Merge tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media

Pull media documentation updates from Mauro Carvalho Chehab:
 "This patch series does the conversion of all media documentation stuff
  to Restrutured Text markup format and add them to the
  Documentation/index.rst file.

  The media documentation was grouped into 4 books:

    - media uAPI
    - media kAPI
    - V4L driver-specific documentation
    - DVB driver-specific documentation

  It also contains several documentation improvements and one fixup
  patch for a core issue with cropcap.

  PS.  After this patch series, the media DocBook is deprecated and
  should be removed.  I'll add such patch on a future pull request"

* tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (322 commits)
  [media] cx23885-cardlist.rst: add a new card
  [media] doc-rst: add some needed escape codes
  [media] doc-rst: kapi: use :c:func: instead of :cpp:func
  doc-rst: kernel-doc: fix a change introduced by mistake
  [media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops
  [media] dvb_ringbuffer.h: some documentation improvements
  [media] v4l2-ctrls.h: fully document the header file
  [media] doc-rst: Fix some typedef ugly warnings
  [media] doc-rst: reorganize the kAPI v4l2 chapters
  [media] rename v4l2-framework.rst to v4l2-intro.rst
  [media] move V4L2 clocks to a separate .rst file
  [media] v4l2-fh.rst: add cross references and markups
  [media] v4l2-fh.rst: add fh contents from v4l2-framework.rst
  [media] v4l2-fh.h: add documentation for it
  [media] v4l2-event.rst: add cross-references and markups
  [media] v4l2-event.h: document all functions
  [media] v4l2-event.rst: add text from v4l2-framework.rst
  [media] v4l2-framework.rst: remove videobuf quick chapter
  [media] v4l2-dev: add cross-references and improve markup
  [media] doc-rst: move v4l2-dev doc to a separate file
  ...

1 files changed, 105 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/vidioc-g-ctrl.rst b/Documentation/media/uapi/v4l/vidioc-g-ctrl.rst
new file mode 100644
index 0000000..ee929f6
--- /dev/null
+++ b/Documentation/media/uapi/v4l/vidioc-g-ctrl.rst
@@ -0,0 +1,105 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_G_CTRL:
+
+**********************************
+ioctl VIDIOC_G_CTRL, VIDIOC_S_CTRL
+**********************************
+
+Name
+====
+
+VIDIOC_G_CTRL - VIDIOC_S_CTRL - Get or set the value of a control
+
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, struct v4l2_control *argp )
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``request``
+    VIDIOC_G_CTRL, VIDIOC_S_CTRL
+
+``argp``
+
+
+Description
+===========
+
+To get the current value of a control applications initialize the ``id``
+field of a struct :ref:`struct v4l2_control <v4l2-control>` and call the
+:ref:`VIDIOC_G_CTRL <VIDIOC_G_CTRL>` ioctl with a pointer to this structure. To change the
+value of a control applications initialize the ``id`` and ``value``
+fields of a struct :ref:`struct v4l2_control <v4l2-control>` and call the
+:ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` ioctl.
+
+When the ``id`` is invalid drivers return an ``EINVAL`` error code. When the
+``value`` is out of bounds drivers can choose to take the closest valid
+value or return an ``ERANGE`` error code, whatever seems more appropriate.
+However, :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` is a write-only ioctl, it does not return the
+actual new value. If the ``value`` is inappropriate for the control
+(e.g. if it refers to an unsupported menu index of a menu control), then
+EINVAL error code is returned as well.
+
+These ioctls work only with user controls. For other control classes the
+:ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>`,
+:ref:`VIDIOC_S_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` or
+:ref:`VIDIOC_TRY_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` must be used.
+
+
+.. _v4l2-control:
+
+.. flat-table:: struct v4l2_control
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+
+    -  .. row 1
+
+       -  __u32
+
+       -  ``id``
+
+       -  Identifies the control, set by the application.
+
+    -  .. row 2
+
+       -  __s32
+
+       -  ``value``
+
+       -  New value or current value.
+
+
+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 :ref:`v4l2_control <v4l2-control>` ``id`` is invalid
+    or the ``value`` is inappropriate for the given control (i.e. if a
+    menu item is selected that is not supported by the driver according
+    to :ref:`VIDIOC_QUERYMENU <VIDIOC_QUERYCTRL>`).
+
+ERANGE
+    The struct :ref:`v4l2_control <v4l2-control>` ``value`` is out of
+    bounds.
+
+EBUSY
+    The control is temporarily not changeable, possibly because another
+    applications took over control of the device function this control
+    belongs to.
+
+EACCES
+    Attempt to set a read-only control or to get a write-only control.