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, 104 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/audio.rst b/Documentation/userspace-api/media/v4l/audio.rst
new file mode 100644
index 000000000000..d6bb85092e02
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/audio.rst
@@ -0,0 +1,104 @@
+.. 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
+
+.. _audio:
+
+************************
+Audio Inputs and Outputs
+************************
+
+Audio inputs and outputs are physical connectors of a device. Video
+capture devices have inputs, output devices have outputs, zero or more
+each. Radio devices have no audio inputs or outputs. They have exactly
+one tuner which in fact *is* an audio source, but this API associates
+tuners with video inputs or outputs only, and radio devices have none of
+these. [#f1]_ A connector on a TV card to loop back the received audio
+signal to a sound card is not considered an audio output.
+
+Audio and video inputs and outputs are associated. Selecting a video
+source also selects an audio source. This is most evident when the video
+and audio source is a tuner. Further audio connectors can combine with
+more than one video input or output. Assumed two composite video inputs
+and two audio inputs exist, there may be up to four valid combinations.
+The relation of video and audio connectors is defined in the
+``audioset`` field of the respective struct
+:c:type:`v4l2_input` or struct
+:c:type:`v4l2_output`, where each bit represents the index
+number, starting at zero, of one audio input or output.
+
+To learn about the number and attributes of the available inputs and
+outputs applications can enumerate them with the
+:ref:`VIDIOC_ENUMAUDIO` and
+:ref:`VIDIOC_ENUMAUDOUT <VIDIOC_ENUMAUDOUT>` ioctl, respectively.
+The struct :c:type:`v4l2_audio` returned by the
+:ref:`VIDIOC_ENUMAUDIO` ioctl also contains signal
+status information applicable when the current audio input is queried.
+
+The :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` and
+:ref:`VIDIOC_G_AUDOUT <VIDIOC_G_AUDOUT>` ioctls report the current
+audio input and output, respectively.
+
+.. note::
+
+   Note that, unlike :ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` and
+   :ref:`VIDIOC_G_OUTPUT <VIDIOC_G_OUTPUT>` these ioctls return a
+   structure as :ref:`VIDIOC_ENUMAUDIO` and
+   :ref:`VIDIOC_ENUMAUDOUT <VIDIOC_ENUMAUDOUT>` do, not just an index.
+
+To select an audio input and change its properties applications call the
+:ref:`VIDIOC_S_AUDIO <VIDIOC_G_AUDIO>` ioctl. To select an audio
+output (which presently has no changeable properties) applications call
+the :ref:`VIDIOC_S_AUDOUT <VIDIOC_G_AUDOUT>` ioctl.
+
+Drivers must implement all audio input ioctls when the device has
+multiple selectable audio inputs, all audio output ioctls when the
+device has multiple selectable audio outputs. When the device has any
+audio inputs or outputs the driver must set the ``V4L2_CAP_AUDIO`` flag
+in the struct :c:type:`v4l2_capability` returned by
+the :ref:`VIDIOC_QUERYCAP` ioctl.
+
+
+Example: Information about the current audio input
+==================================================
+
+.. code-block:: c
+
+    struct v4l2_audio audio;
+
+    memset(&audio, 0, sizeof(audio));
+
+    if (-1 == ioctl(fd, VIDIOC_G_AUDIO, &audio)) {
+	perror("VIDIOC_G_AUDIO");
+	exit(EXIT_FAILURE);
+    }
+
+    printf("Current input: %s\\n", audio.name);
+
+
+Example: Switching to the first audio input
+===========================================
+
+.. code-block:: c
+
+    struct v4l2_audio audio;
+
+    memset(&audio, 0, sizeof(audio)); /* clear audio.mode, audio.reserved */
+
+    audio.index = 0;
+
+    if (-1 == ioctl(fd, VIDIOC_S_AUDIO, &audio)) {
+	perror("VIDIOC_S_AUDIO");
+	exit(EXIT_FAILURE);
+    }
+
+.. [#f1]
+   Actually struct :c:type:`v4l2_audio` ought to have a
+   ``tuner`` field like struct :c:type:`v4l2_input`, not
+   only making the API more consistent but also permitting radio devices
+   with multiple tuners.