1-*- org -*-
2
3It is somehow important to provide consistent interface to the
4userland. LED devices have one problem there, and that is naming of
5directories in /sys/class/leds. It would be nice if userland would
6just know right "name" for given LED function, but situation got more
7complex.
8
9Anyway, if backwards compatibility is not an issue, new code should
10use one of the "good" names from this list, and you should extend the
11list where applicable.
12
13Legacy names are listed, too; in case you are writing application that
14wants to use particular feature, you should probe for good name, first,
15but then try the legacy ones, too.
16
17Notice there's a list of functions in include/dt-bindings/leds/common.h .
18
19* Gamepads and joysticks
20
21Game controllers may feature LEDs to indicate a player number. This is commonly
22used on game consoles in which multiple controllers can be connected to a system.
23The "player LEDs" are then programmed with a pattern to indicate a particular
24player. For example, a game controller with 4 LEDs, may be programmed with "x---"
25to indicate player 1, "-x--" to indicate player 2 etcetera where "x" means on.
26Input drivers can utilize the LED class to expose the individual player LEDs
27of a game controller using the function "player".
28Note: tracking and management of Player IDs is the responsibility of user space,
29though drivers may pick a default value.
30
31Good: "input*:*:player-{1,2,3,4,5}
32
33* Keyboards
34
35Good: "input*:*:capslock"
36Good: "input*:*:scrolllock"
37Good: "input*:*:numlock"
38Legacy: "shift-key-light" (Motorola Droid 4, capslock)
39
40Set of common keyboard LEDs, going back to PC AT or so.
41
42Legacy: "tpacpi::thinklight" (IBM/Lenovo Thinkpads)
43Legacy: "lp5523:kb{1,2,3,4,5,6}" (Nokia N900)
44
45Frontlight/backlight of main keyboard.
46
47Legacy: "button-backlight" (Motorola Droid 4)
48
49Some phones have touch buttons below screen; it is different from main
50keyboard. And this is their backlight.
51
52* Sound subsystem
53
54Good: "platform:*:mute"
55Good: "platform:*:micmute"
56
57LEDs on notebook body, indicating that sound input / output is muted.
58
59* System notification
60
61Legacy: "status-led:{red,green,blue}" (Motorola Droid 4)
62Legacy: "lp5523:{r,g,b}" (Nokia N900)
63
64Phones usually have multi-color status LED.
65
66* Power management
67
68Good: "platform:*:charging" (allwinner sun50i)
69
70* Screen
71
72Good: ":backlight" (Motorola Droid 4)
73
74* Ethernet LEDs
75
76Currently two types of Network LEDs are support, those controlled by
77the PHY and those by the MAC. In theory both can be present at the
78same time for one Linux netdev, hence the names need to differ between
79MAC and PHY.
80
81Do not use the netdev name, such as eth0, enp1s0. These are not stable
82and are not unique. They also don't differentiate between MAC and PHY.
83
84** MAC LEDs
85
86Good: f1070000.ethernet:white:WAN
87Good: mdio_mux-0.1:00:green:left
88Good: 0000:02:00.0:yellow:top
89
90The first part must uniquely name the MAC controller. Then follows the
91colour.  WAN/LAN should be used for a single LED. If there are
92multiple LEDs, use left/right, or top/bottom to indicate their
93position on the RJ45 socket.
94
95** PHY LEDs
96
97Good: f1072004.mdio-mii:00: white:WAN
98Good: !mdio-mux!mdio@2!switch@0!mdio:01:green:right
99Good: r8169-0-200:00:yellow:bottom
100
101The first part must uniquely name the PHY. This often means uniquely
102identifying the MDIO bus controller, and the address on the bus.
103