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, 49 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/cec/cec-intro.rst b/Documentation/userspace-api/media/cec/cec-intro.rst
new file mode 100644
index 000000000000..a4db82388202
--- /dev/null
+++ b/Documentation/userspace-api/media/cec/cec-intro.rst
@@ -0,0 +1,49 @@
+.. 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
+
+.. _cec-intro:
+
+Introduction
+============
+
+HDMI connectors provide a single pin for use by the Consumer Electronics
+Control protocol. This protocol allows different devices connected by an
+HDMI cable to communicate. The protocol for CEC version 1.4 is defined
+in supplements 1 (CEC) and 2 (HEAC or HDMI Ethernet and Audio Return
+Channel) of the HDMI 1.4a (:ref:`hdmi`) specification and the
+extensions added to CEC version 2.0 are defined in chapter 11 of the
+HDMI 2.0 (:ref:`hdmi2`) specification.
+
+The bitrate is very slow (effectively no more than 36 bytes per second)
+and is based on the ancient AV.link protocol used in old SCART
+connectors. The protocol closely resembles a crazy Rube Goldberg
+contraption and is an unholy mix of low and high level messages. Some
+messages, especially those part of the HEAC protocol layered on top of
+CEC, need to be handled by the kernel, others can be handled either by
+the kernel or by userspace.
+
+In addition, CEC can be implemented in HDMI receivers, transmitters and
+in USB devices that have an HDMI input and an HDMI output and that
+control just the CEC pin.
+
+Drivers that support CEC will create a CEC device node (/dev/cecX) to
+give userspace access to the CEC adapter. The
+:ref:`CEC_ADAP_G_CAPS` ioctl will tell userspace what it is allowed to do.
+
+In order to check the support and test it, it is suggested to download
+the `v4l-utils <https://git.linuxtv.org/v4l-utils.git/>`_ package. It
+provides three tools to handle CEC:
+
+- cec-ctl: the Swiss army knife of CEC. Allows you to configure, transmit
+  and monitor CEC messages.
+
+- cec-compliance: does a CEC compliance test of a remote CEC device to
+  determine how compliant the CEC implementation is.
+
+- cec-follower: emulates a CEC follower.