1 Device Tree Bindings for Register Bit LEDs
2
3 Register bit leds are used with syscon multifunctional devices
4 where single bits in a certain register can turn on/off a
5 single LED. The register bit LEDs appear as children to the
6 syscon device, with the proper compatible string. For the
7 syscon bindings see:
8 Documentation/devicetree/bindings/mfd/syscon.yaml
9
10 Each LED is represented as a sub-node of the syscon device. Each
11 node's name represents the name of the corresponding LED.
12
13 LED sub-node properties:
14
15 Required properties:
16 - compatible : must be "register-bit-led"
17 - offset : register offset to the register controlling this LED
18 - mask : bit mask for the bit controlling this LED in the register
19 typically 0x01, 0x02, 0x04 ...
20
21 Optional properties:
22 - label : (optional)
23 see Documentation/devicetree/bindings/leds/common.txt
24 - linux,default-trigger : (optional)
25 see Documentation/devicetree/bindings/leds/common.txt
26 - default-state: (optional) The initial state of the LED
27 see Documentation/devicetree/bindings/leds/common.txt
28
29 Example:
30
31 syscon: syscon@10000000 {
32 compatible = "arm,realview-pb1176-syscon", "syscon";
33 reg = <0x10000000 0x1000>;
34
35 led@8.0 {
36 compatible = "register-bit-led";
37 offset = <0x08>;
38 mask = <0x01>;
39 label = "versatile:0";
40 linux,default-trigger = "heartbeat";
41 default-state = "on";
42 };
43 led@8.1 {
44 compatible = "register-bit-led";
45 offset = <0x08>;
46 mask = <0x02>;
47 label = "versatile:1";
48 linux,default-trigger = "mmc0";
49 default-state = "off";
50 };
51 led@8.2 {
52 compatible = "register-bit-led";
53 offset = <0x08>;
54 mask = <0x04>;
55 label = "versatile:2";
56 linux,default-trigger = "cpu0";
57 default-state = "off";
58 };
59 led@8.3 {
60 compatible = "register-bit-led";
61 offset = <0x08>;
62 mask = <0x08>;
63 label = "versatile:3";
64 default-state = "off";
65 };
66 led@8.4 {
67 compatible = "register-bit-led";
68 offset = <0x08>;
69 mask = <0x10>;
70 label = "versatile:4";
71 default-state = "off";
72 };
73 led@8.5 {
74 compatible = "register-bit-led";
75 offset = <0x08>;
76 mask = <0x20>;
77 label = "versatile:5";
78 default-state = "off";
79 };
80 led@8.6 {
81 compatible = "register-bit-led";
82 offset = <0x08>;
83 mask = <0x40>;
84 label = "versatile:6";
85 default-state = "off";
86 };
87 led@8.7 {
88 compatible = "register-bit-led";
89 offset = <0x08>;
90 mask = <0x80>;
91 label = "versatile:7";
92 default-state = "off";
93 };
94 };
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