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-rw-r--r--Documentation/devicetree/bindings/leds/common.txt35
1 files changed, 33 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
index 24b656014089..1d4afe9644b6 100644
--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt
@@ -1,4 +1,4 @@
-Common leds properties.
+* 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
@@ -49,6 +49,22 @@ Optional properties for child nodes:
- 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
@@ -59,7 +75,17 @@ property can be omitted.
For controllers that have no configurable timeout the flash-max-timeout-us
property can be omitted.
-Examples:
+* 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
gpio-leds {
compatible = "gpio-leds";
@@ -69,6 +95,11 @@ gpio-leds {
linux,default-trigger = "heartbeat";
gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
};
+
+ usb {
+ gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
+ trigger-sources = <&ohci_port1>, <&ehci_port1>;
+ };
};
max77693-led {