diff options
Diffstat (limited to 'SOURCES/arm64-pwm-rockchip-Keep-enabled-PWMs-running-while-probing.patch')
| -rw-r--r-- | SOURCES/arm64-pwm-rockchip-Keep-enabled-PWMs-running-while-probing.patch | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/SOURCES/arm64-pwm-rockchip-Keep-enabled-PWMs-running-while-probing.patch b/SOURCES/arm64-pwm-rockchip-Keep-enabled-PWMs-running-while-probing.patch new file mode 100644 index 0000000..4bdb5cb --- /dev/null +++ b/SOURCES/arm64-pwm-rockchip-Keep-enabled-PWMs-running-while-probing.patch @@ -0,0 +1,141 @@ +From patchwork Sat Sep 19 19:33:06 2020 +Content-Type: text/plain; charset="utf-8" +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit +X-Patchwork-Submitter: Simon South <simon@simonsouth.net> +X-Patchwork-Id: 11787259 +Return-Path: + <SRS0=uBh2=C4=lists.infradead.org=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@kernel.org> +Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org + [172.30.200.123]) + by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D0780618 + for <patchwork-linux-arm@patchwork.kernel.org>; + Sat, 19 Sep 2020 19:33:55 +0000 (UTC) +Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) + (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) + (No client certificate requested) + by mail.kernel.org (Postfix) with ESMTPS id 9DF4C21707 + for <patchwork-linux-arm@patchwork.kernel.org>; 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Sat, 19 Sep 2020 19:33:37 +0000 (UTC) +Received: from jupiter.simonsouth.net (unknown [108.162.141.195]) + (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) + (No client certificate requested) + by mailout.easymail.ca (Postfix) with ESMTPSA id 77C83A025D; + Sat, 19 Sep 2020 19:33:27 +0000 (UTC) +From: Simon South <simon@simonsouth.net> +To: thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de, + lee.jones@linaro.org, heiko@sntech.de, linux-pwm@vger.kernel.org, + linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org +Subject: [PATCH v2] pwm: rockchip: Keep enabled PWMs running while probing +Date: Sat, 19 Sep 2020 15:33:06 -0400 +Message-Id: <20200919193306.1023-1-simon@simonsouth.net> +X-Mailer: git-send-email 2.28.0 +MIME-Version: 1.0 +X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 +X-CRM114-CacheID: sfid-20200919_153338_624271_ABEEE8C4 +X-CRM114-Status: GOOD ( 16.76 ) +X-Spam-Score: -2.3 (--) +X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: + Content analysis details: (-2.3 points) + pts rule name description + ---- ---------------------- + -------------------------------------------------- + -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, + medium trust [64.68.200.34 listed in list.dnswl.org] + 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record + -0.0 SPF_PASS SPF: sender matches SPF record +X-BeenThere: linux-arm-kernel@lists.infradead.org +X-Mailman-Version: 2.1.29 +Precedence: list +List-Id: <linux-arm-kernel.lists.infradead.org> +List-Unsubscribe: + <http://lists.infradead.org/mailman/options/linux-arm-kernel>, + <mailto:linux-arm-kernel-request@lists.infradead.org?subject=unsubscribe> +List-Archive: <http://lists.infradead.org/pipermail/linux-arm-kernel/> +List-Post: <mailto:linux-arm-kernel@lists.infradead.org> +List-Help: <mailto:linux-arm-kernel-request@lists.infradead.org?subject=help> +List-Subscribe: + <http://lists.infradead.org/mailman/listinfo/linux-arm-kernel>, + <mailto:linux-arm-kernel-request@lists.infradead.org?subject=subscribe> +Cc: Simon South <simon@simonsouth.net> +Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> +Errors-To: + linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org + +Following commit cfc4c189bc70 ("pwm: Read initial hardware state at +request time") the Rockchip PWM driver can no longer assume a device's +pwm_state structure has been populated after a call to pwmchip_add(). +Consequently, the test in rockchip_pwm_probe() intended to prevent the +driver from stopping PWM devices already enabled by the bootloader no +longer functions reliably and this can lead to the kernel hanging +during startup, particularly on devices like the Pinebook Pro that use +a PWM-controlled backlight for their display. + +Avoid this by querying the device directly at probe time to determine +whether or not it is enabled. + +Fixes: cfc4c189bc70 ("pwm: Read initial hardware state at request time") +Signed-off-by: Simon South <simon@simonsouth.net> +Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> +Reviewed-by: Heiko Stuebner <heiko@sntech.de> +--- + drivers/pwm/pwm-rockchip.c | 5 ++++- + 1 file changed, 4 insertions(+), 1 deletion(-) + +diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c +index eb8c9cb645a6..098e94335cb5 100644 +--- a/drivers/pwm/pwm-rockchip.c ++++ b/drivers/pwm/pwm-rockchip.c +@@ -288,6 +288,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) + const struct of_device_id *id; + struct rockchip_pwm_chip *pc; + struct resource *r; ++ u32 enable_conf, ctrl; + int ret, count; + + id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev); +@@ -362,7 +363,9 @@ static int rockchip_pwm_probe(struct platform_device *pdev) + } + + /* Keep the PWM clk enabled if the PWM appears to be up and running. */ +- if (!pwm_is_enabled(pc->chip.pwms)) ++ enable_conf = pc->data->enable_conf; ++ ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl); ++ if ((ctrl & enable_conf) != enable_conf) + clk_disable(pc->clk); + + return 0; |