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
  ...

1 files changed, 108 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/dev-output.rst b/Documentation/userspace-api/media/v4l/dev-output.rst
new file mode 100644
index 000000000000..e4f2a1d8b0fc
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/dev-output.rst
@@ -0,0 +1,108 @@
+.. 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
+
+.. _output:
+
+**********************
+Video Output Interface
+**********************
+
+Video output devices encode stills or image sequences as analog video
+signal. With this interface applications can control the encoding
+process and move images from user space to the driver.
+
+Conventionally V4L2 video output devices are accessed through character
+device special files named ``/dev/video`` and ``/dev/video0`` to
+``/dev/video63`` with major number 81 and minor numbers 0 to 63.
+``/dev/video`` is typically a symbolic link to the preferred video
+device.
+
+.. note:: The same device file names are used also for video capture devices.
+
+
+Querying Capabilities
+=====================
+
+Devices supporting the video output interface set the
+``V4L2_CAP_VIDEO_OUTPUT`` or ``V4L2_CAP_VIDEO_OUTPUT_MPLANE`` flag in
+the ``capabilities`` field of struct
+:c:type:`v4l2_capability` returned by the
+:ref:`VIDIOC_QUERYCAP` ioctl. As secondary device
+functions they may also support the :ref:`raw VBI output <raw-vbi>`
+(``V4L2_CAP_VBI_OUTPUT``) interface. At least one of the read/write or
+streaming I/O methods must be supported. Modulators and audio outputs
+are optional.
+
+
+Supplemental Functions
+======================
+
+Video output devices shall support :ref:`audio output <audio>`,
+:ref:`modulator <tuner>`, :ref:`controls <control>`,
+:ref:`cropping and scaling <crop>` and
+:ref:`streaming parameter <streaming-par>` ioctls as needed. The
+:ref:`video output <video>` ioctls must be supported by all video
+output devices.
+
+
+Image Format Negotiation
+========================
+
+The output is determined by cropping and image format parameters. The
+former select an area of the video picture where the image will appear,
+the latter how images are stored in memory, i. e. in RGB or YUV format,
+the number of bits per pixel or width and height. Together they also
+define how images are scaled in the process.
+
+As usual these parameters are *not* reset at :ref:`open() <func-open>`
+time to permit Unix tool chains, programming a device and then writing
+to it as if it was a plain file. Well written V4L2 applications ensure
+they really get what they want, including cropping and scaling.
+
+Cropping initialization at minimum requires to reset the parameters to
+defaults. An example is given in :ref:`crop`.
+
+To query the current image format applications set the ``type`` field of
+a struct :c:type:`v4l2_format` to
+``V4L2_BUF_TYPE_VIDEO_OUTPUT`` or ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``
+and call the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl with a pointer
+to this structure. Drivers fill the struct
+:c:type:`v4l2_pix_format` ``pix`` or the struct
+:c:type:`v4l2_pix_format_mplane` ``pix_mp``
+member of the ``fmt`` union.
+
+To request different parameters applications set the ``type`` field of a
+struct :c:type:`v4l2_format` as above and initialize all
+fields of the struct :c:type:`v4l2_pix_format`
+``vbi`` member of the ``fmt`` union, or better just modify the results
+of :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, and call the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`
+ioctl with a pointer to this structure. Drivers may adjust the
+parameters and finally return the actual parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`
+does.
+
+Like :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` the :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` ioctl
+can be used to learn about hardware limitations without disabling I/O or
+possibly time consuming hardware preparations.
+
+The contents of struct :c:type:`v4l2_pix_format` and
+struct :c:type:`v4l2_pix_format_mplane` are
+discussed in :ref:`pixfmt`. See also the specification of the
+:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` and :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` ioctls for
+details. Video output devices must implement both the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`
+and :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl, even if :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ignores all
+requests and always returns default parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` does.
+:ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` is optional.
+
+
+Writing Images
+==============
+
+A video output device may support the :ref:`write() function <rw>`
+and/or streaming (:ref:`memory mapping <mmap>` or
+:ref:`user pointer <userp>`) I/O. See :ref:`io` for details.