Re: [PATCH v3 20/29] media: raspberrypi: cfe: Use v4l2_subdev_get_frame_desc()

On Mon, Aug 24, 2026 at 03:14:42PM +0300, Sakari Ailus wrote:
> Call v4l2_subdev_get_frame_desc() to obtain the frame descriptor. This is
> preferred over calling the get_frame_desc() pad operation directly. Also
> remove the workaround for drivers not implementing the get_frame_desc()
> pad op.
>
> Signed-off-by: Sakari Ailus <[email protected]>
> ---
Reviewed-by: Frank Li <[email protected]>

>  .../media/platform/raspberrypi/rp1-cfe/cfe.c  | 51 ++++---------------
>  1 file changed, 11 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/media/platform/raspberrypi/rp1-cfe/cfe.c b/drivers/media/platform/raspberrypi/rp1-cfe/cfe.c
> index 8375ed3e97b9..e99a77e0878e 100644
> --- a/drivers/media/platform/raspberrypi/rp1-cfe/cfe.c
> +++ b/drivers/media/platform/raspberrypi/rp1-cfe/cfe.c
> @@ -6,6 +6,7 @@
>   * Copyright (c) 2023-2024 Ideas on Board Oy
>   */
>
> +#include <linux/cleanup.h>
>  #include <linux/clk.h>
>  #include <linux/debugfs.h>
>  #include <linux/delay.h>
> @@ -778,32 +779,9 @@ static irqreturn_t cfe_isr(int irq, void *dev)
>   * Stream helpers
>   */
>
> -static int cfe_get_vc_dt_fallback(struct cfe_device *cfe, u8 *vc, u8 *dt)
> -{
> -	struct v4l2_subdev_state *state;
> -	struct v4l2_mbus_framefmt *fmt;
> -	const struct cfe_fmt *cfe_fmt;
> -
> -	state = v4l2_subdev_get_locked_active_state(&cfe->csi2.sd);
> -
> -	fmt = v4l2_subdev_state_get_format(state, CSI2_PAD_SINK, 0);
> -	if (!fmt)
> -		return -EINVAL;
> -
> -	cfe_fmt = find_format_by_code(fmt->code);
> -	if (!cfe_fmt)
> -		return -EINVAL;
> -
> -	*vc = 0;
> -	*dt = cfe_fmt->csi_dt;
> -
> -	return 0;
> -}
> -
>  static int cfe_get_vc_dt(struct cfe_device *cfe, unsigned int channel, u8 *vc,
>  			 u8 *dt)
>  {
> -	struct v4l2_mbus_frame_desc remote_desc;
>  	struct v4l2_subdev_state *state;
>  	u32 sink_stream;
>  	unsigned int i;
> @@ -816,34 +794,27 @@ static int cfe_get_vc_dt(struct cfe_device *cfe, unsigned int channel, u8 *vc,
>  	if (ret)
>  		return ret;
>
> -	ret = v4l2_subdev_call(cfe->source_sd, pad, get_frame_desc,
> -			       cfe->source_pad, &remote_desc);
> -	if (ret == -ENOIOCTLCMD) {
> -		cfe_dbg(cfe, "source does not support get_frame_desc, use fallback\n");
> -		return cfe_get_vc_dt_fallback(cfe, vc, dt);
> -	} else if (ret) {
> +	struct v4l2_mbus_frame_desc *fd __free(v4l2_subdev_free_frame_desc) =
> +		v4l2_subdev_get_frame_desc(cfe->source_sd, cfe->source_pad,
> +					   V4L2_MBUS_FRAME_DESC_TYPE_CSI2);
> +	if (IS_ERR(fd)) {
>  		cfe_err(cfe, "Failed to get frame descriptor\n");
> -		return ret;
> -	}
> -
> -	if (remote_desc.type != V4L2_MBUS_FRAME_DESC_TYPE_CSI2) {
> -		cfe_err(cfe, "Frame descriptor does not describe CSI-2 link");
> -		return -EINVAL;
> +		return PTR_ERR(fd);
>  	}
>
> -	for (i = 0; i < remote_desc.num_entries; i++) {
> -		if (remote_desc.entry[i].stream == sink_stream)
> +	for (i = 0; i < fd->num_entries; i++) {
> +		if (fd->entry[i].stream == sink_stream)
>  			break;
>  	}
>
> -	if (i == remote_desc.num_entries) {
> +	if (i == fd->num_entries) {
>  		cfe_err(cfe, "Stream %u not found in remote frame desc\n",
>  			sink_stream);
>  		return -EINVAL;
>  	}
>
> -	*vc = remote_desc.entry[i].bus.csi2.vc;
> -	*dt = remote_desc.entry[i].bus.csi2.dt;
> +	*vc = fd->entry[i].bus.csi2.vc;
> +	*dt = fd->entry[i].bus.csi2.dt;
>
>  	return 0;
>  }
> --
> 2.47.3
>