Re: [PATCH v6 3/5] media: v4l2-common: Add kernel-doc for v4l2_fill_pixfmt_mp_aligned()

Hi Tommaso,

On 8/19/26 12:28, Tommaso Merciai wrote:
> Replace the bare placeholder comment with a full kernel-doc block
> documenting all parameters, the function behaviour for both single
> memory plane (mem_planes == 1) and multiple memory plane (mem_planes > 1)
> formats, and the return value.
>
> Reviewed-by: Jacopo Mondi <[email protected]>
> Signed-off-by: Tommaso Merciai <[email protected]>
> ---
> v5->v6:
>   - No changes.
>
> v4->v5:
>   - No changes.
>
> v3->v4:
>   - Collected tag.
>   - Fixed function documentation.
>
> v2->v3:
>   - Moved to PATCH 3/4
>   - Fixed documentation as suggested by Sven Püschel
>
> v1->v2:
>   - New patch
>
>   include/media/v4l2-common.h | 28 +++++++++++++++++++++++++++-
>   1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
> index 4e5c5ffaf651..33f5713734cb 100644
> --- a/include/media/v4l2-common.h
> +++ b/include/media/v4l2-common.h
> @@ -591,7 +591,33 @@ static inline int v4l2_fill_pixfmt(struct v4l2_pix_format *pixfmt,
>   	return v4l2_fill_pixfmt_aligned(pixfmt, pixelformat, width, height, 1);
>   }
>   
> -/* @stride_alignment is a power of 2 value in bytes */
> +/**
> + * v4l2_fill_pixfmt_mp_aligned - Fill in a &struct v4l2_pix_format_mplane with
> + *	stride alignment requirements.
> + *
> + * @pixfmt: pointer to the &struct v4l2_pix_format_mplane to be filled
> + * @pixelformat: the V4L2 pixel format (V4L2_PIX_FMT_*)
> + * @width: image width in pixels
> + * @height: image height in pixels
> + * @stride_alignment: stride alignment in bytes; must be a power of 2
> + *
> + * Fills all fields of @pixfmt for the given pixel format, dimensions, and
> + * stride alignment.
> + *
> + * For formats stored in a single memory plane (mem_planes == 1), the
> + * behaviour matches v4l2_fill_pixfmt_aligned(): plane_fmt[0].bytesperline
> + * is set to the primary plane stride. The strides of all components are
> + * aligned to the @stride_alignment. To keep the chroma strides consistently
> + * derivable from the luma stride, strides may be aligned to a multiple of
> + * the @stride_alignment instead. plane_fmt[0].sizeimage covers all
> + * component planes.

Given that the behavior matches the non mp function, it feels a bit 
redundant to explain the stride scaling again. But I don't mind keeping 
it to make the stride scaling behavior more obvious, so feel free to add

Reviewed-by: Sven Püschel <[email protected]>

> + *
> + * For formats with multiple memory planes (mem_planes > 1), each plane's
> + * bytesperline is independently rounded up to @stride_alignment, and each
> + * plane's sizeimage is set to bytesperline multiplied by the plane height.
> + *
> + * Return: 0 on success, -EINVAL if @pixelformat is unknown.
> + */
>   int v4l2_fill_pixfmt_mp_aligned(struct v4l2_pix_format_mplane *pixfmt,
>   				u32 pixelformat, u32 width, u32 height,
>   				u8 stride_alignment);