* Observing port driver

Required properties:
- compatible : "sony,obs_port"
- gpios: OF device-tree gpio specification
- event: String, uevent name of gpio port

Optional properties:
- debounce-interval: Duration of debounce-interval (If not specified defaults to 0 ms)
- emergency: emergency warning log output (If not specified defaults to no log output)

Example:
	protect {
		compatible = "sony,obs_port";
		gpios = <&gpio3 16 GPIO_ACTIVE_LOW>;
		event = "PROTECT";
		emergency;
	};

	fuse_det {
		compatible = "sony,obs_port";
		gpios = <&ioexp 17 GPIO_ACTIVE_LOW>;
		event = "FUSE_DET";
		emergency;
	};

	fan_det {
		compatible = "sony,obs_port";
		gpios = <&ioexp 23 GPIO_ACTIVE_LOW>;
		event = "FAN_DET";
		emergency;
	};

	hp_det {
		compatible = "sony,obs_port";
		gpios = <&ioexp 20 GPIO_ACTIVE_HIGH>;
		event = "HP_DET";
		debounce-interval = <100>;
	};
