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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 21:58:31 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 21:58:31 (GMT)
commitff9a082fda424257976f08fce942609f358015e0 (patch)
tree478e6b449b19baaf842369a13923499ce83ef895 /Documentation/media/uapi/rc/lirc-dev-intro.rst
parent6a492b0f23d28e1f946cdf08e54617484400dafb (diff)
parent85538b1ad145c67198cb55d02de14ba269cc323d (diff)
downloadlinux-ff9a082fda424257976f08fce942609f358015e0.tar.xz
Merge tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media documentation updates from Mauro Carvalho Chehab: "This patch series does the conversion of all media documentation stuff to Restrutured Text markup format and add them to the Documentation/index.rst file. The media documentation was grouped into 4 books: - media uAPI - media kAPI - V4L driver-specific documentation - DVB driver-specific documentation It also contains several documentation improvements and one fixup patch for a core issue with cropcap. PS. After this patch series, the media DocBook is deprecated and should be removed. I'll add such patch on a future pull request" * tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (322 commits) [media] cx23885-cardlist.rst: add a new card [media] doc-rst: add some needed escape codes [media] doc-rst: kapi: use :c:func: instead of :cpp:func doc-rst: kernel-doc: fix a change introduced by mistake [media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops [media] dvb_ringbuffer.h: some documentation improvements [media] v4l2-ctrls.h: fully document the header file [media] doc-rst: Fix some typedef ugly warnings [media] doc-rst: reorganize the kAPI v4l2 chapters [media] rename v4l2-framework.rst to v4l2-intro.rst [media] move V4L2 clocks to a separate .rst file [media] v4l2-fh.rst: add cross references and markups [media] v4l2-fh.rst: add fh contents from v4l2-framework.rst [media] v4l2-fh.h: add documentation for it [media] v4l2-event.rst: add cross-references and markups [media] v4l2-event.h: document all functions [media] v4l2-event.rst: add text from v4l2-framework.rst [media] v4l2-framework.rst: remove videobuf quick chapter [media] v4l2-dev: add cross-references and improve markup [media] doc-rst: move v4l2-dev doc to a separate file ...
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+.. -*- 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.