ADS1015 (I2C)

This device is a 12-bit A-D converter with 4 inputs.

The inputs can be used single ended or in certain differential combinations.

For configuration all possible combinations are mapped to 8 channels:
0: Voltage over AIN0 and AIN1.
1: Voltage over AIN0 and AIN3.
2: Voltage over AIN1 and AIN3.
3: Voltage over AIN2 and AIN3.
4: Voltage over AIN0 and GND.
5: Voltage over AIN1 and GND.
6: Voltage over AIN2 and GND.
7: Voltage over AIN3 and GND.

Optional properties:

 - exported-channels : exported_channels is a bitmask that specifies which
		       channels should be accessable by the user.

Example:
ads1015@49 {
	compatible = "ti,ads1015";
	reg = <0x49>;
	exported-channels = <0x14>;
};

In this example only channel 2 and 4 would be accessable by the user.