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author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-27 13:45:04 (GMT) |
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committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-27 13:45:04 (GMT) |
commit | 85538b1ad145c67198cb55d02de14ba269cc323d (patch) | |
tree | 409fca93b357839b8c89b7099f2888c087694b64 /Documentation/media/uapi/rc/lirc-dev-intro.rst | |
parent | 9c1958fc326a0a0a533ec8e86ea6fa30977207de (diff) | |
parent | d271d3d9b333c94cd54a12fa506e17772a04617c (diff) | |
download | linux-85538b1ad145c67198cb55d02de14ba269cc323d.tar.xz |
Merge branch 'topic/docs-next' into v4l_for_linus
* topic/docs-next: (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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Diffstat (limited to 'Documentation/media/uapi/rc/lirc-dev-intro.rst')
-rw-r--r-- | Documentation/media/uapi/rc/lirc-dev-intro.rst | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/Documentation/media/uapi/rc/lirc-dev-intro.rst b/Documentation/media/uapi/rc/lirc-dev-intro.rst new file mode 100644 index 0000000..ef97e40 --- /dev/null +++ b/Documentation/media/uapi/rc/lirc-dev-intro.rst @@ -0,0 +1,62 @@ +.. -*- 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. |