iio: Add ABI documentation for proximity

has been in use for a long time, but never documented
proximity is unit-less, except otherwise stated, see e.g.
the as3935 driver where it is meter

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index a9757dcf2e81..738b56f862b4 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -895,6 +895,19 @@ Description:
                 on-chip EEPROM. After power-up or chip reset the device will
                 automatically load the saved configuration.
 
+What:           /sys/.../iio:deviceX/in_proximity_raw
+What:           /sys/.../iio:deviceX/in_proximity_input
+What:           /sys/.../iio:deviceX/in_proximityY_raw
+KernelVersion:  3.4
+Contact:        linux-iio@vger.kernel.org
+Description:
+                Proximity measurement indicating that some
+                object is near the sensor, usually be observing
+                reflectivity of infrared or ultrasound emitted.
+                Often these sensors are unit less and as such conversion
+                to SI units is not possible.  Where it is, the units should
+                be meters.
+
 What:           /sys/.../iio:deviceX/in_illuminanceY_input
 What:           /sys/.../iio:deviceX/in_illuminanceY_raw
 What:           /sys/.../iio:deviceX/in_illuminanceY_mean_raw