[PATCH v2 1/3] iio: Add IIO_DENSITY channel type

[surajsonawane0215]

From: Suraj Sonawane <surajsonawane0215@xxxxxxxxx>

Add IIO_DENSITY channel type for particulate matter sensors,
with base units of grams per cubic meter (g/m³). This is needed
for optical dust sensors like the Sharp GP2Y1010AU0F that measure
airborne particle concentration rather than raw voltage.

Signed-off-by: Suraj Sonawane <surajsonawane0215@xxxxxxxxx>
---
V2: Initial version introducing IIO_DENSITY channel type

 Documentation/ABI/testing/sysfs-bus-iio | 8 ++++++++
 include/uapi/linux/iio/types.h          | 1 +
 2 files changed, 9 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 190bfcc1e..9b1b538ce 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -2383,3 +2383,11 @@ Description:
 		Value representing the user's attention to the system expressed
 		in units as percentage. This usually means if the user is
 		looking at the screen or not.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_density_raw
+KernelVersion:	6.15
+Contact:	linux-iio@xxxxxxxxxxxxxxx
+Description:
+		Raw reading from an optical dust sensor.
+		This value is proportional to dust density in air,
+		with base units of g/m^3.
+
diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h
index 3eb0821af..e7d09ec0b 100644
--- a/include/uapi/linux/iio/types.h
+++ b/include/uapi/linux/iio/types.h
@@ -37,6 +37,7 @@ enum iio_chan_type {
 	IIO_DISTANCE,
 	IIO_VELOCITY,
 	IIO_CONCENTRATION,
+	IIO_DENSITY,
 	IIO_RESISTANCE,
 	IIO_PH,
 	IIO_UVINDEX,
-- 
2.43.0