[media] doc-rst: document LIRC_SET_SEND_DUTY_CYCLE

Add a separate 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-set-send-duty-cycle.rst b/Documentation/media/uapi/rc/lirc-set-send-duty-cycle.rst
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _lirc_set_send_duty_cycle:
+
+******************************
+ioctl LIRC_SET_SEND_DUTY_CYCLE
+******************************
+
+Name
+====
+
+LIRC_SET_SEND_DUTY_CYCLE - Set the duty cycle of the carrier signal for
+IR transmit.
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, __u32 *duty_cycle)
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by open().
+
+``request``
+    LIRC_SET_SEND_DUTY_CYCLE
+
+``duty_cycle``
+    Duty cicle, describing the pulse width in percent (from 1 to 99) of
+    the total cycle. Values 0 and 100 are reserved.
+
+
+Description
+===========
+
+Get/set the duty cycle of the carrier signal for IR transmit.
+
+Currently, no special meaning is defined for 0 or 100, but this
+could be used to switch off carrier generation in the future, so
+these values should be reserved.
+
+
+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.