Re: [PATCH v3 17/29] media: bcm2835-unicam: Use v4l2_subdev_get_frame_desc()

On Mon, Aug 24, 2026 at 03:14:39PM +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.
>
> Signed-off-by: Sakari Ailus <[email protected]>
> ---
>  .../media/platform/broadcom/bcm2835-unicam.c  | 22 +++++++++----------
>  1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/media/platform/broadcom/bcm2835-unicam.c b/drivers/media/platform/broadcom/bcm2835-unicam.c
> index 14bb916dd7b1..2322d3df3915 100644
> --- a/drivers/media/platform/broadcom/bcm2835-unicam.c
> +++ b/drivers/media/platform/broadcom/bcm2835-unicam.c
> @@ -27,6 +27,7 @@
>   * output interface and V4L2 subdevice driver.
>   */
>
> +#include <linux/cleanup.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/device.h>
> @@ -888,7 +889,6 @@ static int unicam_get_image_vc_dt(struct unicam_device *unicam,
>  				  struct v4l2_subdev_state *state,
>  				  u8 *vc, u8 *dt)
>  {
> -	struct v4l2_mbus_frame_desc fd;
>  	u32 stream;
>  	int ret;
>
> @@ -898,17 +898,15 @@ static int unicam_get_image_vc_dt(struct unicam_device *unicam,
>  	if (ret)
>  		return ret;
>
> -	ret = v4l2_subdev_call(unicam->sensor.subdev, pad, get_frame_desc,
> -			       unicam->sensor.pad->index, &fd);
> -	if (ret)
> -		return ret;
> -
> -	/* Only CSI-2 supports DTs. */
> -	if (fd.type != V4L2_MBUS_FRAME_DESC_TYPE_CSI2)
> -		return -EINVAL;
> +	struct v4l2_mbus_frame_desc *fd __free(v4l2_subdev_free_frame_desc) =
> +		v4l2_subdev_get_frame_desc(unicam->sensor.subdev,
> +					   unicam->sensor.pad->index,
> +					   V4L2_MBUS_FRAME_DESC_TYPE_CSI2);
> +	if (IS_ERR(fd))
> +		return PTR_ERR(fd);
>
> -	for (unsigned int i = 0; i < fd.num_entries; ++i) {
> -		const struct v4l2_mbus_frame_desc_entry *fde = &fd.entry[i];
> +	for (unsigned int i = 0; i < fd->num_entries; ++i) {
> +		const struct v4l2_mbus_frame_desc_entry *fde = &fd->entry[i];
>
>  		if (fde->stream == stream) {
>  			*vc = fde->bus.csi2.vc;
> @@ -927,7 +925,7 @@ static void unicam_start_rx(struct unicam_device *unicam,
>  	const struct unicam_format_info *fmtinfo;
>  	const struct v4l2_mbus_framefmt *fmt;
>  	unsigned int line_int_freq;
> -	u8 vc, dt;
> +	u8 vc = 0, dt = 0;

not sure why need here,

if unicam_get_image_vc_dt() return failure, vc will be set to 0
if unicam_get_image_vc_dt() return success, vc will be expected value.

Frank

>  	u32 val;
>  	int ret;
>
> --
> 2.47.3
>