iio: resistance: add IIO_RESISTANCE channel type

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/ABI/testing/sysfs-bus-iio

@@ -1471,3 +1471,11 @@ KernelVersion:	4.3
 Contact:	linux-iio@vger.kernel.org
 Description:
 		Raw (unscaled no offset etc.) percentage reading of a substance.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_resistance_raw
+What:		/sys/bus/iio/devices/iio:deviceX/in_resistanceX_raw
+KernelVersion:	4.3
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Raw (unscaled no offset etc.) resistance reading that can be processed
+		into an ohm value.

drivers/iio/industrialio-core.c

@@ -76,6 +76,7 @@ static const char * const iio_chan_type_name_spec[] = {
 	[IIO_DISTANCE] = "distance",
 	[IIO_VELOCITY] = "velocity",
 	[IIO_CONCENTRATION] = "concentration",
+	[IIO_RESISTANCE] = "resistance",
 };
 
 static const char * const iio_modifier_names[] = {

include/uapi/linux/iio/types.h

@@ -36,6 +36,7 @@ enum iio_chan_type {
 	IIO_DISTANCE,
 	IIO_VELOCITY,
 	IIO_CONCENTRATION,
+	IIO_RESISTANCE,
 };
 
 enum iio_modifier {