linux-kernel - Re: [PATCH v3 7/9] media: subdev: Support privacy led in v4l2_subdev_enable/disable

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Message-ID: <20240412182026.GJ31122@pendragon.ideasonboard.com>
Date: Fri, 12 Apr 2024 21:20:26 +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 7/9] media: subdev: Support privacy led in
 v4l2_subdev_enable/disable_streams()

Hi Tomi,

Thank you for the patch.

On Wed, Apr 10, 2024 at 03:35:54PM +0300, Tomi Valkeinen wrote:
> We support camera privacy leds with the .s_stream, in call_s_stream, but

s/the .s_stream/the .s_stream() operation/

> we don't have that support when the subdevice implements
> .enable/disable_streams.
> 
> Add the support by enabling the led when the first stream for a
> subdevice is enabled, and disabling the led then the last stream is
> disabled.

I wonder if that will always be the correct constraint for all devices,
but I suppose we can worry about it later.

> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 20b5a00cbeeb..f44aaa4e1fab 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -2150,6 +2150,7 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>  {
>  	struct device *dev = sd->entity.graph_obj.mdev->dev;
>  	struct v4l2_subdev_state *state;
> +	bool already_streaming;
>  	u64 found_streams = 0;
>  	unsigned int i;
>  	int ret;
> @@ -2198,6 +2199,8 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>  
>  	dev_dbg(dev, "enable streams %u:%#llx\n", pad, streams_mask);
>  
> +	already_streaming = v4l2_subdev_is_streaming(sd);
> +
>  	/* Call the .enable_streams() operation. */
>  	ret = v4l2_subdev_call(sd, pad, enable_streams, state, pad,
>  			       streams_mask);
> @@ -2216,6 +2219,9 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>  			cfg->enabled = true;
>  	}
>  
> +	if (!already_streaming)
> +		v4l2_subdev_enable_privacy_led(sd);
> +
>  done:
>  	v4l2_subdev_unlock_state(state);
>  
> @@ -2340,6 +2346,9 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
>  	}
>  
>  done:
> +	if (!v4l2_subdev_is_streaming(sd))

Wouldn't it be more efficient to check this while looping over the
stream configs in the loop just above ? Same for
v4l2_subdev_enable_streams().

> +		v4l2_subdev_disable_privacy_led(sd);
> +
>  	v4l2_subdev_unlock_state(state);
>  
>  	return ret;
> 

-- 
Regards,

Laurent Pinchart