Documentation/devicetree/bindings/leds/common.txt - linux - Git at Google

 * Common leds properties.

 LED and flash LED devices provide the same basic functionality as current
 regulators, but extended with LED and flash LED specific features like
 blinking patterns, flash timeout, flash faults and external flash strobe mode.

 Many LED devices expose more than one current output that can be connected
 to one or more discrete LED component. Since the arrangement of connections
 can influence the way of the LED device initialization, the LED components
 have to be tightly coupled with the LED device binding. They are represented
 by child nodes of the parent LED device binding.


 Optional properties for child nodes:
 - led-sources : List of device current outputs the LED is connected to. The
 		outputs are identified by the numbers that must be defined
 		in the LED device binding documentation.

 - function: LED functon. Use one of the LED_FUNCTION_* prefixed definitions
 	    from the header include/dt-bindings/leds/common.h.
 	    If there is no matching LED_FUNCTION available, add a new one.

 - color : Color of the LED. Use one of the LED_COLOR_ID_* prefixed definitions
 	  from the header include/dt-bindings/leds/common.h.
 	  If there is no matching LED_COLOR_ID available, add a new one.

 - function-enumerator: Integer to be used when more than one instance
                        of the same function is needed, differing only with
 		       an ordinal number.

 - label : The label for this LED. If omitted, the label is taken from the node
 	  name (excluding the unit address). It has to uniquely identify
 	  a device, i.e. no other LED class device can be assigned the same
 	  label. This property is deprecated - use 'function' and 'color'
 	  properties instead. function-enumerator has no effect when this
 	  property is present.

 - default-state : The initial state of the LED. Valid values are "on", "off",
   and "keep". If the LED is already on or off and the default-state property is
   set the to same value, then no glitch should be produced where the LED
   momentarily turns off (or on). The "keep" setting will keep the LED at
   whatever its current state is, without producing a glitch.  The default is
   off if this property is not present.

 - linux,default-trigger :  This parameter, if present, is a
     string defining the trigger assigned to the LED.  Current triggers are:
      "backlight" - LED will act as a back-light, controlled by the framebuffer
 		   system
      "default-on" - LED will turn on (but for leds-gpio see "default-state"
 		    property in Documentation/devicetree/bindings/leds/leds-gpio.txt)
      "heartbeat" - LED "double" flashes at a load average based rate
      "disk-activity" - LED indicates disk activity
      "ide-disk" - LED indicates IDE disk activity (deprecated),
                   in new implementations use "disk-activity"
      "timer" - LED flashes at a fixed, configurable rate
      "pattern" - LED alters the brightness for the specified duration with one
                  software timer (requires "led-pattern" property)

 - led-pattern : Array of integers with default pattern for certain triggers.
                 Each trigger may parse this property differently:
                 - one-shot : two numbers specifying delay on and delay off (in ms),
                 - timer : two numbers specifying delay on and delay off (in ms),
                 - pattern : the pattern is given by a series of tuples, of
                   brightness and duration (in ms).  The exact format is
                   described in:
                   Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt


 - led-max-microamp : Maximum LED supply current in microamperes. This property
                      can be made mandatory for the board configurations
                      introducing a risk of hardware damage in case an excessive
                      current is set.
                      For flash LED controllers with configurable current this
                      property is mandatory for the LEDs in the non-flash modes
                      (e.g. torch or indicator).

 - panic-indicator : This property specifies that the LED should be used,
 		    if at all possible, as a panic indicator.

 - trigger-sources : List of devices which should be used as a source triggering
 		    this LED activity. Some LEDs can be related to a specific
 		    device and should somehow indicate its state. E.g. USB 2.0
 		    LED may react to device(s) in a USB 2.0 port(s).
 		    Another common example is switch or router with multiple
 		    Ethernet ports each of them having its own LED assigned
 		    (assuming they are not hardwired). In such cases this
 		    property should contain phandle(s) of related source
 		    device(s).
 		    In many cases LED can be related to more than one device
 		    (e.g. one USB LED vs. multiple USB ports). Each source
 		    should be represented by a node in the device tree and be
 		    referenced by a phandle and a set of phandle arguments. A
 		    length of arguments should be specified by the
 		    #trigger-source-cells property in the source node.

 Required properties for flash LED child nodes:
 - flash-max-microamp : Maximum flash LED supply current in microamperes.
 - flash-max-timeout-us : Maximum timeout in microseconds after which the flash
                          LED is turned off.

 For controllers that have no configurable current the flash-max-microamp
 property can be omitted.
 For controllers that have no configurable timeout the flash-max-timeout-us
 property can be omitted.

 * Trigger source providers

 Each trigger source should be represented by a device tree node. It may be e.g.
 a USB port or an Ethernet device.

 Required properties for trigger source:
 - #trigger-source-cells : Number of cells in a source trigger. Typically 0 for
 			  nodes of simple trigger sources (e.g. a specific USB
 			  port).

 * Examples

 #include <dt-bindings/leds/common.h>

 led-controller@0 {
 	compatible = "gpio-leds";

 	led0 {
 		function = LED_FUNCTION_STATUS;
 		linux,default-trigger = "heartbeat";
 		gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
 	};

 	led1 {
 		function = LED_FUNCTION_USB;
 		gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
 		trigger-sources = <&ohci_port1>, <&ehci_port1>;
 	};
 };

 led-controller@0 {
 	compatible = "maxim,max77693-led";

 	led {
 		function = LED_FUNCTION_FLASH;
 		color = <LED_COLOR_ID_WHITE>;
 		led-sources = <0>, <1>;
 		led-max-microamp = <50000>;
 		flash-max-microamp = <320000>;
 		flash-max-timeout-us = <500000>;
 	};
 };

 led-controller@30 {
         compatible = "panasonic,an30259a";
         reg = <0x30>;
         #address-cells = <1>;
         #size-cells = <0>;

         led@1 {
 		reg = <1>;
 		linux,default-trigger = "heartbeat";
 		function = LED_FUNCTION_INDICATOR;
 		function-enumerator = <1>;
         };

         led@2 {
 		reg = <2>;
 		function = LED_FUNCTION_INDICATOR;
 		function-enumerator = <2>;
         };

         led@3 {
 		reg = <3>;
 		function = LED_FUNCTION_INDICATOR;
 		function-enumerator = <3>;
         };
 };
	* Common leds properties.

	LED and flash LED devices provide the same basic functionality as current
	regulators, but extended with LED and flash LED specific features like
	blinking patterns, flash timeout, flash faults and external flash strobe mode.

	Many LED devices expose more than one current output that can be connected
	to one or more discrete LED component. Since the arrangement of connections
	can influence the way of the LED device initialization, the LED components
	have to be tightly coupled with the LED device binding. They are represented
	by child nodes of the parent LED device binding.


	Optional properties for child nodes:
	- led-sources : List of device current outputs the LED is connected to. The
	outputs are identified by the numbers that must be defined
	in the LED device binding documentation.

	- function: LED functon. Use one of the LED_FUNCTION_* prefixed definitions
	from the header include/dt-bindings/leds/common.h.
	If there is no matching LED_FUNCTION available, add a new one.

	- color : Color of the LED. Use one of the LED_COLOR_ID_* prefixed definitions
	from the header include/dt-bindings/leds/common.h.
	If there is no matching LED_COLOR_ID available, add a new one.

	- function-enumerator: Integer to be used when more than one instance
	of the same function is needed, differing only with
	an ordinal number.

	- label : The label for this LED. If omitted, the label is taken from the node
	name (excluding the unit address). It has to uniquely identify
	a device, i.e. no other LED class device can be assigned the same
	label. This property is deprecated - use 'function' and 'color'
	properties instead. function-enumerator has no effect when this
	property is present.

	- default-state : The initial state of the LED. Valid values are "on", "off",
	and "keep". If the LED is already on or off and the default-state property is
	set the to same value, then no glitch should be produced where the LED
	momentarily turns off (or on). The "keep" setting will keep the LED at
	whatever its current state is, without producing a glitch. The default is
	off if this property is not present.

	- linux,default-trigger : This parameter, if present, is a
	string defining the trigger assigned to the LED. Current triggers are:
	"backlight" - LED will act as a back-light, controlled by the framebuffer
	system
	"default-on" - LED will turn on (but for leds-gpio see "default-state"
	property in Documentation/devicetree/bindings/leds/leds-gpio.txt)
	"heartbeat" - LED "double" flashes at a load average based rate
	"disk-activity" - LED indicates disk activity
	"ide-disk" - LED indicates IDE disk activity (deprecated),
	in new implementations use "disk-activity"
	"timer" - LED flashes at a fixed, configurable rate
	"pattern" - LED alters the brightness for the specified duration with one
	software timer (requires "led-pattern" property)

	- led-pattern : Array of integers with default pattern for certain triggers.
	Each trigger may parse this property differently:
	- one-shot : two numbers specifying delay on and delay off (in ms),
	- timer : two numbers specifying delay on and delay off (in ms),
	- pattern : the pattern is given by a series of tuples, of
	brightness and duration (in ms). The exact format is
	described in:
	Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt


	- led-max-microamp : Maximum LED supply current in microamperes. This property
	can be made mandatory for the board configurations
	introducing a risk of hardware damage in case an excessive
	current is set.
	For flash LED controllers with configurable current this
	property is mandatory for the LEDs in the non-flash modes
	(e.g. torch or indicator).

	- panic-indicator : This property specifies that the LED should be used,
	if at all possible, as a panic indicator.

	- trigger-sources : List of devices which should be used as a source triggering
	this LED activity. Some LEDs can be related to a specific
	device and should somehow indicate its state. E.g. USB 2.0
	LED may react to device(s) in a USB 2.0 port(s).
	Another common example is switch or router with multiple
	Ethernet ports each of them having its own LED assigned
	(assuming they are not hardwired). In such cases this
	property should contain phandle(s) of related source
	device(s).
	In many cases LED can be related to more than one device
	(e.g. one USB LED vs. multiple USB ports). Each source
	should be represented by a node in the device tree and be
	referenced by a phandle and a set of phandle arguments. A
	length of arguments should be specified by the
	#trigger-source-cells property in the source node.

	Required properties for flash LED child nodes:
	- flash-max-microamp : Maximum flash LED supply current in microamperes.
	- flash-max-timeout-us : Maximum timeout in microseconds after which the flash
	LED is turned off.

	For controllers that have no configurable current the flash-max-microamp
	property can be omitted.
	For controllers that have no configurable timeout the flash-max-timeout-us
	property can be omitted.

	* Trigger source providers

	Each trigger source should be represented by a device tree node. It may be e.g.
	a USB port or an Ethernet device.

	Required properties for trigger source:
	- #trigger-source-cells : Number of cells in a source trigger. Typically 0 for
	nodes of simple trigger sources (e.g. a specific USB
	port).

	* Examples

	#include <dt-bindings/leds/common.h>

	led-controller@0 {
	compatible = "gpio-leds";

	led0 {
	function = LED_FUNCTION_STATUS;
	linux,default-trigger = "heartbeat";
	gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
	};

	led1 {
	function = LED_FUNCTION_USB;
	gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
	trigger-sources = <&ohci_port1>, <&ehci_port1>;
	};
	};

	led-controller@0 {
	compatible = "maxim,max77693-led";

	led {
	function = LED_FUNCTION_FLASH;
	color = <LED_COLOR_ID_WHITE>;
	led-sources = <0>, <1>;
	led-max-microamp = <50000>;
	flash-max-microamp = <320000>;
	flash-max-timeout-us = <500000>;
	};
	};

	led-controller@30 {
	compatible = "panasonic,an30259a";
	reg = <0x30>;
	#address-cells = <1>;
	#size-cells = <0>;

	led@1 {
	reg = <1>;
	linux,default-trigger = "heartbeat";
	function = LED_FUNCTION_INDICATOR;
	function-enumerator = <1>;
	};

	led@2 {
	reg = <2>;
	function = LED_FUNCTION_INDICATOR;
	function-enumerator = <2>;
	};

	led@3 {
	reg = <3>;
	function = LED_FUNCTION_INDICATOR;
	function-enumerator = <3>;
	};
	};