iio: light: Add support for TI OPT4060 color sensor

Add support for Texas Instruments OPT4060 RGBW Color sensor.

Signed-off-by: Per-Daniel Olsson <perdaniel.olsson@axis.com>
Link: https://patch.msgid.link/20241218104836.2784523-3-perdaniel.olsson@axis.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio

@@ -508,6 +508,9 @@ What:		/sys/bus/iio/devices/iio:deviceX/in_angl_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_x_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_y_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_z_scale
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_red_scale
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_green_scale
+What:		/sys/bus/iio/devices/iio:deviceX/in_intensity_blue_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_concentration_co2_scale
 KernelVersion:	2.6.35
 Contact:	linux-iio@vger.kernel.org
@@ -1633,6 +1636,10 @@ What:		/sys/.../iio:deviceX/in_intensityY_uv_raw
 What:		/sys/.../iio:deviceX/in_intensityY_uva_raw
 What:		/sys/.../iio:deviceX/in_intensityY_uvb_raw
 What:		/sys/.../iio:deviceX/in_intensityY_duv_raw
+What:		/sys/.../iio:deviceX/in_intensity_red_raw
+What:		/sys/.../iio:deviceX/in_intensity_green_raw
+What:		/sys/.../iio:deviceX/in_intensity_blue_raw
+What:		/sys/.../iio:deviceX/in_intensity_clear_raw
 KernelVersion:	3.4
 Contact:	linux-iio@vger.kernel.org
 Description:

Documentation/iio/index.rst

@@ -29,3 +29,4 @@ Industrial I/O Kernel Drivers
    adxl380
    bno055
    ep93xx_adc
+   opt4060

Documentation/iio/opt4060.rst

@@ -0,0 +1,61 @@
+==============================
+OPT4060 driver
+==============================
+
+1. Overview
+=============================
+
+This driver supports the Texas Instrument RGBW high resolution color sensor over
+I2C.
+https://www.ti.com/lit/gpn/opt4060
+
+The driver supports:
+- Raw values for red, green, blue and clear.
+- Illuminance values.
+- Scaled color values for red, green and blue.
+- IIO events for thresholds.
+- IIO triggered buffer using both its own data ready trigger and triggers from
+other drivers.
+
+2. Illuminance calculation
+=============================
+
+Illuminance is calculated using the wide spectrum green channel.
+
+lux = GREEN_RAW x 2.15e-3
+
+The value is accessed from:
+/sys/bus/iio/devices/iio:deviceX/in_illuminance_input
+
+See section 8.4.5.2 in the data sheet for additional details.
+
+3. Color scale values
+=============================
+
+The sensor has different sensitivity for the different color components and
+compensating factors are exposed from the driver.
+
+The values are accessed from:
+/sys/bus/iio/devices/iio:deviceX/in_intensity_red_scale
+/sys/bus/iio/devices/iio:deviceX/in_intensity_green_scale
+/sys/bus/iio/devices/iio:deviceX/in_intensity_blue_scale
+
+A userspace application can multiply the raw values with the scale values so
+that for a particular test light source, typically white, the measurement
+intensity is the same across the different color channels. This is calculated
+in the following way:
+
+R = RED_RAW x SCALE_RED(2.4)
+G = GREEN_RAW x SCALE_GREEN(1.0)
+B = BLUE_RAW x SCALE_BLUE(1.3)
+
+The data sheet suggests using the scaled values to normalize the scaled R, G
+and B values. This is useful to get a value for the ratio between colors
+independent of light intensity. A userspace application can do this in the
+following way:
+
+R_NORMALIZED = R / (R + G + B)
+G_NORMALIZED = G / (R + G + B)
+B_NORMALIZED = B / (R + G + B)
+
+See section 8.4.5.2 in the data sheet for additional details.

drivers/iio/light/Kconfig

@@ -475,6 +475,19 @@ config OPT4001
 	  If built as a dynamically linked module, it will be called
 	  opt4001.
 
+config OPT4060
+	tristate "Texas Instruments OPT4060 RGBW Color Sensor"
+	depends on I2C
+	select REGMAP_I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  If you say Y or M here, you get support for Texas Instruments
+	  OPT4060 RGBW Color Sensor.
+
+	  If built as a dynamically linked module, it will be called
+	  opt4060.
+
 config PA12203001
 	tristate "TXC PA12203001 light and proximity sensor"
 	depends on I2C

drivers/iio/light/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_MAX44009)		+= max44009.o
 obj-$(CONFIG_NOA1305)		+= noa1305.o
 obj-$(CONFIG_OPT3001)		+= opt3001.o
 obj-$(CONFIG_OPT4001)		+= opt4001.o
+obj-$(CONFIG_OPT4060)		+= opt4060.o
 obj-$(CONFIG_PA12203001)	+= pa12203001.o
 obj-$(CONFIG_ROHM_BU27034)	+= rohm-bu27034.o
 obj-$(CONFIG_RPR0521)		+= rpr0521.o