6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
[ Upstream commit 76fe464c8e64e71b2e4af11edeef0e5d85eeb6aa ]
Disabling a PWM (i.e. calling pwm_apply_state with .enabled = false)
gives no guarantees what the PWM output does. It might freeze where it
currently is, or go in a High-Z state or drive the active or inactive
state, it might even continue to toggle.
To ensure that the LED gets really disabled, don't disable the PWM even
when .duty_cycle is zero.
This fixes disabling a leds-pwm LED on i.MX28. The PWM on this SoC is
one of those that freezes its output on disable, so if you disable an
LED that is full on, it stays on. If you disable a LED with half
brightness it goes off in 50% of the cases and full on in the other 50%.
Fixes: 41c42ff5dbe2 ("leds: simple driver for pwm driven LEDs")
Reported-by: Rogan Dawes <rogan@xxxxxxxxxxxx>
Reported-by: Fabio Estevam <festevam@xxxxxxx>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Reviewed-by: Fabio Estevam <festevam@xxxxxxx>
Link: https://lore.kernel.org/r/20230922192834.1695727-1-u.kleine-koenig@xxxxxxxxxxxxxx
Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/leds/leds-pwm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index 419b710984ab6..2b3bf1353b707 100644
--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -53,7 +53,7 @@ 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 = duty > 0;
+ led_dat->pwmstate.enabled = true;
return pwm_apply_state(led_dat->pwm, &led_dat->pwmstate);
}
--
2.42.0
