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linux-next/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
Mauro Carvalho Chehab 54f38fcae5 media: docs: move uAPI book to userspace-api/media
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee38 ("docs: Create a user-space API guide").

As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.

Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-04-14 10:31:49 +02:00

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.. Permission is granted to copy, distribute and/or modify this
.. document under the terms of the GNU Free Documentation License,
.. Version 1.1 or any later version published by the Free Software
.. Foundation, with no Invariant Sections, no Front-Cover Texts
.. and no Back-Cover Texts. A copy of the license is included at
.. Documentation/userspace-api/media/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
.. _VIDIOC_SUBDEV_ENUM_MBUS_CODE:
**********************************
ioctl VIDIOC_SUBDEV_ENUM_MBUS_CODE
**********************************
Name
====
VIDIOC_SUBDEV_ENUM_MBUS_CODE - Enumerate media bus formats
Synopsis
========
.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_ENUM_MBUS_CODE, struct v4l2_subdev_mbus_code_enum * argp )
:name: VIDIOC_SUBDEV_ENUM_MBUS_CODE
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``argp``
Pointer to struct :c:type:`v4l2_subdev_mbus_code_enum`.
Description
===========
To enumerate media bus formats available at a given sub-device pad
applications initialize the ``pad``, ``which`` and ``index`` fields of
struct
:c:type:`v4l2_subdev_mbus_code_enum` and
call the :ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE` ioctl with a pointer to this
structure. Drivers fill the rest of the structure or return an ``EINVAL``
error code if either the ``pad`` or ``index`` are invalid. All media bus
formats are enumerable by beginning at index zero and incrementing by
one until ``EINVAL`` is returned.
Available media bus formats may depend on the current 'try' formats at
other pads of the sub-device, as well as on the current active links.
See :ref:`VIDIOC_SUBDEV_G_FMT` for more
information about the try formats.
.. c:type:: v4l2_subdev_mbus_code_enum
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
.. flat-table:: struct v4l2_subdev_mbus_code_enum
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
* - __u32
- ``pad``
- Pad number as reported by the media controller API.
* - __u32
- ``index``
- Number of the format in the enumeration, set by the application.
* - __u32
- ``code``
- The media bus format code, as defined in
:ref:`v4l2-mbus-format`.
* - __u32
- ``which``
- Media bus format codes to be enumerated, from enum
:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
* - __u32
- ``reserved``\ [8]
- Reserved for future extensions. Applications and drivers must set
the array to zero.
Return Value
============
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
The struct
:c:type:`v4l2_subdev_mbus_code_enum`
``pad`` references a non-existing pad, or the ``index`` field is out
of bounds.