xref: /openbmc/linux/Documentation/leds/well-known-leds.txt (revision 61177c088a57bed259122f3c7bc6d61984936a12)
109f12730SPavel Machek-*- org -*-
209f12730SPavel Machek
309f12730SPavel MachekIt is somehow important to provide consistent interface to the
409f12730SPavel Machekuserland. LED devices have one problem there, and that is naming of
509f12730SPavel Machekdirectories in /sys/class/leds. It would be nice if userland would
609f12730SPavel Machekjust know right "name" for given LED function, but situation got more
709f12730SPavel Machekcomplex.
809f12730SPavel Machek
909f12730SPavel MachekAnyway, if backwards compatibility is not an issue, new code should
1009f12730SPavel Machekuse one of the "good" names from this list, and you should extend the
1109f12730SPavel Macheklist where applicable.
1209f12730SPavel Machek
1309f12730SPavel MachekLegacy names are listed, too; in case you are writing application that
1409f12730SPavel Machekwants to use particular feature, you should probe for good name, first,
1509f12730SPavel Machekbut then try the legacy ones, too.
1609f12730SPavel Machek
1709f12730SPavel MachekNotice there's a list of functions in include/dt-bindings/leds/common.h .
1809f12730SPavel Machek
19*61177c08SRoderick Colenbrander* Gamepads and joysticks
20*61177c08SRoderick Colenbrander
21*61177c08SRoderick ColenbranderGame controllers may feature LEDs to indicate a player number. This is commonly
22*61177c08SRoderick Colenbranderused on game consoles in which multiple controllers can be connected to a system.
23*61177c08SRoderick ColenbranderThe "player LEDs" are then programmed with a pattern to indicate a particular
24*61177c08SRoderick Colenbranderplayer. For example, a game controller with 4 LEDs, may be programmed with "x---"
25*61177c08SRoderick Colenbranderto indicate player 1, "-x--" to indicate player 2 etcetera where "x" means on.
26*61177c08SRoderick ColenbranderInput drivers can utilize the LED class to expose the individual player LEDs
27*61177c08SRoderick Colenbranderof a game controller using the function "player".
28*61177c08SRoderick ColenbranderNote: tracking and management of Player IDs is the responsibility of user space,
29*61177c08SRoderick Colenbranderthough drivers may pick a default value.
30*61177c08SRoderick Colenbrander
31*61177c08SRoderick ColenbranderGood: "input*:*:player-{1,2,3,4,5}
32*61177c08SRoderick Colenbrander
3309f12730SPavel Machek* Keyboards
3409f12730SPavel Machek
3509f12730SPavel MachekGood: "input*:*:capslock"
3609f12730SPavel MachekGood: "input*:*:scrolllock"
3709f12730SPavel MachekGood: "input*:*:numlock"
3809f12730SPavel MachekLegacy: "shift-key-light" (Motorola Droid 4, capslock)
3909f12730SPavel Machek
4009f12730SPavel MachekSet of common keyboard LEDs, going back to PC AT or so.
4109f12730SPavel Machek
4209f12730SPavel MachekLegacy: "tpacpi::thinklight" (IBM/Lenovo Thinkpads)
4309f12730SPavel MachekLegacy: "lp5523:kb{1,2,3,4,5,6}" (Nokia N900)
4409f12730SPavel Machek
4509f12730SPavel MachekFrontlight/backlight of main keyboard.
4609f12730SPavel Machek
4709f12730SPavel MachekLegacy: "button-backlight" (Motorola Droid 4)
4809f12730SPavel Machek
4909f12730SPavel MachekSome phones have touch buttons below screen; it is different from main
5009f12730SPavel Machekkeyboard. And this is their backlight.
5109f12730SPavel Machek
5209f12730SPavel Machek* Sound subsystem
5309f12730SPavel Machek
5409f12730SPavel MachekGood: "platform:*:mute"
5509f12730SPavel MachekGood: "platform:*:micmute"
5609f12730SPavel Machek
5709f12730SPavel MachekLEDs on notebook body, indicating that sound input / output is muted.
5809f12730SPavel Machek
5909f12730SPavel Machek* System notification
6009f12730SPavel Machek
6109f12730SPavel MachekLegacy: "status-led:{red,green,blue}" (Motorola Droid 4)
6209f12730SPavel MachekLegacy: "lp5523:{r,g,b}" (Nokia N900)
6309f12730SPavel Machek
6409f12730SPavel MachekPhones usually have multi-color status LED.
6509f12730SPavel Machek
6609f12730SPavel Machek* Power management
6709f12730SPavel Machek
6809f12730SPavel MachekGood: "platform:*:charging" (allwinner sun50i)
6909f12730SPavel Machek
7009f12730SPavel Machek* Screen
7109f12730SPavel Machek
7209f12730SPavel MachekGood: ":backlight" (Motorola Droid 4)
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