164 lines
5.5 KiB
ReStructuredText
164 lines
5.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
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.. c:namespace:: V4L
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.. _VIDIOC_SUBDEV_ENUM_MBUS_CODE:
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**********************************
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ioctl VIDIOC_SUBDEV_ENUM_MBUS_CODE
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**********************************
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Name
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====
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VIDIOC_SUBDEV_ENUM_MBUS_CODE - Enumerate media bus formats
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Synopsis
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========
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.. c:macro:: VIDIOC_SUBDEV_ENUM_MBUS_CODE
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``int ioctl(int fd, VIDIOC_SUBDEV_ENUM_MBUS_CODE, struct v4l2_subdev_mbus_code_enum * argp)``
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Arguments
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=========
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``fd``
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File descriptor returned by :c:func:`open()`.
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``argp``
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Pointer to struct :c:type:`v4l2_subdev_mbus_code_enum`.
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Description
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===========
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This call is used by the application to access the enumeration
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of media bus formats for the selected pad.
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The enumerations are defined by the driver, and indexed using the ``index`` field
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of struct :c:type:`v4l2_subdev_mbus_code_enum`.
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Each enumeration starts with the ``index`` of 0, and
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the lowest invalid index marks the end of enumeration.
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Therefore, to enumerate media bus formats available at a given sub-device pad,
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initialize the ``pad``, and ``which`` fields to desired values,
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and set ``index`` to 0.
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Then call the :ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE` ioctl
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with a pointer to this structure.
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A successful call will return with the ``code`` field filled in
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with a mbus code value.
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Repeat with increasing ``index`` until ``EINVAL`` is received.
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``EINVAL`` means that either ``pad`` is invalid,
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or that there are no more codes available at this pad.
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The driver must not return the same value of ``code`` for different indices
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at the same pad.
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Available media bus formats may depend on the current 'try' formats at
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other pads of the sub-device, as well as on the current active links.
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See :ref:`VIDIOC_SUBDEV_G_FMT` for more
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information about the try formats.
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.. c:type:: v4l2_subdev_mbus_code_enum
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.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
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.. flat-table:: struct v4l2_subdev_mbus_code_enum
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:header-rows: 0
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:stub-columns: 0
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:widths: 1 1 2
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* - __u32
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- ``pad``
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- Pad number as reported by the media controller API. Filled in by the
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application.
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* - __u32
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- ``index``
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- Index of the mbus code in the enumeration belonging to the given pad.
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Filled in by the application.
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* - __u32
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- ``code``
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- The media bus format code, as defined in
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:ref:`v4l2-mbus-format`. Filled in by the driver.
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* - __u32
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- ``which``
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- Media bus format codes to be enumerated, from enum
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:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
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* - __u32
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- ``flags``
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- See :ref:`v4l2-subdev-mbus-code-flags`
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* - __u32
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- ``stream``
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- Stream identifier.
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* - __u32
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- ``reserved``\ [6]
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- Reserved for future extensions. Applications and drivers must set
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the array to zero.
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.. raw:: latex
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\footnotesize
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.. tabularcolumns:: |p{8.8cm}|p{2.2cm}|p{6.3cm}|
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.. _v4l2-subdev-mbus-code-flags:
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.. flat-table:: Subdev Media Bus Code Enumerate Flags
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:header-rows: 0
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:stub-columns: 0
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:widths: 1 1 2
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* - V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE
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- 0x00000001
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- The driver allows the application to try to change the default colorspace
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encoding. The application can ask to configure the colorspace of the
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subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
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ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
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See :ref:`v4l2-mbus-format` on how to do this.
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* - V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC
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- 0x00000002
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- The driver allows the application to try to change the default transform function.
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The application can ask to configure the transform function of
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the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
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ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
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See :ref:`v4l2-mbus-format` on how to do this.
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* - V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
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- 0x00000004
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- The driver allows the application to try to change the default Y'CbCr
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encoding. The application can ask to configure the Y'CbCr encoding of the
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subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
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ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
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See :ref:`v4l2-mbus-format` on how to do this.
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* - V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
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- 0x00000004
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- The driver allows the application to try to change the default HSV
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encoding. The application can ask to configure the HSV encoding of the
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subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
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ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
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See :ref:`v4l2-mbus-format` on how to do this.
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* - V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
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- 0x00000008
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- The driver allows the application to try to change the default
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quantization. The application can ask to configure the quantization of
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the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
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ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
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See :ref:`v4l2-mbus-format` on how to do this.
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.. raw:: latex
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\normalsize
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Return Value
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============
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On success 0 is returned, on error -1 and the ``errno`` variable is set
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appropriately. The generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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EINVAL
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The struct :c:type:`v4l2_subdev_mbus_code_enum` ``pad`` references a
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non-existing pad, the ``which`` field has an unsupported value, or the
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``index`` field is out of bounds.
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