[deliverable/linux.git] / Documentation / media / uapi / rc / lirc-dev-intro.rst

.. -*- coding: utf-8; mode: rst -*-

.. _lirc_dev_intro:

************
Introduction
************

The LIRC device interface is a bi-directional interface for transporting
raw IR data between userspace and kernelspace. Fundamentally, it is just
a chardev (/dev/lircX, for X = 0, 1, 2, ...), with a number of standard
struct file_operations defined on it. With respect to transporting raw
IR data to and fro, the essential fops are read, write and ioctl.

Example dmesg output upon a driver registering w/LIRC:

.. code-block:: none

    $ dmesg |grep lirc_dev
    lirc_dev: IR Remote Control driver registered, major 248
    rc rc0: lirc_dev: driver ir-lirc-codec (mceusb) registered at minor = 0

What you should see for a chardev:

.. code-block:: none

    $ ls -l /dev/lirc*
    crw-rw---- 1 root root 248, 0 Jul 2 22:20 /dev/lirc0

**********
LIRC modes
**********

LIRC supports some modes of receiving and sending IR codes, as shown
on the following table.

.. _lirc-mode-mode2:

``LIRC_MODE_MODE2``

    The driver returns a sequence of pulse and space codes to userspace.

    This mode is used only for IR receive.

.. _lirc-mode-lirccode:

``LIRC_MODE_LIRCCODE``

    The IR signal is decoded internally by the receiver. The LIRC interface
    returns the scancode as an integer value. This is the usual mode used
    by several TV media cards.

    This mode is used only for IR receive.

.. _lirc-mode-pulse:

``LIRC_MODE_PULSE``

    On puse mode, a sequence of pulse/space integer values are written to the
    lirc device using :Ref:`lirc-write`.

    This mode is used only for IR send.
Commit	Line	Data
5377d91f MH	1	.. -- coding: utf-8; mode: rst --
	2
	3	.. _lirc_dev_intro:
	4
	5	************
	6	Introduction
	7	************
	8
	9	The LIRC device interface is a bi-directional interface for transporting
	10	raw IR data between userspace and kernelspace. Fundamentally, it is just
	11	a chardev (/dev/lircX, for X = 0, 1, 2, ...), with a number of standard
	12	struct file_operations defined on it. With respect to transporting raw
	13	IR data to and fro, the essential fops are read, write and ioctl.
	14
	15	Example dmesg output upon a driver registering w/LIRC:
	16
a23f4191	17	.. code-block:: none
5377d91f	18
a23f4191	19	$ dmesg \|grep lirc_dev
5377d91f	20	lirc_dev: IR Remote Control driver registered, major 248
a23f4191	21	rc rc0: lirc_dev: driver ir-lirc-codec (mceusb) registered at minor = 0
5377d91f MH	22
	23	What you should see for a chardev:
	24
a23f4191	25	.. code-block:: none
5377d91f	26
a23f4191	27	$ ls -l /dev/lirc*
5377d91f	28	crw-rw---- 1 root root 248, 0 Jul 2 22:20 /dev/lirc0
048eb3ef MCC	29
	30	**********
	31	LIRC modes
	32	**********
	33
	34	LIRC supports some modes of receiving and sending IR codes, as shown
	35	on the following table.
	36
	37	.. _lirc-mode-mode2:
	38
	39	``LIRC_MODE_MODE2``
	40
	41	The driver returns a sequence of pulse and space codes to userspace.
	42
	43	This mode is used only for IR receive.
	44
	45	.. _lirc-mode-lirccode:
	46
	47	``LIRC_MODE_LIRCCODE``
	48
	49	The IR signal is decoded internally by the receiver. The LIRC interface
	50	returns the scancode as an integer value. This is the usual mode used
	51	by several TV media cards.
	52
	53	This mode is used only for IR receive.
	54
	55	.. _lirc-mode-pulse:
	56
	57	``LIRC_MODE_PULSE``
	58
	59	On puse mode, a sequence of pulse/space integer values are written to the
	60	lirc device using :Ref:`lirc-write`.
	61
	62	This mode is used only for IR send.