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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-27 14:58:31 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-27 14:58:31 -0700 |
commit | ff9a082fda424257976f08fce942609f358015e0 (patch) | |
tree | 478e6b449b19baaf842369a13923499ce83ef895 /Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst | |
parent | 6a492b0f23d28e1f946cdf08e54617484400dafb (diff) | |
parent | 85538b1ad145c67198cb55d02de14ba269cc323d (diff) |
Merge tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media documentation updates from Mauro Carvalho Chehab:
"This patch series does the conversion of all media documentation stuff
to Restrutured Text markup format and add them to the
Documentation/index.rst file.
The media documentation was grouped into 4 books:
- media uAPI
- media kAPI
- V4L driver-specific documentation
- DVB driver-specific documentation
It also contains several documentation improvements and one fixup
patch for a core issue with cropcap.
PS. After this patch series, the media DocBook is deprecated and
should be removed. I'll add such patch on a future pull request"
* tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (322 commits)
[media] cx23885-cardlist.rst: add a new card
[media] doc-rst: add some needed escape codes
[media] doc-rst: kapi: use :c:func: instead of :cpp:func
doc-rst: kernel-doc: fix a change introduced by mistake
[media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops
[media] dvb_ringbuffer.h: some documentation improvements
[media] v4l2-ctrls.h: fully document the header file
[media] doc-rst: Fix some typedef ugly warnings
[media] doc-rst: reorganize the kAPI v4l2 chapters
[media] rename v4l2-framework.rst to v4l2-intro.rst
[media] move V4L2 clocks to a separate .rst file
[media] v4l2-fh.rst: add cross references and markups
[media] v4l2-fh.rst: add fh contents from v4l2-framework.rst
[media] v4l2-fh.h: add documentation for it
[media] v4l2-event.rst: add cross-references and markups
[media] v4l2-event.h: document all functions
[media] v4l2-event.rst: add text from v4l2-framework.rst
[media] v4l2-framework.rst: remove videobuf quick chapter
[media] v4l2-dev: add cross-references and improve markup
[media] doc-rst: move v4l2-dev doc to a separate file
...
Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst')
-rw-r--r-- | Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst b/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst new file mode 100644 index 000000000000..7a5811b71b68 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst @@ -0,0 +1,162 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_SUBDEV_ENUM_FRAME_SIZE: + +*********************************** +ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE +*********************************** + +Name +==== + +VIDIOC_SUBDEV_ENUM_FRAME_SIZE - Enumerate media bus frame sizes + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, struct v4l2_subdev_frame_size_enum * argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``request`` + VIDIOC_SUBDEV_ENUM_FRAME_SIZE + +``argp`` + + +Description +=========== + +This ioctl allows applications to enumerate all frame sizes supported by +a sub-device on the given pad for the given media bus format. Supported +formats can be retrieved with the +:ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE` +ioctl. + +To enumerate frame sizes applications initialize the ``pad``, ``which`` +, ``code`` and ``index`` fields of the struct +:ref:`v4l2_subdev_mbus_code_enum <v4l2-subdev-mbus-code-enum>` and +call the :ref:`VIDIOC_SUBDEV_ENUM_FRAME_SIZE` ioctl with a pointer to the +structure. Drivers fill the minimum and maximum frame sizes or return an +EINVAL error code if one of the input parameters is invalid. + +Sub-devices that only support discrete frame sizes (such as most +sensors) will return one or more frame sizes with identical minimum and +maximum values. + +Not all possible sizes in given [minimum, maximum] ranges need to be +supported. For instance, a scaler that uses a fixed-point scaling ratio +might not be able to produce every frame size between the minimum and +maximum values. Applications must use the +:ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>` ioctl to try the +sub-device for an exact supported frame size. + +Available frame sizes may depend on the current 'try' formats at other +pads of the sub-device, as well as on the current active links and the +current values of V4L2 controls. See +:ref:`VIDIOC_SUBDEV_G_FMT` for more +information about try formats. + + +.. _v4l2-subdev-frame-size-enum: + +.. flat-table:: struct v4l2_subdev_frame_size_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 + + - ``min_width`` + + - Minimum frame width, in pixels. + + - .. row 5 + + - __u32 + + - ``max_width`` + + - Maximum frame width, in pixels. + + - .. row 6 + + - __u32 + + - ``min_height`` + + - Minimum frame height, in pixels. + + - .. row 7 + + - __u32 + + - ``max_height`` + + - Maximum frame height, in pixels. + + - .. row 8 + + - __u32 + + - ``which`` + + - Frame sizes to be enumerated, from enum + :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. + + - .. row 9 + + - __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_size_enum <v4l2-subdev-frame-size-enum>` + ``pad`` references a non-existing pad, the ``code`` is invalid for + the given pad or the ``index`` field is out of bounds. |