iio:light: Add support for STMicro VL6180 sensor

This patch adds support for STMicro VL6180 - ALS, range and proximity sensor. Sensor is capable of measuring the light
intensity as well as object distance using TOF (Time of Flight) technology.
Signed-off-by: Manivannan Sadhasivam <manivannanece23@gmail.com>
Signed-off-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/iio/light/vl6180.txt

+STMicro VL6180 -  ALS, range and proximity sensor
+
+Link to datasheet: http://www.st.com/resource/en/datasheet/vl6180x.pdf
+
+Required properties:
+
+	-compatible: should be "st,vl6180"
+	-reg: the I2C address of the sensor
+
+Example:
+
+vl6180@29 {
+	compatible = "st,vl6180";
+	reg = <0x29>;
+};

drivers/iio/light/Kconfig

@@ -405,4 +405,14 @@ config VEML6070
 	 To compile this driver as a module, choose M here: the
 	 module will be called veml6070.
 
+config VL6180
+	tristate "VL6180 ALS, range and proximity sensor"
+	depends on I2C
+	help
+	 Say Y here if you want to build a driver for the STMicroelectronics
+	 VL6180 combined ambient light, range and proximity sensor.
+
+	 To compile this driver as a module, choose M here: the
+	 module will be called vl6180.
+
 endmenu

drivers/iio/light/Makefile

@@ -38,3 +38,4 @@ obj-$(CONFIG_TSL4531)		+= tsl4531.o
 obj-$(CONFIG_US5182D)		+= us5182d.o
 obj-$(CONFIG_VCNL4000)		+= vcnl4000.o
 obj-$(CONFIG_VEML6070)		+= veml6070.o
+obj-$(CONFIG_VL6180)		+= vl6180.o