# SPDX-License-Identifier: GPL-2.0-only
%YAML 1.2
---
$id: http://devicetree.org/schemas/leds/common.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Common leds properties
maintainers:
- Jacek Anaszewski <[email protected]>
- Pavel Machek <[email protected]>
description:
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.
properties:
led-sources:
description:
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.
$ref: /schemas/types.yaml#/definitions/uint32-array
function:
description:
LED function. 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.
$ref: /schemas/types.yaml#/definitions/string
color:
description:
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.
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 0
maximum: 14
function-enumerator:
description:
Integer to be used when more than one instance of the same function is
needed, differing only with an ordinal number.
$ref: /schemas/types.yaml#/definitions/uint32
label:
description:
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:
description:
The initial state of the LED. 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.
$ref: /schemas/types.yaml#/definitions/string
enum:
- on
- off
- keep
default: off
linux,default-trigger:
description:
This parameter, if present, is a string defining the trigger assigned to
the LED.
$ref: /schemas/types.yaml#/definitions/string
oneOf:
- enum:
# LED will act as a back-light, controlled by the framebuffer system
- backlight
# LED will turn on (see also "default-state" property)
- default-on
# LED "double" flashes at a load average based rate
- heartbeat
# LED indicates disk activity
- disk-activity
# LED indicates disk read activity
- disk-read
# LED indicates disk write activity
- disk-write
# LED flashes at a fixed, configurable rate
- timer
# LED alters the brightness for the specified duration with one software
# timer (requires "led-pattern" property)
- pattern
# LED indicates mic mute state
- audio-micmute
# LED indicates audio mute state
- audio-mute
# LED indicates bluetooth power state
- bluetooth-power
# LED indicates camera flash state
- flash
# LED indicated keyboard capslock
- kbd-capslock
# LED indicates MTD memory activity
- mtd
# LED indicates NAND memory activity (deprecated),
# in new implementations use "mtd"
- nand-disk
# No trigger assigned to the LED. This is the default mode
# if trigger is absent
- none
# LED indicates camera torch state
- torch
# LED indicates USB gadget activity
- usb-gadget
# LED indicates USB host activity
- usb-host
# LED indicates USB port state
- usbport
# LED is triggered by CPU activity
- pattern: "^cpu[0-9]*$"
# LED is triggered by Bluetooth activity
- pattern: "^hci[0-9]+-power$"
# LED is triggered by SD/MMC activity
- pattern: "^mmc[0-9]+$"
# LED is triggered by WLAN activity
- pattern: "^phy[0-9]+tx$"
led-pattern:
description: |
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
$ref: /schemas/types.yaml#/definitions/uint32-matrix
items:
minItems: 2
maxItems: 2
led-max-microamp:
description:
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).
max-brightness:
description:
Normally, the maximum brightness is determined by the hardware, and this
property is not required. This property is used to set a software limit.
It could happen that an LED is made so bright that it gets damaged or
causes damage due to restrictions in a specific system, such as mounting
conditions.
Note that this flag is mainly used for PWM-LEDs, where it is not possible
to map brightness to current. Drivers for other controllers should use
led-max-microamp.
$ref: /schemas/types.yaml#/definitions/uint32
panic-indicator:
description:
This property specifies that the LED should be used, if at all possible,
as a panic indicator.
type: boolean
retain-state-shutdown:
description:
This property specifies that the LED should not be turned off or changed
when the system shuts down.
type: boolean
trigger-sources:
description: |
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).
Another example is a GPIO line that will be monitored and mirror the
state of the line (with or without inversion flags) to the LED.
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.
$ref: /schemas/types.yaml#/definitions/phandle-array
active-low:
type: boolean
description:
Makes LED active low. To turn the LED ON, line needs to be
set to low voltage instead of high.
inactive-high-impedance:
type: boolean
description:
Set LED to high-impedance mode to turn the LED OFF. LED might also
describe this mode as tristate.
# Required properties for flash LED child nodes:
flash-max-microamp:
description:
Maximum flash LED supply current in microamperes. Required for flash LED
nodes with configurable current.
flash-max-timeout-us:
description:
Maximum timeout in microseconds after which the flash LED is turned off.
Required for flash LED nodes with configurable timeout.
additionalProperties: true
examples:
- |
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/leds/common.h>
led-controller {
compatible = "gpio-leds";
led-0 {
function = LED_FUNCTION_STATUS;
linux,default-trigger = "heartbeat";
gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
};
led-1 {
function = LED_FUNCTION_USB;
gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
trigger-sources = <&ohci_port1>, <&ehci_port1>;
};
};
- |
#include <dt-bindings/leds/common.h>
led-controller {
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>;
};
};
- |
#include <dt-bindings/leds/common.h>
i2c {
#address-cells = <1>;
#size-cells = <0>;
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>;
};
};
};
...
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