media: lirc: document LIRC_MODE_SCANCODE

Lirc supports a new mode which requires documentation.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 15 insertions, 4 deletions

diff --git a/Documentation/media/uapi/rc/lirc-write.rst b/Documentation/media/uapi/rc/lirc-write.rst
index 2aad0fef4a5b..3d7541bad8b9 100644
--- a/Documentation/media/uapi/rc/lirc-write.rst
+++ b/Documentation/media/uapi/rc/lirc-write.rst
@@ -42,21 +42,32 @@ Description
 referenced by the file descriptor ``fd`` from the buffer starting at
 ``buf``.
 
-The exact format of the data depends on what mode a driver uses, use
-:ref:`lirc_get_features` to get the supported mode.
+The exact format of the data depends on what mode a driver is in, use
+:ref:`lirc_get_features` to get the supported modes and use
+:ref:`lirc_set_send_mode` set the mode.
 
 When in :ref:`LIRC_MODE_PULSE <lirc-mode-PULSE>` mode, the data written to
 the chardev is a pulse/space sequence of integer values. Pulses and spaces
 are only marked implicitly by their position. The data must start and end
 with a pulse, therefore, the data must always include an uneven number of
-samples. The write function must block until the data has been transmitted
+samples. The write function blocks until the data has been transmitted
 by the hardware. If more data is provided than the hardware can send, the
 driver returns ``EINVAL``.
 
+When in :ref:`LIRC_MODE_SCANCODE <lirc-mode-scancode>` mode, one
+``struct lirc_scancode`` must be written to the chardev at a time, else
+``EINVAL`` is returned. Set the desired scancode in the ``scancode`` member,
+and the protocol in the ``rc_proto`` member. All other members must be set
+to 0, else ``EINVAL`` is returned. If there is no protocol encoder
+for the protocol or the scancode is not valid for the specified protocol,
+``EINVAL`` is returned. The write function may not wait until the scancode
+is transmitted.
+
+
 Return Value
 ============
 
-On success, the number of bytes read is returned. It is not an error if
+On success, the number of bytes written is returned. It is not an error if
 this number is smaller than the number of bytes requested, or the amount
 of data required for one frame.  On error, -1 is returned, and the ``errno``
 variable is set appropriately. The generic error codes are described at the