Texas Instruments - TSC / ADC multi-functional device

ti_tscadc is a multi-function device with touchscreen and ADC on chip.
This document describes the binding for mfd device.

Required properties:
- compatible: "ti,ti-tscadc"
- reg: Specifies the address of MFD block
- interrupts: IRQ line connected to the main SoC
- interrupt-parent: The parent interrupt controller

Optional properties:
- ti,hwmods: Hardware information related to TSC/ADC MFD device

Sub-nodes:
Device			Description
------			-----------
tsc			Touchscreen
adc			Analog to digital converter

Sub-node device required properties:
tsc:
- ti,wires:  4/5/8 wire touchscreen support on the platform.
- ti,x-plate-resistance: X plate resistance.
- ti,steps-to-configure: A step is configured to read a single co-ordinate value,
			can be applied more number of times for better results.
- ti,wire-config: Order for connecting wires on touchscreen.

adc:
- ti,adc-channels: Number of ADC channels used.

Example:

	tscadc: tscadc@44e0d000 {
		compatible = "ti,ti-tscadc";
		reg = <0x44e0d000 0x1000>;

		interrupt-parent = <&intc>;
		interrupts = <16>;
		ti,hwmods = "adc_tsc";

		tsc {
			ti,wires = <4>;
			ti,x-plate-resistance = <200>;
			ti,steps-to-configure = <5>;
			ti,wire-config = <0x00 0x11 0x22 0x33>;
		};

		adc {
			ti,adc-channels = <4>;
		};
	};
