iio: Add ABI documentation for illuminance

has been in use for a long time, but never documented;
state that this measurement should be in lux (drivers may feel
different about this)

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

1 files changed, 9 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 9669c1ff8491..a9757dcf2e81 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -895,6 +895,15 @@ Description:
                 on-chip EEPROM. After power-up or chip reset the device will
                 automatically load the saved configuration.
 
+What:           /sys/.../iio:deviceX/in_illuminanceY_input
+What:           /sys/.../iio:deviceX/in_illuminanceY_raw
+What:           /sys/.../iio:deviceX/in_illuminanceY_mean_raw
+KernelVersion:  3.4
+Contact:        linux-iio@vger.kernel.org
+Description:
+                Illuminance measurement, units after application of scale
+                and offset are lux.
+
 What:           /sys/.../iio:deviceX/in_intensityY_raw
 What:           /sys/.../iio:deviceX/in_intensityY_ir_raw
 What:           /sys/.../iio:deviceX/in_intensityY_both_raw