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Message-ID: <626c87dc2aede6998053bf2184f8aacace92ba93.camel@ndufresne.ca>
Subject: Re: [RFC PATCH 1/3] media: Add 10, 12, and 16 bit RGB formats
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     =?UTF-8?Q?Pawe=C5=82?= Anikiel <pan@semihalf.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org
Cc:     dinguyen@kernel.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        mchehab@kernel.org, upstream@semihalf.com, amstan@chromium.org,
        ribalda@chromium.org
Date:   Fri, 07 Jul 2023 14:34:13 -0400
In-Reply-To: <20230630144006.1513270-2-pan@semihalf.com>
References: <20230630144006.1513270-1-pan@semihalf.com>
         <20230630144006.1513270-2-pan@semihalf.com>
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Hi,

Le vendredi 30 juin 2023 =C3=A0 16:40 +0200, Pawe=C5=82 Anikiel a =C3=A9cri=
t=C2=A0:
> Add the RGB30U, RGB30L, RGB36U, RGB36L, and RGB48 pixel formats.
>=20
> Signed-off-by: Pawe=C5=82 Anikiel <pan@semihalf.com>
> ---
>  drivers/media/v4l2-core/v4l2-ioctl.c | 5 +++++
>  include/uapi/linux/videodev2.h       | 5 +++++
>  2 files changed, 10 insertions(+)
>=20
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-co=
re/v4l2-ioctl.c
> index a858acea6547..5ee616704225 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1300,6 +1300,11 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *=
fmt)
>  	case V4L2_PIX_FMT_ARGB2101010:	descr =3D "32-bit ARGB 2-10-10-10"; brea=
k;
>  	case V4L2_PIX_FMT_BGR48_12:	descr =3D "12-bit Depth BGR"; break;
>  	case V4L2_PIX_FMT_ABGR64_12:	descr =3D "12-bit Depth BGRA"; break;
> +	case V4L2_PIX_FMT_RGB30U:	descr =3D "30-bit RXGXBX-10-10-10"; break;
> +	case V4L2_PIX_FMT_RGB30L:	descr =3D "30-bit XRXGXB-10-10-10"; break;
> +	case V4L2_PIX_FMT_RGB36U:	descr =3D "36-bit RXGXBX-12-12-12"; break;
> +	case V4L2_PIX_FMT_RGB36L:	descr =3D "36-bit XRXGXB-12-12-12"; break;
> +	case V4L2_PIX_FMT_RGB48:	descr =3D "48-bit RGB-16-16-16"; break;
>  	case V4L2_PIX_FMT_GREY:		descr =3D "8-bit Greyscale"; break;
>  	case V4L2_PIX_FMT_Y4:		descr =3D "4-bit Greyscale"; break;
>  	case V4L2_PIX_FMT_Y6:		descr =3D "6-bit Greyscale"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev=
2.h
> index aee75eb9e686..3568819eabeb 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -583,6 +583,11 @@ struct v4l2_pix_format {
>  /* 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 */
>  #define V4L2_PIX_FMT_ABGR64_12   v4l2_fourcc('B', '4', '1', '2') /* 64  =
BGRA 12-bit per component */
> +#define V4L2_PIX_FMT_RGB30U  v4l2_fourcc('R', '3', '0', 'U') /* 30  RXGX=
BX-10-10-10 */
> +#define V4L2_PIX_FMT_RGB30L  v4l2_fourcc('R', '3', '0', 'L') /* 30  XRXG=
XB-10-10-10 */
> +#define V4L2_PIX_FMT_RGB36U  v4l2_fourcc('R', '3', '6', 'U') /* 36  RXGX=
BX-12-12-12 */
> +#define V4L2_PIX_FMT_RGB36L  v4l2_fourcc('R', '3', '6', 'L') /* 36  XRXG=
XB-12-12-12 */
> +#define V4L2_PIX_FMT_RGB48   v4l2_fourcc('R', 'G', 'B', '6') /* 48  RGB-=
16-16-16    */

In a finalize patch, this would also need to be documented in
Documentation/userspace-api/media/v4l/pixfmt-rgb.rst . About this, what doe=
s  U
and L stands for ? Upper/lower for the padded bit placement ? Though, it lo=
oks
like the other way around in the comment, which may underline a Linux DRM s=
tyle
format documentation.

Nicolas

> =20
>  /* Grey formats */
>  #define V4L2_PIX_FMT_GREY    v4l2_fourcc('G', 'R', 'E', 'Y') /*  8  Grey=
scale     */