63 lines
1.6 KiB
ReStructuredText
63 lines
1.6 KiB
ReStructuredText
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.. -*- coding: utf-8; mode: rst -*-
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.. _lirc_dev_intro:
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************
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Introduction
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************
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The LIRC device interface is a bi-directional interface for transporting
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raw IR data between userspace and kernelspace. Fundamentally, it is just
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a chardev (/dev/lircX, for X = 0, 1, 2, ...), with a number of standard
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struct file_operations defined on it. With respect to transporting raw
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IR data to and fro, the essential fops are read, write and ioctl.
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Example dmesg output upon a driver registering w/LIRC:
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.. code-block:: none
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$ dmesg |grep lirc_dev
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lirc_dev: IR Remote Control driver registered, major 248
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rc rc0: lirc_dev: driver ir-lirc-codec (mceusb) registered at minor = 0
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What you should see for a chardev:
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.. code-block:: none
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$ ls -l /dev/lirc*
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crw-rw---- 1 root root 248, 0 Jul 2 22:20 /dev/lirc0
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**********
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LIRC modes
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**********
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LIRC supports some modes of receiving and sending IR codes, as shown
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on the following table.
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.. _lirc-mode-mode2:
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``LIRC_MODE_MODE2``
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The driver returns a sequence of pulse and space codes to userspace.
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This mode is used only for IR receive.
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.. _lirc-mode-lirccode:
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``LIRC_MODE_LIRCCODE``
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The IR signal is decoded internally by the receiver. The LIRC interface
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returns the scancode as an integer value. This is the usual mode used
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by several TV media cards.
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This mode is used only for IR receive.
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.. _lirc-mode-pulse:
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``LIRC_MODE_PULSE``
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On puse mode, a sequence of pulse/space integer values are written to the
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lirc device using :Ref:`lirc-write`.
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This mode is used only for IR send.
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