From d0b2f91bede3bd5e3d24dd6803e56eee959c1797 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Thu, 20 Oct 2016 00:10:27 -0300 Subject: Linux-libre 4.8.2-gnu --- .../uapi/v4l/vidioc-subdev-enum-frame-size.rst | 162 +++++++++++++++++++++ 1 file changed, 162 insertions(+) create mode 100644 Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst (limited to 'Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst') 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 000000000..7a5811b71 --- /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() `. + +``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 ` 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 ` 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 `. + + - .. 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 ` chapter. + +EINVAL + The struct + :ref:`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. -- cgit v1.2.3-54-g00ecf