Specifying wakeup capability for devices
============================================

Any device nodes
----------------
Nodes that describe devices which has wakeup capability must contain an
"wakeup-source" boolean property.

Also, if device is marked as a wakeup source, then all the primary
interrupt(s) can be used as wakeup interrupt(s).

However if the devices have dedicated interrupt as the wakeup source
then they need to specify/identify the same using device specific
interrupt name. In such cases only that interrupt can be used as wakeup
interrupt.

List of legacy properties and respective binding document
---------------------------------------------------------

1. "enable-sdio-wakeup"		Documentation/devicetree/bindings/mmc/mmc.txt
2. "gpio-key,wakeup"		Documentation/devicetree/bindings/input/gpio-keys{,-polled}.txt
3. "has-tpo"			Documentation/devicetree/bindings/rtc/rtc-opal.txt
4. "linux,wakeup"		Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt
				Documentation/devicetree/bindings/mfd/tc3589x.txt
				Documentation/devicetree/bindings/input/touchscreen/ads7846.txt
5. "linux,keypad-wakeup"	Documentation/devicetree/bindings/input/qcom,pm8xxx-keypad.txt
6. "linux,input-wakeup"		Documentation/devicetree/bindings/input/samsung-keypad.txt
7. "nvidia,wakeup-source"	Documentation/devicetree/bindings/input/nvidia,tegra20-kbc.txt

Examples
--------

1. With "wakeup" interrupt name

	device@10000 {
		compatible	= "vendor,device-id";
		reg		= <0x10000 0x1000>;
		interrupts	= <0 19 4>, <0 21 4>, <0 22 4>;
		interrupt-names	= "ack", "err", "wakeup";
		wakeup-source;
	};

2. Without "wakeup" interrupt name

	embedded-controller {
		compatible = "google,cros-ec-i2c";
		reg = <0x1e>;
		interrupts = <6 0>;
		interrupt-parent = <&gpx1>;
		pinctrl-names = "default";
		pinctrl-0 = <&ec_irq>;
		wakeup-source;
	};

3. Without interrupts

	gpio_keys {
		compatible = "gpio-keys";
		#address-cells = <1>;
		#size-cells = <0>;

		button@1 {
			debounce-interval = <50>;
			wakeup-source;
			linux,code = <116>;
			label = "POWER";
			gpios = <&iofpga_gpio0 0 0x4>;
		};
		[....]
	};
