct ipts_command {
+	u32 code;
+	u8 payload[320];
+} __packed;
+
+/**
+ * struct ipts_device_info - Payload for the GET_DEVICE_INFO response.
+ * @vendor_id:     Vendor ID of the touch sensor.
+ * @device_id:     Device ID of the touch sensor.
+ * @hw_rev:        Hardware revision of the touch sensor.
+ * @fw_rev:        Firmware revision of the touch sensor.
+ * @data_size:     Required size of one data buffer.
+ * @feedback_size: Required size of one feedback buffer.
+ * @mode:          Current operation mode of IPTS.
+ * @max_contacts:  The amount of concurrent touches supported by the sensor.
+ */
+struct ipts_get_device_info_rsp {
+	u16 vendor_id;
+	u16 device_id;
+	u32 hw_rev;
+	u32 fw_rev;
+	u32 data_size;
+	u32 feedback_size;
+	enum ipts_mode mode;
+	u8 max_contacts;
+	u8 reserved[19];
+} __packed;
+
+/**
+ * struct ipts_feedback_rsp - Payload for the FEEDBACK response.
+ * @buffer: The buffer that has received feedback.
+ */
+struct ipts_feedback_rsp {
+	u32 buffer;
+} __packed;
+
+/**
+ * struct ipts_response - A message sent from the ME to the host.
+ * @code:    The message code describing the response. (see IPTS_RSP_*)
+ * @status:  The status code returned by the command.
+ * @payload: Payload returned by the command.
+ */
+struct ipts_response {
+	u32 code;
+	enum ipts_status status;
+	u8 payload[80];
+} __packed;
+
+#endif /* _IPTS_PROTOCOL_H_ */
diff --git a/drivers/misc/ipts/receiver.c b/drivers/misc/ipts/receiver.c
new file mode 100644
index 000000000000..23dca13c2139
--- /dev/null
+++ b/drivers/misc/ipts/receiver.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/mei_cl_bus.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+
+#include "context.h"
+#include "control.h"
+#include "protocol.h"
+#include "resources.h"
+
+/*
+ * Temporary parameter to guard gen7 multitouch mode.
+ * Remove once gen7 has stable iptsd support.
+ */
+static bool gen7mt;
+module_param(gen7mt, bool, 0644);
+
+static int ipts_receiver_handle_get_device_info(struct ipts_context *ipts,
+						struct ipts_response *rsp)
+{
+	struct ipts_set_mode_cmd cmd;
+
+	memcpy(&ipts->device_info, rsp->payload,
+	       sizeof(struct ipts_get_device_info_rsp));
+
+	memset(&cmd, 0, sizeof(struct ipts_set_mode_cmd));
+	cmd.mode = IPTS_MODE_MULTITOUCH;
+
+	return ipts_control_send(ipts, IPTS_CMD_SET_MODE, &cmd,
+				 sizeof(struct ipts_set_mode_cmd));
+}
+
+static int ipts_receiver_handle_set_mode(struct ipts_context *ipts)
+{
+	int i, ret;
+	struct ipts_set_mem_window_cmd cmd;
+
+	ret = ipts_resources_alloc(ipts);
+	if (ret) {
+		dev_err(ipts->dev, "Failed to allocate resources\n");
+		return ret;
+	}
+
+	memset(&cmd, 0, sizeof(struct ipts_set_mem_window_cmd));
+
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		cmd.data_buffer_addr_lower[i] =
+			lower_32_bits(ipts->data[i].dma_address);
+
+		cmd.data_buffer_addr_upper[i] =
+			upper_32_bits(ipts->data[i].dma_address);
+
+		cmd.feedback_buffer_addr_lower[i] =
+			lower_32_bits(ipts->feedback[i].dma_address);
+
+		cmd.feedback_buffer_addr_upper[i] =
+			upper_32_bits(ipts->feedback[i].dma_address);
+	}
+
+	cmd.workqueue_addr_lower = lower_32_bits(ipts->workqueue.dma_address);
+	cmd.workqueue_addr_upper = upper_32_bits(ipts->workqueue.dma_address);
+
+	cmd.doorbell_addr_lower = lower_32_bits(ipts->doorbell.dma_address);
+	cmd.doorbell_addr_upper = upper_32_bits(ipts->doorbell.dma_address);
+
+	cmd.host2me_addr_lower = lower_32_bits(ipts->host2me.dma_address);
+	cmd.host2me_addr_upper = upper_32_bits(ipts->host2me.dma_address);
+
+	cmd.workqueue_size = IPTS_WORKQUEUE_SIZE;
+	cmd.workqueue_item_size = IPTS_WORKQUEUE_ITEM_SIZE;
+
+	return ipts_control_send(ipts, IPTS_CMD_SET_MEM_WINDOW, &cmd,
+				 sizeof(struct ipts_set_mem_window_cmd));
+}
+
+static int ipts_receiver_handle_set_mem_window(struct ipts_context *ipts)
+{
+	int ret;
+
+	dev_info(ipts->dev, "Device %04hX:%04hX ready\n",
+		 ipts->device_info.vendor_id, ipts->device_info.device_id);
+	ipts->status = IPTS_HOST_STATUS_STARTED;
+
+	ret = ipts_control_send(ipts, IPTS_CMD_READY_FOR_DATA, NULL, 0);
+	if (ret)
+		return ret;
+
+	if (!gen7mt)
+		return 0;
+
+	return ipts_control_set_feature(ipts, 0x5, 0x1);
+}
+
+static int ipts_receiver_handle_feedback(struct ipts_context *ipts,
+					 struct ipts_response *rsp)
+{
+	struct ipts_feedback_rsp feedback;
+
+	if (ipts->status != IPTS_HOST_STATUS_STOPPING)
+		return 0;
+
+	memcpy(&feedback, rsp->payload, sizeof(feedback));
+
+	if (feedback.buffer < IPTS_BUFFERS - 1)
+		return ipts_control_send_feedback(ipts, feedback.buffer + 1);
+
+	return ipts_control_send(ipts, IPTS_CMD_CLEAR_MEM_WINDOW, NULL, 0);
+}
+
+static int ipts_receiver_handle_clear_mem_window(struct ipts_context *ipts)
+{
+	ipts->status = IPTS_HOST_STATUS_STOPPED;
+
+	if (ipts->restart)
+		return ipts_control_start(ipts);
+
+	return 0;
+}
+
+static bool ipts_receiver_sensor_was_reset(u32 status)
+{
+	return status == IPTS_STATUS_SENSOR_EXPECTED_RESET ||
+	       status == IPTS_STATUS_SENSOR_UNEXPECTED_RESET;
+}
+
+static bool ipts_receiver_handle_error(struct ipts_context *ipts,
+				       struct ipts_response *rsp)
+{
+	bool error;
+
+	switch (rsp->status) {
+	case IPTS_STATUS_SUCCESS:
+	case IPTS_STATUS_COMPAT_CHECK_FAIL:
+		error = false;
+		break;
+	case IPTS_STATUS_INVALID_PARAMS:
+		error = rsp->code != IPTS_RSP_FEEDBACK;
+		break;
+	case IPTS_STATUS_SENSOR_DISABLED:
+		error = ipts->status != IPTS_HOST_STATUS_STOPPING;
+		break;
+	default:
+		error = true;
+		break;
+	}
+
+	if (!error)
+		return false;
+
+	dev_err(ipts->dev, "Command 0x%08x failed: %d\n", rsp->code,
+		rsp->status);
+
+	if (ipts_receiver_sensor_was_reset(rsp->status)) {
+		dev_err(ipts->dev, "Sensor was reset\n");
+
+		if (ipts_control_restart(ipts))
+			dev_err(ipts->dev, "Failed to restart IPTS\n");
+	}
+
+	return true;
+}
+
+static void ipts_receiver_handle_response(struct ipts_context *ipts,
+					  struct ipts_response *rsp)
+{
+	int ret;
+
+	if (ipts_receiver_handle_error(ipts, rsp))
+		return;
+
+	switch (rsp->code) {
+	case IPTS_RSP_GET_DEVICE_INFO:
+		ret = ipts_receiver_handle_get_device_info(ipts, rsp);
+		break;
+	case IPTS_RSP_SET_MODE:
+		ret = ipts_receiver_handle_set_mode(ipts);
+		break;
+	case IPTS_RSP_SET_MEM_WINDOW:
+		ret = ipts_receiver_handle_set_mem_window(ipts);
+		break;
+	case IPTS_RSP_FEEDBACK:
+		ret = ipts_receiver_handle_feedback(ipts, rsp);
+		break;
+	case IPTS_RSP_CLEAR_MEM_WINDOW:
+		ret = ipts_receiver_handle_clear_mem_window(ipts);
+		break;
+	default:
+		ret = 0;
+		break;
+	}
+
+	if (!ret)
+		return;
+
+	dev_err(ipts->dev, "Error while handling response 0x%08x: %d\n",
+		rsp->code, ret);
+
+	if (ipts_control_stop(ipts))
+		dev_err(ipts->dev, "Failed to stop IPTS\n");
+}
+
+void ipts_receiver_callback(struct mei_cl_device *cldev)
+{
+	int ret;
+	struct ipts_response rsp;
+	struct ipts_context *ipts;
+
+	ipts = mei_cldev_get_drvdata(cldev);
+
+	ret = mei_cldev_recv(cldev, (u8 *)&rsp, sizeof(struct ipts_response));
+	if (ret <= 0) {
+		dev_err(ipts->dev, "Error while reading response: %d\n", ret);
+		return;
+	}
+
+	ipts_receiver_handle_response(ipts, &rsp);
+}
diff --git a/drivers/misc/ipts/receiver.h b/drivers/misc/ipts/receiver.h
new file mode 100644
index 000000000000..7f075afa7ef8
--- /dev/null
+++ b/drivers/misc/ipts/receiver.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_RECEIVER_H_
+#define _IPTS_RECEIVER_H_
+
+#include <linux/mei_cl_bus.h>
+
+void ipts_receiver_callback(struct mei_cl_device *cldev);
+
+#endif /* _IPTS_RECEIVER_H_ */
diff --git a/drivers/misc/ipts/resources.c b/drivers/misc/ipts/resources.c
new file mode 100644
index 000000000000..8e3a2409e438
--- /dev/null
+++ b/drivers/misc/ipts/resources.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/dma-mapping.h>
+
+#include "context.h"
+
+void ipts_resources_free(struct ipts_context *ipts)
+{
+	int i;
+	struct ipts_buffer_info *buffers;
+
+	u32 data_buffer_size = ipts->device_info.data_size;
+	u32 feedback_buffer_size = ipts->device_info.feedback_size;
+
+	buffers = ipts->data;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		if (!buffers[i].address)
+			continue;
+
+		dma_free_coherent(ipts->dev, data_buffer_size,
+				  buffers[i].address, buffers[i].dma_address);
+
+		buffers[i].address = NULL;
+		buffers[i].dma_address = 0;
+	}
+
+	buffers = ipts->feedback;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		if (!buffers[i].address)
+			continue;
+
+		dma_free_coherent(ipts->dev, feedback_buffer_size,
+				  buffers[i].address, buffers[i].dma_address);
+
+		buffers[i].address = NULL;
+		buffers[i].dma_address = 0;
+	}
+
+	if (ipts->doorbell.address) {
+		dma_free_coherent(ipts->dev, sizeof(u32),
+				  ipts->doorbell.address,
+				  ipts->doorbell.dma_address);
+
+		ipts->doorbell.address = NULL;
+		ipts->doorbell.dma_address = 0;
+	}
+
+	if (ipts->workqueue.address) {
+		dma_free_coherent(ipts->dev, sizeof(u32),
+				  ipts->workqueue.address,
+				  ipts->workqueue.dma_address);
+
+		ipts->workqueue.address = NULL;
+		ipts->workqueue.dma_address = 0;
+	}
+
+	if (ipts->host2me.address) {
+		dma_free_coherent(ipts->dev, feedback_buffer_size,
+				  ipts->host2me.address,
+				  ipts->host2me.dma_address);
+
+		ipts->host2me.address = NULL;
+		ipts->host2me.dma_address = 0;
+	}
+}
+
+int ipts_resources_alloc(struct ipts_context *ipts)
+{
+	int i;
+	struct ipts_buffer_info *buffers;
+
+	u32 data_buffer_size = ipts->device_info.data_size;
+	u32 feedback_buffer_size = ipts->device_info.feedback_size;
+
+	buffers = ipts->data;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		buffers[i].address =
+			dma_alloc_coherent(ipts->dev, data_buffer_size,
+					   &buffers[i].dma_address, GFP_KERNEL);
+
+		if (!buffers[i].address)
+			goto release_resources;
+	}
+
+	buffers = ipts->feedback;
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		buffers[i].address =
+			dma_alloc_coherent(ipts->dev, feedback_buffer_size,
+					   &buffers[i].dma_address, GFP_KERNEL);
+
+		if (!buffers[i].address)
+			goto release_resources;
+	}
+
+	ipts->doorbell.address =
+		dma_alloc_coherent(ipts->dev, sizeof(u32),
+				   &ipts->doorbell.dma_address, GFP_KERNEL);
+
+	if (!ipts->doorbell.address)
+		goto release_resources;
+
+	ipts->workqueue.address =
+		dma_alloc_coherent(ipts->dev, sizeof(u32),
+				   &ipts->workqueue.dma_address, GFP_KERNEL);
+
+	if (!ipts->workqueue.address)
+		goto release_resources;
+
+	ipts->host2me.address =
+		dma_alloc_coherent(ipts->dev, feedback_buffer_size,
+				   &ipts->host2me.dma_address, GFP_KERNEL);
+
+	if (!ipts->workqueue.address)
+		goto release_resources;
+
+	return 0;
+
+release_resources:
+
+	ipts_resources_free(ipts);
+	return -ENOMEM;
+}
diff --git a/drivers/misc/ipts/resources.h b/drivers/misc/ipts/resources.h
new file mode 100644
index 000000000000..fdac0eee9156
--- /dev/null
+++ b/drivers/misc/ipts/resources.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_RESOURCES_H_
+#define _IPTS_RESOURCES_H_
+
+#include "context.h"
+
+int ipts_resources_alloc(struct ipts_context *ipts);
+void ipts_resources_free(struct ipts_context *ipts);
+
+#endif /* _IPTS_RESOURCES_H_ */
diff --git a/drivers/misc/ipts/uapi.c b/drivers/misc/ipts/uapi.c
new file mode 100644
index 000000000000..598f0710ad64
--- /dev/null
+++ b/drivers/misc/ipts/uapi.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/cdev.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include "context.h"
+#include "control.h"
+#include "protocol.h"
+#include "uapi.h"
+
+struct ipts_uapi uapi;
+
+static ssize_t ipts_uapi_read(struct file *file, char __user *buf, size_t count,
+			      loff_t *offset)
+{
+	int buffer;
+	int maxbytes;
+	struct ipts_context *ipts = uapi.ipts;
+
+	buffer = MINOR(file->f_path.dentry->d_inode->i_rdev);
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	maxbytes = ipts->device_info.data_size - *offset;
+	if (maxbytes <= 0 || count > maxbytes)
+		return -EINVAL;
+
+	if (copy_to_user(buf, ipts->data[buffer].address + *offset, count))
+		return -EFAULT;
+
+	return count;
+}
+
+static long ipts_uapi_ioctl_get_device_ready(struct ipts_context *ipts,
+					     unsigned long arg)
+{
+	void __user *buffer = (void __user *)arg;
+	u8 ready = 0;
+
+	if (ipts)
+		ready = ipts->status == IPTS_HOST_STATUS_STARTED;
+
+	if (copy_to_user(buffer, &ready, sizeof(u8)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_get_device_info(struct ipts_context *ipts,
+					    unsigned long arg)
+{
+	struct ipts_device_info info;
+	void __user *buffer = (void __user *)arg;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	info.vendor = ipts->device_info.vendor_id;
+	info.product = ipts->device_info.device_id;
+	info.version = ipts->device_info.fw_rev;
+	info.buffer_size = ipts->device_info.data_size;
+	info.max_contacts = ipts->device_info.max_contacts;
+
+	if (copy_to_user(buffer, &info, sizeof(struct ipts_device_info)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_get_doorbell(struct ipts_context *ipts,
+					 unsigned long arg)
+{
+	void __user *buffer = (void __user *)arg;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	if (copy_to_user(buffer, ipts->doorbell.address, sizeof(u32)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_send_feedback(struct ipts_context *ipts,
+					  struct file *file)
+{
+	int ret;
+	u32 buffer;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	buffer = MINOR(file->f_path.dentry->d_inode->i_rdev);
+
+	ret = ipts_control_send_feedback(ipts, buffer);
+	if (ret)
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl_send_reset(struct ipts_context *ipts)
+{
+	int ret;
+	struct ipts_reset_sensor_cmd cmd;
+
+	if (!ipts || ipts->status != IPTS_HOST_STATUS_STARTED)
+		return -ENODEV;
+
+	memset(&cmd, 0, sizeof(struct ipts_reset_sensor_cmd));
+	cmd.type = IPTS_RESET_TYPE_SOFT;
+
+	ret = ipts_control_send(ipts, IPTS_CMD_RESET_SENSOR, &cmd,
+				sizeof(struct ipts_reset_sensor_cmd));
+
+	if (ret)
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ipts_uapi_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct ipts_context *ipts = uapi.ipts;
+
+	switch (cmd) {
+	case IPTS_IOCTL_GET_DEVICE_READY:
+		return ipts_uapi_ioctl_get_device_ready(ipts, arg);
+	case IPTS_IOCTL_GET_DEVICE_INFO:
+		return ipts_uapi_ioctl_get_device_info(ipts, arg);
+	case IPTS_IOCTL_GET_DOORBELL:
+		return ipts_uapi_ioctl_get_doorbell(ipts, arg);
+	case IPTS_IOCTL_SEND_FEEDBACK:
+		return ipts_uapi_ioctl_send_feedback(ipts, file);
+	case IPTS_IOCTL_SEND_RESET:
+		return ipts_uapi_ioctl_send_reset(ipts);
+	default:
+		return -ENOTTY;
+	}
+}
+
+static const struct file_operations ipts_uapi_fops = {
+	.owner = THIS_MODULE,
+	.read = ipts_uapi_read,
+	.unlocked_ioctl = ipts_uapi_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = ipts_uapi_ioctl,
+#endif
+};
+
+void ipts_uapi_link(struct ipts_context *ipts)
+{
+	uapi.ipts = ipts;
+}
+
+void ipts_uapi_unlink(void)
+{
+	uapi.ipts = NULL;
+}
+
+int ipts_uapi_init(void)
+{
+	int i, major;
+
+	alloc_chrdev_region(&uapi.dev, 0, IPTS_BUFFERS, "ipts");
+	uapi.class = class_create(THIS_MODULE, "ipts");
+
+	major = MAJOR(uapi.dev);
+
+	cdev_init(&uapi.cdev, &ipts_uapi_fops);
+	uapi.cdev.owner = THIS_MODULE;
+	cdev_add(&uapi.cdev, MKDEV(major, 0), IPTS_BUFFERS);
+
+	for (i = 0; i < IPTS_BUFFERS; i++) {
+		device_create(uapi.class, NULL, MKDEV(major, i), NULL,
+			      "ipts/%d", i);
+	}
+
+	return 0;
+}
+
+void ipts_uapi_free(void)
+{
+	int i;
+	int major;
+
+	major = MAJOR(uapi.dev);
+
+	for (i = 0; i < IPTS_BUFFERS; i++)
+		device_destroy(uapi.class, MKDEV(major, i));
+
+	cdev_del(&uapi.cdev);
+
+	unregister_chrdev_region(MKDEV(major, 0), MINORMASK);
+	class_destroy(uapi.class);
+}
diff --git a/drivers/misc/ipts/uapi.h b/drivers/misc/ipts/uapi.h
new file mode 100644
index 000000000000..53fb86a88f97
--- /dev/null
+++ b/drivers/misc/ipts/uapi.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef _IPTS_UAPI_H_
+#define _IPTS_UAPI_H_
+
+#include <linux/types.h>
+
+#include "context.h"
+
+struct ipts_uapi {
+	dev_t dev;
+	struct class *class;
+	struct cdev cdev;
+
+	struct ipts_context *ipts;
+};
+
+struct ipts_device_info {
+	__u16 vendor;
+	__u16 product;
+	__u32 version;
+	__u32 buffer_size;
+	__u8 max_contacts;
+
+	/* For future expansion */
+	__u8 reserved[19];
+};
+
+#define IPTS_IOCTL_GET_DEVICE_READY _IOR(0x86, 0x01, __u8)
+#define IPTS_IOCTL_GET_DEVICE_INFO  _IOR(0x86, 0x02, struct ipts_device_info)
+#define IPTS_IOCTL_GET_DOORBELL	    _IOR(0x86, 0x03, __u32)
+#define IPTS_IOCTL_SEND_FEEDBACK    _IO(0x86, 0x04)
+#define IPTS_IOCTL_SEND_RESET	    _IO(0x86, 0x05)
+
+void ipts_uapi_link(struct ipts_context *ipts);
+void ipts_uapi_unlink(void);
+
+int ipts_uapi_init(void);
+void ipts_uapi_free(void);
+
+#endif /* _IPTS_UAPI_H_ */
-- 
2.36.0

From db68833d47e0d5ee2bc2003b9e410a4f672aa43a Mon Sep 17 00:00:00 2001
From: zouxiaoh <xiaohong.zou@intel.com>
Date: Fri, 25 Jun 2021 08:52:59 +0800
Subject: [PATCH] iommu: intel-ipu: use IOMMU passthrough mode for Intel IPUs

Intel IPU(Image Processing Unit) has its own (IO)MMU hardware,
The IPU driver allocates its own page table that is not mapped
via the DMA, and thus the Intel IOMMU driver blocks access giving
this error: DMAR: DRHD: handling fault status reg 3 DMAR:
[DMA Read] Request device [00:05.0] PASID ffffffff
fault addr 76406000 [fault reason 06] PTE Read access is not set
As IPU is not an external facing device which is not risky, so use
IOMMU passthrough mode for Intel IPUs.

Change-Id: I6dcccdadac308cf42e20a18e1b593381391e3e6b
Depends-On: Iacd67578e8c6a9b9ac73285f52b4081b72fb68a6
Tracked-On: #JIITL8-411
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: zouxiaoh <xiaohong.zou@intel.com>
Signed-off-by: Xu Chongyang <chongyang.xu@intel.com>
Patchset: ipts
---
 drivers/iommu/intel/iommu.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5b196cfe9ed2..a5fc95dbb06d 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -57,6 +57,12 @@
 #define IS_GFX_DEVICE(pdev) ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY)
 #define IS_USB_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_SERIAL_USB)
 #define IS_ISA_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA)
+#define IS_INTEL_IPU(pdev) ((pdev)->vendor == PCI_VENDOR_ID_INTEL &&	\
+			   ((pdev)->device == 0x9a19 ||		\
+			    (pdev)->device == 0x9a39 ||		\
+			    (pdev)->device == 0x4e19 ||		\
+			    (pdev)->device == 0x465d ||		\
+			    (pdev)->device == 0x1919))
 #define IS_AZALIA(pdev) ((pdev)->vendor == 0x8086 && (pdev)->device == 0x3a3e)
 
 #define IOAPIC_RANGE_START	(0xfee00000)
@@ -332,12 +338,14 @@ int intel_iommu_enabled = 0;
 EXPORT_SYMBOL_GPL(intel_iommu_enabled);
 
 static int dmar_map_gfx = 1;
+static int dmar_map_ipu = 1;
 static int intel_iommu_superpage = 1;
 static int iommu_identity_mapping;
 static int iommu_skip_te_disable;
 
 #define IDENTMAP_GFX		2
 #define IDENTMAP_AZALIA		4
+#define IDENTMAP_IPU		8
 
 int intel_iommu_gfx_mapped;
 EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);
@@ -2966,6 +2974,9 @@ static int device_def_domain_type(struct device *dev)
 
 		if ((iommu_identity_mapping & IDENTMAP_GFX) && IS_GFX_DEVICE(pdev))
 			return IOMMU_DOMAIN_IDENTITY;
+
+		if ((iommu_identity_mapping & IDENTMAP_IPU) && IS_INTEL_IPU(pdev))
+			return IOMMU_DOMAIN_IDENTITY;
 	}
 
 	return 0;
@@ -3402,6 +3413,9 @@ static int __init init_dmars(void)
 	if (!dmar_map_gfx)
 		iommu_identity_mapping |= IDENTMAP_GFX;
 
+	if (!dmar_map_ipu)
+		iommu_identity_mapping |= IDENTMAP_IPU;
+
 	check_tylersburg_isoch();
 
 	ret = si_domain_init(hw_pass_through);
@@ -5643,6 +5657,18 @@ static void quirk_iommu_igfx(struct pci_dev *dev)
 	dmar_map_gfx = 0;
 }
 
+static void quirk_iommu_ipu(struct pci_dev *dev)
+{
+	if (!IS_INTEL_IPU(dev))
+		return;
+
+	if (risky_device(dev))
+		return;
+
+	pci_info(dev, "Passthrough IOMMU for integrated Intel IPU\n");
+	dmar_map_ipu = 0;
+}
+
 /* G4x/GM45 integrated gfx dmar support is totally busted. */
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_igfx);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e00, quirk_iommu_igfx);
@@ -5678,6 +5704,9 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x1632, quirk_iommu_igfx);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163A, quirk_iommu_igfx);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163D, quirk_iommu_igfx);
 
+/* disable IPU dmar support */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, quirk_iommu_ipu);
+
 static void quirk_iommu_rwbf(struct pci_dev *dev)
 {
 	if (risky_device(dev))
-- 
2.36.0

From b3fbdb5c4552d9d98715e19ca13302615e7aca80 Mon Sep 17 00:00:00 2001
From: Liban Hannan <liban.p@gmail.com>
Date: Tue, 12 Apr 2022 23:31:12 +0100
Subject: [PATCH] iommu: ipts: use IOMMU passthrough mode for IPTS

Adds a quirk so that IOMMU uses passthrough mode for the IPTS device.
Otherwise, when IOMMU is enabled, IPTS produces DMAR errors like:

DMAR: [DMA Read NO_PASID] Request device [00:16.4] fault addr
0x104ea3000 [fault reason 0x06] PTE Read access is not set

This is very similar to the bug described at:
https://bugs.launchpad.net/bugs/1958004

Fixed with the following patch which this patch basically copies:
https://launchpadlibrarian.net/586396847/43255ca.diff
Patchset: ipts
---
 drivers/iommu/intel/iommu.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index a5fc95dbb06d..b3f6213048fd 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -63,6 +63,8 @@
 			    (pdev)->device == 0x4e19 ||		\
 			    (pdev)->device == 0x465d ||		\
 			    (pdev)->device == 0x1919))
+#define IS_IPTS(pdev) ((pdev)->vendor == PCI_VENDOR_ID_INTEL &&	\
+			    ((pdev)->device == 0x9d3e))
 #define IS_AZALIA(pdev) ((pdev)->vendor == 0x8086 && (pdev)->device == 0x3a3e)
 
 #define IOAPIC_RANGE_START	(0xfee00000)
@@ -339,6 +341,7 @@ EXPORT_SYMBOL_GPL(intel_iommu_enabled);
 
 static int dmar_map_gfx = 1;
 static int dmar_map_ipu = 1;
+static int dmar_map_ipts = 1;
 static int intel_iommu_superpage = 1;
 static int iommu_identity_mapping;
 static int iommu_skip_te_disable;
@@ -346,6 +349,7 @@ static int iommu_skip_te_disable;
 #define IDENTMAP_GFX		2
 #define IDENTMAP_AZALIA		4
 #define IDENTMAP_IPU		8
+#define IDENTMAP_IPTS		16
 
 int intel_iommu_gfx_mapped;
 EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);
@@ -2977,6 +2981,9 @@ static int device_def_domain_type(struct device *dev)
 
 		if ((iommu_identity_mapping & IDENTMAP_IPU) && IS_INTEL_IPU(pdev))
 			return IOMMU_DOMAIN_IDENTITY;
+
+		if ((iommu_identity_mapping & IDENTMAP_IPTS) && IS_IPTS(pdev))
+			return IOMMU_DOMAIN_IDENTITY;
 	}
 
 	return 0;
@@ -3416,6 +3423,9 @@ static int __init init_dmars(void)
 	if (!dmar_map_ipu)
 		iommu_identity_mapping |= IDENTMAP_IPU;
 
+	if (!dmar_map_ipts)
+		iommu_identity_mapping |= IDENTMAP_IPTS;
+
 	check_tylersburg_isoch();
 
 	ret = si_domain_init(hw_pass_through);
@@ -5669,6 +5679,17 @@ static void quirk_iommu_ipu(struct pci_dev *dev)
 	dmar_map_ipu = 0;
 }
 
+static void quirk_iommu_ipts(struct pci_dev *dev)
+{
+	if (!IS_IPTS(dev))
+		return;
+
+	if (risky_device(dev))
+		return;
+
+	pci_info(dev, "Passthrough IOMMU for IPTS\n");
+	dmar_map_ipts = 0;
+}
 /* G4x/GM45 integrated gfx dmar support is totally busted. */
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_igfx);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e00, quirk_iommu_igfx);
@@ -5707,6 +5728,9 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163D, quirk_iommu_igfx);
 /* disable IPU dmar support */
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, quirk_iommu_ipu);
 
+/* disable IPTS dmar support */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9D3E, quirk_iommu_ipts);
+
 static void quirk_iommu_rwbf(struct pci_dev *dev)
 {
 	if (risky_device(dev))
-- 
2.36.0

From 2bb8c3daadfa4daa1f2d0f35b7753f850d0f0b62 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 00:24:47 +0200
Subject: [PATCH] platform/surface: aggregator: Allow devices to be marked as
 hot-removed

Some SSAM devices, notably the keyboard cover (keyboard and touchpad) on
the Surface Pro 8, can be hot-removed. When this occurs, communication
with the device may fail and time out. This timeout can unnecessarily
block and slow down device removal and even cause issues when the
devices are detached and re-attached quickly. Thus, communication should
generally be avoided once hot-removal is detected.

While we already remove a device as soon as we detect its (hot-)removal,
the corresponding device driver may still attempt to communicate with
the device during teardown. This is especially critical as communication
failure may also extend to disabling of events, which is typically done
at that stage.

Add a flag to allow marking devices as hot-removed. This can then be
used during client driver teardown to check if any communication
attempts should be avoided.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/aggregator/bus.c |  3 ++
 include/linux/surface_aggregator/device.h | 48 +++++++++++++++++++++--
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/surface/aggregator/bus.c b/drivers/platform/surface/aggregator/bus.c
index abbbb5b08b07..2b003dcbfc4b 100644
--- a/drivers/platform/surface/aggregator/bus.c
+++ b/drivers/platform/surface/aggregator/bus.c
@@ -388,6 +388,9 @@ void ssam_remove_clients(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(ssam_remove_clients);
 
+
+/* -- Bus registration. ----------------------------------------------------- */
+
 /**
  * ssam_bus_register() - Register and set-up the SSAM client device bus.
  */
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
index cc257097eb05..491aa7e9f4bc 100644
--- a/include/linux/surface_aggregator/device.h
+++ b/include/linux/surface_aggregator/device.h
@@ -148,17 +148,30 @@ struct ssam_device_uid {
 #define SSAM_SDEV(cat, tid, iid, fun) \
 	SSAM_DEVICE(SSAM_DOMAIN_SERIALHUB, SSAM_SSH_TC_##cat, tid, iid, fun)
 
+/*
+ * enum ssam_device_flags - Flags for SSAM client devices.
+ * @SSAM_DEVICE_HOT_REMOVED_BIT:
+ *	The device has been hot-removed. Further communication with it may time
+ *	out and should be avoided.
+ */
+enum ssam_device_flags {
+	SSAM_DEVICE_HOT_REMOVED_BIT = 0,
+};
+
 /**
  * struct ssam_device - SSAM client device.
- * @dev:  Driver model representation of the device.
- * @ctrl: SSAM controller managing this device.
- * @uid:  UID identifying the device.
+ * @dev:   Driver model representation of the device.
+ * @ctrl:  SSAM controller managing this device.
+ * @uid:   UID identifying the device.
+ * @flags: Device state flags, see &enum ssam_device_flags.
  */
 struct ssam_device {
 	struct device dev;
 	struct ssam_controller *ctrl;
 
 	struct ssam_device_uid uid;
+
+	unsigned long flags;
 };
 
 /**
@@ -240,6 +253,35 @@ struct ssam_device *ssam_device_alloc(struct ssam_controller *ctrl,
 int ssam_device_add(struct ssam_device *sdev);
 void ssam_device_remove(struct ssam_device *sdev);
 
+/**
+ * ssam_device_mark_hot_removed() - Mark the given device as hot-removed.
+ * @sdev: The device to mark as hot-removed.
+ *
+ * Mark the device as having been hot-removed. This signals drivers using the
+ * device that communication with the device should be avoided and may lead to
+ * timeouts.
+ */
+static inline void ssam_device_mark_hot_removed(struct ssam_device *sdev)
+{
+	dev_dbg(&sdev->dev, "marking device as hot-removed\n");
+	set_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
+}
+
+/**
+ * ssam_device_is_hot_removed() - Check if the given device has been
+ * hot-removed.
+ * @sdev: The device to check.
+ *
+ * Checks if the given device has been marked as hot-removed. See
+ * ssam_device_mark_hot_removed() for more details.
+ *
+ * Return: Returns ``true`` if the device has been marked as hot-removed.
+ */
+static inline bool ssam_device_is_hot_removed(struct ssam_device *sdev)
+{
+	return test_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
+}
+
 /**
  * ssam_device_get() - Increment reference count of SSAM client device.
  * @sdev: The device to increment the reference count of.
-- 
2.36.0

From e1da5a5135346e7091651f7fe2aa8c43b9d03f7d Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 00:48:22 +0200
Subject: [PATCH] platform/surface: aggregator: Allow notifiers to avoid
 communication on unregistering

When SSAM client devices have been (physically) hot-removed,
communication attempts with those devices may fail and time out. This
can even extend to event notifiers, due to which timeouts may occur
during device removal, slowing down that process.

Add a flag to the notifier unregister function that allows skipping
communication with the EC to prevent this. Furthermore, add wrappers for
registering and unregistering notifiers belonging to SSAM client devices
that automatically check if the device has been marked as hot-removed
and communication should be avoided.

Note that non-SSAM client devices can generally not be hot-removed, so
also add a convenience wrapper for those, defaulting to allow
communication.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../driver-api/surface_aggregator/client.rst  |  6 +-
 .../platform/surface/aggregator/controller.c  | 53 ++++++++++------
 include/linux/surface_aggregator/controller.h | 24 +++++++-
 include/linux/surface_aggregator/device.h     | 60 +++++++++++++++++++
 4 files changed, 122 insertions(+), 21 deletions(-)

diff --git a/Documentation/driver-api/surface_aggregator/client.rst b/Documentation/driver-api/surface_aggregator/client.rst
index e519d374c378..27f95abdbe99 100644
--- a/Documentation/driver-api/surface_aggregator/client.rst
+++ b/Documentation/driver-api/surface_aggregator/client.rst
@@ -17,6 +17,8 @@
 .. |SSAM_DEVICE| replace:: :c:func:`SSAM_DEVICE`
 .. |ssam_notifier_register| replace:: :c:func:`ssam_notifier_register`
 .. |ssam_notifier_unregister| replace:: :c:func:`ssam_notifier_unregister`
+.. |ssam_device_notifier_register| replace:: :c:func:`ssam_device_notifier_register`
+.. |ssam_device_notifier_unregister| replace:: :c:func:`ssam_device_notifier_unregister`
 .. |ssam_request_sync| replace:: :c:func:`ssam_request_sync`
 .. |ssam_event_mask| replace:: :c:type:`enum ssam_event_mask <ssam_event_mask>`
 
@@ -312,7 +314,9 @@ Handling Events
 To receive events from the SAM EC, an event notifier must be registered for
 the desired event via |ssam_notifier_register|. The notifier must be
 unregistered via |ssam_notifier_unregister| once it is not required any
-more.
+more. For |ssam_device| type clients, the |ssam_device_notifier_register| and
+|ssam_device_notifier_unregister| wrappers should be preferred as they properly
+handle hot-removal of client devices.
 
 Event notifiers are registered by providing (at minimum) a callback to call
 in case an event has been received, the registry specifying how the event
diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c
index b8c377b3f932..6de834b52b63 100644
--- a/drivers/platform/surface/aggregator/controller.c
+++ b/drivers/platform/surface/aggregator/controller.c
@@ -2199,16 +2199,26 @@ static int ssam_nf_refcount_enable(struct ssam_controller *ctrl,
 }
 
 /**
- * ssam_nf_refcount_disable_free() - Disable event for reference count entry if it is
- * no longer in use and free the corresponding entry.
+ * ssam_nf_refcount_disable_free() - Disable event for reference count entry if
+ * it is no longer in use and free the corresponding entry.
  * @ctrl:  The controller to disable the event on.
  * @entry: The reference count entry for the event to be disabled.
  * @flags: The flags used for enabling the event on the EC.
+ * @ec:    Flag specifying if the event should actually be disabled on the EC.
  *
- * If the reference count equals zero, i.e. the event is no longer requested by
- * any client, the event will be disabled and the corresponding reference count
- * entry freed. The reference count entry must not be used any more after a
- * call to this function.
+ * If ``ec`` equals ``true`` and the reference count equals zero (i.e. the
+ * event is no longer requested by any client), the specified event will be
+ * disabled on the EC via the corresponding request.
+ *
+ * If ``ec`` equals ``false``, no request will be sent to the EC and the event
+ * can be considered in a detached state (i.e. no longer used but still
+ * enabled). Disabling an event via this method may be required for
+ * hot-removable devices, where event disable requests may time out after the
+ * device has been physically removed.
+ *
+ * In both cases, if the reference count equals zero, the corresponding
+ * reference count entry will be freed. The reference count entry must not be
+ * used any more after a call to this function.
  *
  * Also checks if the flags used for disabling the event match the flags used
  * for enabling the event and warns if they do not (regardless of reference
@@ -2223,7 +2233,7 @@ static int ssam_nf_refcount_enable(struct ssam_controller *ctrl,
  * returns the status of the event-enable EC command.
  */
 static int ssam_nf_refcount_disable_free(struct ssam_controller *ctrl,
-					 struct ssam_nf_refcount_entry *entry, u8 flags)
+					 struct ssam_nf_refcount_entry *entry, u8 flags, bool ec)
 {
 	const struct ssam_event_registry reg = entry->key.reg;
 	const struct ssam_event_id id = entry->key.id;
@@ -2232,8 +2242,9 @@ static int ssam_nf_refcount_disable_free(struct ssam_controller *ctrl,
 
 	lockdep_assert_held(&nf->lock);
 
-	ssam_dbg(ctrl, "disabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n",
-		 reg.target_category, id.target_category, id.instance, entry->refcount);
+	ssam_dbg(ctrl, "%s event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n",
+		 ec ? "disabling" : "detaching", reg.target_category, id.target_category,
+		 id.instance, entry->refcount);
 
 	if (entry->flags != flags) {
 		ssam_warn(ctrl,
@@ -2242,7 +2253,7 @@ static int ssam_nf_refcount_disable_free(struct ssam_controller *ctrl,
 			  id.instance);
 	}
 
-	if (entry->refcount == 0) {
+	if (ec && entry->refcount == 0) {
 		status = ssam_ssh_event_disable(ctrl, reg, id, flags);
 		kfree(entry);
 	}
@@ -2322,20 +2333,26 @@ int ssam_notifier_register(struct ssam_controller *ctrl, struct ssam_event_notif
 EXPORT_SYMBOL_GPL(ssam_notifier_register);
 
 /**
- * ssam_notifier_unregister() - Unregister an event notifier.
- * @ctrl: The controller the notifier has been registered on.
- * @n:    The event notifier to unregister.
+ * __ssam_notifier_unregister() - Unregister an event notifier.
+ * @ctrl:    The controller the notifier has been registered on.
+ * @n:       The event notifier to unregister.
+ * @disable: Whether to disable the corresponding event on the EC.
  *
  * Unregister an event notifier. Decrement the usage counter of the associated
  * SAM event if the notifier is not marked as an observer. If the usage counter
- * reaches zero, the event will be disabled.
+ * reaches zero and ``disable`` equals ``true``, the event will be disabled.
+ *
+ * Useful for hot-removable devices, where communication may fail once the
+ * device has been physically removed. In that case, specifying ``disable`` as
+ * ``false`` avoids communication with the EC.
  *
  * Return: Returns zero on success, %-ENOENT if the given notifier block has
  * not been registered on the controller. If the given notifier block was the
  * last one associated with its specific event, returns the status of the
  * event-disable EC-command.
  */
-int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n)
+int __ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n,
+			       bool disable)
 {
 	u16 rqid = ssh_tc_to_rqid(n->event.id.target_category);
 	struct ssam_nf_refcount_entry *entry;
@@ -2373,7 +2390,7 @@ int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_not
 			goto remove;
 		}
 
-		status = ssam_nf_refcount_disable_free(ctrl, entry, n->event.flags);
+		status = ssam_nf_refcount_disable_free(ctrl, entry, n->event.flags, disable);
 	}
 
 remove:
@@ -2383,7 +2400,7 @@ int ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_not
 
 	return status;
 }
-EXPORT_SYMBOL_GPL(ssam_notifier_unregister);
+EXPORT_SYMBOL_GPL(__ssam_notifier_unregister);
 
 /**
  * ssam_controller_event_enable() - Enable the specified event.
@@ -2477,7 +2494,7 @@ int ssam_controller_event_disable(struct ssam_controller *ctrl,
 		return -ENOENT;
 	}
 
-	status = ssam_nf_refcount_disable_free(ctrl, entry, flags);
+	status = ssam_nf_refcount_disable_free(ctrl, entry, flags, true);
 
 	mutex_unlock(&nf->lock);
 	return status;
diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h
index 74bfdffaf7b0..50a2b4926c06 100644
--- a/include/linux/surface_aggregator/controller.h
+++ b/include/linux/surface_aggregator/controller.h
@@ -835,8 +835,28 @@ struct ssam_event_notifier {
 int ssam_notifier_register(struct ssam_controller *ctrl,
 			   struct ssam_event_notifier *n);
 
-int ssam_notifier_unregister(struct ssam_controller *ctrl,
-			     struct ssam_event_notifier *n);
+int __ssam_notifier_unregister(struct ssam_controller *ctrl,
+			       struct ssam_event_notifier *n, bool disable);
+
+/**
+ * ssam_notifier_unregister() - Unregister an event notifier.
+ * @ctrl:    The controller the notifier has been registered on.
+ * @n:       The event notifier to unregister.
+ *
+ * Unregister an event notifier. Decrement the usage counter of the associated
+ * SAM event if the notifier is not marked as an observer. If the usage counter
+ * reaches zero, the event will be disabled.
+ *
+ * Return: Returns zero on success, %-ENOENT if the given notifier block has
+ * not been registered on the controller. If the given notifier block was the
+ * last one associated with its specific event, returns the status of the
+ * event-disable EC-command.
+ */
+static inline int ssam_notifier_unregister(struct ssam_controller *ctrl,
+					   struct ssam_event_notifier *n)
+{
+	return __ssam_notifier_unregister(ctrl, n, true);
+}
 
 int ssam_controller_event_enable(struct ssam_controller *ctrl,
 				 struct ssam_event_registry reg,
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
index 491aa7e9f4bc..16816c34da3e 100644
--- a/include/linux/surface_aggregator/device.h
+++ b/include/linux/surface_aggregator/device.h
@@ -472,4 +472,64 @@ static inline void ssam_remove_clients(struct device *dev) {}
 				    sdev->uid.instance, ret);		\
 	}
 
+
+/* -- Helpers for client-device notifiers. ---------------------------------- */
+
+/**
+ * ssam_device_notifier_register() - Register an event notifier for the
+ * specified client device.
+ * @sdev: The device the notifier should be registered on.
+ * @n:    The event notifier to register.
+ *
+ * Register an event notifier. Increment the usage counter of the associated
+ * SAM event if the notifier is not marked as an observer. If the event is not
+ * marked as an observer and is currently not enabled, it will be enabled
+ * during this call. If the notifier is marked as an observer, no attempt will
+ * be made at enabling any event and no reference count will be modified.
+ *
+ * Notifiers marked as observers do not need to be associated with one specific
+ * event, i.e. as long as no event matching is performed, only the event target
+ * category needs to be set.
+ *
+ * Return: Returns zero on success, %-ENOSPC if there have already been
+ * %INT_MAX notifiers for the event ID/type associated with the notifier block
+ * registered, %-ENOMEM if the corresponding event entry could not be
+ * allocated, %-ENODEV if the device is marked as hot-removed. If this is the
+ * first time that a notifier block is registered for the specific associated
+ * event, returns the status of the event-enable EC-command.
+ */
+static inline int ssam_device_notifier_register(struct ssam_device *sdev,
+						struct ssam_event_notifier *n)
+{
+	if (ssam_device_is_hot_removed(sdev))
+		return -ENODEV;
+
+	return ssam_notifier_register(sdev->ctrl, n);
+}
+
+/**
+ * ssam_device_notifier_unregister() - Unregister an event notifier for the
+ * specified client device.
+ * @sdev: The device the notifier has been registered on.
+ * @n:    The event notifier to unregister.
+ *
+ * Unregister an event notifier. Decrement the usage counter of the associated
+ * SAM event if the notifier is not marked as an observer. If the usage counter
+ * reaches zero, the event will be disabled.
+ *
+ * In case the device has been marked as hot-removed, the event will not be
+ * disabled on the EC, as in those cases any attempt at doing so may time out.
+ *
+ * Return: Returns zero on success, %-ENOENT if the given notifier block has
+ * not been registered on the controller. If the given notifier block was the
+ * last one associated with its specific event, returns the status of the
+ * event-disable EC-command.
+ */
+static inline int ssam_device_notifier_unregister(struct ssam_device *sdev,
+						  struct ssam_event_notifier *n)
+{
+	return __ssam_notifier_unregister(sdev->ctrl, n,
+					  !ssam_device_is_hot_removed(sdev));
+}
+
 #endif /* _LINUX_SURFACE_AGGREGATOR_DEVICE_H */
-- 
2.36.0

From bf9269161d0e15076508e0ca776a31d860eacb7f Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 01:20:49 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Use client device
 wrappers for notifier registration

Use newly introduced client device wrapper functions for notifier
registration and unregistration.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/surface_aggregator_registry.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index ce2bd88feeaa..9f630e890ff7 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -468,7 +468,7 @@ static int ssam_base_hub_probe(struct ssam_device *sdev)
 
 	ssam_device_set_drvdata(sdev, hub);
 
-	status = ssam_notifier_register(sdev->ctrl, &hub->notif);
+	status = ssam_device_notifier_register(sdev, &hub->notif);
 	if (status)
 		return status;
 
@@ -480,7 +480,7 @@ static int ssam_base_hub_probe(struct ssam_device *sdev)
 	return 0;
 
 err:
-	ssam_notifier_unregister(sdev->ctrl, &hub->notif);
+	ssam_device_notifier_unregister(sdev, &hub->notif);
 	cancel_delayed_work_sync(&hub->update_work);
 	ssam_remove_clients(&sdev->dev);
 	return status;
@@ -492,7 +492,7 @@ static void ssam_base_hub_remove(struct ssam_device *sdev)
 
 	sysfs_remove_group(&sdev->dev.kobj, &ssam_base_hub_group);
 
-	ssam_notifier_unregister(sdev->ctrl, &hub->notif);
+	ssam_device_notifier_unregister(sdev, &hub->notif);
 	cancel_delayed_work_sync(&hub->update_work);
 	ssam_remove_clients(&sdev->dev);
 }
-- 
2.36.0

From 7dffc0d5aa0b675201815f0db11d4207ed1bcf47 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Thu, 28 Oct 2021 03:37:06 +0200
Subject: [PATCH] power/supply: surface_charger: Use client device wrappers for
 notifier registration

Use newly introduced client device wrapper functions for notifier
registration and unregistration.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/power/supply/surface_charger.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/surface_charger.c b/drivers/power/supply/surface_charger.c
index a060c36c7766..59182d55742d 100644
--- a/drivers/power/supply/surface_charger.c
+++ b/drivers/power/supply/surface_charger.c
@@ -216,7 +216,7 @@ static int spwr_ac_register(struct spwr_ac_device *ac)
 	if (IS_ERR(ac->psy))
 		return PTR_ERR(ac->psy);
 
-	return ssam_notifier_register(ac->sdev->ctrl, &ac->notif);
+	return ssam_device_notifier_register(ac->sdev, &ac->notif);
 }
 
 
@@ -251,7 +251,7 @@ static void surface_ac_remove(struct ssam_device *sdev)
 {
 	struct spwr_ac_device *ac = ssam_device_get_drvdata(sdev);
 
-	ssam_notifier_unregister(sdev->ctrl, &ac->notif);
+	ssam_device_notifier_unregister(sdev, &ac->notif);
 }
 
 static const struct spwr_psy_properties spwr_psy_props_adp1 = {
-- 
2.36.0

From bf04f91eb86cd24faed47f078d4c7cba0d3afb0a Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Thu, 28 Oct 2021 03:38:09 +0200
Subject: [PATCH] power/supply: surface_battery: Use client device wrappers for
 notifier registration

Use newly introduced client device wrapper functions for notifier
registration and unregistration.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/power/supply/surface_battery.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/surface_battery.c b/drivers/power/supply/surface_battery.c
index 5ec2e6bb2465..540707882bb0 100644
--- a/drivers/power/supply/surface_battery.c
+++ b/drivers/power/supply/surface_battery.c
@@ -802,7 +802,7 @@ static int spwr_battery_register(struct spwr_battery_device *bat)
 	if (IS_ERR(bat->psy))
 		return PTR_ERR(bat->psy);
 
-	return ssam_notifier_register(bat->sdev->ctrl, &bat->notif);
+	return ssam_device_notifier_register(bat->sdev, &bat->notif);
 }
 
 
@@ -837,7 +837,7 @@ static void surface_battery_remove(struct ssam_device *sdev)
 {
 	struct spwr_battery_device *bat = ssam_device_get_drvdata(sdev);
 
-	ssam_notifier_unregister(sdev->ctrl, &bat->notif);
+	ssam_device_notifier_unregister(sdev, &bat->notif);
 	cancel_delayed_work_sync(&bat->update_work);
 }
 
-- 
2.36.0

From ec5de9e26ab336abeb4510101843ca9215f306ac Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 01:33:02 +0200
Subject: [PATCH] HID: surface-hid: Add support for hot-removal

Add support for hot-removal of SSAM HID client devices.

Once a device has been hot-removed, further communication with it should
be avoided as it may fail and time out. While the device will be removed
as soon as we detect hot-removal, communication may still occur during
teardown, especially when unregistering notifiers.

While hot-removal is a surprise event that can happen any time, try to
avoid communication as much as possible once it has been detected to
prevent timeouts that can slow down device removal and cause issues,
e.g. when quickly re-attaching the device.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/hid/surface-hid/surface_hid_core.c | 38 +++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/surface-hid/surface_hid_core.c b/drivers/hid/surface-hid/surface_hid_core.c
index e46330b2e561..87637f813de2 100644
--- a/drivers/hid/surface-hid/surface_hid_core.c
+++ b/drivers/hid/surface-hid/surface_hid_core.c
@@ -19,12 +19,30 @@
 #include "surface_hid_core.h"
 
 
+/* -- Utility functions. ---------------------------------------------------- */
+
+static bool surface_hid_is_hot_removed(struct surface_hid_device *shid)
+{
+	/*
+	 * Non-ssam client devices, i.e. platform client devices, cannot be
+	 * hot-removed.
+	 */
+	if (!is_ssam_device(shid->dev))
+		return false;
+
+	return ssam_device_is_hot_removed(to_ssam_device(shid->dev));
+}
+
+
 /* -- Device descriptor access. --------------------------------------------- */
 
 static int surface_hid_load_hid_descriptor(struct surface_hid_device *shid)
 {
 	int status;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_HID,
 			(u8 *)&shid->hid_desc, sizeof(shid->hid_desc));
 	if (status)
@@ -61,6 +79,9 @@ static int surface_hid_load_device_attributes(struct surface_hid_device *shid)
 {
 	int status;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_ATTRS,
 			(u8 *)&shid->attrs, sizeof(shid->attrs));
 	if (status)
@@ -88,9 +109,18 @@ static int surface_hid_start(struct hid_device *hid)
 static void surface_hid_stop(struct hid_device *hid)
 {
 	struct surface_hid_device *shid = hid->driver_data;
+	bool hot_removed;
+
+	/*
+	 * Communication may fail for devices that have been hot-removed. This
+	 * also includes unregistration of HID events, so we need to check this
+	 * here. Only if the device has not been marked as hot-removed, we can
+	 * safely disable events.
+	 */
+	hot_removed = surface_hid_is_hot_removed(shid);
 
 	/* Note: This call will log errors for us, so ignore them here. */
-	ssam_notifier_unregister(shid->ctrl, &shid->notif);
+	__ssam_notifier_unregister(shid->ctrl, &shid->notif, !hot_removed);
 }
 
 static int surface_hid_open(struct hid_device *hid)
@@ -109,6 +139,9 @@ static int surface_hid_parse(struct hid_device *hid)
 	u8 *buf;
 	int status;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	buf = kzalloc(len, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -126,6 +159,9 @@ static int surface_hid_raw_request(struct hid_device *hid, unsigned char reportn
 {
 	struct surface_hid_device *shid = hid->driver_data;
 
+	if (surface_hid_is_hot_removed(shid))
+		return -ENODEV;
+
 	if (rtype == HID_OUTPUT_REPORT && reqtype == HID_REQ_SET_REPORT)
 		return shid->ops.output_report(shid, reportnum, buf, len);
 
-- 
2.36.0

From 4bdf54b718375e303f8fe6745ffa90c4b153e20c Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sun, 31 Oct 2021 12:34:08 +0100
Subject: [PATCH] platform/surface: aggregator: Add comment for KIP subsystem
 category

The KIP subsystem (full name unknown, abbreviation has been obtained
through reverse engineering) handles detachable peripherals such as the
keyboard cover on the Surface Pro X and Surface Pro 8.

It is currently not entirely clear what this subsystem entails, but at
the very least it provides event notifications for when the keyboard
cover on the Surface Pro X and Surface Pro 8 have been detached or
re-attached, as well as the state that the keyboard cover is currently
in (e.g. folded-back, folded laptop-like, closed, etc.).

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 include/linux/surface_aggregator/serial_hub.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/surface_aggregator/serial_hub.h b/include/linux/surface_aggregator/serial_hub.h
index c3de43edcffa..d1efac85caf1 100644
--- a/include/linux/surface_aggregator/serial_hub.h
+++ b/include/linux/surface_aggregator/serial_hub.h
@@ -306,7 +306,7 @@ enum ssam_ssh_tc {
 	SSAM_SSH_TC_LPC = 0x0b,
 	SSAM_SSH_TC_TCL = 0x0c,
 	SSAM_SSH_TC_SFL = 0x0d,
-	SSAM_SSH_TC_KIP = 0x0e,
+	SSAM_SSH_TC_KIP = 0x0e, /* Manages detachable peripherals (Pro X/8 keyboard cover) */
 	SSAM_SSH_TC_EXT = 0x0f,
 	SSAM_SSH_TC_BLD = 0x10,
 	SSAM_SSH_TC_BAS = 0x11,	/* Detachment system (Surface Book 2/3). */
-- 
2.36.0

From b05a57a23fb0dce8c1be11eda511116493d1e114 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sun, 10 Oct 2021 23:56:23 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Add KIP device hub

Add a Surface System Aggregator Module (SSAM) client device hub for
hot-removable devices managed via the KIP subsystem.

The KIP subsystem (full name unknown, abbreviation has been obtained
through reverse engineering) is a subsystem that manages hot-removable
SSAM client devices. Specifically, it manages HID input devices
contained in the detachable keyboard cover of the Surface Pro 8 and
Surface Pro X.

To properly handle detachable devices, we need to remove their kernel
representation when the physical device has been detached and (re-)add
and (re-)initialize said representation when the physical device has
been (re-)attached. Note that we need to hot-remove those devices, as
communication (especially during event notifier unregistration) may time
out when the physical device is no longer present, which would lead to
an unnecessary delay. This delay might become problematic when devices
are detached and re-attached quickly.

The KIP subsystem handles a single group of devices (e.g. all devices
contained in the keyboard cover) and cannot handle devices individually.
Thus we model it as a client device hub, which removes all devices
contained under it once removal of the hub (e.g. keyboard cover) has
been detected and (re-)adds all devices once the physical hub device has
been (re-)attached.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../surface/surface_aggregator_registry.c     | 247 +++++++++++++++++-
 1 file changed, 245 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 9f630e890ff7..4838ce6519a6 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -514,6 +514,237 @@ static struct ssam_device_driver ssam_base_hub_driver = {
 };
 
 
+/* -- SSAM KIP-subsystem hub driver. ---------------------------------------- */
+
+/*
+ * Some devices may need a bit of time to be fully usable after being
+ * (re-)connected. This delay has been determined via experimentation.
+ */
+#define SSAM_KIP_UPDATE_CONNECT_DELAY		msecs_to_jiffies(250)
+
+#define SSAM_EVENT_KIP_CID_CONNECTION		0x2c
+
+enum ssam_kip_hub_state {
+	SSAM_KIP_HUB_UNINITIALIZED,
+	SSAM_KIP_HUB_CONNECTED,
+	SSAM_KIP_HUB_DISCONNECTED,
+};
+
+struct ssam_kip_hub {
+	struct ssam_device *sdev;
+
+	enum ssam_kip_hub_state state;
+	struct delayed_work update_work;
+
+	struct ssam_event_notifier notif;
+};
+
+SSAM_DEFINE_SYNC_REQUEST_R(__ssam_kip_get_connection_state, u8, {
+	.target_category = SSAM_SSH_TC_KIP,
+	.target_id       = 0x01,
+	.command_id      = 0x2c,
+	.instance_id     = 0x00,
+});
+
+static int ssam_kip_get_connection_state(struct ssam_kip_hub *hub, enum ssam_kip_hub_state *state)
+{
+	int status;
+	u8 connected;
+
+	status = ssam_retry(__ssam_kip_get_connection_state, hub->sdev->ctrl, &connected);
+	if (status < 0) {
+		dev_err(&hub->sdev->dev, "failed to query KIP connection state: %d\n", status);
+		return status;
+	}
+
+	*state = connected ? SSAM_KIP_HUB_CONNECTED : SSAM_KIP_HUB_DISCONNECTED;
+	return 0;
+}
+
+static ssize_t ssam_kip_hub_state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ssam_kip_hub *hub = dev_get_drvdata(dev);
+	const char *state;
+
+	switch (hub->state) {
+	case SSAM_KIP_HUB_UNINITIALIZED:
+		state = "uninitialized";
+		break;
+
+	case SSAM_KIP_HUB_CONNECTED:
+		state = "connected";
+		break;
+
+	case SSAM_KIP_HUB_DISCONNECTED:
+		state = "disconnected";
+		break;
+
+	default:
+		/*
+		 * Any value not handled in the above cases is invalid and
+		 * should never have been set. Thus this case should be
+		 * impossible to reach.
+		 */
+		WARN(1, "invalid KIP hub state: %d\n", hub->state);
+		state = "<invalid>";
+		break;
+	}
+
+	return sysfs_emit(buf, "%s\n", state);
+}
+
+static struct device_attribute ssam_kip_hub_attr_state =
+	__ATTR(state, 0444, ssam_kip_hub_state_show, NULL);
+
+static struct attribute *ssam_kip_hub_attrs[] = {
+	&ssam_kip_hub_attr_state.attr,
+	NULL,
+};
+
+static const struct attribute_group ssam_kip_hub_group = {
+	.attrs = ssam_kip_hub_attrs,
+};
+
+static int ssam_kip_hub_mark_hot_removed(struct device *dev, void *_data)
+{
+	struct ssam_device *sdev = to_ssam_device(dev);
+
+	if (is_ssam_device(dev))
+		ssam_device_mark_hot_removed(sdev);
+
+	return 0;
+}
+
+static void ssam_kip_hub_update_workfn(struct work_struct *work)
+{
+	struct ssam_kip_hub *hub = container_of(work, struct ssam_kip_hub, update_work.work);
+	struct fwnode_handle *node = dev_fwnode(&hub->sdev->dev);
+	enum ssam_kip_hub_state state;
+	int status = 0;
+
+	status = ssam_kip_get_connection_state(hub, &state);
+	if (status)
+		return;
+
+	if (hub->state == state)
+		return;
+	hub->state = state;
+
+	if (hub->state == SSAM_KIP_HUB_CONNECTED)
+		status = ssam_hub_register_clients(&hub->sdev->dev, hub->sdev->ctrl, node);
+	else
+		ssam_remove_clients(&hub->sdev->dev);
+
+	if (status)
+		dev_err(&hub->sdev->dev, "failed to update KIP-hub devices: %d\n", status);
+}
+
+static u32 ssam_kip_hub_notif(struct ssam_event_notifier *nf, const struct ssam_event *event)
+{
+	struct ssam_kip_hub *hub = container_of(nf, struct ssam_kip_hub, notif);
+	unsigned long delay;
+
+	if (event->command_id != SSAM_EVENT_KIP_CID_CONNECTION)
+		return 0;	/* Return "unhandled". */
+
+	if (event->length < 1) {
+		dev_err(&hub->sdev->dev, "unexpected payload size: %u\n", event->length);
+		return 0;
+	}
+
+	/* Mark devices as hot-removed before we remove any */
+	if (!event->data[0])
+		device_for_each_child_reverse(&hub->sdev->dev, NULL, ssam_kip_hub_mark_hot_removed);
+
+	/*
+	 * Delay update when KIP devices are being connected to give devices/EC
+	 * some time to set up.
+	 */
+	delay = event->data[0] ? SSAM_KIP_UPDATE_CONNECT_DELAY : 0;
+
+	schedule_delayed_work(&hub->update_work, delay);
+	return SSAM_NOTIF_HANDLED;
+}
+
+static int __maybe_unused ssam_kip_hub_resume(struct device *dev)
+{
+	struct ssam_kip_hub *hub = dev_get_drvdata(dev);
+
+	schedule_delayed_work(&hub->update_work, 0);
+	return 0;
+}
+static SIMPLE_DEV_PM_OPS(ssam_kip_hub_pm_ops, NULL, ssam_kip_hub_resume);
+
+static int ssam_kip_hub_probe(struct ssam_device *sdev)
+{
+	struct ssam_kip_hub *hub;
+	int status;
+
+	hub = devm_kzalloc(&sdev->dev, sizeof(*hub), GFP_KERNEL);
+	if (!hub)
+		return -ENOMEM;
+
+	hub->sdev = sdev;
+	hub->state = SSAM_KIP_HUB_UNINITIALIZED;
+
+	hub->notif.base.priority = INT_MAX;  /* This notifier should run first. */
+	hub->notif.base.fn = ssam_kip_hub_notif;
+	hub->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;
+	hub->notif.event.id.target_category = SSAM_SSH_TC_KIP,
+	hub->notif.event.id.instance = 0,
+	hub->notif.event.mask = SSAM_EVENT_MASK_TARGET;
+	hub->notif.event.flags = SSAM_EVENT_SEQUENCED;
+
+	INIT_DELAYED_WORK(&hub->update_work, ssam_kip_hub_update_workfn);
+
+	ssam_device_set_drvdata(sdev, hub);
+
+	status = ssam_device_notifier_register(sdev, &hub->notif);
+	if (status)
+		return status;
+
+	status = sysfs_create_group(&sdev->dev.kobj, &ssam_kip_hub_group);
+	if (status)
+		goto err;
+
+	schedule_delayed_work(&hub->update_work, 0);
+	return 0;
+
+err:
+	ssam_device_notifier_unregister(sdev, &hub->notif);
+	cancel_delayed_work_sync(&hub->update_work);
+	ssam_remove_clients(&sdev->dev);
+	return status;
+}
+
+static void ssam_kip_hub_remove(struct ssam_device *sdev)
+{
+	struct ssam_kip_hub *hub = ssam_device_get_drvdata(sdev);
+
+	sysfs_remove_group(&sdev->dev.kobj, &ssam_kip_hub_group);
+
+	ssam_device_notifier_unregister(sdev, &hub->notif);
+	cancel_delayed_work_sync(&hub->update_work);
+	ssam_remove_clients(&sdev->dev);
+}
+
+static const struct ssam_device_id ssam_kip_hub_match[] = {
+	{ SSAM_SDEV(KIP, 0x01, 0x00, 0x00) },
+	{ },
+};
+
+static struct ssam_device_driver ssam_kip_hub_driver = {
+	.probe = ssam_kip_hub_probe,
+	.remove = ssam_kip_hub_remove,
+	.match_table = ssam_kip_hub_match,
+	.driver = {
+		.name = "surface_kip_hub",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.pm = &ssam_kip_hub_pm_ops,
+	},
+};
+
+
 /* -- SSAM platform/meta-hub driver. ---------------------------------------- */
 
 static const struct acpi_device_id ssam_platform_hub_match[] = {
@@ -636,18 +867,30 @@ static int __init ssam_device_hub_init(void)
 
 	status = platform_driver_register(&ssam_platform_hub_driver);
 	if (status)
-		return status;
+		goto err_platform;
 
 	status = ssam_device_driver_register(&ssam_base_hub_driver);
 	if (status)
-		platform_driver_unregister(&ssam_platform_hub_driver);
+		goto err_base;
+
+	status = ssam_device_driver_register(&ssam_kip_hub_driver);
+	if (status)
+		goto err_kip;
 
+	return 0;
+
+err_kip:
+	ssam_device_driver_unregister(&ssam_base_hub_driver);
+err_base:
+	platform_driver_unregister(&ssam_platform_hub_driver);
+err_platform:
 	return status;
 }
 module_init(ssam_device_hub_init);
 
 static void __exit ssam_device_hub_exit(void)
 {
+	ssam_device_driver_unregister(&ssam_kip_hub_driver);
 	ssam_device_driver_unregister(&ssam_base_hub_driver);
 	platform_driver_unregister(&ssam_platform_hub_driver);
 }
-- 
2.36.0

From 0e443bc77964f90eed651cb32af45398060ba42e Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Wed, 27 Oct 2021 22:33:03 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Add support for
 keyboard cover on Surface Pro 8

Add support for the detachable keyboard cover on the Surface Pro 8.

The keyboard cover on the Surface Pro 8 is, unlike the keyboard covers
of earlier Surface Pro generations, handled via the Surface System
Aggregator Module (SSAM). The keyboard and touchpad (as well as other
HID input devices) of this cover are standard SSAM HID client devices
(just like keyboard and touchpad on e.g. the Surface Laptop 3 and 4),
however, some care needs to be taken as they can be physically detached
(similarly to the Surface Book 3). Specifically, the respective SSAM
client devices need to be removed when the keyboard cover has been
detached and (re-)initialized when the keyboard cover has been
(re-)attached.

On the Surface Pro 8, detachment of the keyboard cover (and by extension
its devices) is managed via the KIP subsystem. Therefore, said devices
need to be registered under the KIP device hub, which in turn will
remove and re-create/re-initialize those devices as needed.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 .../surface/surface_aggregator_registry.c     | 37 ++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 4838ce6519a6..c0e29c0514df 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -47,6 +47,12 @@ static const struct software_node ssam_node_hub_base = {
 	.parent = &ssam_node_root,
 };
 
+/* KIP device hub (connects keyboard cover devices on Surface Pro 8). */
+static const struct software_node ssam_node_hub_kip = {
+	.name = "ssam:01:0e:01:00:00",
+	.parent = &ssam_node_root,
+};
+
 /* AC adapter. */
 static const struct software_node ssam_node_bat_ac = {
 	.name = "ssam:01:02:01:01:01",
@@ -155,6 +161,30 @@ static const struct software_node ssam_node_hid_base_iid6 = {
 	.parent = &ssam_node_hub_base,
 };
 
+/* HID keyboard (KIP hub). */
+static const struct software_node ssam_node_hid_kip_keyboard = {
+	.name = "ssam:01:15:02:01:00",
+	.parent = &ssam_node_hub_kip,
+};
+
+/* HID pen stash (KIP hub; pen taken / stashed away evens). */
+static const struct software_node ssam_node_hid_kip_penstash = {
+	.name = "ssam:01:15:02:02:00",
+	.parent = &ssam_node_hub_kip,
+};
+
+/* HID touchpad (KIP hub). */
+static const struct software_node ssam_node_hid_kip_touchpad = {
+	.name = "ssam:01:15:02:03:00",
+	.parent = &ssam_node_hub_kip,
+};
+
+/* HID device instance 5 (KIP hub, unknown HID device). */
+static const struct software_node ssam_node_hid_kip_iid5 = {
+	.name = "ssam:01:15:02:05:00",
+	.parent = &ssam_node_hub_kip,
+};
+
 /*
  * Devices for 5th- and 6th-generations models:
  * - Surface Book 2,
@@ -230,10 +260,15 @@ static const struct software_node *ssam_node_group_sp7[] = {
 
 static const struct software_node *ssam_node_group_sp8[] = {
 	&ssam_node_root,
+	&ssam_node_hub_kip,
 	&ssam_node_bat_ac,
 	&ssam_node_bat_main,
 	&ssam_node_tmp_pprof,
-	/* TODO: Add support for keyboard cover. */
+	&ssam_node_hid_kip_keyboard,
+	&ssam_node_hid_kip_penstash,
+	&ssam_node_hid_kip_touchpad,
+	&ssam_node_hid_kip_iid5,
+	/* TODO: Add support for tablet mode switch. */
 	NULL,
 };
 
-- 
2.36.0

From f3ff67b118c39ab15a3443f953f93fa933c1d957 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Jun 2021 03:19:20 +0200
Subject: [PATCH] platform/surface: Add KIP tablet-mode switch

Add a driver providing a tablet-mode switch input device for Surface
models using the KIP subsystem to manage detachable peripherals.

The Surface Pro 8 has a detachable keyboard cover. Unlike the keyboard
covers of previous generation Surface Pro models, this cover is fully
handled by the Surface System Aggregator Module (SSAM). The SSAM KIP
subsystem (full name unknown, abbreviation found through reverse
engineering) provides notifications for mode changes of the cover.
Specifically, it allows us to know when the cover has been folded back,
detached, or whether it is in laptop mode.

The driver introduced with this change captures these events and
translates them to standard SW_TABLET_MODE input events.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 MAINTAINERS                                   |   6 +
 drivers/platform/surface/Kconfig              |  22 ++
 drivers/platform/surface/Makefile             |   1 +
 .../surface/surface_kip_tablet_switch.c       | 245 ++++++++++++++++++
 4 files changed, 274 insertions(+)
 create mode 100644 drivers/platform/surface/surface_kip_tablet_switch.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d9b2f1731ee0..4d83cd26e299 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12823,6 +12823,12 @@ L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
 F:	drivers/platform/surface/surface_hotplug.c
 
+MICROSOFT SURFACE KIP TABLET-MODE SWITCH
+M:	Maximilian Luz <luzmaximilian@gmail.com>
+L:	platform-driver-x86@vger.kernel.org
+S:	Maintained
+F:	drivers/platform/surface/surface_kip_tablet_switch.c
+
 MICROSOFT SURFACE PLATFORM PROFILE DRIVER
 M:	Maximilian Luz <luzmaximilian@gmail.com>
 L:	platform-driver-x86@vger.kernel.org
diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig
index 463f1ec5c14e..9c228090c35b 100644
--- a/drivers/platform/surface/Kconfig
+++ b/drivers/platform/surface/Kconfig
@@ -156,6 +156,28 @@ config SURFACE_HOTPLUG
 	  Select M or Y here, if you want to (fully) support hot-plugging of
 	  dGPU devices on the Surface Book 2 and/or 3 during D3cold.
 
+config SURFACE_KIP_TABLET_SWITCH
+	tristate "Surface KIP Tablet-Mode Switch Driver"
+	depends on SURFACE_AGGREGATOR
+	depends on SURFACE_AGGREGATOR_BUS
+	depends on INPUT
+	help
+	  Provides a tablet-mode switch input device on Microsoft Surface models
+	  using the KIP subsystem for detachable keyboards (e.g. keyboard
+	  covers).
+
+	  The KIP subsystem is used on newer Surface generations to handle
+	  detachable input peripherals, specifically the keyboard cover
+	  (containing keyboard and touchpad) on the Surface Pro 8. This module
+	  provides a driver to let user-space know when the device should be
+	  considered in tablet-mode due to the keyboard cover being detached or
+	  folded back (essentially signaling when the keyboard is not available
+	  for input). It does so by creating a tablet-mode switch input device,
+	  sending the standard SW_TABLET_MODE event on mode change.
+
+	  Select M or Y here, if you want to provide tablet-mode switch input
+	  events on the Surface Pro 8.
+
 config SURFACE_PLATFORM_PROFILE
 	tristate "Surface Platform Profile Driver"
 	depends on ACPI
diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile
index 32889482de55..6d9291c993c4 100644
--- a/drivers/platform/surface/Makefile
+++ b/drivers/platform/surface/Makefile
@@ -14,5 +14,6 @@ obj-$(CONFIG_SURFACE_AGGREGATOR_REGISTRY) += surface_aggregator_registry.o
 obj-$(CONFIG_SURFACE_DTX)		+= surface_dtx.o
 obj-$(CONFIG_SURFACE_GPE)		+= surface_gpe.o
 obj-$(CONFIG_SURFACE_HOTPLUG)		+= surface_hotplug.o
+obj-$(CONFIG_SURFACE_KIP_TABLET_SWITCH)	+= surface_kip_tablet_switch.o
 obj-$(CONFIG_SURFACE_PLATFORM_PROFILE)	+= surface_platform_profile.o
 obj-$(CONFIG_SURFACE_PRO3_BUTTON)	+= surfacepro3_button.o
diff --git a/drivers/platform/surface/surface_kip_tablet_switch.c b/drivers/platform/surface/surface_kip_tablet_switch.c
new file mode 100644
index 000000000000..458470067579
--- /dev/null
+++ b/drivers/platform/surface/surface_kip_tablet_switch.c
@@ -0,0 +1,245 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Surface System Aggregator Module (SSAM) tablet mode switch via KIP
+ * subsystem.
+ *
+ * Copyright (C) 2021 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+#include <linux/surface_aggregator/controller.h>
+#include <linux/surface_aggregator/device.h>
+
+#define SSAM_EVENT_KIP_CID_LID_STATE		0x1d
+
+enum ssam_kip_lid_state {
+	SSAM_KIP_LID_STATE_DISCONNECTED   = 0x01,
+	SSAM_KIP_LID_STATE_CLOSED         = 0x02,
+	SSAM_KIP_LID_STATE_LAPTOP         = 0x03,
+	SSAM_KIP_LID_STATE_FOLDED_CANVAS  = 0x04,
+	SSAM_KIP_LID_STATE_FOLDED_BACK    = 0x05,
+};
+
+struct ssam_kip_sw {
+	struct ssam_device *sdev;
+
+	enum ssam_kip_lid_state state;
+	struct work_struct update_work;
+	struct input_dev *mode_switch;
+
+	struct ssam_event_notifier notif;
+};
+
+SSAM_DEFINE_SYNC_REQUEST_R(__ssam_kip_get_lid_state, u8, {
+	.target_category = SSAM_SSH_TC_KIP,
+	.target_id       = 0x01,
+	.command_id      = 0x1d,
+	.instance_id     = 0x00,
+});
+
+static int ssam_kip_get_lid_state(struct ssam_kip_sw *sw, enum ssam_kip_lid_state *state)
+{
+	int status;
+	u8 raw;
+
+	status = ssam_retry(__ssam_kip_get_lid_state, sw->sdev->ctrl, &raw);
+	if (status < 0) {
+		dev_err(&sw->sdev->dev, "failed to query KIP lid state: %d\n", status);
+		return status;
+	}
+
+	*state = raw;
+	return 0;
+}
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ssam_kip_sw *sw = dev_get_drvdata(dev);
+	const char *state;
+
+	switch (sw->state) {
+	case SSAM_KIP_LID_STATE_DISCONNECTED:
+		state = "disconnected";
+		break;
+
+	case SSAM_KIP_LID_STATE_CLOSED:
+		state = "closed";
+		break;
+
+	case SSAM_KIP_LID_STATE_LAPTOP:
+		state = "laptop";
+		break;
+
+	case SSAM_KIP_LID_STATE_FOLDED_CANVAS:
+		state = "folded-canvas";
+		break;
+
+	case SSAM_KIP_LID_STATE_FOLDED_BACK:
+		state = "folded-back";
+		break;
+
+	default:
+		state = "<unknown>";
+		dev_warn(dev, "unknown KIP lid state: %d\n", sw->state);
+		break;
+	}
+
+	return sysfs_emit(buf, "%s\n", state);
+}
+static DEVICE_ATTR_RO(state);
+
+static struct attribute *ssam_kip_sw_attrs[] = {
+	&dev_attr_state.attr,
+	NULL,
+};
+
+static const struct attribute_group ssam_kip_sw_group = {
+	.attrs = ssam_kip_sw_attrs,
+};
+
+static void ssam_kip_sw_update_workfn(struct work_struct *work)
+{
+	struct ssam_kip_sw *sw = container_of(work, struct ssam_kip_sw, update_work);
+	enum ssam_kip_lid_state state;
+	int tablet, status;
+
+	status = ssam_kip_get_lid_state(sw, &state);
+	if (status)
+		return;
+
+	if (sw->state == state)
+		return;
+	sw->state = state;
+
+	/* Send SW_TABLET_MODE event. */
+	tablet = state != SSAM_KIP_LID_STATE_LAPTOP;
+	input_report_switch(sw->mode_switch, SW_TABLET_MODE, tablet);
+	input_sync(sw->mode_switch);
+}
+
+static u32 ssam_kip_sw_notif(struct ssam_event_notifier *nf, const struct ssam_event *event)
+{
+	struct ssam_kip_sw *sw = container_of(nf, struct ssam_kip_sw, notif);
+
+	if (event->command_id != SSAM_EVENT_KIP_CID_LID_STATE)
+		return 0;	/* Return "unhandled". */
+
+	if (event->length < 1) {
+		dev_err(&sw->sdev->dev, "unexpected payload size: %u\n", event->length);
+		return 0;
+	}
+
+	schedule_work(&sw->update_work);
+	return SSAM_NOTIF_HANDLED;
+}
+
+static int __maybe_unused ssam_kip_sw_resume(struct device *dev)
+{
+	struct ssam_kip_sw *sw = dev_get_drvdata(dev);
+
+	schedule_work(&sw->update_work);
+	return 0;
+}
+static SIMPLE_DEV_PM_OPS(ssam_kip_sw_pm_ops, NULL, ssam_kip_sw_resume);
+
+static int ssam_kip_sw_probe(struct ssam_device *sdev)
+{
+	struct ssam_kip_sw *sw;
+	int tablet, status;
+
+	sw = devm_kzalloc(&sdev->dev, sizeof(*sw), GFP_KERNEL);
+	if (!sw)
+		return -ENOMEM;
+
+	sw->sdev = sdev;
+	INIT_WORK(&sw->update_work, ssam_kip_sw_update_workfn);
+
+	ssam_device_set_drvdata(sdev, sw);
+
+	/* Get initial state. */
+	status = ssam_kip_get_lid_state(sw, &sw->state);
+	if (status)
+		return status;
+
+	/* Set up tablet mode switch. */
+	sw->mode_switch = devm_input_allocate_device(&sdev->dev);
+	if (!sw->mode_switch)
+		return -ENOMEM;
+
+	sw->mode_switch->name = "Microsoft Surface KIP Tablet Mode Switch";
+	sw->mode_switch->phys = "ssam/01:0e:01:00:01/input0";
+	sw->mode_switch->id.bustype = BUS_HOST;
+	sw->mode_switch->dev.parent = &sdev->dev;
+
+	tablet = sw->state != SSAM_KIP_LID_STATE_LAPTOP;
+	input_set_capability(sw->mode_switch, EV_SW, SW_TABLET_MODE);
+	input_report_switch(sw->mode_switch, SW_TABLET_MODE, tablet);
+
+	status = input_register_device(sw->mode_switch);
+	if (status)
+		return status;
+
+	/* Set up notifier. */
+	sw->notif.base.priority = 0;
+	sw->notif.base.fn = ssam_kip_sw_notif;
+	sw->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;
+	sw->notif.event.id.target_category = SSAM_SSH_TC_KIP,
+	sw->notif.event.id.instance = 0,
+	sw->notif.event.mask = SSAM_EVENT_MASK_TARGET;
+	sw->notif.event.flags = SSAM_EVENT_SEQUENCED;
+
+	status = ssam_device_notifier_register(sdev, &sw->notif);
+	if (status)
+		return status;
+
+	status = sysfs_create_group(&sdev->dev.kobj, &ssam_kip_sw_group);
+	if (status)
+		goto err;
+
+	/* We might have missed events during setup, so check again. */
+	schedule_work(&sw->update_work);
+	return 0;
+
+err:
+	ssam_device_notifier_unregister(sdev, &sw->notif);
+	cancel_work_sync(&sw->update_work);
+	return status;
+}
+
+static void ssam_kip_sw_remove(struct ssam_device *sdev)
+{
+	struct ssam_kip_sw *sw = ssam_device_get_drvdata(sdev);
+
+	sysfs_remove_group(&sdev->dev.kobj, &ssam_kip_sw_group);
+
+	ssam_device_notifier_unregister(sdev, &sw->notif);
+	cancel_work_sync(&sw->update_work);
+}
+
+static const struct ssam_device_id ssam_kip_sw_match[] = {
+	{ SSAM_SDEV(KIP, 0x01, 0x00, 0x01) },
+	{ },
+};
+MODULE_DEVICE_TABLE(ssam, ssam_kip_sw_match);
+
+static struct ssam_device_driver ssam_kip_sw_driver = {
+	.probe = ssam_kip_sw_probe,
+	.remove = ssam_kip_sw_remove,
+	.match_table = ssam_kip_sw_match,
+	.driver = {
+		.name = "surface_kip_tablet_mode_switch",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.pm = &ssam_kip_sw_pm_ops,
+	},
+};
+module_ssam_device_driver(ssam_kip_sw_driver);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("Tablet mode switch driver for Surface devices using KIP subsystem");
+MODULE_LICENSE("GPL");
-- 
2.36.0

From 228072592809b63575ea69a4d2bb9192beb74b02 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Wed, 27 Oct 2021 22:33:03 +0200
Subject: [PATCH] platform/surface: aggregator_registry: Add support for tablet
 mode switch on Surface Pro 8

Add a KIP subsystem tablet-mode switch device for the Surface Pro 8.
The respective driver for this device provides SW_TABLET_MODE input
events for user-space based on the state of the keyboard cover (e.g.
detached, folded-back, normal/laptop mode).

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam
---
 drivers/platform/surface/surface_aggregator_registry.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index c0e29c0514df..eaf0054627a5 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -77,6 +77,12 @@ static const struct software_node ssam_node_tmp_pprof = {
 	.parent = &ssam_node_root,
 };
 
+/* Tablet-mode switch via KIP subsystem. */
+static const struct software_node ssam_node_kip_tablet_switch = {
+	.name = "ssam:01:0e:01:00:01",
+	.parent = &ssam_node_root,
+};
+
 /* DTX / detachment-system device (Surface Book 3). */
 static const struct software_node ssam_node_bas_dtx = {
 	.name = "ssam:01:11:01:00:00",
@@ -264,11 +270,11 @@ static const struct software_node *ssam_node_group_sp8[] = {
 	&ssam_node_bat_ac,
 	&ssam_node_bat_main,
 	&ssam_node_tmp_pprof,
+	&ssam_node_kip_tablet_switch,
 	&ssam_node_hid_kip_keyboard,
 	&ssam_node_hid_kip_penstash,
 	&ssam_node_hid_kip_touchpad,
 	&ssam_node_hid_kip_iid5,
-	/* TODO: Add support for tablet mode switch. */
 	NULL,
 };
 
-- 
2.36.0

From 82ae885ad1824b149d18d7ac938988d9a5b279d5 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sat, 25 Jul 2020 17:19:53 +0200
Subject: [PATCH] i2c: acpi: Implement RawBytes read access

Microsoft Surface Pro 4 and Book 1 devices access the MSHW0030 I2C
device via a generic serial bus operation region and RawBytes read
access. On the Surface Book 1, this access is required to turn on (and
off) the discrete GPU.

Multiple things are to note here:

a) The RawBytes access is device/driver dependent. The ACPI
   specification states:

   > Raw accesses assume that the writer has knowledge of the bus that
   > the access is made over and the device that is being accessed. The
   > protocol may only ensure that the buffer is transmitted to the
   > appropriate driver, but the driver must be able to interpret the
   > buffer to communicate to a register.

   Thus this implementation may likely not work on other devices
   accessing I2C via the RawBytes accessor type.

b) The MSHW0030 I2C device is an HID-over-I2C device which seems to
   serve multiple functions:

   1. It is the main access point for the legacy-type Surface Aggregator
      Module (also referred to as SAM-over-HID, as opposed to the newer
      SAM-over-SSH/UART). It has currently not been determined on how
      support for the legacy SAM should be implemented. Likely via a
      custom HID driver.

   2. It seems to serve as the HID device for the Integrated Sensor Hub.
      This might complicate matters with regards to implementing a
      SAM-over-HID driver required by legacy SAM.

In light of this, the simplest approach has been chosen for now.
However, it may make more sense regarding breakage and compatibility to
either provide functionality for replacing or enhancing the default
operation region handler via some additional API functions, or even to
completely blacklist MSHW0030 from the I2C core and provide a custom
driver for it.

Replacing/enhancing the default operation region handler would, however,
either require some sort of secondary driver and access point for it,
from which the new API functions would be called and the new handler
(part) would be installed, or hard-coding them via some sort of
quirk-like interface into the I2C core.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-sam-over-hid
---
 drivers/i2c/i2c-core-acpi.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 85ed4c1d4924..942c1c9a4ea5 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -624,6 +624,28 @@ static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
 	return (ret == 1) ? 0 : -EIO;
 }
 
+static int acpi_gsb_i2c_write_raw_bytes(struct i2c_client *client,
+		u8 *data, u8 data_len)
+{
+	struct i2c_msg msgs[1];
+	int ret = AE_OK;
+
+	msgs[0].addr = client->addr;
+	msgs[0].flags = client->flags;
+	msgs[0].len = data_len + 1;
+	msgs[0].buf = data;
+
+	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+
+	if (ret < 0) {
+		dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
+		return ret;
+	}
+
+	/* 1 transfer must have completed successfully */
+	return (ret == 1) ? 0 : -EIO;
+}
+
 static acpi_status
 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
 			u32 bits, u64 *value64,
@@ -725,6 +747,19 @@ i2c_acpi_space_handler(u32 function, acpi_physical_address command,
 		}
 		break;
 
+	case ACPI_GSB_ACCESS_ATTRIB_RAW_BYTES:
+		if (action == ACPI_READ) {
+			dev_warn(&adapter->dev,
+				 "protocol 0x%02x not supported for client 0x%02x\n",
+				 accessor_type, client->addr);
+			ret = AE_BAD_PARAMETER;
+			goto err;
+		} else {
+			status = acpi_gsb_i2c_write_raw_bytes(client,
+					gsb->data, info->access_length);
+		}
+		break;
+
 	default:
 		dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
 			 accessor_type, client->addr);
-- 
2.36.0

From 704aa16555465b0f83471aa84c3a5be3c7133d67 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Sat, 13 Feb 2021 16:41:18 +0100
Subject: [PATCH] platform/surface: Add driver for Surface Book 1 dGPU switch

Add driver exposing the discrete GPU power-switch of the  Microsoft
Surface Book 1 to user-space.

On the Surface Book 1, the dGPU power is controlled via the Surface
System Aggregator Module (SAM). The specific SAM-over-HID command for
this is exposed via ACPI. This module provides a simple driver exposing
the ACPI call via a sysfs parameter to user-space, so that users can
easily power-on/-off the dGPU.

Patchset: surface-sam-over-hid
---
 drivers/platform/surface/Kconfig              |   7 +
 drivers/platform/surface/Makefile             |   1 +
 .../surface/surfacebook1_dgpu_switch.c        | 162 ++++++++++++++++++
 3 files changed, 170 insertions(+)
 create mode 100644 drivers/platform/surface/surfacebook1_dgpu_switch.c

diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig
index 9c228090c35b..c6c3c9bd3b57 100644
--- a/drivers/platform/surface/Kconfig
+++ b/drivers/platform/surface/Kconfig
@@ -106,6 +106,13 @@ config SURFACE_AGGREGATOR_REGISTRY
 	  the respective client devices. Drivers for these devices still need to
 	  be selected via the other options.
 
+config SURFACE_BOOK1_DGPU_SWITCH
+	tristate "Surface Book 1 dGPU Switch Driver"
+	depends on SYSFS
+	help
+	  This driver provides a sysfs switch to set the power-state of the
+	  discrete GPU found on the Microsoft Surface Book 1.
+
 config SURFACE_DTX
 	tristate "Surface DTX (Detachment System) Driver"
 	depends on SURFACE_AGGREGATOR
diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile
index 6d9291c993c4..9eb3a7e6382c 100644
--- a/drivers/platform/surface/Makefile
+++ b/drivers/platform/surface/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_SURFACE_ACPI_NOTIFY)	+= surface_acpi_notify.o
 obj-$(CONFIG_SURFACE_AGGREGATOR)	+= aggregator/
 obj-$(CONFIG_SURFACE_AGGREGATOR_CDEV)	+= surface_aggregator_cdev.o
 obj-$(CONFIG_SURFACE_AGGREGATOR_REGISTRY) += surface_aggregator_registry.o
+obj-$(CONFIG_SURFACE_BOOK1_DGPU_SWITCH) += surfacebook1_dgpu_switch.o
 obj-$(CONFIG_SURFACE_DTX)		+= surface_dtx.o
 obj-$(CONFIG_SURFACE_GPE)		+= surface_gpe.o
 obj-$(CONFIG_SURFACE_HOTPLUG)		+= surface_hotplug.o
diff --git a/drivers/platform/surface/surfacebook1_dgpu_switch.c b/drivers/platform/surface/surfacebook1_dgpu_switch.c
new file mode 100644
index 000000000000..8b816ed8f35c
--- /dev/null
+++ b/drivers/platform/surface/surfacebook1_dgpu_switch.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__
+
+
+static const guid_t dgpu_sw_guid = GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4,
+	0x95, 0xed, 0xab, 0x16, 0x65, 0x49, 0x80, 0x35);
+
+#define DGPUSW_ACPI_PATH_DSM	"\\_SB_.PCI0.LPCB.EC0_.VGBI"
+#define DGPUSW_ACPI_PATH_HGON	"\\_SB_.PCI0.RP05.HGON"
+#define DGPUSW_ACPI_PATH_HGOF	"\\_SB_.PCI0.RP05.HGOF"
+
+
+static int sb1_dgpu_sw_dsmcall(void)
+{
+	union acpi_object *ret;
+	acpi_handle handle;
+	acpi_status status;
+
+	status = acpi_get_handle(NULL, DGPUSW_ACPI_PATH_DSM, &handle);
+	if (status)
+		return -EINVAL;
+
+	ret = acpi_evaluate_dsm_typed(handle, &dgpu_sw_guid, 1, 1, NULL, ACPI_TYPE_BUFFER);
+	if (!ret)
+		return -EINVAL;
+
+	ACPI_FREE(ret);
+	return 0;
+}
+
+static int sb1_dgpu_sw_hgon(void)
+{
+	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
+	acpi_status status;
+
+	status = acpi_evaluate_object(NULL, DGPUSW_ACPI_PATH_HGON, NULL, &buf);
+	if (status) {
+		pr_err("failed to run HGON: %d\n", status);
+		return -EINVAL;
+	}
+
+	if (buf.pointer)
+		ACPI_FREE(buf.pointer);
+
+	pr_info("turned-on dGPU via HGON\n");
+	return 0;
+}
+
+static int sb1_dgpu_sw_hgof(void)
+{
+	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
+	acpi_status status;
+
+	status = acpi_evaluate_object(NULL, DGPUSW_ACPI_PATH_HGOF, NULL, &buf);
+	if (status) {
+		pr_err("failed to run HGOF: %d\n", status);
+		return -EINVAL;
+	}
+
+	if (buf.pointer)
+		ACPI_FREE(buf.pointer);
+
+	pr_info("turned-off dGPU via HGOF\n");
+	return 0;
+}
+
+
+static ssize_t dgpu_dsmcall_store(struct device *dev, struct device_attribute *attr,
+				  const char *buf, size_t len)
+{
+	int status, value;
+
+	status = kstrtoint(buf, 0, &value);
+	if (status < 0)
+		return status;
+
+	if (value != 1)
+		return -EINVAL;
+
+	status = sb1_dgpu_sw_dsmcall();
+
+	return status < 0 ? status : len;
+}
+
+static ssize_t dgpu_power_store(struct device *dev, struct device_attribute *attr,
+				const char *buf, size_t len)
+{
+	bool power;
+	int status;
+
+	status = kstrtobool(buf, &power);
+	if (status < 0)
+		return status;
+
+	if (power)
+		status = sb1_dgpu_sw_hgon();
+	else
+		status = sb1_dgpu_sw_hgof();
+
+	return status < 0 ? status : len;
+}
+
+static DEVICE_ATTR_WO(dgpu_dsmcall);
+static DEVICE_ATTR_WO(dgpu_power);
+
+static struct attribute *sb1_dgpu_sw_attrs[] = {
+	&dev_attr_dgpu_dsmcall.attr,
+	&dev_attr_dgpu_power.attr,
+	NULL,
+};
+
+static const struct attribute_group sb1_dgpu_sw_attr_group = {
+	.attrs = sb1_dgpu_sw_attrs,
+};
+
+
+static int sb1_dgpu_sw_probe(struct platform_device *pdev)
+{
+	return sysfs_create_group(&pdev->dev.kobj, &sb1_dgpu_sw_attr_group);
+}
+
+static int sb1_dgpu_sw_remove(struct platform_device *pdev)
+{
+	sysfs_remove_group(&pdev->dev.kobj, &sb1_dgpu_sw_attr_group);
+	return 0;
+}
+
+/*
+ * The dGPU power seems to be actually handled by MSHW0040. However, that is
+ * also the power-/volume-button device with a mainline driver. So let's use
+ * MSHW0041 instead for now, which seems to be the LTCH (latch/DTX) device.
+ */
+static const struct acpi_device_id sb1_dgpu_sw_match[] = {
+	{ "MSHW0041", },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, sb1_dgpu_sw_match);
+
+static struct platform_driver sb1_dgpu_sw = {
+	.probe = sb1_dgpu_sw_probe,
+	.remove = sb1_dgpu_sw_remove,
+	.driver = {
+		.name = "surfacebook1_dgpu_switch",
+		.acpi_match_table = sb1_dgpu_sw_match,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+module_platform_driver(sb1_dgpu_sw);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("Discrete GPU Power-Switch for Surface Book 1");
+MODULE_LICENSE("GPL");
-- 
2.36.0

From 5a6d26ae3ff1334f0540aef76b28c596ebb67d81 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Wed, 27 Oct 2021 00:56:11 +0200
Subject: [PATCH] platform/surface: gpe: Add support for Surface Pro 8

The new Surface Pro 8 uses GPEs for lid events as well. Add an entry for
that so that the lid can be used to wake the device. Note that this is a
device with a keyboard type cover, where this acts as the "lid".

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-gpe
---
 drivers/platform/surface/surface_gpe.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/platform/surface/surface_gpe.c b/drivers/platform/surface/surface_gpe.c
index c1775db29efb..ec66fde28e75 100644
--- a/drivers/platform/surface/surface_gpe.c
+++ b/drivers/platform/surface/surface_gpe.c
@@ -99,6 +99,14 @@ static const struct dmi_system_id dmi_lid_device_table[] = {
 		},
 		.driver_data = (void *)lid_device_props_l4D,
 	},
+	{
+		.ident = "Surface Pro 8",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Surface Pro 8"),
+		},
+		.driver_data = (void *)lid_device_props_l4B,
+	},
 	{
 		.ident = "Surface Book 1",
 		.matches = {
-- 
2.36.0

From 8944aec8973646c474c14bd6763adee38f0430a3 Mon Sep 17 00:00:00 2001
From: Sachi King <nakato@nakato.io>
Date: Tue, 5 Oct 2021 00:05:09 +1100
Subject: [PATCH] Input: soc_button_array - support AMD variant Surface devices

The power button on the AMD variant of the Surface Laptop uses the
same MSHW0040 device ID as the 5th and later generation of Surface
devices, however they report 0 for their OEM platform revision.  As the
_DSM does not exist on the devices requiring special casing, check for
the existance of the _DSM to determine if soc_button_array should be
loaded.

Fixes: c394159310d0 ("Input: soc_button_array - add support for newer surface devices")
Co-developed-by: Maximilian Luz <luzmaximilian@gmail.com>

Signed-off-by: Sachi King <nakato@nakato.io>
Patchset: surface-button
---
 drivers/input/misc/soc_button_array.c | 33 +++++++--------------------
 1 file changed, 8 insertions(+), 25 deletions(-)

diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c
index cb6ec59a045d..4e8944f59def 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -474,8 +474,8 @@ static const struct soc_device_data soc_device_INT33D3 = {
  * Both, the Surface Pro 4 (surfacepro3_button.c) and the above mentioned
  * devices use MSHW0040 for power and volume buttons, however the way they
  * have to be addressed differs. Make sure that we only load this drivers
- * for the correct devices by checking the OEM Platform Revision provided by
- * the _DSM method.
+ * for the correct devices by checking if the OEM Platform Revision DSM call
+ * exists.
  */
 #define MSHW0040_DSM_REVISION		0x01
 #define MSHW0040_DSM_GET_OMPR		0x02	// get OEM Platform Revision
@@ -486,31 +486,14 @@ static const guid_t MSHW0040_DSM_UUID =
 static int soc_device_check_MSHW0040(struct device *dev)
 {
 	acpi_handle handle = ACPI_HANDLE(dev);
-	union acpi_object *result;
-	u64 oem_platform_rev = 0;	// valid revisions are nonzero
-
-	// get OEM platform revision
-	result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
-					 MSHW0040_DSM_REVISION,
-					 MSHW0040_DSM_GET_OMPR, NULL,
-					 ACPI_TYPE_INTEGER);
-
-	if (result) {
-		oem_platform_rev = result->integer.value;
-		ACPI_FREE(result);
-	}
-
-	/*
-	 * If the revision is zero here, the _DSM evaluation has failed. This
-	 * indicates that we have a Pro 4 or Book 1 and this driver should not
-	 * be used.
-	 */
-	if (oem_platform_rev == 0)
-		return -ENODEV;
+	bool exists;
 
-	dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev);
+	// check if OEM platform revision DSM call exists
+	exists = acpi_check_dsm(handle, &MSHW0040_DSM_UUID,
+				MSHW0040_DSM_REVISION,
+				BIT(MSHW0040_DSM_GET_OMPR));
 
-	return 0;
+	return exists ? 0 : -ENODEV;
 }
 
 /*
-- 
2.36.0

From 421af81b0297af32e058cd79dcf3073eb3cf51fa Mon Sep 17 00:00:00 2001
From: Sachi King <nakato@nakato.io>
Date: Tue, 5 Oct 2021 00:22:57 +1100
Subject: [PATCH] platform/surface: surfacepro3_button: don't load on amd
 variant

The AMD variant of the Surface Laptop report 0 for their OEM platform
revision.  The Surface devices that require the surfacepro3_button
driver do not have the _DSM that gets the OEM platform revision.  If the
method does not exist, load surfacepro3_button.

Fixes: 64dd243d7356 ("platform/x86: surfacepro3_button: Fix device check")
Co-developed-by: Maximilian Luz <luzmaximilian@gmail.com>

Signed-off-by: Sachi King <nakato@nakato.io>
Patchset: surface-button
---
 drivers/platform/surface/surfacepro3_button.c | 30 ++++---------------
 1 file changed, 6 insertions(+), 24 deletions(-)

diff --git a/drivers/platform/surface/surfacepro3_button.c b/drivers/platform/surface/surfacepro3_button.c
index 242fb690dcaf..30eea54dbb47 100644
--- a/drivers/platform/surface/surfacepro3_button.c
+++ b/drivers/platform/surface/surfacepro3_button.c
@@ -149,7 +149,8 @@ static int surface_button_resume(struct device *dev)
 /*
  * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
  * ID (MSHW0040) for the power/volume buttons. Make sure this is the right
- * device by checking for the _DSM method and OEM Platform Revision.
+ * device by checking for the _DSM method and OEM Platform Revision DSM
+ * function.
  *
  * Returns true if the driver should bind to this device, i.e. the device is
  * either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
@@ -157,30 +158,11 @@ static int surface_button_resume(struct device *dev)
 static bool surface_button_check_MSHW0040(struct acpi_device *dev)
 {
 	acpi_handle handle = dev->handle;
-	union acpi_object *result;
-	u64 oem_platform_rev = 0;	// valid revisions are nonzero
-
-	// get OEM platform revision
-	result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
-					 MSHW0040_DSM_REVISION,
-					 MSHW0040_DSM_GET_OMPR,
-					 NULL, ACPI_TYPE_INTEGER);
-
-	/*
-	 * If evaluating the _DSM fails, the method is not present. This means
-	 * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
-	 * should use this driver. We use revision 0 indicating it is
-	 * unavailable.
-	 */
-
-	if (result) {
-		oem_platform_rev = result->integer.value;
-		ACPI_FREE(result);
-	}
-
-	dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
 
-	return oem_platform_rev == 0;
+	// make sure that OEM platform revision DSM call does not exist
+	return !acpi_check_dsm(handle, &MSHW0040_DSM_UUID,
+			       MSHW0040_DSM_REVISION,
+			       BIT(MSHW0040_DSM_GET_OMPR));
 }
 
 
-- 
2.36.0

From 734da7d8f5beb9be996ba99a80f7e603b72130ab Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Thu, 24 Feb 2022 12:02:40 +0100
Subject: [PATCH] Input: soc_button_array - add support for Microsoft Surface 3
 (MSHW0028) buttons

The drivers/platform/surface/surface3_button.c code is alsmost a 1:1 copy
of the soc_button_array code.

The only big difference is that it binds to an i2c_client rather then to
a platform_device. The cause of this is the ACPI resources for the MSHW0028
device containing a bogus I2cSerialBusV2 resource which causes the kernel
to instantiate an i2c_client for it instead of a platform_device.

Add "MSHW0028" to the ignore_serial_bus_ids[] list in drivers/apci/scan.c,
so that a platform_device will be instantiated and add support for
the MSHW0028 HID to soc_button_array.

This fully replaces surface3_button, which will be removed in a separate
commit (since it binds to the now no longer created i2c_client it no
longer does anyyhing after this commit).

Note the MSHW0028 id is used by Microsoft to describe the tablet buttons on
both the Surface 3 and the Surface 3 Pro and the actual API/implementation
for the Surface 3 Pro is quite different. The changes in this commit should
not impact the separate surfacepro3_button driver:

1. Because of the bogus I2cSerialBusV2 resource problem that driver binds
   to the acpi_device itself, so instantiating a platform_device instead of
   an i2c_client does not matter.

2. The soc_button_array driver will not bind to the MSHW0028 device on
   the Surface 3 Pro, because it has no GPIO resources.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com
Patchset: surface-button
---
 drivers/acpi/scan.c                   |  5 +++++
 drivers/input/misc/soc_button_array.c | 24 +++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 8b2e5ef15559..c82b1bfa1c3d 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1753,6 +1753,11 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
 	 */
 		{"BCM4752", },
 		{"LNV4752", },
+	/*
+	 * Some ACPI devs contain SerialBus resources even though they are not
+	 * attached to a serial bus at all.
+	 */
+		{"MSHW0028", },
 		{}
 	};
 
diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c
index 4e8944f59def..f044c731c6a9 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -469,6 +469,27 @@ static const struct soc_device_data soc_device_INT33D3 = {
 	.button_info = soc_button_INT33D3,
 };
 
+/*
+ * Button info for Microsoft Surface 3 (non pro), this is indentical to
+ * the PNP0C40 info except that the home button is active-high.
+ *
+ * The Surface 3 Pro also has a MSHW0028 ACPI device, but that uses a custom
+ * version of the drivers/platform/x86/intel/hid.c 5 button array ACPI API
+ * instead. A check() callback is not necessary though as the Surface 3 Pro
+ * MSHW0028 ACPI device's resource table does not contain any GPIOs.
+ */
+static const struct soc_button_info soc_button_MSHW0028[] = {
+	{ "power", 0, EV_KEY, KEY_POWER, false, true, true },
+	{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true, false },
+	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true },
+	{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false, true },
+	{ }
+};
+
+static const struct soc_device_data soc_device_MSHW0028 = {
+	.button_info = soc_button_MSHW0028,
+};
+
 /*
  * Special device check for Surface Book 2 and Surface Pro (2017).
  * Both, the Surface Pro 4 (surfacepro3_button.c) and the above mentioned
@@ -518,7 +539,8 @@ static const struct acpi_device_id soc_button_acpi_match[] = {
 	{ "ID9001", (unsigned long)&soc_device_INT33D3 },
 	{ "ACPI0011", 0 },
 
-	/* Microsoft Surface Devices (5th and 6th generation) */
+	/* Microsoft Surface Devices (3th, 5th and 6th generation) */
+	{ "MSHW0028", (unsigned long)&soc_device_MSHW0028 },
 	{ "MSHW0040", (unsigned long)&soc_device_MSHW0040 },
 
 	{ }
-- 
2.36.0

From 33b3e3c489a43b4c71d5886e10af33473a939ca9 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Thu, 24 Feb 2022 12:02:41 +0100
Subject: [PATCH] platform/surface: Remove Surface 3 Button driver

The Surface 3 buttons are now handled by the generic soc_button_array
driver. As part of adding support to soc_button_array the ACPI code
now instantiates a platform_device rather then an i2c_client so there
no longer is an i2c_client for this driver to bind to.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com
Patchset: surface-button
---
 drivers/platform/surface/Kconfig           |   7 -
 drivers/platform/surface/Makefile          |   1 -
 drivers/platform/surface/surface3_button.c | 247 ---------------------
 3 files changed, 255 deletions(-)
 delete mode 100644 drivers/platform/surface/surface3_button.c

diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig
index c6c3c9bd3b57..df387ac34a79 100644
--- a/drivers/platform/surface/Kconfig
+++ b/drivers/platform/surface/Kconfig
@@ -28,13 +28,6 @@ config SURFACE3_WMI
 	  To compile this driver as a module, choose M here: the module will
 	  be called surface3-wmi.
 
-config SURFACE_3_BUTTON
-	tristate "Power/home/volume buttons driver for Microsoft Surface 3 tablet"
-	depends on ACPI
-	depends on KEYBOARD_GPIO && I2C
-	help
-	  This driver handles the power/home/volume buttons on the Microsoft Surface 3 tablet.
-
 config SURFACE_3_POWER_OPREGION
 	tristate "Surface 3 battery platform operation region support"
 	depends on ACPI
diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile
index 9eb3a7e6382c..e4791b47f561 100644
--- a/drivers/platform/surface/Makefile
+++ b/drivers/platform/surface/Makefile
@@ -5,7 +5,6 @@
 #
 
 obj-$(CONFIG_SURFACE3_WMI)		+= surface3-wmi.o
-obj-$(CONFIG_SURFACE_3_BUTTON)		+= surface3_button.o
 obj-$(CONFIG_SURFACE_3_POWER_OPREGION)	+= surface3_power.o
 obj-$(CONFIG_SURFACE_ACPI_NOTIFY)	+= surface_acpi_notify.o
 obj-$(CONFIG_SURFACE_AGGREGATOR)	+= aggregator/
diff --git a/drivers/platform/surface/surface3_button.c b/drivers/platform/surface/surface3_button.c
deleted file mode 100644
index 48d77e7aae76..000000000000
--- a/drivers/platform/surface/surface3_button.c
+++ /dev/null
@@ -1,247 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Supports for the button array on the Surface tablets.
- *
- * (C) Copyright 2016 Red Hat, Inc
- *
- * Based on soc_button_array.c:
- *
- * {C} Copyright 2014 Intel Corporation
- */
-
-#include <linux/module.h>
-#include <linux/input.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/i2c.h>
-#include <linux/slab.h>
-#include <linux/acpi.h>
-#include <linux/gpio/consumer.h>
-#include <linux/gpio_keys.h>
-#include <linux/gpio.h>
-#include <linux/platform_device.h>
-
-
-#define SURFACE_BUTTON_OBJ_NAME		"TEV2"
-#define MAX_NBUTTONS			4
-
-/*
- * Some of the buttons like volume up/down are auto repeat, while others
- * are not. To support both, we register two platform devices, and put
- * buttons into them based on whether the key should be auto repeat.
- */
-#define BUTTON_TYPES			2
-
-/*
- * Power button, Home button, Volume buttons support is supposed to
- * be covered by drivers/input/misc/soc_button_array.c, which is implemented
- * according to "Windows ACPI Design Guide for SoC Platforms".
- * However surface 3 seems not to obey the specs, instead it uses
- * device TEV2(MSHW0028) for declaring the GPIOs. The gpios are also slightly
- * different in which the Home button is active high.
- * Compared to surfacepro3_button.c which also handles MSHW0028, the Surface 3
- * is a reduce platform and thus uses GPIOs, not ACPI events.
- * We choose an I2C driver here because we need to access the resources
- * declared under the device node, while surfacepro3_button.c only needs
- * the ACPI companion node.
- */
-static const struct acpi_device_id surface3_acpi_match[] = {
-	{ "MSHW0028", 0 },
-	{ }
-};
-MODULE_DEVICE_TABLE(acpi, surface3_acpi_match);
-
-struct surface3_button_info {
-	const char *name;
-	int acpi_index;
-	unsigned int event_type;
-	unsigned int event_code;
-	bool autorepeat;
-	bool wakeup;
-	bool active_low;
-};
-
-struct surface3_button_data {
-	struct platform_device *children[BUTTON_TYPES];
-};
-
-/*
- * Get the Nth GPIO number from the ACPI object.
- */
-static int surface3_button_lookup_gpio(struct device *dev, int acpi_index)
-{
-	struct gpio_desc *desc;
-	int gpio;
-
-	desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);
-	if (IS_ERR(desc))
-		return PTR_ERR(desc);
-
-	gpio = desc_to_gpio(desc);
-
-	gpiod_put(desc);
-
-	return gpio;
-}
-
-static struct platform_device *
-surface3_button_device_create(struct i2c_client *client,
-			      const struct surface3_button_info *button_info,
-			      bool autorepeat)
-{
-	const struct surface3_button_info *info;
-	struct platform_device *pd;
-	struct gpio_keys_button *gpio_keys;
-	struct gpio_keys_platform_data *gpio_keys_pdata;
-	int n_buttons = 0;
-	int gpio;
-	int error;
-
-	gpio_keys_pdata = devm_kzalloc(&client->dev,
-				       sizeof(*gpio_keys_pdata) +
-				       sizeof(*gpio_keys) * MAX_NBUTTONS,
-				       GFP_KERNEL);
-	if (!gpio_keys_pdata)
-		return ERR_PTR(-ENOMEM);
-
-	gpio_keys = (void *)(gpio_keys_pdata + 1);
-
-	for (info = button_info; info->name; info++) {
-		if (info->autorepeat != autorepeat)
-			continue;
-
-		gpio = surface3_button_lookup_gpio(&client->dev,
-						   info->acpi_index);
-		if (!gpio_is_valid(gpio))
-			continue;
-
-		gpio_keys[n_buttons].type = info->event_type;
-		gpio_keys[n_buttons].code = info->event_code;
-		gpio_keys[n_buttons].gpio = gpio;
-		gpio_keys[n_buttons].active_low = info->active_low;
-		gpio_keys[n_buttons].desc = info->name;
-		gpio_keys[n_buttons].wakeup = info->wakeup;
-		n_buttons++;
-	}
-
-	if (n_buttons == 0) {
-		error = -ENODEV;
-		goto err_free_mem;
-	}
-
-	gpio_keys_pdata->buttons = gpio_keys;
-	gpio_keys_pdata->nbuttons = n_buttons;
-	gpio_keys_pdata->rep = autorepeat;
-
-	pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);
-	if (!pd) {
-		error = -ENOMEM;
-		goto err_free_mem;
-	}
-
-	error = platform_device_add_data(pd, gpio_keys_pdata,
-					 sizeof(*gpio_keys_pdata));
-	if (error)
-		goto err_free_pdev;
-
-	error = platform_device_add(pd);
-	if (error)
-		goto err_free_pdev;
-
-	return pd;
-
-err_free_pdev:
-	platform_device_put(pd);
-err_free_mem:
-	devm_kfree(&client->dev, gpio_keys_pdata);
-	return ERR_PTR(error);
-}
-
-static int surface3_button_remove(struct i2c_client *client)
-{
-	struct surface3_button_data *priv = i2c_get_clientdata(client);
-
-	int i;
-
-	for (i = 0; i < BUTTON_TYPES; i++)
-		if (priv->children[i])
-			platform_device_unregister(priv->children[i]);
-
-	return 0;
-}
-
-static struct surface3_button_info surface3_button_surface3[] = {
-	{ "power", 0, EV_KEY, KEY_POWER, false, true, true },
-	{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true, false },
-	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true },
-	{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false, true },
-	{ }
-};
-
-static int surface3_button_probe(struct i2c_client *client,
-				 const struct i2c_device_id *id)
-{
-	struct device *dev = &client->dev;
-	struct surface3_button_data *priv;
-	struct platform_device *pd;
-	int i;
-	int error;
-
-	if (strncmp(acpi_device_bid(ACPI_COMPANION(&client->dev)),
-		    SURFACE_BUTTON_OBJ_NAME,
-		    strlen(SURFACE_BUTTON_OBJ_NAME)))
-		return -ENODEV;
-
-	error = gpiod_count(dev, NULL);
-	if (error < 0) {
-		dev_dbg(dev, "no GPIO attached, ignoring...\n");
-		return error;
-	}
-
-	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
-
-	i2c_set_clientdata(client, priv);
-
-	for (i = 0; i < BUTTON_TYPES; i++) {
-		pd = surface3_button_device_create(client,
-						   surface3_button_surface3,
-						   i == 0);
-		if (IS_ERR(pd)) {
-			error = PTR_ERR(pd);
-			if (error != -ENODEV) {
-				surface3_button_remove(client);
-				return error;
-			}
-			continue;
-		}
-
-		priv->children[i] = pd;
-	}
-
-	if (!priv->children[0] && !priv->children[1])
-		return -ENODEV;
-
-	return 0;
-}
-
-static const struct i2c_device_id surface3_id[] = {
-	{ }
-};
-MODULE_DEVICE_TABLE(i2c, surface3_id);
-
-static struct i2c_driver surface3_driver = {
-	.probe = surface3_button_probe,
-	.remove = surface3_button_remove,
-	.id_table = surface3_id,
-	.driver = {
-		.name = "surface3",
-		.acpi_match_table = ACPI_PTR(surface3_acpi_match),
-	},
-};
-module_i2c_driver(surface3_driver);
-
-MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
-MODULE_DESCRIPTION("surface3 button array driver");
-MODULE_LICENSE("GPL v2");
-- 
2.36.0

From 6854ba2ebc5761be240d5fd1d57555011f307f2c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>
Date: Thu, 5 Nov 2020 13:09:45 +0100
Subject: [PATCH] hid/multitouch: Turn off Type Cover keyboard backlight when
 suspending

The Type Cover for Microsoft Surface devices supports a special usb
control request to disable or enable the built-in keyboard backlight.
On Windows, this request happens when putting the device into suspend or
resuming it, without it the backlight of the Type Cover will remain
enabled for some time even though the computer is suspended, which looks
weird to the user.

So add support for this special usb control request to hid-multitouch,
which is the driver that's handling the Type Cover.

The reason we have to use a pm_notifier for this instead of the usual
suspend/resume methods is that those won't get called in case the usb
device is already autosuspended.

Also, if the device is autosuspended, we have to briefly autoresume it
in order to send the request. Doing that should be fine, the usb-core
driver does something similar during suspend inside choose_wakeup().

To make sure we don't send that request to every device but only to
devices which support it, add a new quirk
MT_CLS_WIN_8_MS_SURFACE_TYPE_COVER to hid-multitouch. For now this quirk
is only enabled for the usb id of the Surface Pro 2017 Type Cover, which
is where I confirmed that it's working.

Patchset: surface-typecover
---
 drivers/hid/hid-multitouch.c | 100 ++++++++++++++++++++++++++++++++++-
 1 file changed, 98 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 99eabfb4145b..bbfcae39f375 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -34,7 +34,10 @@
 #include <linux/device.h>
 #include <linux/hid.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/usb.h>
 #include <linux/input/mt.h>
 #include <linux/jiffies.h>
 #include <linux/string.h>
@@ -47,6 +50,7 @@ MODULE_DESCRIPTION("HID multitouch panels");
 MODULE_LICENSE("GPL");
 
 #include "hid-ids.h"
+#include "usbhid/usbhid.h"
 
 /* quirks to control the device */
 #define MT_QUIRK_NOT_SEEN_MEANS_UP	BIT(0)
@@ -71,12 +75,15 @@ MODULE_LICENSE("GPL");
 #define MT_QUIRK_SEPARATE_APP_REPORT	BIT(19)
 #define MT_QUIRK_FORCE_MULTI_INPUT	BIT(20)
 #define MT_QUIRK_DISABLE_WAKEUP		BIT(21)
+#define MT_QUIRK_HAS_TYPE_COVER_BACKLIGHT	BIT(22)
 
 #define MT_INPUTMODE_TOUCHSCREEN	0x02
 #define MT_INPUTMODE_TOUCHPAD		0x03
 
 #define MT_BUTTONTYPE_CLICKPAD		0
 
+#define MS_TYPE_COVER_FEATURE_REPORT_USAGE	0xff050086
+
 enum latency_mode {
 	HID_LATENCY_NORMAL = 0,
 	HID_LATENCY_HIGH = 1,
@@ -168,6 +175,8 @@ struct mt_device {
 
 	struct list_head applications;
 	struct list_head reports;
+
+	struct notifier_block pm_notifier;
 };
 
 static void mt_post_parse_default_settings(struct mt_device *td,
@@ -211,6 +220,7 @@ static void mt_post_parse(struct mt_device *td, struct mt_application *app);
 #define MT_CLS_GOOGLE				0x0111
 #define MT_CLS_RAZER_BLADE_STEALTH		0x0112
 #define MT_CLS_SMART_TECH			0x0113
+#define MT_CLS_WIN_8_MS_SURFACE_TYPE_COVER	0x0114
 
 #define MT_DEFAULT_MAXCONTACT	10
 #define MT_MAX_MAXCONTACT	250
@@ -386,6 +396,16 @@ static const struct mt_class mt_classes[] = {
 			MT_QUIRK_CONTACT_CNT_ACCURATE |
 			MT_QUIRK_SEPARATE_APP_REPORT,
 	},
+	{ .name = MT_CLS_WIN_8_MS_SURFACE_TYPE_COVER,
+		.quirks = MT_QUIRK_HAS_TYPE_COVER_BACKLIGHT |
+			MT_QUIRK_ALWAYS_VALID |
+			MT_QUIRK_IGNORE_DUPLICATES |
+			MT_QUIRK_HOVERING |
+			MT_QUIRK_CONTACT_CNT_ACCURATE |
+			MT_QUIRK_STICKY_FINGERS |
+			MT_QUIRK_WIN8_PTP_BUTTONS,
+		.export_all_inputs = true
+	},
 	{ }
 };
 
@@ -1695,6 +1715,69 @@ static void mt_expired_timeout(struct timer_list *t)
 	clear_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);
 }
 
+static void get_type_cover_backlight_field(struct hid_device *hdev,
+					   struct hid_field **field)
+{
+	struct hid_report_enum *rep_enum;
+	struct hid_report *rep;
+	struct hid_field *cur_field;
+	int i, j;
+
+	rep_enum = &hdev->report_enum[HID_FEATURE_REPORT];
+	list_for_each_entry(rep, &rep_enum->report_list, list) {
+		for (i = 0; i < rep->maxfield; i++) {
+			cur_field = rep->field[i];
+
+			for (j = 0; j < cur_field->maxusage; j++) {
+				if (cur_field->usage[j].hid
+				    == MS_TYPE_COVER_FEATURE_REPORT_USAGE) {
+					*field = cur_field;
+					return;
+				}
+			}
+		}
+	}
+}
+
+static void update_keyboard_backlight(struct hid_device *hdev, bool enabled)
+{
+	struct usb_device *udev = hid_to_usb_dev(hdev);
+	struct hid_field *field = NULL;
+
+	/* Wake up the device in case it's already suspended */
+	pm_runtime_get_sync(&udev->dev);
+
+	get_type_cover_backlight_field(hdev, &field);
+	if (!field) {
+		hid_err(hdev, "couldn't find backlight field\n");
+		goto out;
+	}
+
+	field->value[field->index] = enabled ? 0x01ff00ff : 0x00ff00ff;
+	hid_hw_request(hdev, field->report, HID_REQ_SET_REPORT);
+
+out:
+	pm_runtime_put_sync(&udev->dev);
+}
+
+static int mt_pm_notifier(struct notifier_block *notifier,
+			  unsigned long pm_event,
+			  void *unused)
+{
+	struct mt_device *td =
+		container_of(notifier, struct mt_device, pm_notifier);
+	struct hid_device *hdev = td->hdev;
+
+	if (td->mtclass.quirks & MT_QUIRK_HAS_TYPE_COVER_BACKLIGHT) {
+		if (pm_event == PM_SUSPEND_PREPARE)
+			update_keyboard_backlight(hdev, 0);
+		else if (pm_event == PM_POST_SUSPEND)
+			update_keyboard_backlight(hdev, 1);
+	}
+
+	return NOTIFY_DONE;
+}
+
 static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	int ret, i;
@@ -1718,6 +1801,9 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	td->inputmode_value = MT_INPUTMODE_TOUCHSCREEN;
 	hid_set_drvdata(hdev, td);
 
+	td->pm_notifier.notifier_call = mt_pm_notifier;
+	register_pm_notifier(&td->pm_notifier);
+
 	INIT_LIST_HEAD(&td->applications);
 	INIT_LIST_HEAD(&td->reports);
 
@@ -1747,15 +1833,19 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	timer_setup(&td->release_timer, mt_expired_timeout, 0);
 
 	ret = hid_parse(hdev);
-	if (ret != 0)
+	if (ret != 0) {
+		unregister_pm_notifier(&td->pm_notifier);
 		return ret;
+	}
 
 	if (mtclass->quirks & MT_QUIRK_FIX_CONST_CONTACT_ID)
 		mt_fix_const_fields(hdev, HID_DG_CONTACTID);
 
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
-	if (ret)
+	if (ret) {
+		unregister_pm_notifier(&td->pm_notifier);
 		return ret;
+	}
 
 	ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
 	if (ret)
@@ -1807,6 +1897,7 @@ static void mt_remove(struct hid_device *hdev)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
 
+	unregister_pm_notifier(&td->pm_notifier);
 	del_timer_sync(&td->release_timer);
 
 	sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
@@ -2174,6 +2265,11 @@ static const struct hid_device_id mt_devices[] = {
 		MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
 			USB_DEVICE_ID_XIROKU_CSR2) },
 
+	/* Microsoft Surface type cover */
+	{ .driver_data = MT_CLS_WIN_8_MS_SURFACE_TYPE_COVER,
+		HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY,
+			USB_VENDOR_ID_MICROSOFT, 0x09c0) },
+
 	/* Google MT devices */
 	{ .driver_data = MT_CLS_GOOGLE,
 		HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY, USB_VENDOR_ID_GOOGLE,
-- 
2.36.0

From 48eab1c5e0d9fe67384d6c2e91efdf0ec3ff54b5 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Tue, 8 Feb 2022 01:29:48 +0100
Subject: [PATCH] ACPI: battery: Add "Not Charging" quirk for Microsoft Surface
 devices

Microsoft Surface devices have a limiter that sets a fixed maximum
charge capacity for the battery. When that maximum capacity has been
reached, charging stops. In that case, _BST returns a battery state
field with both "charging" and "discharging" bits cleared. The battery
driver, however, returns "unknown" as status.

This seems to be the same behavior as observed on the ThinkPads, so
let's use the same quirk to handle that as well.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Patchset: surface-battery

---
For what it's worth, I don't think the ACPI spec explicitly states that
any of the status bits need to be set, or that there are only the
"charging" and "discharging" states. As far as I can tell, ACPI only
states:

    Notice that the Charging bit and the Discharging bit are mutually
    exclusive and must not both be set at the same time. Even in
    critical state, hardware should report the corresponding
    charging/discharging state.

But that does not exclude the case that no bit is set. So, strictly
going by spec, I don't think it's necessary to put all of this behind a
quirk.
---
 drivers/acpi/battery.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index dc208f5f5a1f..db2aa56c746a 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -1152,6 +1152,14 @@ static const struct dmi_system_id bat_dmi_table[] __initconst = {
 			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad"),
 		},
 	},
+	{
+		.callback = battery_quirk_not_charging,
+		.ident = "Microsoft Surface",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Surface"),
+		},
+	},
 	{
 		/* Microsoft Surface Go 3 */
 		.callback = battery_notification_delay_quirk,
-- 
2.36.0

From f31a3ad42c2c04a17f8675438a1b5a6500bafea5 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Sun, 10 Oct 2021 20:56:57 +0200
Subject: [PATCH] ACPI: delay enumeration of devices with a _DEP pointing to an
 INT3472 device

The clk and regulator frameworks expect clk/regulator consumer-devices
to have info about the consumed clks/regulators described in the device's
fw_node.

To work around cases where this info is not present in the firmware tables,
which is often the case on x86/ACPI devices, both frameworks allow the
provider-driver to attach info about consumers to the clks/regulators
when registering these.

This causes problems with the probe ordering wrt drivers for consumers
of these clks/regulators. Since the lookups are only registered when the
provider-driver binds, trying to get these clks/regulators before then
results in a -ENOENT error for clks and a dummy regulator for regulators.

One case where we hit this issue is camera sensors such as e.g. the OV8865
sensor found on the Microsoft Surface Go. The sensor uses clks, regulators
and GPIOs provided by a TPS68470 PMIC which is described in an INT3472
ACPI device. There is special platform code handling this and setting
platform_data with the necessary consumer info on the MFD cells
instantiated for the PMIC under: drivers/platform/x86/intel/int3472.

For this to work properly the ov8865 driver must not bind to the I2C-client
for the OV8865 sensor until after the TPS68470 PMIC gpio, regulator and
clk MFD cells have all been fully setup.

The OV8865 on the Microsoft Surface Go is just one example, all X86
devices using the Intel IPU3 camera block found on recent Intel SoCs
have similar issues where there is an INT3472 HID ACPI-device, which
describes the clks and regulators, and the driver for this INT3472 device
must be fully initialized before the sensor driver (any sensor driver)
binds for things to work properly.

On these devices the ACPI nodes describing the sensors all have a _DEP
dependency on the matching INT3472 ACPI device (there is one per sensor).

This allows solving the probe-ordering problem by delaying the enumeration
(instantiation of the I2C-client in the ov8865 example) of ACPI-devices
which have a _DEP dependency on an INT3472 device.

The new acpi_dev_ready_for_enumeration() helper used for this is also
exported because for devices, which have the enumeration_by_parent flag
set, the parent-driver will do its own scan of child ACPI devices and
it will try to enumerate those during its probe(). Code doing this such
as e.g. the i2c-core-acpi.c code must call this new helper to ensure
that it too delays the enumeration until all the _DEP dependencies are
met on devices which have the new honor_deps flag set.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Patchset: cameras
---
 drivers/acpi/scan.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index c82b1bfa1c3d..2227625202aa 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2130,6 +2130,9 @@ static acpi_status acpi_bus_check_add_2(acpi_handle handle, u32 lvl_not_used,
 
 static void acpi_default_enumeration(struct acpi_device *device)
 {
+	if (!acpi_dev_ready_for_enumeration(device))
+		return;
+
 	/*
 	 * Do not enumerate devices with enumeration_by_parent flag set as
 	 * they will be enumerated by their respective parents.
-- 
2.36.0

From 3f7aa178a14b5cdaa3ca424743299d0c271fd202 Mon Sep 17 00:00:00 2001
From: Daniel Scally <djrscally@gmail.com>
Date: Sun, 10 Oct 2021 20:57:02 +0200
Subject: [PATCH] platform/x86: int3472: Enable I2c daisy chain

The TPS68470 PMIC has an I2C passthrough mode through which I2C traffic
can be forwarded to a device connected to the PMIC as though it were
connected directly to the system bus. Enable this mode when the chip
is initialised.

Signed-off-by: Daniel Scally <djrscally@gmail.com>
Patchset: cameras
---
 drivers/platform/x86/intel/int3472/tps68470.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/platform/x86/intel/int3472/tps68470.c b/drivers/platform/x86/intel/int3472/tps68470.c
index 22f61b47f9e5..e1de1ff40bba 100644
--- a/drivers/platform/x86/intel/int3472/tps68470.c
+++ b/drivers/platform/x86/intel/int3472/tps68470.c
@@ -45,6 +45,13 @@ static int tps68470_chip_init(struct device *dev, struct regmap *regmap)
 		return ret;
 	}
 
+	/* Enable I2C daisy chain */
+	ret = regmap_write(regmap, TPS68470_REG_S_I2C_CTL, 0x03);
+	if (ret) {
+		dev_err(dev, "Failed to enable i2c daisy chain\n");
+		return ret;
+	}
+
 	dev_info(dev, "TPS68470 REVID: 0x%02x\n", version);
 
 	return 0;
-- 
2.36.0

From 2bd2d24b1a9f413760ef333262833def4c4c7ab2 Mon Sep 17 00:00:00 2001
From: Sachi King <nakato@nakato.io>
Date: Sat, 29 May 2021 17:47:38 +1000
Subject: [PATCH] ACPI: Add quirk for Surface Laptop 4 AMD missing irq 7
 override

This patch is the work of Thomas Gleixner <tglx@linutronix.de> and is
copied from:
https://lore.kernel.org/lkml/87lf8ddjqx.ffs@nanos.tec.linutronix.de/

This patch adds a quirk to the ACPI setup to patch in the the irq 7 pin
setup that is missing in the laptops ACPI table.

This patch was used for validation of the issue, and is not a proper
fix, but is probably a better temporary hack than continuing to probe
the Legacy PIC and run with the PIC in an unknown state.

Patchset: amd-gpio
---
 arch/x86/kernel/acpi/boot.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 0d01e7f5078c..2b06cf5f2b1f 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -22,6 +22,7 @@
 #include <linux/efi-bgrt.h>
 #include <linux/serial_core.h>
 #include <linux/pgtable.h>
+#include <linux/dmi.h>
 
 #include <asm/e820/api.h>
 #include <asm/irqdomain.h>
@@ -1152,6 +1153,17 @@ static void __init mp_config_acpi_legacy_irqs(void)
 	}
 }
 
+static const struct dmi_system_id surface_quirk[] __initconst = {
+	{
+		.ident = "Microsoft Surface Laptop 4 (AMD)",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
+			DMI_MATCH(DMI_PRODUCT_SKU, "Surface_Laptop_4_1952:1953")
+		},
+	},
+	{}
+};
+
 /*
  * Parse IOAPIC related entries in MADT
  * returns 0 on success, < 0 on error
@@ -1207,6 +1219,11 @@ static int __init acpi_parse_madt_ioapic_entries(void)
 		acpi_sci_ioapic_setup(acpi_gbl_FADT.sci_interrupt, 0, 0,
 				      acpi_gbl_FADT.sci_interrupt);
 
+	if (dmi_check_system(surface_quirk)) {
+		pr_warn("Surface hack: Override irq 7\n");
+		mp_override_legacy_irq(7, 3, 3, 7);
+	}
+
 	/* Fill in identity legacy mappings where no override */
 	mp_config_acpi_legacy_irqs();
 
-- 
2.36.0

From 4413582ad25091f1ff7c163c97f938550430834a Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Thu, 3 Jun 2021 14:04:26 +0200
Subject: [PATCH] ACPI: Add AMD 13" Surface Laptop 4 model to irq 7 override
 quirk

The 13" version of the Surface Laptop 4 has the same problem as the 15"
version, but uses a different SKU. Add that SKU to the quirk as well.

Patchset: amd-gpio
---
 arch/x86/kernel/acpi/boot.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 2b06cf5f2b1f..caaec200bea2 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1155,12 +1155,19 @@ static void __init mp_config_acpi_legacy_irqs(void)
 
 static const struct dmi_system_id surface_quirk[] __initconst = {
 	{
-		.ident = "Microsoft Surface Laptop 4 (AMD)",
+		.ident = "Microsoft Surface Laptop 4 (AMD 15\")",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 			DMI_MATCH(DMI_PRODUCT_SKU, "Surface_Laptop_4_1952:1953")
 		},
 	},
+	{
+		.ident = "Microsoft Surface Laptop 4 (AMD 13\")",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
+			DMI_MATCH(DMI_PRODUCT_SKU, "Surface_Laptop_4_1958:1959")
+		},
+	},
 	{}
 };
 
-- 
2.36.0