[media] v4l-with-ir.rst: update it to reflect the current status
This document were really old. Update it to reflect the current status of the IR drivers for TV. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab
parent
31cae7ca8d
commit
2e97d6d301
|
|
@ -1,31 +1,34 @@
|
|||
infrared remote control support in video4linux drivers
|
||||
Infrared remote control support in video4linux drivers
|
||||
======================================================
|
||||
|
||||
Author: Gerd Hoffmann
|
||||
|
||||
.. note::
|
||||
|
||||
This section is outdated.
|
||||
Authors: Gerd Hoffmann, Mauro Carvalho Chehab
|
||||
|
||||
Basics
|
||||
------
|
||||
|
||||
Current versions use the linux input layer to support infrared
|
||||
remote controls. I suggest to download my input layer tools
|
||||
from http://bytesex.org/snapshot/input-<date>.tar.gz
|
||||
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").
|
||||
|
||||
Modules you have to load:
|
||||
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.
|
||||
|
||||
saa7134 statically built in, i.e. just the driver :)
|
||||
bttv ir-kbd-gpio or ir-kbd-i2c depending on your
|
||||
card.
|
||||
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-kbd-gpio and ir-kbd-i2c don't support all cards lirc supports
|
||||
(yet), mainly for the reason that the code of lirc_i2c and lirc_gpio
|
||||
was very confusing and I decided to basically start over from scratch.
|
||||
Feel free to contact me in case of trouble. Note that the ir-kbd-*
|
||||
modules work on 2.6.x kernels only through ...
|
||||
- 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
|
||||
------------
|
||||
|
|
@ -36,40 +39,35 @@ layer, i.e. you'll see the keys of the remote as normal key strokes
|
|||
|
||||
Using the event devices (CONFIG_INPUT_EVDEV) it is possible for
|
||||
applications to access the remote via /dev/input/event<n> devices.
|
||||
You might have to create the special files using "/sbin/MAKEDEV
|
||||
input". The input layer tools mentioned above use the event device.
|
||||
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 input layer tools are nice for trouble shooting, i.e. to check
|
||||
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 the kbd utility to change the
|
||||
keymaps (2.6.x kernels only through).
|
||||
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 cvs version of the lircd daemon supports reading events from the
|
||||
linux input layer (via event device). The input layer tools tarball
|
||||
comes with a lircd config file.
|
||||
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
|
||||
===================
|
||||
|
||||
XFree86 likely can be configured to recognise the remote keys. Once I
|
||||
simply tried to configure one of the multimedia keyboards as input
|
||||
device, which had the effect that XFree86 recognised some of the keys
|
||||
of my remote control and passed volume up/down key presses as
|
||||
XF86AudioRaiseVolume and XF86AudioLowerVolume key events to the X11
|
||||
clients.
|
||||
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.
|
||||
|
||||
It likely is possible to make that fly with a nice xkb config file,
|
||||
I know next to nothing about that through.
|
||||
|
||||
|
||||
Have fun,
|
||||
|
||||
Gerd
|
||||
|
||||
--
|
||||
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.
|
||||
|
|
|
|||
Loading…
Reference in New Issue