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linux-next/Documentation/userspace-api/media/v4l/vidioc-dv-timings-cap.rst
Mauro Carvalho Chehab 407e84cd1e media: docs: make V4L documents more compatible with Sphinx 3.1+
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Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-10-15 07:49:39 +02:00

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.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: V4L
.. _VIDIOC_DV_TIMINGS_CAP:
*********************************************************
ioctl VIDIOC_DV_TIMINGS_CAP, VIDIOC_SUBDEV_DV_TIMINGS_CAP
*********************************************************
Name
====
VIDIOC_DV_TIMINGS_CAP - VIDIOC_SUBDEV_DV_TIMINGS_CAP - The capabilities of the Digital Video receiver/transmitter
Synopsis
========
.. c:macro:: VIDIOC_DV_TIMINGS_CAP
``int ioctl(int fd, VIDIOC_DV_TIMINGS_CAP, struct v4l2_dv_timings_cap *argp)``
.. c:macro:: VIDIOC_SUBDEV_DV_TIMINGS_CAP
``int ioctl(int fd, VIDIOC_SUBDEV_DV_TIMINGS_CAP, struct v4l2_dv_timings_cap *argp)``
Arguments
=========
``fd``
File descriptor returned by :c:func:`open()`.
``argp``
Pointer to struct :c:type:`v4l2_dv_timings_cap`.
Description
===========
To query the capabilities of the DV receiver/transmitter applications
initialize the ``pad`` field to 0, zero the reserved array of struct
:c:type:`v4l2_dv_timings_cap` and call the
``VIDIOC_DV_TIMINGS_CAP`` ioctl on a video node and the driver will fill
in the structure.
.. note::
Drivers may return different values after
switching the video input or output.
When implemented by the driver DV capabilities of subdevices can be
queried by calling the ``VIDIOC_SUBDEV_DV_TIMINGS_CAP`` ioctl directly
on a subdevice node. The capabilities are specific to inputs (for DV
receivers) or outputs (for DV transmitters), applications must specify
the desired pad number in the struct
:c:type:`v4l2_dv_timings_cap` ``pad`` field and
zero the ``reserved`` array. Attempts to query capabilities on a pad
that doesn't support them will return an ``EINVAL`` error code.
.. tabularcolumns:: |p{1.2cm}|p{3.0cm}|p{13.3cm}|
.. c:type:: v4l2_bt_timings_cap
.. flat-table:: struct v4l2_bt_timings_cap
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
* - __u32
- ``min_width``
- Minimum width of the active video in pixels.
* - __u32
- ``max_width``
- Maximum width of the active video in pixels.
* - __u32
- ``min_height``
- Minimum height of the active video in lines.
* - __u32
- ``max_height``
- Maximum height of the active video in lines.
* - __u64
- ``min_pixelclock``
- Minimum pixelclock frequency in Hz.
* - __u64
- ``max_pixelclock``
- Maximum pixelclock frequency in Hz.
* - __u32
- ``standards``
- The video standard(s) supported by the hardware. See
:ref:`dv-bt-standards` for a list of standards.
* - __u32
- ``capabilities``
- Several flags giving more information about the capabilities. See
:ref:`dv-bt-cap-capabilities` for a description of the flags.
* - __u32
- ``reserved``\ [16]
- Reserved for future extensions.
Drivers must set the array to zero.
.. tabularcolumns:: |p{1.0cm}|p{4.0cm}|p{3.5cm}|p{9.2cm}|
.. c:type:: v4l2_dv_timings_cap
.. flat-table:: struct v4l2_dv_timings_cap
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
* - __u32
- ``type``
- Type of DV timings as listed in :ref:`dv-timing-types`.
* - __u32
- ``pad``
- Pad number as reported by the media controller API. This field is
only used when operating on a subdevice node. When operating on a
video node applications must set this field to zero.
* - __u32
- ``reserved``\ [2]
- Reserved for future extensions.
Drivers and applications must set the array to zero.
* - union {
- (anonymous)
* - struct :c:type:`v4l2_bt_timings_cap`
- ``bt``
- BT.656/1120 timings capabilities of the hardware.
* - __u32
- ``raw_data``\ [32]
* - }
-
.. tabularcolumns:: |p{7.0cm}|p{10.5cm}|
.. _dv-bt-cap-capabilities:
.. flat-table:: DV BT Timing capabilities
:header-rows: 0
:stub-columns: 0
* - Flag
- Description
* -
-
* - ``V4L2_DV_BT_CAP_INTERLACED``
- Interlaced formats are supported.
* - ``V4L2_DV_BT_CAP_PROGRESSIVE``
- Progressive formats are supported.
* - ``V4L2_DV_BT_CAP_REDUCED_BLANKING``
- CVT/GTF specific: the timings can make use of reduced blanking
(CVT) or the 'Secondary GTF' curve (GTF).
* - ``V4L2_DV_BT_CAP_CUSTOM``
- Can support non-standard timings, i.e. timings not belonging to
the standards set in the ``standards`` field.
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.