Re: [PATCH v12 08/15] media: uapi: Define audio sample format fourcc type

[Mauro Carvalho Chehab <mchehab@kernel.org>]

Em Thu, 18 Jan 2024 20:32:01 +0800
Shengjiu Wang <shengjiu.wang@nxp.com> escreveu:

> The audio sample format definition is from alsa,
> the header file is include/uapi/sound/asound.h, but
> don't include this header file directly, because in
> user space, there is another copy in alsa-lib.
> There will be conflict in userspace for include
> videodev2.h & asound.h and asoundlib.h
> 
> Here still use the fourcc format.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> ---
>  .../userspace-api/media/v4l/pixfmt-audio.rst  | 87 +++++++++++++++++++
>  .../userspace-api/media/v4l/pixfmt.rst        |  1 +
>  drivers/media/v4l2-core/v4l2-ioctl.c          | 13 +++
>  include/uapi/linux/videodev2.h                | 23 +++++
>  4 files changed, 124 insertions(+)
>  create mode 100644 Documentation/userspace-api/media/v4l/pixfmt-audio.rst
> 
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-audio.rst b/Documentation/userspace-api/media/v4l/pixfmt-audio.rst
> new file mode 100644
> index 000000000000..04b4a7fbd8f4
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-audio.rst
> @@ -0,0 +1,87 @@
> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> +
> +.. _pixfmt-audio:
> +
> +*************
> +Audio Formats
> +*************
> +
> +These formats are used for :ref:`audiomem2mem` interface only.
> +
> +.. tabularcolumns:: |p{5.8cm}|p{1.2cm}|p{10.3cm}|
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: Audio Format
> +    :header-rows:  1
> +    :stub-columns: 0
> +    :widths:       3 1 4
> +
> +    * - Identifier
> +      - Code
> +      - Details
> +    * .. _V4L2-AUDIO-FMT-S8:
> +
> +      - ``V4L2_AUDIO_FMT_S8``
> +      - 'S8'
> +      - Corresponds to SNDRV_PCM_FORMAT_S8 in ALSA
> +    * .. _V4L2-AUDIO-FMT-S16-LE:

Hmm... why can't we just use SNDRV_*_FORMAT_*? Those are already part of
an uAPI header. No need to add any abstraction here and/or redefine
what is there already at include/uapi/sound/asound.h.

Thanks,
Mauro