>From: Nicolas Dufresne <nicolas@xxxxxxxxxxxx>
>Sent: 2023年2月10日 23:18
>To: Ming Qian <ming.qian@xxxxxxx>; mchehab@xxxxxxxxxx; Mirela Rabulea
>(OSS) <mirela.rabulea@xxxxxxxxxxx>; hverkuil-cisco@xxxxxxxxx
>Cc: shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
>festevam@xxxxxxxxx; X.H. Bao <xiahong.bao@xxxxxxx>; dl-linux-imx <linux-
>imx@xxxxxxx>; linux-media@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
>devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>Subject: [EXT] Re: [PATCH v2 02/10] media: Add Y012 video format
>
>Caution: EXT Email
>
>Le mercredi 01 février 2023 à 14:02 +0800, Ming Qian a écrit :
>> Y012 is a luma-only formats with 12-bits per pixel, 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@xxxxxxx>
>> ---
>> .../userspace-api/media/v4l/pixfmt-yuv-luma.rst | 11 +++++++++++
>> drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
>> include/uapi/linux/videodev2.h | 1 +
>> 3 files changed, 13 insertions(+)
>>
>> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-luma.rst
>> b/Documentation/userspace-api/media/v4l/pixfmt-yuv-luma.rst
>> index 6a387f9df3ba..3ffa29000238 100644
>> --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-luma.rst
>> +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-luma.rst
>> @@ -103,6 +103,17 @@ are often referred to as greyscale formats.
>> - ...
>> - ...
>>
>> + * .. _V4L2-PIX-FMT-Y012:
>
>Why the 0, can't this be name Y12 (just like Y14) ?
>
Hi Nicolas,
As the V4L2_PIX_FMT_Y12 is defined, but it's data is in the 12 low bits, zeros in the high bits.
Here I want to place the 12 bits data in the high bits, with zeros in the 4 low bits.
So I add 0 before 12, I want to say that the low bits are padding data 0.
Or do you have a better suggestion?
Ming
>> +
>> + - ``V4L2_PIX_FMT_Y012``
>> + - 'Y012'
>> +
>> + - Y'\ :sub:`0`\ [3:0] `0000`
>> + - Y'\ :sub:`0`\ [11:4]
>> + - ...
>> + - ...
>> + - ...
>> +
>> * .. _V4L2-PIX-FMT-Y14:
>>
>> - ``V4L2_PIX_FMT_Y14``
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c
>> b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 067dbdd0a9ef..0ee730aa6cc7 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -1303,6 +1303,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc
>*fmt)
>> case V4L2_PIX_FMT_Y6: descr = "6-bit Greyscale"; break;
>> case V4L2_PIX_FMT_Y10: descr = "10-bit Greyscale"; break;
>> case V4L2_PIX_FMT_Y12: descr = "12-bit Greyscale"; break;
>> + case V4L2_PIX_FMT_Y012: descr = "12-bit Greyscale"; break;
>> case V4L2_PIX_FMT_Y14: descr = "14-bit Greyscale"; break;
>> case V4L2_PIX_FMT_Y16: descr = "16-bit Greyscale"; break;
>> case V4L2_PIX_FMT_Y16_BE: descr = "16-bit Greyscale BE"; break;
>> diff --git a/include/uapi/linux/videodev2.h
>> b/include/uapi/linux/videodev2.h index 5448aa3b7858..3d8f89bff33c
>> 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -583,6 +583,7 @@ struct v4l2_pix_format {
>> #define V4L2_PIX_FMT_Y6 v4l2_fourcc('Y', '0', '6', ' ') /* 6 Greyscale */
>> #define V4L2_PIX_FMT_Y10 v4l2_fourcc('Y', '1', '0', ' ') /* 10 Greyscale
>*/
>> #define V4L2_PIX_FMT_Y12 v4l2_fourcc('Y', '1', '2', ' ') /* 12 Greyscale
>*/
>> +#define V4L2_PIX_FMT_Y012 v4l2_fourcc('Y', '0', '1', '2') /* 12 Greyscale
>*/
>> #define V4L2_PIX_FMT_Y14 v4l2_fourcc('Y', '1', '4', ' ') /* 14 Greyscale
>*/
>> #define V4L2_PIX_FMT_Y16 v4l2_fourcc('Y', '1', '6', ' ') /* 16 Greyscale
>*/
>> #define V4L2_PIX_FMT_Y16_BE v4l2_fourcc_be('Y', '1', '6', ' ') /* 16
>> Greyscale BE */
