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- -*- org -*-
- It is somehow important to provide consistent interface to the
- userland. LED devices have one problem there, and that is naming of
- directories in /sys/class/leds. It would be nice if userland would
- just know right "name" for given LED function, but situation got more
- complex.
- Anyway, if backwards compatibility is not an issue, new code should
- use one of the "good" names from this list, and you should extend the
- list where applicable.
- Legacy names are listed, too; in case you are writing application that
- wants to use particular feature, you should probe for good name, first,
- but then try the legacy ones, too.
- Notice there's a list of functions in include/dt-bindings/leds/common.h .
- * Gamepads and joysticks
- Game controllers may feature LEDs to indicate a player number. This is commonly
- used on game consoles in which multiple controllers can be connected to a system.
- The "player LEDs" are then programmed with a pattern to indicate a particular
- player. For example, a game controller with 4 LEDs, may be programmed with "x---"
- to indicate player 1, "-x--" to indicate player 2 etcetera where "x" means on.
- Input drivers can utilize the LED class to expose the individual player LEDs
- of a game controller using the function "player".
- Note: tracking and management of Player IDs is the responsibility of user space,
- though drivers may pick a default value.
- Good: "input*:*:player-{1,2,3,4,5}
- * Keyboards
-
- Good: "input*:*:capslock"
- Good: "input*:*:scrolllock"
- Good: "input*:*:numlock"
- Legacy: "shift-key-light" (Motorola Droid 4, capslock)
- Set of common keyboard LEDs, going back to PC AT or so.
- Legacy: "tpacpi::thinklight" (IBM/Lenovo Thinkpads)
- Legacy: "lp5523:kb{1,2,3,4,5,6}" (Nokia N900)
- Frontlight/backlight of main keyboard.
- Legacy: "button-backlight" (Motorola Droid 4)
- Some phones have touch buttons below screen; it is different from main
- keyboard. And this is their backlight.
- * Sound subsystem
- Good: "platform:*:mute"
- Good: "platform:*:micmute"
- LEDs on notebook body, indicating that sound input / output is muted.
- * System notification
- Legacy: "status-led:{red,green,blue}" (Motorola Droid 4)
- Legacy: "lp5523:{r,g,b}" (Nokia N900)
- Phones usually have multi-color status LED.
- * Power management
- Good: "platform:*:charging" (allwinner sun50i)
- * Screen
- Good: ":backlight" (Motorola Droid 4)
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