Re: [PATCH v3 10/15] media: rcar-csi2: Add .get_frame_desc op

["Niklas Söderlund" <niklas.soderlund@ragnatech.se>]

Hi Tomi,

Thanks for your work.

On 2025-05-30 16:50:39 +0300, 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 | 56 ++++++++++++++++++++++++++++++
>  1 file changed, 56 insertions(+)
> 
> diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
> index 20bd44274bd2..65c7f3040696 100644
> --- a/drivers/media/platform/renesas/rcar-csi2.c
> +++ b/drivers/media/platform/renesas/rcar-csi2.c
> @@ -1676,12 +1676,68 @@ 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)
> +{
> +	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);
> +
> +	fmt = v4l2_subdev_state_get_format(state, RCAR_CSI2_SINK, 0);
> +	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 = 0;
> +	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;

This looks odd, why can't we support the frame descriptor and streams on 
Gen3 that do not use the ISP Channel Selector?

> +
> +	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);
> +	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 = {
> 
> -- 
> 2.43.0
> 

-- 
Kind Regards,
Niklas Söderlund