linux-kernel - Re: [PATCH v3 1/9] media: subdev: Add privacy led helpers

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Message-ID: <20240412173659.GD31122@pendragon.ideasonboard.com>
Date: Fri, 12 Apr 2024 20:36:59 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Hans Verkuil <hverkuil@...all.nl>,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Umang Jain <umang.jain@...asonboard.com>,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/9] media: subdev: Add privacy led helpers

Hi Tomi,

Thank you for the patch.

On Wed, Apr 10, 2024 at 03:35:48PM +0300, Tomi Valkeinen wrote:
> Add helper functions to enable and disable the privacy led. This moves
> the #if from the call site to the privacy led functions, and makes
> adding privacy led support to v4l2_subdev_enable/disable_streams()
> cleaner.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 30 +++++++++++++++++++++---------
>  1 file changed, 21 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 012b757eac9f..13957543d153 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -148,6 +148,23 @@ static int subdev_close(struct file *file)
>  }
>  #endif /* CONFIG_VIDEO_V4L2_SUBDEV_API */
>  
> +static void v4l2_subdev_enable_privacy_led(struct v4l2_subdev *sd)
> +{
> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> +	if (!IS_ERR_OR_NULL(sd->privacy_led))
> +		led_set_brightness(sd->privacy_led,
> +				   sd->privacy_led->max_brightness);
> +#endif
> +}
> +
> +static void v4l2_subdev_disable_privacy_led(struct v4l2_subdev *sd)
> +{
> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> +	if (!IS_ERR_OR_NULL(sd->privacy_led))
> +		led_set_brightness(sd->privacy_led, 0);
> +#endif
> +}

I would have written this as

#if IS_REACHABLE(CONFIG_LEDS_CLASS)
static void v4l2_subdev_enable_privacy_led(struct v4l2_subdev *sd)
{
	if (!IS_ERR_OR_NULL(sd->privacy_led))
		led_set_brightness(sd->privacy_led,
				   sd->privacy_led->max_brightness);
}

static void v4l2_subdev_disable_privacy_led(struct v4l2_subdev *sd)
{
	if (!IS_ERR_OR_NULL(sd->privacy_led))
		led_set_brightness(sd->privacy_led, 0);
}
#else
static inline void v4l2_subdev_enable_privacy_led(struct v4l2_subdev *sd)
{
}

static inline void v4l2_subdev_disable_privacy_led(struct v4l2_subdev *sd)
{
}
#endif /* CONFIG_LEDS_CLASS */

to avoid multipe #if but that likely makes no difference in the
generated code. Either way,

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> +
>  static inline int check_which(u32 which)
>  {
>  	if (which != V4L2_SUBDEV_FORMAT_TRY &&
> @@ -422,15 +439,10 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  	if (!ret) {
>  		sd->enabled_streams = enable ? BIT(0) : 0;
>  
> -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> -		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> -			if (enable)
> -				led_set_brightness(sd->privacy_led,
> -						   sd->privacy_led->max_brightness);
> -			else
> -				led_set_brightness(sd->privacy_led, 0);
> -		}
> -#endif
> +		if (enable)
> +			v4l2_subdev_enable_privacy_led(sd);
> +		else
> +			v4l2_subdev_disable_privacy_led(sd);
>  	}
>  
>  	return ret;
> 

-- 
Regards,

Laurent Pinchart