1 -*- org -*-
2
3 It is somehow important to provide consistent interface to the
4 userland. LED devices have one problem there, and that is naming of
5 directories in /sys/class/leds. It would be nice if userland would
6 just know right "name" for given LED function, but situation got more
7 complex.
8
9 Anyway, if backwards compatibility is not an issue, new code should
10 use one of the "good" names from this list, and you should extend the
11 list where applicable.
12
13 Legacy names are listed, too; in case you are writing application that
14 wants to use particular feature, you should probe for good name, first,
15 but then try the legacy ones, too.
16
17 Notice there's a list of functions in include/dt-bindings/leds/common.h .
18
19 * Gamepads and joysticks
20
21 Game controllers may feature LEDs to indicate a player number. This is commonly
22 used on game consoles in which multiple controllers can be connected to a system.
23 The "player LEDs" are then programmed with a pattern to indicate a particular
24 player. For example, a game controller with 4 LEDs, may be programmed with "x---"
25 to indicate player 1, "-x--" to indicate player 2 etcetera where "x" means on.
26 Input drivers can utilize the LED class to expose the individual player LEDs
27 of a game controller using the function "player".
28 Note: tracking and management of Player IDs is the responsibility of user space,
29 though drivers may pick a default value.
30
31 Good: "input*:*:player-{1,2,3,4,5}
32
33 * Keyboards
34
35 Good: "input*:*:capslock"
36 Good: "input*:*:scrolllock"
37 Good: "input*:*:numlock"
38 Legacy: "shift-key-light" (Motorola Droid 4, capslock)
39
40 Set of common keyboard LEDs, going back to PC AT or so.
41
42 Legacy: "tpacpi::thinklight" (IBM/Lenovo Thinkpads)
43 Legacy: "lp5523:kb{1,2,3,4,5,6}" (Nokia N900)
44
45 Frontlight/backlight of main keyboard.
46
47 Legacy: "button-backlight" (Motorola Droid 4)
48
49 Some phones have touch buttons below screen; it is different from main
50 keyboard. And this is their backlight.
51
52 * Sound subsystem
53
54 Good: "platform:*:mute"
55 Good: "platform:*:micmute"
56
57 LEDs on notebook body, indicating that sound input / output is muted.
58
59 * System notification
60
61 Good: "rgb:status"
62 Legacy: "status-led:{red,green,blue}" (Motorola Droid 4)
63 Legacy: "lp5523:{r,g,b}" (Nokia N900)
64
65 Phones usually have multi-color status LED.
66
67 * Power management
68
69 Good: "platform:*:charging" (allwinner sun50i, leds-cht-wcove)
70
71 * Screen
72
73 Good: ":backlight" (Motorola Droid 4)
74
75 * Indicators
76
77 Good: ":indicator" (Blinkm)
78
79 * RGB
80
81 Good: ":rgb" (Blinkm)
82
83 * Ethernet LEDs
84
85 Currently two types of Network LEDs are support, those controlled by
86 the PHY and those by the MAC. In theory both can be present at the
87 same time for one Linux netdev, hence the names need to differ between
88 MAC and PHY.
89
90 Do not use the netdev name, such as eth0, enp1s0. These are not stable
91 and are not unique. They also don't differentiate between MAC and PHY.
92
93 ** MAC LEDs
94
95 Good: f1070000.ethernet:white:WAN
96 Good: mdio_mux-0.1:00:green:left
97 Good: 0000:02:00.0:yellow:top
98
99 The first part must uniquely name the MAC controller. Then follows the
100 colour. WAN/LAN should be used for a single LED. If there are
101 multiple LEDs, use left/right, or top/bottom to indicate their
102 position on the RJ45 socket.
103
104 ** PHY LEDs
105
106 Good: f1072004.mdio-mii:00: white:WAN
107 Good: !mdio-mux!mdio@2!switch@0!mdio:01:green:right
108 Good: r8169-0-200:00:yellow:bottom
109
110 The first part must uniquely name the PHY. This often means uniquely
111 identifying the MDIO bus controller, and the address on the bus.
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