From ae56fbfa274b8f2d693d32f2c760685d6ed9e624 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
Date: Mon, 9 Oct 2023 11:32:23 +0200
Subject: backlight: pwm_bl: Disable PWM on shutdown, suspend and remove
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Git-commit: 40da4737717b252fd01d92ff38d3b95a491167cc
Patch-mainline: v6.7-rc1
References: jsc#PED-3527 jsc#PED-5475 jsc#PED-6068 jsc#PED-6070 jsc#PED-6116 jsc#PED-6120 jsc#PED-5065 jsc#PED-5477 jsc#PED-5511 jsc#PED-6041 jsc#PED-6069 jsc#PED-6071
Since commit 00e7e698bff1 ("backlight: pwm_bl: Configure pwm only once
per backlight toggle") calling pwm_backlight_power_off() doesn't disable
the PWM any more. However this is necessary to suspend because PWM
drivers usually refuse to suspend if they are still enabled.
Also adapt shutdown and remove callbacks to disable the PWM for similar
reasons.
Fixes: 00e7e698bff1 ("backlight: pwm_bl: Configure pwm only once per backlight toggle")
Reported-by: Aisheng Dong <aisheng.dong@nxp.com>
Tested-by: Aisheng Dong <aisheng.dong@nxp.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20231009093223.227286-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Lee Jones <lee@kernel.org>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/video/backlight/pwm_bl.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index a51fbab96368..289bd9ce4d36 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -626,9 +626,14 @@ static void pwm_backlight_remove(struct platform_device *pdev)
{
struct backlight_device *bl = platform_get_drvdata(pdev);
struct pwm_bl_data *pb = bl_get_data(bl);
+ struct pwm_state state;
backlight_device_unregister(bl);
pwm_backlight_power_off(pb);
+ pwm_get_state(pb->pwm, &state);
+ state.duty_cycle = 0;
+ state.enabled = false;
+ pwm_apply_state(pb->pwm, &state);
if (pb->exit)
pb->exit(&pdev->dev);
@@ -638,8 +643,13 @@ static void pwm_backlight_shutdown(struct platform_device *pdev)
{
struct backlight_device *bl = platform_get_drvdata(pdev);
struct pwm_bl_data *pb = bl_get_data(bl);
+ struct pwm_state state;
pwm_backlight_power_off(pb);
+ pwm_get_state(pb->pwm, &state);
+ state.duty_cycle = 0;
+ state.enabled = false;
+ pwm_apply_state(pb->pwm, &state);
}
#ifdef CONFIG_PM_SLEEP
@@ -647,12 +657,24 @@ static int pwm_backlight_suspend(struct device *dev)
{
struct backlight_device *bl = dev_get_drvdata(dev);
struct pwm_bl_data *pb = bl_get_data(bl);
+ struct pwm_state state;
if (pb->notify)
pb->notify(pb->dev, 0);
pwm_backlight_power_off(pb);
+ /*
+ * Note that disabling the PWM doesn't guarantee that the output stays
+ * at its inactive state. However without the PWM disabled, the PWM
+ * driver refuses to suspend. So disable here even though this might
+ * enable the backlight on poorly designed boards.
+ */
+ pwm_get_state(pb->pwm, &state);
+ state.duty_cycle = 0;
+ state.enabled = false;
+ pwm_apply_state(pb->pwm, &state);
+
if (pb->notify_after)
pb->notify_after(pb->dev, 0);
--
2.43.0