iio: Add channel type light color temperature

In most cases, ambient color sensors also support light color
temperature, which is measured in kelvin. Thus, add channel type light
color temperature.
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Link: https://lore.kernel.org/r/20230919081054.2050714-3-Basavaraj.Natikar@amd.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio

@@ -2179,3 +2179,10 @@ Contact:	linux-iio@vger.kernel.org
 Description:
 		Number of conditions that must occur, during a running
 		period, before an event is generated.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_colortemp_raw
+KernelVersion:	6.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Represents light color temperature, which measures light color
+		temperature in Kelvin.

drivers/iio/industrialio-core.c

@@ -90,6 +90,7 @@ static const char * const iio_chan_type_name_spec[] = {
 	[IIO_POSITIONRELATIVE]  = "positionrelative",
 	[IIO_PHASE] = "phase",
 	[IIO_MASSCONCENTRATION] = "massconcentration",
+	[IIO_COLORTEMP] = "colortemp",
 };
 
 static const char * const iio_modifier_names[] = {

include/uapi/linux/iio/types.h

@@ -47,6 +47,7 @@ enum iio_chan_type {
 	IIO_POSITIONRELATIVE,
 	IIO_PHASE,
 	IIO_MASSCONCENTRATION,
+	IIO_COLORTEMP,
 };
 
 enum iio_modifier {

tools/iio/iio_event_monitor.c

@@ -59,6 +59,7 @@ static const char * const iio_chan_type_name_spec[] = {
 	[IIO_POSITIONRELATIVE] = "positionrelative",
 	[IIO_PHASE] = "phase",
 	[IIO_MASSCONCENTRATION] = "massconcentration",
+	[IIO_COLORTEMP] = "colortemp",
 };
 
 static const char * const iio_ev_type_text[] = {
@@ -173,6 +174,7 @@ static bool event_is_known(struct iio_event_data *event)
 	case IIO_POSITIONRELATIVE:
 	case IIO_PHASE:
 	case IIO_MASSCONCENTRATION:
+	case IIO_COLORTEMP:
 		break;
 	default:
 		return false;