vidioc-subdev-enum-mbus-code.rst

  1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
  2.. c:namespace:: V4L
  3
  4.. _VIDIOC_SUBDEV_ENUM_MBUS_CODE:
  5
  6**********************************
  7ioctl VIDIOC_SUBDEV_ENUM_MBUS_CODE
  8**********************************
  9
 10Name
 11====
 12
 13VIDIOC_SUBDEV_ENUM_MBUS_CODE - Enumerate media bus formats
 14
 15Synopsis
 16========
 17
 18.. c:macro:: VIDIOC_SUBDEV_ENUM_MBUS_CODE
 19
 20``int ioctl(int fd, VIDIOC_SUBDEV_ENUM_MBUS_CODE, struct v4l2_subdev_mbus_code_enum * argp)``
 21
 22Arguments
 23=========
 24
 25``fd``
 26    File descriptor returned by :c:func:`open()`.
 27
 28``argp``
 29    Pointer to struct :c:type:`v4l2_subdev_mbus_code_enum`.
 30
 31Description
 32===========
 33
 34This call is used by the application to access the enumeration
 35of media bus formats for the selected pad.
 36
 37The enumerations are defined by the driver, and indexed using the ``index`` field
 38of struct :c:type:`v4l2_subdev_mbus_code_enum`.
 39Each enumeration starts with the ``index`` of 0, and
 40the lowest invalid index marks the end of enumeration.
 41
 42Therefore, to enumerate media bus formats available at a given sub-device pad,
 43initialize the ``pad``, and ``which`` fields to desired values,
 44and set ``index`` to 0.
 45Then call the :ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE` ioctl
 46with a pointer to this structure.
 47
 48A successful call will return with the ``code`` field filled in
 49with a mbus code value.
 50Repeat with increasing ``index`` until ``EINVAL`` is received.
 51``EINVAL`` means that either ``pad`` is invalid,
 52or that there are no more codes available at this pad.
 53
 54The driver must not return the same value of ``code`` for different indices
 55at the same pad.
 56
 57Available media bus formats may depend on the current 'try' formats at
 58other pads of the sub-device, as well as on the current active links.
 59See :ref:`VIDIOC_SUBDEV_G_FMT` for more
 60information about the try formats.
 61
 62.. c:type:: v4l2_subdev_mbus_code_enum
 63
 64.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
 65
 66.. flat-table:: struct v4l2_subdev_mbus_code_enum
 67    :header-rows:  0
 68    :stub-columns: 0
 69    :widths:       1 1 2
 70
 71    * - __u32
 72      - ``pad``
 73      - Pad number as reported by the media controller API. Filled in by the
 74        application.
 75    * - __u32
 76      - ``index``
 77      - Index of the mbus code in the enumeration belonging to the given pad.
 78        Filled in by the application.
 79    * - __u32
 80      - ``code``
 81      - The media bus format code, as defined in
 82	:ref:`v4l2-mbus-format`. Filled in by the driver.
 83    * - __u32
 84      - ``which``
 85      - Media bus format codes to be enumerated, from enum
 86	:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
 87    * - __u32
 88      - ``flags``
 89      - See :ref:`v4l2-subdev-mbus-code-flags`
 90    * - __u32
 91      - ``stream``
 92      - Stream identifier.
 93    * - __u32
 94      - ``reserved``\ [6]
 95      - Reserved for future extensions. Applications and drivers must set
 96	the array to zero.
 97
 98
 99
100.. raw:: latex
101
102   \footnotesize
103
104.. tabularcolumns:: |p{8.8cm}|p{2.2cm}|p{6.3cm}|
105
106.. _v4l2-subdev-mbus-code-flags:
107
108.. flat-table:: Subdev Media Bus Code Enumerate Flags
109    :header-rows:  0
110    :stub-columns: 0
111    :widths:       1 1 2
112
113    * - V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE
114      - 0x00000001
115      - The driver allows the application to try to change the default colorspace
116	encoding. The application can ask to configure the colorspace of the
117	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
118	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
119	See :ref:`v4l2-mbus-format` on how to do this.
120    * - V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC
121      - 0x00000002
122      - The driver allows the application to try to change the default transform function.
123	The application can ask to configure the transform function of
124	the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
125	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
126	See :ref:`v4l2-mbus-format` on how to do this.
127    * - V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
128      - 0x00000004
129      - The driver allows the application to try to change the default Y'CbCr
130	encoding. The application can ask to configure the Y'CbCr encoding of the
131	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
132	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
133	See :ref:`v4l2-mbus-format` on how to do this.
134    * - V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
135      - 0x00000004
136      - The driver allows the application to try to change the default HSV
137	encoding. The application can ask to configure the HSV encoding of the
138	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
139	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
140	See :ref:`v4l2-mbus-format` on how to do this.
141    * - V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
142      - 0x00000008
143      - The driver allows the application to try to change the default
144	quantization. The application can ask to configure the quantization of
145	the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
146	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
147	See :ref:`v4l2-mbus-format` on how to do this.
148
149.. raw:: latex
150
151   \normalsize
152
153Return Value
154============
155
156On success 0 is returned, on error -1 and the ``errno`` variable is set
157appropriately. The generic error codes are described at the
158:ref:`Generic Error Codes <gen-errors>` chapter.
159
160EINVAL
161    The struct :c:type:`v4l2_subdev_mbus_code_enum` ``pad`` references a
162    non-existing pad, the ``which`` field has an unsupported value, or the
163    ``index`` field is out of bounds.