[PATCH 6.9 071/374] leds: pwm: Disable PWM when going to suspend

Greg Kroah-Hartman
2024-06-06T14:08:47Z

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

[ Upstream commit 974afccd37947a6951a052ef8118c961e57eaf7b ]

On stm32mp1xx based machines (and others) a PWM consumer has to disable
the PWM because an enabled PWM refuses to suspend. So check the
LED_SUSPENDED flag and depending on that set the .enabled property.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=218559
Fixes: 76fe464c8e64 ("leds: pwm: Don't disable the PWM when the LED should be off")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20240417153846.271751-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/leds/leds-pwm.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index 4e3936a39d0ed..e1b414b403534 100644
--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -53,7 +53,13 @@ static int led_pwm_set(struct led_classdev *led_cdev,
duty = led_dat->pwmstate.period - duty;

led_dat->pwmstate.duty_cycle = duty;
- led_dat->pwmstate.enabled = true;
+ /*
+ * Disabling a PWM doesn't guarantee that it emits the inactive level.
+ * So keep it on. Only for suspending the PWM should be disabled because
+ * otherwise it refuses to suspend. The possible downside is that the
+ * LED might stay (or even go) on.
+ */
+ led_dat->pwmstate.enabled = !(led_cdev->flags & LED_SUSPENDED);
return pwm_apply_might_sleep(led_dat->pwm, &led_dat->pwmstate);
}

--
2.43.0