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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-27 23:58:31 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-27 23:58:31 +0200 |
commit | ff9a082fda424257976f08fce942609f358015e0 (patch) | |
tree | 478e6b449b19baaf842369a13923499ce83ef895 /Documentation/media/v4l-drivers/v4l-with-ir.rst | |
parent | Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi (diff) | |
parent | Merge branch 'topic/docs-next' into v4l_for_linus (diff) | |
download | linux-ff9a082fda424257976f08fce942609f358015e0.tar.xz linux-ff9a082fda424257976f08fce942609f358015e0.zip |
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
...
Diffstat (limited to 'Documentation/media/v4l-drivers/v4l-with-ir.rst')
-rw-r--r-- | Documentation/media/v4l-drivers/v4l-with-ir.rst | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/Documentation/media/v4l-drivers/v4l-with-ir.rst b/Documentation/media/v4l-drivers/v4l-with-ir.rst new file mode 100644 index 000000000000..613e1e79fc96 --- /dev/null +++ b/Documentation/media/v4l-drivers/v4l-with-ir.rst @@ -0,0 +1,73 @@ +Infrared remote control support in video4linux drivers +====================================================== + +Authors: Gerd Hoffmann, Mauro Carvalho Chehab + +Basics +------ + +Most analog and digital TV boards support remote controllers. Several of +them have a microprocessor that receives the IR carriers, convert into +pulse/space sequences and then to scan codes, returning such codes to +userspace ("scancode mode"). Other boards return just the pulse/space +sequences ("raw mode"). + +The support for remote controller in scancode mode is provided by the +standard Linux input layer. The support for raw mode is provided via LIRC. + +In order to check the support and test it, it is suggested to download +the `v4l-utils <https://git.linuxtv.org/v4l-utils.git/>`_. It provides +two tools to handle remote controllers: + +- ir-keytable: provides a way to query the remote controller, list the + protocols it supports, enable in-kernel support for IR decoder or + switch the protocol and to test the reception of scan codes; + +- ir-ctl: provide tools to handle remote controllers that support raw mode + via LIRC interface. + +Usually, the remote controller module is auto-loaded when the TV card is +detected. However, for a few devices, you need to manually load the +ir-kbd-i2c module. + +How it works +------------ + +The modules register the remote as keyboard within the linux input +layer, i.e. you'll see the keys of the remote as normal key strokes +(if CONFIG_INPUT_KEYBOARD is enabled). + +Using the event devices (CONFIG_INPUT_EVDEV) it is possible for +applications to access the remote via /dev/input/event<n> devices. +The udev/systemd will automatically create the devices. If you install +the `v4l-utils <https://git.linuxtv.org/v4l-utils.git/>`_, it may also +automatically load a different keytable than the default one. Please see +`v4l-utils <https://git.linuxtv.org/v4l-utils.git/>`_ ir-keytable.1 +man page for details. + +The ir-keytable tool is nice for trouble shooting, i.e. to check +whenever the input device is really present, which of the devices it +is, check whenever pressing keys on the remote actually generates +events and the like. You can also use any other input utility that changes +the keymaps, like the input kbd utility. + + +Using with lircd +================ + +The latest versions of the lircd daemon supports reading events from the +linux input layer (via event device). It also supports receiving IR codes +in lirc mode. + + +Using without lircd +=================== + +Xorg recognizes several IR keycodes that have its numerical value lower +than 247. With the advent of Wayland, the input driver got updated too, +and should now accept all keycodes. Yet, you may want to just reasign +the keycodes to something that your favorite media application likes. + +This can be done by setting +`v4l-utils <https://git.linuxtv.org/v4l-utils.git/>`_ to load your own +keytable in runtime. Please read ir-keytable.1 man page for details. |