[media] doc-rst: document LIRC_GET_REC_RESOLUTION

Improve the documentation for this ioctl, adding it to
a separate file, in order to look like the rest of the
book, and to later allow to generate a man page for this
ioctl.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/Documentation/media/uapi/rc/lirc-get-rec-resolution.rst b/Documentation/media/uapi/rc/lirc-get-rec-resolution.rst
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _lirc_get_rec_resolution:
+
+*****************************
+ioctl LIRC_GET_REC_RESOLUTION
+*****************************
+
+Name
+====
+
+LIRC_GET_REC_RESOLUTION - Obtain the value of receive resolution, in microseconds.
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, __u32 *microseconds)
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by open().
+
+``request``
+    LIRC_GET_REC_RESOLUTION
+
+``microseconds``
+    Resolution, in microseconds.
+
+
+Description
+===========
+
+Some receivers have maximum resolution which is defined by internal
+sample rate or data format limitations. E.g. it's common that
+signals can only be reported in 50 microsecond steps.
+
+This ioctl returns the integer value with such resolution, with can be
+used by userspace applications like lircd to automatically adjust the
+tolerance 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.