iio: Add ABI documentation for input current readings

Add information on in_current related readings.
Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/ABI/testing/sysfs-bus-iio

@@ -92,6 +92,18 @@ Description:
 		is required is a consistent labeling.  Units after application
 		of scale and offset are millivolts.
 
+What:		/sys/bus/iio/devices/iio:deviceX/in_currentY_raw
+What:		/sys/bus/iio/devices/iio:deviceX/in_currentY_supply_raw
+KernelVersion:	3.17
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Raw (unscaled no bias removal etc.) current measurement from
+		channel Y. In special cases where the channel does not
+		correspond to externally available input one of the named
+		versions may be used. The number must always be specified and
+		unique to allow association with event codes. Units after
+		application of scale and offset are milliamps.
+
 What:		/sys/bus/iio/devices/iio:deviceX/in_capacitanceY_raw
 KernelVersion:	3.2
 Contact:	linux-iio@vger.kernel.org
@@ -234,6 +246,8 @@ What:		/sys/bus/iio/devices/iio:deviceX/in_accel_y_offset
 What:		/sys/bus/iio/devices/iio:deviceX/in_accel_z_offset
 What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_offset
 What:		/sys/bus/iio/devices/iio:deviceX/in_voltage_offset
+What:		/sys/bus/iio/devices/iio:deviceX/in_currentY_offset
+What:		/sys/bus/iio/devices/iio:deviceX/in_current_offset
 What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_offset
 What:		/sys/bus/iio/devices/iio:deviceX/in_temp_offset
 What:		/sys/bus/iio/devices/iio:deviceX/in_pressureY_offset
@@ -262,6 +276,9 @@ What:		/sys/bus/iio/devices/iio:deviceX/in_voltage_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_voltage-voltage_scale
 What:		/sys/bus/iio/devices/iio:deviceX/out_voltageY_scale
 What:		/sys/bus/iio/devices/iio:deviceX/out_altvoltageY_scale
+What:		/sys/bus/iio/devices/iio:deviceX/in_currentY_scale
+What:		/sys/bus/iio/devices/iio:deviceX/in_currentY_supply_scale
+What:		/sys/bus/iio/devices/iio:deviceX/in_current_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_accel_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_accel_peak_scale
 What:		/sys/bus/iio/devices/iio:deviceX/in_anglvel_scale