Re: [PATCH v5 06/10] media: rcar-csi2: Add .get_frame_desc op

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Mar 11, 2026 at 03:53:19PM +0200, Tomi Valkeinen wrote:
> Add v4l2_subdev_pad_ops.get_frame_desc() implementation.
> 
> We also implement a fallback for the case where the upstream subdevice
> does not implement .get_frame_desc. It assumes a single stream with VC =
> 0 and DT based on the configured stream mbus format.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
> ---
>  drivers/media/platform/renesas/rcar-csi2.c | 70 ++++++++++++++++++++++++++++++
>  1 file changed, 70 insertions(+)
> 
> diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
> index ad62c95c8f9a..b8baf7c65e90 100644
> --- a/drivers/media/platform/renesas/rcar-csi2.c
> +++ b/drivers/media/platform/renesas/rcar-csi2.c
> @@ -1935,12 +1935,82 @@ static int rcsi2_set_pad_format(struct v4l2_subdev *sd,
>  	return 0;
>  }
>  
> +static int rcsi2_get_frame_desc_fallback(struct v4l2_subdev *sd,
> +					 unsigned int pad,
> +					 struct v4l2_mbus_frame_desc *fd)
> +{
> +	struct v4l2_subdev_route *route;
> +	const struct rcar_csi2_format *format;
> +	struct v4l2_subdev_state *state;
> +	struct v4l2_mbus_framefmt *fmt;
> +	int ret = 0;
> +
> +	state = v4l2_subdev_lock_and_get_active_state(sd);
> +
> +	if (state->routing.num_routes != 1) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	route = &state->routing.routes[0];
> +
> +	if (route->source_pad != pad) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	fmt = v4l2_subdev_state_get_format(state, route->sink_pad,
> +					   route->sink_stream);
> +	if (!fmt) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	format = rcsi2_code_to_fmt(fmt->code);
> +	if (!format) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	fd->num_entries = 1;
> +	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
> +	fd->entry[0].stream = route->source_stream;
> +	fd->entry[0].pixelcode = fmt->code;
> +	fd->entry[0].bus.csi2.vc = 0;
> +	fd->entry[0].bus.csi2.dt = format->datatype;
> +
> +out:
> +	v4l2_subdev_unlock_state(state);
> +
> +	return ret;
> +}
> +
> +static int rcsi2_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> +				struct v4l2_mbus_frame_desc *fd)
> +{
> +	struct rcar_csi2 *priv = sd_to_csi2(sd);
> +	int ret;
> +
> +	if (WARN_ON(!priv->info->use_isp))
> +		return -ENOTTY;

Why is that, can't the get frame desc operation be supported on Gen3 ?

> +
> +	if (WARN_ON(pad != RCAR_CSI2_SOURCE_VC0))
> +		return -EINVAL;
> +
> +	ret = v4l2_subdev_get_frame_desc_passthrough(sd, pad, fd);
> +	if (ret == -ENOIOCTLCMD)
> +		ret = rcsi2_get_frame_desc_fallback(sd, pad, fd);

A dev_warn_once() would be good here, to get people to fix the source
device driver.

> +	return ret;
> +}
> +
>  static const struct v4l2_subdev_pad_ops rcar_csi2_pad_ops = {
>  	.enable_streams = rcsi2_enable_streams,
>  	.disable_streams = rcsi2_disable_streams,
>  
>  	.set_fmt = rcsi2_set_pad_format,
>  	.get_fmt = v4l2_subdev_get_fmt,
> +
> +	.get_frame_desc = rcsi2_get_frame_desc,
>  };
>  
>  static const struct v4l2_subdev_ops rcar_csi2_subdev_ops = {
> 

-- 
Regards,

Laurent Pinchart