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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-03 20:59:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-03 20:59:38 -0700
commita98f670e41a99f53acb1fb33cee9c6abbb2e6f23 (patch)
treef8ae10a4cb91758ad7f9422053753a8c5d0f04dc /Documentation/userspace-api/media/v4l/vidioc-subdev-enum-frame-interval.rst
parentee01c4d72adffb7d424535adf630f2955748fa8b (diff)
parent938b29db3aa9c293c7c1366b16e55e308f1a1ddd (diff)
Merge tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab: - Media documentation is now split into admin-guide, driver-api and userspace-api books (a longstanding request from Jon); - The media Kconfig was reorganized, in order to make easier to select drivers and their dependencies; - The testing drivers now has a separate directory; - added a new driver for Rockchip Video Decoder IP; - The atomisp staging driver was resurrected. It is meant to work with 4 generations of cameras on Atom-based laptops, tablets and cell phones. So, it seems worth investing time to cleanup this driver and making it in good shape. - Added some V4L2 core ancillary routines to help with h264 codecs; - Added an ov2740 image sensor driver; - The si2157 gained support for Analog TV, which, in turn, added support for some cx231xx and cx23885 boards to also support analog standards; - Added some V4L2 controls (V4L2_CID_CAMERA_ORIENTATION and V4L2_CID_CAMERA_SENSOR_ROTATION) to help identifying where the camera is located at the device; - VIDIOC_ENUM_FMT was extended to support MC-centric devices; - Lots of drivers improvements and cleanups. * tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (503 commits) media: Documentation: media: Refer to mbus format documentation from CSI-2 docs media: s5k5baf: Replace zero-length array with flexible-array media: i2c: imx219: Drop <linux/clk-provider.h> and <linux/clkdev.h> media: i2c: Add ov2740 image sensor driver media: ov8856: Implement sensor module revision identification media: ov8856: Add devicetree support media: dt-bindings: ov8856: Document YAML bindings media: dvb-usb: Add Cinergy S2 PCIe Dual Port support media: dvbdev: Fix tuner->demod media controller link media: dt-bindings: phy: phy-rockchip-dphy-rx0: move rockchip dphy rx0 bindings out of staging media: staging: dt-bindings: phy-rockchip-dphy-rx0: remove non-used reg property media: atomisp: unify the version for isp2401 a0 and b0 versions media: atomisp: update TODO with the current data media: atomisp: adjust some code at sh_css that could be broken media: atomisp: don't produce errs for ignored IRQs media: atomisp: print IRQ when debugging media: atomisp: isp_mmu: don't use kmem_cache media: atomisp: add a notice about possible leak resources media: atomisp: disable the dynamic and reserved pools media: atomisp: turn on camera before setting it ...
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+.. 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
+
+.. _VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL:
+
+***************************************
+ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL
+***************************************
+
+Name
+====
+
+VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL - Enumerate frame intervals
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL, struct v4l2_subdev_frame_interval_enum * argp )
+ :name: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL
+
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :ref:`open() <func-open>`.
+
+``argp``
+ Pointer to struct :c:type:`v4l2_subdev_frame_interval_enum`.
+
+
+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
+:c:type:`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.
+
+.. c:type:: v4l2_subdev_frame_interval_enum
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct v4l2_subdev_frame_interval_enum
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - __u32
+ - ``index``
+ - Number of the format in the enumeration, set by the application.
+ * - __u32
+ - ``pad``
+ - Pad number as reported by the media controller API.
+ * - __u32
+ - ``code``
+ - The media bus format code, as defined in
+ :ref:`v4l2-mbus-format`.
+ * - __u32
+ - ``width``
+ - Frame width, in pixels.
+ * - __u32
+ - ``height``
+ - Frame height, in pixels.
+ * - struct :c:type:`v4l2_fract`
+ - ``interval``
+ - Period, in seconds, between consecutive video frames.
+ * - __u32
+ - ``which``
+ - Frame intervals to be enumerated, from enum
+ :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
+ * - __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
+ :c:type:`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.