leds: pwm: Disable PWM when going to suspend

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>

diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index 4e3936a39d0ed3262c3fa8fc000b1f8de38279d8..e1b414b403534791c684d830e37dc51ab7bf1644 100644 (file)
--- 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);
 }