linux-kernel - Re: [PATCH/RFC 2/8] leds: Improve and export led_update

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Message-ID: <20140323232038.GB2054@valkosipuli.retiisi.org.uk>
Date:	Mon, 24 Mar 2014 01:20:39 +0200
From:	Sakari Ailus <sakari.ailus@....fi>
To:	Jacek Anaszewski <j.anaszewski@...sung.com>
Cc:	linux-media@...r.kernel.org, linux-leds@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	s.nawrocki@...sung.com, a.hajda@...sung.com,
	kyungmin.park@...sung.com, Bryan Wu <cooloney@...il.com>,
	Richard Purdie <rpurdie@...ys.net>
Subject: Re: [PATCH/RFC 2/8] leds: Improve and export led_update_brightness
 function


Hi Jacek,

On Thu, Mar 20, 2014 at 03:51:04PM +0100, Jacek Anaszewski wrote:
> led_update_brightness helper function used to be exploited
> only locally in the led-class.c module, where its result was
> being passed to the brightness_show sysfs callback. With the
> introduction of v4l2-flash subdevice the same functionality
> became required for checking the current flash strobe status.
> This patch adds checking brightness_get callback error code
> and adds the function to the LED subsystem public API.
> 
> Signed-off-by: Jacek Anaszewski <j.anaszewski@...sung.com>
> Acked-by: Kyungmin Park <kyungmin.park@...sung.com>
> Cc: Bryan Wu <cooloney@...il.com>
> Cc: Richard Purdie <rpurdie@...ys.net>
> ---
>  drivers/leds/led-class.c |    6 ------
>  drivers/leds/led-core.c  |   17 +++++++++++++++++
>  include/linux/leds.h     |   10 ++++++++++
>  3 files changed, 27 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 0510532..04de352 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -27,12 +27,6 @@
>  
>  static struct class *leds_class;
>  
> -static void led_update_brightness(struct led_classdev *led_cdev)
> -{
> -	if (led_cdev->brightness_get)
> -		led_cdev->brightness = led_cdev->brightness_get(led_cdev);
> -}
> -
>  static ssize_t brightness_show(struct device *dev,
>  		struct device_attribute *attr, char *buf)
>  {
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index 093703c..21ceda1 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -166,6 +166,23 @@ void led_set_brightness(struct led_classdev *led_cdev,
>  }
>  EXPORT_SYMBOL(led_set_brightness);
>  
> +int led_update_brightness(struct led_classdev *led_cdev)
> +{
> +	int ret;
> +
> +	if (led_cdev->brightness_get == NULL)
> +		return -EINVAL;
> +
> +	ret = led_cdev->brightness_get(led_cdev);
> +	if (ret >= 0)
> +		led_cdev->brightness = ret;
> +	else
> +		return ret;

You don't really need the else branch here. It'd be cleaner without, I
think.

> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(led_update_brightness);
> +
>  int led_set_flash_mode(struct led_classdev *led_cdev,
>  			bool flash_mode)
>  {
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index 1bf0ab3..5bf05cc 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -190,6 +190,16 @@ extern void led_blink_set_oneshot(struct led_classdev *led_cdev,
>  extern void led_set_brightness(struct led_classdev *led_cdev,
>  			       enum led_brightness brightness);
>  /**
> + * led_update_brightness - update LED brightness
> + * @led_cdev: the LED to query about
> + *
> + * Get an LED's current brightness and update led_cdev->brightness
> + * member with the obtained value.
> + *
> + * Returns: 0 on success or negative error value on failure
> + */
> +extern int led_update_brightness(struct led_classdev *led_cdev);
> +
>  /**
>   * led_set_flash_mode - set LED flash mode
>   * @led_cdev: the LED to set

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@....fi	XMPP: sailus@...iisi.org.uk
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