linux-kernel - Re: [PATCH v4 05/10] media: Add BGR48

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Message-ID: <2b93f81f-a0d6-2a09-31af-393e94faa83c@xs4all.nl>
Date:   Tue, 21 Mar 2023 11:54:52 +0100
From:   Hans Verkuil <hverkuil-cisco@...all.nl>
To:     Ming Qian <ming.qian@....com>, mchehab@...nel.org,
        mirela.rabulea@....nxp.com
Cc:     shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        festevam@...il.com, xiahong.bao@....com, linux-imx@....com,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 05/10] media: Add BGR48_12 video format

On 14/03/2023 11:08, Ming Qian wrote:
> BGR48_12 is a reversed RGB format with 12 bits per component like BGR24,
> expanded to 16bits.
> Data in the 12 high bits, zeros in the 4 low bits,
> arranged in little endian order.
> 
> Signed-off-by: Ming Qian <ming.qian@....com>
> ---
>  .../userspace-api/media/v4l/pixfmt-rgb.rst    | 33 +++++++++++++++++++
>  drivers/media/v4l2-core/v4l2-common.c         |  1 +
>  drivers/media/v4l2-core/v4l2-ioctl.c          |  1 +
>  include/uapi/linux/videodev2.h                |  3 ++
>  4 files changed, 38 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-rgb.rst b/Documentation/userspace-api/media/v4l/pixfmt-rgb.rst
> index d330aeb4d3eb..fc98a10991f1 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-rgb.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-rgb.rst
> @@ -956,6 +956,39 @@ number of bits for each component.
>  
>      \endgroup
>  
> +12 Bits Per Component
> +==============================
> +
> +These formats store an RGB triplet in six or eighth bytes, with 12 bits per component.

eighth -> eight

> +expand the bits per component to 16 bits, data in the high bits, zeros in the low bits,

expand -> Expand

> +arranged in little endian order.
> +
> +.. raw:: latex
> +
> +    \small
> +
> +.. flat-table:: RGB Formats With 12 Bits Per Component
> +    :header-rows:  1
> +
> +    * - Identifier
> +      - Code
> +      - Byte 1-0
> +      - Byte 3-2
> +      - Byte 5-4
> +      - Byte 7-6
> +    * .. _V4L2-PIX-FMT-BGR48-12:
> +
> +      - ``V4L2_PIX_FMT_BGR48_12``
> +      - 'B312'
> +
> +      - B\ :sub:`15-4`
> +      - G\ :sub:`15-4`
> +      - R\ :sub:`15-4`
> +      -
> +
> +.. raw:: latex
> +
> +    \normalsize
>  
>  Deprecated RGB Formats
>  ======================
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index da313a0637de..16d3c91c7da2 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -252,6 +252,7 @@ const struct v4l2_format_info *v4l2_format_info(u32 format)
>  		{ .format = V4L2_PIX_FMT_RGB565,  .pixel_enc = V4L2_PIXEL_ENC_RGB, .mem_planes = 1, .comp_planes = 1, .bpp = { 2, 0, 0, 0 }, .hdiv = 1, .vdiv = 1 },
>  		{ .format = V4L2_PIX_FMT_RGB555,  .pixel_enc = V4L2_PIXEL_ENC_RGB, .mem_planes = 1, .comp_planes = 1, .bpp = { 2, 0, 0, 0 }, .hdiv = 1, .vdiv = 1 },
>  		{ .format = V4L2_PIX_FMT_BGR666,  .pixel_enc = V4L2_PIXEL_ENC_RGB, .mem_planes = 1, .comp_planes = 1, .bpp = { 4, 0, 0, 0 }, .hdiv = 1, .vdiv = 1 },
> +		{ .format = V4L2_PIX_FMT_BGR48_12, .pixel_enc = V4L2_PIXEL_ENC_RGB, .mem_planes = 1, .comp_planes = 1, .bpp = { 6, 0, 0, 0 }, .hdiv = 1, .vdiv = 1 },
>  
>  		/* YUV packed formats */
>  		{ .format = V4L2_PIX_FMT_YUYV,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 1, .bpp = { 2, 0, 0, 0 }, .hdiv = 2, .vdiv = 1 },
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 6543cda5815f..6d9599391d7b 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1302,6 +1302,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>  	case V4L2_PIX_FMT_RGBX1010102:	descr = "32-bit RGBX 10-10-10-2"; break;
>  	case V4L2_PIX_FMT_RGBA1010102:	descr = "32-bit RGBA 10-10-10-2"; break;
>  	case V4L2_PIX_FMT_ARGB2101010:	descr = "32-bit ARGB 2-10-10-10"; break;
> +	case V4L2_PIX_FMT_BGR48_12:	descr = "12-bit Depth BGR"; break;
>  	case V4L2_PIX_FMT_GREY:		descr = "8-bit Greyscale"; break;
>  	case V4L2_PIX_FMT_Y4:		descr = "4-bit Greyscale"; break;
>  	case V4L2_PIX_FMT_Y6:		descr = "6-bit Greyscale"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 8a6430bc4a00..3c5acd72606c 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -580,6 +580,9 @@ struct v4l2_pix_format {
>  #define V4L2_PIX_FMT_RGBA1010102 v4l2_fourcc('R', 'A', '3', '0') /* 32  RGBA-10-10-10-2 */
>  #define V4L2_PIX_FMT_ARGB2101010 v4l2_fourcc('A', 'R', '3', '0') /* 32  ARGB-2-10-10-10 */
>  
> +/* RGB formats (6 or 8 bytes per pixel) */
> +#define V4L2_PIX_FMT_BGR48_12    v4l2_fourcc('B', '3', '1', '2') /* 48  BGR 12-bit per component */
> +
>  /* Grey formats */
>  #define V4L2_PIX_FMT_GREY    v4l2_fourcc('G', 'R', 'E', 'Y') /*  8  Greyscale     */
>  #define V4L2_PIX_FMT_Y4      v4l2_fourcc('Y', '0', '4', ' ') /*  4  Greyscale     */

Regards,

	Hans