media: docs: move uAPI book to userspace-api/media

Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee3862 ("docs: Create a user-space API guide").

As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.

Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 90 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/dvb/video-fwrite.rst b/Documentation/userspace-api/media/dvb/video-fwrite.rst
new file mode 100644
index 000000000000..08dfafa9c6a1
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@@ -0,0 +1,90 @@
+.. 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
+
+.. _video_fwrite:
+
+=================
+dvb video write()
+=================
+
+Name
+----
+
+dvb video write()
+
+.. attention:: This ioctl is deprecated.
+
+Synopsis
+--------
+
+.. c:function:: size_t write(int fd, const void *buf, size_t count)
+
+
+Arguments
+---------
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+
+
+    -  .. row 1
+
+       -  int fd
+
+       -  File descriptor returned by a previous call to open().
+
+    -  .. row 2
+
+       -  void \*buf
+
+       -  Pointer to the buffer containing the PES data.
+
+    -  .. row 3
+
+       -  size_t count
+
+       -  Size of buf.
+
+
+Description
+-----------
+
+This system call can only be used if VIDEO_SOURCE_MEMORY is selected
+in the ioctl call VIDEO_SELECT_SOURCE. The data provided shall be in
+PES format, unless the capability allows other formats. If O_NONBLOCK
+is not specified the function will block until buffer space is
+available. The amount of data to be transferred is implied by count.
+
+
+Return Value
+------------
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+
+
+    -  .. row 1
+
+       -  ``EPERM``
+
+       -  Mode VIDEO_SOURCE_MEMORY not selected.
+
+    -  .. row 2
+
+       -  ``ENOMEM``
+
+       -  Attempted to write more data than the internal buffer can hold.
+
+    -  .. row 3
+
+       -  ``EBADF``
+
+       -  fd is not a valid open file descriptor.