1 * Common leds properties.
3 LED and flash LED devices provide the same basic functionality as current
4 regulators, but extended with LED and flash LED specific features like
5 blinking patterns, flash timeout, flash faults and external flash strobe mode.
7 Many LED devices expose more than one current output that can be connected
8 to one or more discrete LED component. Since the arrangement of connections
9 can influence the way of the LED device initialization, the LED components
10 have to be tightly coupled with the LED device binding. They are represented
11 by child nodes of the parent LED device binding.
14 Optional properties for child nodes:
15 - led-sources : List of device current outputs the LED is connected to. The
16 outputs are identified by the numbers that must be defined
17 in the LED device binding documentation.
19 - function: LED functon. Use one of the LED_FUNCTION_* prefixed definitions
20 from the header include/dt-bindings/leds/common.h.
21 If there is no matching LED_FUNCTION available, add a new one.
23 - color : Color of the LED. Use one of the LED_COLOR_ID_* prefixed definitions
24 from the header include/dt-bindings/leds/common.h.
25 If there is no matching LED_COLOR_ID available, add a new one.
27 - function-enumerator: Integer to be used when more than one instance
28 of the same function is needed, differing only with
31 - label : The label for this LED. If omitted, the label is taken from the node
32 name (excluding the unit address). It has to uniquely identify
33 a device, i.e. no other LED class device can be assigned the same
34 label. This property is deprecated - use 'function' and 'color'
35 properties instead. function-enumerator has no effect when this
38 - default-state : The initial state of the LED. Valid values are "on", "off",
39 and "keep". If the LED is already on or off and the default-state property is
40 set the to same value, then no glitch should be produced where the LED
41 momentarily turns off (or on). The "keep" setting will keep the LED at
42 whatever its current state is, without producing a glitch. The default is
43 off if this property is not present.
45 - linux,default-trigger : This parameter, if present, is a
46 string defining the trigger assigned to the LED. Current triggers are:
47 "backlight" - LED will act as a back-light, controlled by the framebuffer
49 "default-on" - LED will turn on (but for leds-gpio see "default-state"
50 property in Documentation/devicetree/bindings/leds/leds-gpio.txt)
51 "heartbeat" - LED "double" flashes at a load average based rate
52 "disk-activity" - LED indicates disk activity
53 "ide-disk" - LED indicates IDE disk activity (deprecated),
54 in new implementations use "disk-activity"
55 "timer" - LED flashes at a fixed, configurable rate
56 "pattern" - LED alters the brightness for the specified duration with one
57 software timer (requires "led-pattern" property)
59 - led-pattern : Array of integers with default pattern for certain triggers.
60 Each trigger may parse this property differently:
61 - one-shot : two numbers specifying delay on and delay off (in ms),
62 - timer : two numbers specifying delay on and delay off (in ms),
63 - pattern : the pattern is given by a series of tuples, of
64 brightness and duration (in ms). The exact format is
66 Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
69 - led-max-microamp : Maximum LED supply current in microamperes. This property
70 can be made mandatory for the board configurations
71 introducing a risk of hardware damage in case an excessive
73 For flash LED controllers with configurable current this
74 property is mandatory for the LEDs in the non-flash modes
75 (e.g. torch or indicator).
77 - panic-indicator : This property specifies that the LED should be used,
78 if at all possible, as a panic indicator.
80 - trigger-sources : List of devices which should be used as a source triggering
81 this LED activity. Some LEDs can be related to a specific
82 device and should somehow indicate its state. E.g. USB 2.0
83 LED may react to device(s) in a USB 2.0 port(s).
84 Another common example is switch or router with multiple
85 Ethernet ports each of them having its own LED assigned
86 (assuming they are not hardwired). In such cases this
87 property should contain phandle(s) of related source
89 In many cases LED can be related to more than one device
90 (e.g. one USB LED vs. multiple USB ports). Each source
91 should be represented by a node in the device tree and be
92 referenced by a phandle and a set of phandle arguments. A
93 length of arguments should be specified by the
94 #trigger-source-cells property in the source node.
96 Required properties for flash LED child nodes:
97 - flash-max-microamp : Maximum flash LED supply current in microamperes.
98 - flash-max-timeout-us : Maximum timeout in microseconds after which the flash
101 For controllers that have no configurable current the flash-max-microamp
102 property can be omitted.
103 For controllers that have no configurable timeout the flash-max-timeout-us
104 property can be omitted.
106 * Trigger source providers
108 Each trigger source should be represented by a device tree node. It may be e.g.
109 a USB port or an Ethernet device.
111 Required properties for trigger source:
112 - #trigger-source-cells : Number of cells in a source trigger. Typically 0 for
113 nodes of simple trigger sources (e.g. a specific USB
118 #include <dt-bindings/leds/common.h>
121 compatible = "gpio-leds";
124 function = LED_FUNCTION_STATUS;
125 linux,default-trigger = "heartbeat";
126 gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
130 function = LED_FUNCTION_USB;
131 gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
132 trigger-sources = <&ohci_port1>, <&ehci_port1>;
137 compatible = "maxim,max77693-led";
140 function = LED_FUNCTION_FLASH;
141 color = <LED_COLOR_ID_WHITE>;
142 led-sources = <0>, <1>;
143 led-max-microamp = <50000>;
144 flash-max-microamp = <320000>;
145 flash-max-timeout-us = <500000>;
150 compatible = "panasonic,an30259a";
152 #address-cells = <1>;
157 linux,default-trigger = "heartbeat";
158 function = LED_FUNCTION_INDICATOR;
159 function-enumerator = <1>;
164 function = LED_FUNCTION_INDICATOR;
165 function-enumerator = <2>;
170 function = LED_FUNCTION_INDICATOR;
171 function-enumerator = <3>;