Re: [PATCH 1/3] media: uapi: videodev2: Add 20-bit Bayer formats

[Jacopo Mondi <jacopo.mondi@ideasonboard.com>]

Hi Niklas

On Thu, Sep 10, 2026 at 07:22:31PM +0200, Niklas Söderlund wrote:
> Add 20-bit Bayer formats and documentation.
>
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> ---
>  .../userspace-api/media/v4l/pixfmt-bayer.rst       |   1 +
>  .../userspace-api/media/v4l/pixfmt-srggb20.rst     | 102 +++++++++++++++++++++
>  drivers/media/v4l2-core/v4l2-ioctl.c               |   4 +
>  include/uapi/linux/videodev2.h                     |   4 +
>  4 files changed, 111 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-bayer.rst b/Documentation/userspace-api/media/v4l/pixfmt-bayer.rst
> index 8b4e413177f5..b93e66d6a27e 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-bayer.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-bayer.rst
> @@ -33,3 +33,4 @@ orders. See also `the Wikipedia article on Bayer filter
>      pixfmt-srggb14
>      pixfmt-srggb14p
>      pixfmt-srggb16
> +    pixfmt-srggb20
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-srggb20.rst b/Documentation/userspace-api/media/v4l/pixfmt-srggb20.rst
> new file mode 100644
> index 000000000000..cf911e93aa8d
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-srggb20.rst
> @@ -0,0 +1,102 @@
> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> +.. c:namespace:: V4L
> +
> +.. _V4L2-PIX-FMT-SRGGB20:
> +.. _v4l2-pix-fmt-sbggr20:
> +.. _v4l2-pix-fmt-sgbrg20:
> +.. _v4l2-pix-fmt-sgrbg20:
> +
> +***************************************************************************************************************************
> +V4L2_PIX_FMT_SBGGR20 ('BG20'), V4L2_PIX_FMT_SGBRG20 ('GB20'), V4L2_PIX_FMT_SGRBG20 ('GR20'), V4L2_PIX_FMT_SRGGB20 ('RG20'),
> +***************************************************************************************************************************
> +
> +
> +====================
> +20-bit Bayer formats
> +====================
> +
> +
> +Description
> +===========
> +
> +These four pixel formats are raw sRGB / Bayer formats with 20 bits per
> +sample. Each sample is stored in a 32-bit word. Each n-pixel row contains
> +n/2 green samples and n/2 blue or red samples, with alternating red and blue
> +rows. Bytes are stored in memory in little endian order. They are
> +conventionally described as GRGR... BGBG..., RGRG... GBGB..., etc. Below is
> +an example of one sample.
> +
> +.. cssclass: longtable
> +
> +.. flat-table:: 20-bit Bayer Formats
> +    :header-rows:  2
> +    :stub-columns: 0
> +
> +    * -
> +      - :cspan:`31` Sample organization
> +    * - Bit

One more question, the other RAW formats show a byte-organized table,
where the R G and B components are shown as line-interleaved
components (hope this is clear, have a look at the tables at
Documentation/output/userspace-api/media/v4l/pixfmt-srggb16.html
and compare it with
Documentation/output/userspace-api/media/v4l/pixfmt-srggb20.html)

Was this intentional ?

> +      - 31
> +      - 30
> +      - 29
> +      - 28
> +      - 27
> +      - 26
> +      - 25
> +      - 24
> +      - 23
> +      - 22
> +      - 21
> +      - 20
> +      - 19
> +      - 18
> +      - 17
> +      - 16
> +      - 15
> +      - 14
> +      - 13
> +      - 12
> +      - 11
> +      - 10
> +      - 9
> +      - 8
> +      - 7
> +      - 6
> +      - 5
> +      - 4
> +      - 3
> +      - 2
> +      - 1
> +      - 0
> +    * -
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - *
> +      - P\ :sub:`19`
> +      - P\ :sub:`18`
> +      - P\ :sub:`17`
> +      - P\ :sub:`16`
> +      - P\ :sub:`15`
> +      - P\ :sub:`14`
> +      - P\ :sub:`13`
> +      - P\ :sub:`12`
> +      - P\ :sub:`11`
> +      - P\ :sub:`10`
> +      - P\ :sub:`9`
> +      - P\ :sub:`8`
> +      - P\ :sub:`7`
> +      - P\ :sub:`6`
> +      - P\ :sub:`5`
> +      - P\ :sub:`4`
> +      - P\ :sub:`3`
> +      - P\ :sub:`2`
> +      - P\ :sub:`1`
> +      - P\ :sub:`0`
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 17ba1ae70735..14cb94591ea8 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1434,6 +1434,10 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>  	case V4L2_PIX_FMT_SGBRG16:	descr = "16-bit Bayer GBGB/RGRG"; break;
>  	case V4L2_PIX_FMT_SGRBG16:	descr = "16-bit Bayer GRGR/BGBG"; break;
>  	case V4L2_PIX_FMT_SRGGB16:	descr = "16-bit Bayer RGRG/GBGB"; break;
> +	case V4L2_PIX_FMT_SBGGR20:	descr = "20-bit Bayer BGBG/GRGR"; break;
> +	case V4L2_PIX_FMT_SGBRG20:	descr = "20-bit Bayer GBGB/RGRG"; break;
> +	case V4L2_PIX_FMT_SGRBG20:	descr = "20-bit Bayer GRGR/BGBG"; break;
> +	case V4L2_PIX_FMT_SRGGB20:	descr = "20-bit Bayer RGRG/GBGB"; break;
>  	case V4L2_PIX_FMT_RAW_CRU20:	descr = "14-bit Raw CRU Packed"; break;
>  	case V4L2_PIX_FMT_SN9C20X_I420:	descr = "GSPCA SN9C20X I420"; break;
>  	case V4L2_PIX_FMT_SPCA501:	descr = "GSPCA SPCA501"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 5373dba640fa..85a32dee4e21 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -744,6 +744,10 @@ struct v4l2_pix_format {
>  #define V4L2_PIX_FMT_SGBRG16 v4l2_fourcc('G', 'B', '1', '6') /* 16  GBGB.. RGRG.. */
>  #define V4L2_PIX_FMT_SGRBG16 v4l2_fourcc('G', 'R', '1', '6') /* 16  GRGR.. BGBG.. */
>  #define V4L2_PIX_FMT_SRGGB16 v4l2_fourcc('R', 'G', '1', '6') /* 16  RGRG.. GBGB.. */
> +#define V4L2_PIX_FMT_SBGGR20 v4l2_fourcc('B', 'G', '2', '0') /* 20  BGBG.. GRGR.. */
> +#define V4L2_PIX_FMT_SGBRG20 v4l2_fourcc('G', 'B', '2', '0') /* 20  GBGB.. RGRG.. */
> +#define V4L2_PIX_FMT_SGRBG20 v4l2_fourcc('G', 'R', '2', '0') /* 20  GRGR.. BGBG.. */
> +#define V4L2_PIX_FMT_SRGGB20 v4l2_fourcc('R', 'G', '2', '0') /* 20  RGRG.. GBGB.. */
>
>  /* HSV formats */
>  #define V4L2_PIX_FMT_HSV24 v4l2_fourcc('H', 'S', 'V', '3')
>
> --
> 2.55.0
>
>