BOSCH BMM150 3-axis magnetic sensor

The BOSCH 3-axis magnetic sensor is a complete 3-axis magnetic sensor with
on-chip signal processing and intergrated i2c bus. It can be connected to host
processor via i2c. It can measure magnetic fields within the full scale range
from -16 Gauss to +16 Gauss.

Required properties:

 - compatible		: Should be "bosch,bmm150".
 - reg			: i2c address of the device.
 - vdd-supply		: Analog power supply needed to power up the device.
 - vio-supply		: Digital IO power supply needed for IO and I2C.
 - bmm,dir		: String value of the direction of the ecompass sensor
	chip. There are 8 patterns of direction:


       x > 0 /___________o
               /        /|
              /        / |* 1st pin is here
             /________/ /|
             |_______/|/ |/ z > 0
                    /
                  |/ y > 0


		The above graph shows the coordination of the sensor chip. Specify the
		following string to bosch,dir to convert it into Android coordination.
		Note the definition of sensor placement on target board is relative to
		Android portrait mode.

						left	right	up	down
		obverse-x-axis-forward		Y+	Y-	X+	X-
		obverse-x-axis-rightward	X-	X+	Y+	Y-
		obverse-x-axis-backward		Y-	Y+	X-	X+
		obverse-x-axis-leftward		X+	X-	Y-	Y+
		reverse-x-axis-forward		Y-	Y+	X+	X-
		reverse-x-axis-rightward	X-	X+	Y-	Y+
		reverse-x-axis-backward		Y+	Y-	X-	X+
		reverse-x-axis-leftward		X+	X-	Y+	Y-

Optional properites:

 - bmm,auto-report	: Boolean value to enable auto-report mode.

 Example:
	A chip on 8916 platform with the pattern as the above graph:
	&i2c_0 { /* BLSP1 QUP2 */
		bosch@12 {
				compatible = "bosch,bmm150";
				reg = <0x12>;
				vdd-supply = <&pm8916_l17>;
				vio-supply = <&pm8916_l6>;
				bmm,dir = "obverse-x-axis-forward";
				bmm,auto-report;
		};
	};