linux-kernel - Re: [PATCH v2] leds: fix brightness changing when software blinking is active

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Date:	Fri, 15 May 2015 10:12:47 +0200
From:	Jacek Anaszewski <j.anaszewski@...sung.com>
To:	Stas Sergeev <stsp@...t.ru>
Cc:	linux-leds@...r.kernel.org,
	Linux kernel <linux-kernel@...r.kernel.org>,
	Bryan Wu <cooloney@...il.com>,
	Richard Purdie <rpurdie@...ys.net>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Stas Sergeev <stsp@...rs.sourceforge.net>
Subject: Re: [PATCH v2] leds: fix brightness changing when software blinking is
 active

Hi Stas,

On 05/14/2015 05:24 PM, Stas Sergeev wrote:
>
> The following sequence:
> echo timer >/sys/class/leds/<name>/trigger
> echo 1 >/sys/class/leds/<name>/brightness
> should change the ON brightness for blinking.
> The function led_set_brightness() was mistakenly initiating the
> delayed blink stop procedure, which resulted in no blinking with
> the timer trigger still active.
>
> This patch fixes the problem by changing led_set_brightness()
> to not initiate the delayed blink stop when brightness is not 0.
>
> CC: Bryan Wu <cooloney@...il.com>
> CC: Richard Purdie <rpurdie@...ys.net>
> CC: Jacek Anaszewski <j.anaszewski@...sung.com>
> CC: Kyungmin Park <kyungmin.park@...sung.com>
> CC: linux-leds@...r.kernel.org
> CC: linux-kernel@...r.kernel.org
>
> Signed-off-by: Stas Sergeev <stsp@...rs.sourceforge.net>
> ---
>   drivers/leds/led-class.c |    5 +++++
>   drivers/leds/led-core.c  |    5 +++--
>   2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 795ec99..65c2c80 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -121,6 +121,11 @@ static void led_timer_function(unsigned long data)
>   	brightness = led_get_brightness(led_cdev);
>   	if (!brightness) {
>   		/* Time to switch the LED on. */
> +		if (led_cdev->delayed_set_value) {
> +			led_cdev->blink_brightness =
> +					led_cdev->delayed_set_value;
> +			led_cdev->delayed_set_value = 0;
> +		}
>   		brightness = led_cdev->blink_brightness;
>   		delay = led_cdev->blink_delay_on;
>   	} else {
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index 356e851..a90dd26 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -119,10 +119,11 @@ void led_set_brightness(struct led_classdev *led_cdev,
>   {
>   	int ret = 0;
>
> -	/* delay brightness setting if need to stop soft-blink timer */
> +	/* delay brightness if soft-blink is active */
>   	if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
>   		led_cdev->delayed_set_value = brightness;
> -		schedule_work(&led_cdev->set_brightness_work);
> +		if (brightness == LED_OFF)
> +			schedule_work(&led_cdev->set_brightness_work);
>   		return;
>   	}
>

Acked-by: Jacek Anaszewski <j.anaszewski@...sung.com>

-- 
Best Regards,
Jacek Anaszewski
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