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, 83 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/func-open.rst b/Documentation/media/uapi/v4l/func-open.rst
new file mode 100644
index 000000000000..06bcadc269a4
--- /dev/null
+++ b/Documentation/media/uapi/v4l/func-open.rst
@@ -0,0 +1,83 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _func-open:
+
+***********
+V4L2 open()
+***********
+
+Name
+====
+
+v4l2-open - Open a V4L2 device
+
+
+Synopsis
+========
+
+.. code-block:: c
+
+    #include <fcntl.h>
+
+
+.. cpp:function:: int open( const char *device_name, int flags )
+
+
+Arguments
+=========
+
+``device_name``
+    Device to be opened.
+
+``flags``
+    Open flags. Access mode must be ``O_RDWR``. This is just a
+    technicality, input devices still support only reading and output
+    devices only writing.
+
+    When the ``O_NONBLOCK`` flag is given, the :ref:`read() <func-read>`
+    function and the :ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctl will
+    return the ``EAGAIN`` error code when no data is available or no
+    buffer is in the driver outgoing queue, otherwise these functions
+    block until data becomes available. All V4L2 drivers exchanging data
+    with applications must support the ``O_NONBLOCK`` flag.
+
+    Other flags have no effect.
+
+
+Description
+===========
+
+To open a V4L2 device applications call :ref:`open() <func-open>` with the
+desired device name. This function has no side effects; all data format
+parameters, current input or output, control values or other properties
+remain unchanged. At the first :ref:`open() <func-open>` call after loading the
+driver they will be reset to default values, drivers are never in an
+undefined state.
+
+
+Return Value
+============
+
+On success :ref:`open() <func-open>` returns the new file descriptor. On error
+-1 is returned, and the ``errno`` variable is set appropriately.
+Possible error codes are:
+
+EACCES
+    The caller has no permission to access the device.
+
+EBUSY
+    The driver does not support multiple opens and the device is already
+    in use.
+
+ENXIO
+    No device corresponding to this device special file exists.
+
+ENOMEM
+    Not enough kernel memory was available to complete the request.
+
+EMFILE
+    The process already has the maximum number of files open.
+
+ENFILE
+    The limit on the total number of files open on the system has been
+    reached.