1 files changed, 122 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-g-audioout.rst b/Documentation/media/uapi/v4l/vidioc-g-audioout.rst
new file mode 100644
index 000000000..b1c1bfeb2
--- /dev/null
+++ b/Documentation/media/uapi/v4l/vidioc-g-audioout.rst
@@ -0,0 +1,122 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_G_AUDOUT:
+
+**************************************
+ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT
+**************************************
+
+Name
+====
+
+VIDIOC_G_AUDOUT - VIDIOC_S_AUDOUT - Query or select the current audio output
+
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, struct v4l2_audioout *argp )
+
+.. cpp:function:: int ioctl( int fd, int request, const struct v4l2_audioout *argp )
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``request``
+    VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT
+
+``argp``
+
+
+Description
+===========
+
+To query the current audio output applications zero out the ``reserved``
+array of a struct :ref:`v4l2_audioout <v4l2-audioout>` and call the
+``VIDIOC_G_AUDOUT`` ioctl with a pointer to this structure. Drivers fill
+the rest of the structure or return an ``EINVAL`` error code when the device
+has no audio inputs, or none which combine with the current video
+output.
+
+Audio outputs have no writable properties. Nevertheless, to select the
+current audio output applications can initialize the ``index`` field and
+``reserved`` array (which in the future may contain writable properties)
+of a :ref:`struct v4l2_audioout <v4l2-audioout>` structure and call the
+``VIDIOC_S_AUDOUT`` ioctl. Drivers switch to the requested output or
+return the ``EINVAL`` error code when the index is out of bounds. This is a
+write-only ioctl, it does not return the current audio output attributes
+as ``VIDIOC_G_AUDOUT`` does.
+
+.. note:: Connectors on a TV card to loop back the received audio signal
+   to a sound card are not audio outputs in this sense.
+
+
+.. _v4l2-audioout:
+
+.. flat-table:: struct v4l2_audioout
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+
+    -  .. row 1
+
+       -  __u32
+
+       -  ``index``
+
+       -  Identifies the audio output, set by the driver or application.
+
+    -  .. row 2
+
+       -  __u8
+
+       -  ``name``\ [32]
+
+       -  Name of the audio output, a NUL-terminated ASCII string, for
+	  example: "Line Out". This information is intended for the user,
+	  preferably the connector label on the device itself.
+
+    -  .. row 3
+
+       -  __u32
+
+       -  ``capability``
+
+       -  Audio capability flags, none defined yet. Drivers must set this
+	  field to zero.
+
+    -  .. row 4
+
+       -  __u32
+
+       -  ``mode``
+
+       -  Audio mode, none defined yet. Drivers and applications (on
+	  ``VIDIOC_S_AUDOUT``) must set this field to zero.
+
+    -  .. row 5
+
+       -  __u32
+
+       -  ``reserved``\ [2]
+
+       -  Reserved for future extensions. Drivers and applications must set
+	  the array to zero.
+
+
+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
+    No audio outputs combine with the current video output, or the
+    number of the selected audio output is out of bounds or it does not
+    combine.