iio: light: introduce si1133

e-mail received from Silicon Lab to confirm that the licensing
isn't a problem.

"
Dear Maxime Roussin-Belanger,

The LUX calculation code only works with Si1133.
As long as the software is used with Silicon Lab's sensor product,
I don't see any problem.

Regards,
Tony
"
Signed-off-by: Maxime Roussin-Bélanger <maxime.roussinbelanger@gmail.com>
Reviewed-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio-light-si1133

+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_ir_small_raw
+KernelVersion:	4.18
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Unit-less infrared intensity. The intensity is measured from 1
+		dark photodiode. "small" indicate the surface area capturing
+		infrared.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_ir_large_raw
+KernelVersion:	4.18
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Unit-less infrared intensity. The intensity is measured from 4
+		dark photodiodes. "large" indicate the surface area capturing
+		infrared.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_large_raw
+KernelVersion:	4.18
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Unit-less light intensity with more diodes.
+

drivers/iio/light/Kconfig

+
 #
 # Light sensors
 #
@@ -319,6 +320,17 @@ config PA12203001
          This driver can also be built as a module.  If so, the module
          will be called pa12203001.
 
+config SI1133
+	tristate "SI1133 UV Index Sensor and Ambient Light Sensor"
+	depends on I2C
+	select REGMAP_I2C
+	  help
+	  Say Y here if you want to build a driver for the Silicon Labs SI1133
+	  UV Index Sensor and Ambient Light Sensor chip.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called si1133.
+
 config SI1145
 	tristate "SI1132 and SI1141/2/3/5/6/7 combined ALS, UV index and proximity sensor"
 	depends on I2C

drivers/iio/light/Makefile

@@ -32,6 +32,7 @@ obj-$(CONFIG_OPT3001)		+= opt3001.o
 obj-$(CONFIG_PA12203001)	+= pa12203001.o
 obj-$(CONFIG_RPR0521)		+= rpr0521.o
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o
+obj-$(CONFIG_SI1133)		+= si1133.o
 obj-$(CONFIG_SI1145)		+= si1145.o
 obj-$(CONFIG_STK3310)          += stk3310.o
 obj-$(CONFIG_ST_UVIS25)		+= st_uvis25_core.o