summaryrefslogtreecommitdiffstats
path: root/Documentation/media/v4l-drivers/v4l-with-ir.rst
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 23:58:31 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 23:58:31 +0200
commitff9a082fda424257976f08fce942609f358015e0 (patch)
tree478e6b449b19baaf842369a13923499ce83ef895 /Documentation/media/v4l-drivers/v4l-with-ir.rst
parentMerge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi (diff)
parentMerge branch 'topic/docs-next' into v4l_for_linus (diff)
downloadlinux-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.rst73
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.