linux/linux-5.18.11/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-cod...

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.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: V4L
.. _VIDIOC_SUBDEV_ENUM_MBUS_CODE:
**********************************
ioctl VIDIOC_SUBDEV_ENUM_MBUS_CODE
**********************************
Name
====
VIDIOC_SUBDEV_ENUM_MBUS_CODE - Enumerate media bus formats
Synopsis
========
.. c:macro:: VIDIOC_SUBDEV_ENUM_MBUS_CODE
``int ioctl(int fd, VIDIOC_SUBDEV_ENUM_MBUS_CODE, struct v4l2_subdev_mbus_code_enum * argp)``
Arguments
=========
``fd``
File descriptor returned by :c: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{8.5cm}|
.. 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
- ``flags``
- See :ref:`v4l2-subdev-mbus-code-flags`
* - __u32
- ``reserved``\ [7]
- Reserved for future extensions. Applications and drivers must set
the array to zero.
.. raw:: latex
\footnotesize
.. tabularcolumns:: |p{8.8cm}|p{2.2cm}|p{6.3cm}|
.. _v4l2-subdev-mbus-code-flags:
.. flat-table:: Subdev Media Bus Code Enumerate Flags
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
* - V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE
- 0x00000001
- The driver allows the application to try to change the default colorspace
encoding. The application can ask to configure the colorspace of the
subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
See :ref:`v4l2-mbus-format` on how to do this.
* - V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC
- 0x00000002
- The driver allows the application to try to change the default transform function.
The application can ask to configure the transform function of
the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
See :ref:`v4l2-mbus-format` on how to do this.
* - V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
- 0x00000004
- The driver allows the application to try to change the default Y'CbCr
encoding. The application can ask to configure the Y'CbCr encoding of the
subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
See :ref:`v4l2-mbus-format` on how to do this.
* - V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
- 0x00000004
- The driver allows the application to try to change the default HSV
encoding. The application can ask to configure the HSV encoding of the
subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
See :ref:`v4l2-mbus-format` on how to do this.
* - V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
- 0x00000008
- The driver allows the application to try to change the default
quantization. The application can ask to configure the quantization of
the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
See :ref:`v4l2-mbus-format` on how to do this.
.. raw:: latex
\normalsize
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.