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author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-08 11:40:06 -0300 |
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committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-08 11:59:40 -0300 |
commit | 60c2820d0f6d3497975b6488e2599f8f611d8b95 (patch) | |
tree | b3b03707c6438ea9b99cc57e847ebf517f968ab1 /Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst | |
parent | a97369b5e21ea9b8b5fef7c0f4f48bbe60c07ca3 (diff) | |
download | talos-obmc-linux-60c2820d0f6d3497975b6488e2599f8f611d8b95.tar.gz talos-obmc-linux-60c2820d0f6d3497975b6488e2599f8f611d8b95.zip |
doc_rst: rename the media Sphinx suff to Documentation/media
The name of the subsystem is "media", and not "linux_tv". Also,
as we plan to add other stuff there in the future, let's
rename also the media uAPI book to media_uapi, to make it
clearer.
No functional changes.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst')
-rw-r--r-- | Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst b/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst new file mode 100644 index 000000000000..0aa6482a91a6 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-interval.rst @@ -0,0 +1,153 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL: + +*************************************** +ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL +*************************************** + +Name +==== + +VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL - Enumerate frame intervals + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, struct v4l2_subdev_frame_interval_enum * argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``request`` + VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL + +``argp`` + + +Description +=========== + +This ioctl lets applications enumerate available frame intervals on a +given sub-device pad. Frame intervals only makes sense for sub-devices +that can control the frame period on their own. This includes, for +instance, image sensors and TV tuners. + +For the common use case of image sensors, the frame intervals available +on the sub-device output pad depend on the frame format and size on the +same pad. Applications must thus specify the desired format and size +when enumerating frame intervals. + +To enumerate frame intervals applications initialize the ``index``, +``pad``, ``which``, ``code``, ``width`` and ``height`` fields of struct +:ref:`v4l2_subdev_frame_interval_enum <v4l2-subdev-frame-interval-enum>` +and call the :ref:`VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL` ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +EINVAL error code if one of the input fields is invalid. All frame +intervals are enumerable by beginning at index zero and incrementing by +one until ``EINVAL`` is returned. + +Available frame intervals 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. + +Sub-devices that support the frame interval enumeration ioctl should +implemented it on a single pad only. Its behaviour when supported on +multiple pads of the same sub-device is not defined. + + +.. _v4l2-subdev-frame-interval-enum: + +.. flat-table:: struct v4l2_subdev_frame_interval_enum + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + + - .. row 1 + + - __u32 + + - ``index`` + + - Number of the format in the enumeration, set by the application. + + - .. row 2 + + - __u32 + + - ``pad`` + + - Pad number as reported by the media controller API. + + - .. row 3 + + - __u32 + + - ``code`` + + - The media bus format code, as defined in + :ref:`v4l2-mbus-format`. + + - .. row 4 + + - __u32 + + - ``width`` + + - Frame width, in pixels. + + - .. row 5 + + - __u32 + + - ``height`` + + - Frame height, in pixels. + + - .. row 6 + + - struct :ref:`v4l2_fract <v4l2-fract>` + + - ``interval`` + + - Period, in seconds, between consecutive video frames. + + - .. row 7 + + - __u32 + + - ``which`` + + - Frame intervals to be enumerated, from enum + :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. + + - .. row 8 + + - __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 + :ref:`v4l2_subdev_frame_interval_enum <v4l2-subdev-frame-interval-enum>` + ``pad`` references a non-existing pad, one of the ``code``, + ``width`` or ``height`` fields are invalid for the given pad or the + ``index`` field is out of bounds. |