Remote controllers

Currently, most analog and digital devices have an Infrared input for a remote control. Each manufacturer has their own type of control. It is not uncommon for the same manufacturer to ship different types of remote controls, depending on the device.

Adding support for new IR's

In order to add support for a new keyboard, you need first to discover how the IR code is sent to the device. There are several possibilities:

 * IR sensor is directly connected with a GPIO pin of the PCI/USB bridge. This is a very common case nowadays.
    * This is probably the easiest way to add support, provided that the driver has already other similar devices. For an example, please see: [add IR support for saa7134].
 * Bridge has an IR decoder inside. Some chipsets have already some internal decoder for IR, like dib0700 and em2884;
 * There's a small chip that does serial to parallel conversion, outputting the IR code at several GPIO pins.

The way to get the data is hardware specific. Once the driver is able to get an IR scancode, it is generally required to create a new table for it.

 NOTE: before adding a new table, please check if the existing ones have already the proper mapping.

The first step to add a new map is to create an alias for it atinclude/media/rc-map.h:

 /* Names of the several keytables defined in-kernel */

 #define RC_MAP_ADSTECH_DVB_T_PCI         "rc-adstech-dvb-t-pci"
 ...
 #define RC_MAP_VIDEOMATE_TV_PVR          "rc-videomate-tv-pvr"
 #define RC_MAP_WINFAST                   "rc-winfast"
 #define RC_MAP_WINFAST_USBII_DELUXE      "rc-winfast-usbii-deluxe"
 /*
  * Please, do not just append newer Remote Controller names at the end.
  * The names should be ordered in alphabetical order
  */

Just add a new line there with the IR name, on alphabetical order:

 #define RC_MAP_NAME_OF_MY_NEW_BOARD_MAP  "rc-name-of-my-new-board-map"

Then copy one of the existing keymaps, for example, drivers/media/IR/keymaps/rc-empty.c, replacing the names for the name of your new IR.

Remove all keys at static struct ir_scancode, and add your new keycodes.

For example, assuming that you have a driver with raw decode. By loading ir_core with debug=1, with:

 modprobe ir_core debug=1
 (be sure that ir_core weren't loaded before)

you'll start to generate lots of logs at the syslog. Use the dmesg command to get those codes:

 dmesg |grep scancode

Let's assume that this get you the following results: for power key:

 ir_nec_decode: NEC scancode 0x0300
 ir_getkeycode: unknown key for scancode 0x0300

for channel up key:

 ir_nec_decode: NEC scancode 0x030c
 ir_getkeycode: unknown key for scancode 0x030c

for channel down key:

 ir_nec_decode: NEC scancode 0x0310
 ir_getkeycode: unknown key for scancode 0x0310

All you need to do is to make sure that those codes are properly mapped at the keycode table, and to specify the ir_type (in this case, IR_TYPE_NEC). So, to support the above, the main content of the new rc map will be:

 static struct ir_scancode name_of_my_new_keyboard[] = {
         { 0x300, KEY_POWER2 },
         { 0x30c, KEY_CHANNELUP },
         { 0x310, KEY_CHANNELDOWN },
 };
 static struct rc_keymap name_of_my_new_keyboard_map = {
         .map = {
                 .scan    = name_of_my_new_keyboard,
                 .size    = ARRAY_SIZE(name_of_my_new_keyboard),
                 .ir_type = IR_TYPE_NEC,
                 .name    = RC_MAP_EMPTY,
         }
 };

IR Keycode map used by media devices

While there has been effort over the years to keep track of the varying IR layouts (documenting them within ir-common.c), unfortunately, there was never any effort to uniform the actual IR keycodes used by the different devices. This lack of uniformity resulted in cases where the same IR keyname was mapped completely different on different IR's. The overall state of confusion that existed is perhaps best demonstrated by viewing what ir-common.c IR summary looked like as of Aug, 26 2009.

On Aug, 27 2009, having a common mapping for supported IR's became the subject of a proposal which would allow userspace applications to make use of common keycode definitions. The table bellow reflects the expected keycode mappings for IR keys.

Key code	Meaning	Key examples on IR	Notes
Numeric keys
KEY_0	Keyboard digit 0	0
KEY_1	Keyboard digit 1	1
KEY_2	Keyboard digit 2	2
KEY_3	Keyboard digit 3	3
KEY_4	Keyboard digit 4	4
KEY_5	Keyboard digit 5	5
KEY_6	Keyboard digit 6	6
KEY_7	Keyboard digit 7	7
KEY_8	Keyboard digit 8	8
KEY_9	Keyboard digit 9	9
Movie play control
KEY_FORWARD	Instantly advance in time	>> / FORWARD
KEY_BACK	Instantly go back in time	<<< / BACK
KEY_FASTFORWARD	Play movie faster	>>> / FORWARD
KEY_REWIND	Play movie back	REWIND / BACKWARD
KEY_NEXT	Select next chapter / sub-chapter / interval	NEXT / SKIP
KEY_PREVIOUS	Select previous chapter / sub-chapter / interval	<< / PREV / PREVIOUS
KEY_AGAIN	Repeat the video or a video interval	REPEAT / LOOP / RECALL
KEY_PAUSE	Pause stream	PAUSE / FREEZE
KEY_PLAY	Play movie at the normal timeshift	NORMAL TIMESHIFT / LIVE / >
KEY_PLAYPAUSE	Alternate between play and pause	PLAY / PAUSE
KEY_STOP	Stop stream	STOP
KEY_RECORD	Start/stop recording stream	CAPTURE / REC / RECORD/PAUSE
KEY_CAMERA	Take a picture of the image	CAMERA ICON / CAPTURE / SNAPSHOT
KEY_SHUFFLE	Enable shuffle mode	SHUFFLE
KEY_TIME	Activate time shift mode	TIME SHIFT
KEY_TITLE	Allow changing the chapter	CHAPTER
KEY_SUBTITLE	Allow changing the subtitle	SUBTITLE
Image control
KEY_BRIGHTNESSDOWN	Decrease Brightness	BRIGHTNESS DECREASE
KEY_BRIGHTNESSUP	Increase Brightness	BRIGHTNESS INCREASE
KEY_ANGLE	Switch video camera angle (on videos with more than one angle stored)	ANGLE / SWAP
KEY_EPG	Open the Electronic Play Guide (EPG)	EPG / GUIDE
KEY_TEXT	Activate/change closed caption mode	CLOSED CAPTION/TELETEXT / DVD TEXT / TELETEXT / TTX
Audio control
KEY_AUDIO	Change audio source	AUDIO SOURCE / AUDIO / MUSIC
KEY_MUTE	Mute/unmute audio	MUTE / DEMUTE / UNMUTE
KEY_VOLUMEDOWN	Decrease volume	VOLUME- / VOLUME DOWN
KEY_VOLUMEUP	Increase volume	VOLUME+ / VOLUME UP
KEY_MODE	Change sound mode	MONO/STEREO
KEY_LANGUAGE	Select Language	1ST / 2ND LANGUAGE / DVD LANG / MTS/SAP / MTS SEL
Channel control
KEY_CHANNEL	Go to the next favorite channel	ALT / CHANNEL / CH SURFING / SURF / FAV
KEY_CHANNELDOWN	Decrease channel sequencially	CHANNEL - / CHANNEL DOWN / DOWN
KEY_CHANNELUP	Increase channel sequencially	CHANNEL + / CHANNEL UP / UP
KEY_DIGITS	Use more than one digit for channel	PLUS / 100/ 1xx / xxx / -/-- / Single Double Triple Digit
KEY_SEARCH	Start channel autoscan	SCAN / AUTOSCAN
Colored keys
KEY_BLUE	IR “Blue” key	BLUE
KEY_GREEN	IR “Green” Key	GREEN
KEY_RED	IR “Red” key	RED
KEY_YELLOW	IR “Yellow” key	YELLOW
Media selection
KEY_CD	Change input source to Compact Disc	CD
KEY_DVD	Change input to DVD	DVD / DVD MENU
KEY_EJECTCLOSECD	Open/close the CD/DVD player	-> ) / CLOSE / OPEN
KEY_MEDIA	Turn on/off Media application	PC/TV / TURN ON/OFF APP
KEY_PC	Selects from TV to PC	PC
KEY_RADIO	Put into AM/FM radio mode	RADIO / TV/FM / TV/RADIO / FM / FM/RADIO
KEY_TV	Select tv mode	TV / LIVE TV
KEY_TV2	Select Cable mode	AIR/CBL
KEY_VCR	Select VCR mode	VCR MODE / DTR
KEY_VIDEO	Alternate between input modes	SOURCE / SELECT / DISPLAY / SWITCH INPUTS / VIDEO
Power control
KEY_POWER	Turn on/off computer	SYSTEM POWER / COMPUTER POWER
KEY_POWER2	Turn on/off application	TV ON/OFF / POWER
KEY_SLEEP	Activate sleep timer	SLEEP / SLEEP TIMER
KEY_SUSPEND	Put computer into suspend mode	STANDBY / SUSPEND
Window control
KEY_CLEAR	Stop stream and return to default input video/audio	CLEAR / RESET / BOSS KEY
KEY_CYCLEWINDOWS	Minimize windows and move to the next one	ALT-TAB / MINIMIZE / DESKTOP
KEY_FAVORITES	Open the favorites stream window	TV WALL / Favorites
KEY_MENU	Call application menu	2ND CONTROLS (USA: MENU) / DVD/MENU / SHOW/HIDE CTRL
KEY_NEW	Open/Close Picture in Picture	PIP
KEY_OK	Send a confirmation code to application	OK / ENTER / RETURN
KEY_SCREEN	Select screen aspect ratio	4:3 16:9 SELECT
KEY_ZOOM	Put device into zoom/full screen mode	ZOOM / FULL SCREEN / ZOOM+ / HIDE PANNEL / SWITCH
Navigation keys
KEY_ESC	Cancel current operation	CANCEL / BACK
KEY_HELP	Open a Help window	HELP
KEY_HOMEPAGE	Navigate to Homepage	HOME
KEY_INFO	Open On Screen Display	DISPLAY INFORMATION / OSD
KEY_WWW	Open the default browser	WEB
KEY_UP	Up key	UP	On simpler IR's, without separate channel keys, you need to map UP as KEY_CHANNELUP
KEY_DOWN	Down key	DOWN	On simpler IR's, without separate channel keys, you need to map DOWN as KEY_CHANNELDOWN
KEY_LEFT	Left key	LEFT	On simpler IR's, without separate volume keys, you need to map LEFT as KEY_VOLUMEDOWN
KEY_RIGHT	Right key	RIGHT	On simpler IR's, without separate volume keys, you need to map RIGHT as KEY_VOLUMEUP
Miscelaneous keys
KEY_DOT	Return a dot	.
KEY_FN	Select a function	FUNCTION

Technical details about IR

http://linuxtv.org/wiki/index.php/Remote_controllers-V4L