* ST Microelectronics STMPE Multi-Functional Device

STMPE is an MFD device which may expose the following inbuilt devices: gpio,
keypad, touchscreen, adc, pwm, rotator.

Required properties:
 - compatible                   : "st,stmpe[610|801|811|1600|1601|2401|2403]"
 - reg                          : I2C/SPI address of the device

Optional properties:
 - interrupts                   : The interrupt outputs from the controller
 - interrupt-controller         : Marks the device node as an interrupt controller
 - interrupt-parent             : Specifies which IRQ controller we're connected to
 - wakeup-source                : Marks the input device as wakable
 - st,autosleep-timeout         : Valid entries (ms); 4, 16, 32, 64, 128, 256, 512 and 1024
 - irq-gpio                     : If present, which GPIO to use for event IRQ

Example:

	stmpe1601: stmpe1601@40 {
		compatible = "st,stmpe1601";
		reg = <0x40>;
		interrupts = <26 0x4>;
		interrupt-parent = <&gpio6>;
		interrupt-controller;

		wakeup-source;
		st,autosleep-timeout = <1024>;
	};