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linux-next/Documentation/media/uapi/v4l/vidioc-subdev-enum-mbus-code.rst
Mauro Carvalho Chehab 1473c75e9a media: v4l uAPI: add descriptions for arguments to all ioctls
Several ioctls are missing descriptions for the third argument
of the ioctl() command. They should have a description, as
otherwise the output won't be ok, and will sound like something
is missing.

So, add them.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-09-05 06:24:28 -04:00

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ReStructuredText

.. -*- coding: utf-8; mode: rst -*-
.. _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.