[PATCH] leds: pwm: fix max_brightness works abnormal when active_low

[PATCH] leds: pwm: fix max_brightness works abnormal when active_low

[Yisheng Xie]

When leds-pwm is active_low, smaller number of  duty kept in led_dat
means less brighness, so we should disable pwm when led_dat->duty is
equal to period instead of zero, which means max_brightness.

Signed-off-by: Yisheng Xie <ysxie@foxmail.com>
---
 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 df80c89..07fb772 100644
--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -41,7 +41,7 @@ static void __led_pwm_set(struct led_pwm_data *led_dat)
 
 	pwm_config(led_dat->pwm, new_duty, led_dat->period);
 
-	if (new_duty == 0)
+	if (led_dat->active_low ? new_duty == led_dat->period : new_duty == 0)
 		pwm_disable(led_dat->pwm);
 	else
 		pwm_enable(led_dat->pwm);
-- 
1.9.1

Re: [PATCH] leds: pwm: fix max_brightness works abnormal when active_low

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 1284 bytes --]

On Sun 2019-02-10 20:37:09, Yisheng Xie wrote:
> When leds-pwm is active_low, smaller number of  duty kept in led_dat
> means less brighness, so we should disable pwm when led_dat->duty is
> equal to period instead of zero, which means max_brightness.

Will all pwm drivers leave the signal 'low' when pwm is disabled? Not
tristate or something?

Plus please use temporary variable. This is really hard to read.

Or maybe

   led_dat->active_low * new_duty == led_dat->period

?
									Pavel

> Signed-off-by: Yisheng Xie <ysxie@foxmail.com>
> ---
>  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 df80c89..07fb772 100644
> --- a/drivers/leds/leds-pwm.c
> +++ b/drivers/leds/leds-pwm.c
> @@ -41,7 +41,7 @@ static void __led_pwm_set(struct led_pwm_data *led_dat)
>  
>  	pwm_config(led_dat->pwm, new_duty, led_dat->period);
>  
> -	if (new_duty == 0)
> +	if (led_dat->active_low ? new_duty == led_dat->period : new_duty == 0)
>  		pwm_disable(led_dat->pwm);
>  	else
>  		pwm_enable(led_dat->pwm);

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]