diff options
Diffstat (limited to 'Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst | 129 |
1 files changed, 97 insertions, 32 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst index 35b8607203a4..3050966b199f 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst @@ -1,11 +1,5 @@ -.. 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 +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L .. _VIDIOC_SUBDEV_ENUM_MBUS_CODE: @@ -18,46 +12,56 @@ 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 +.. 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 :ref:`open() <func-open>`. + 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. +This call is used by the application to access the enumeration +of media bus formats for the selected pad. + +The enumerations are defined by the driver, and indexed using the ``index`` field +of struct :c:type:`v4l2_subdev_mbus_code_enum`. +Each enumeration starts with the ``index`` of 0, and +the lowest invalid index marks the end of enumeration. + +Therefore, to enumerate media bus formats available at a given sub-device pad, +initialize the ``pad``, and ``which`` fields to desired values, +and set ``index`` to 0. +Then call the :ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE` ioctl +with a pointer to this structure. + +A successful call will return with the ``code`` field filled in +with a mbus code value. +Repeat with increasing ``index`` until ``EINVAL`` is received. +``EINVAL`` means that either ``pad`` is invalid, +or that there are no more codes available at this pad. + +The driver must not return the same value of ``code`` for different indices +at the same pad. 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}| +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| .. flat-table:: struct v4l2_subdev_mbus_code_enum :header-rows: 0 @@ -66,24 +70,86 @@ information about the try formats. * - __u32 - ``pad`` - - Pad number as reported by the media controller API. + - Pad number as reported by the media controller API. Filled in by the + application. * - __u32 - ``index`` - - Number of the format in the enumeration, set by the application. + - Index of the mbus code in the enumeration belonging to the given pad. + Filled in by the application. * - __u32 - ``code`` - The media bus format code, as defined in - :ref:`v4l2-mbus-format`. + :ref:`v4l2-mbus-format`. Filled in by the driver. * - __u32 - ``which`` - Media bus format codes to be enumerated, from enum :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. * - __u32 - - ``reserved``\ [8] + - ``flags`` + - See :ref:`v4l2-subdev-mbus-code-flags` + * - __u32 + - ``stream`` + - Stream identifier. + * - __u32 + - ``reserved``\ [6] - 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 ============ @@ -92,7 +158,6 @@ 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. + The struct :c:type:`v4l2_subdev_mbus_code_enum` ``pad`` references a + non-existing pad, the ``which`` field has an unsupported value, or the + ``index`` field is out of bounds. |