Ksawlii/kernel_samsung_a53x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

leds: pwm: Don't disable the PWM when the LED should be off

Browse source 
[ 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@dawes.za.net>
Reported-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
Link: https://lore.kernel.org/r/20230922192834.1695727-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Uwe Kleine-König 2023-09-22 21:28:34 +02:00 committed by Ksawlii
parent eba6fde1b8
commit 45b82bead8
1 changed files with 1 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
drivers/leds/leds-pwm.c
View file

@ -51,7 +51,7 @@ 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);
}