iio: ABI: document mag_referenced

Some accelerometers that support activity and inactivity
events also support a referenced mode, in which the
gravitational acceleration is taken as a point of
reference before comparing the acceleration to the
specified activity and inactivity magnitude.

For example, in the case of the ADXL367, for activity
detection, the formula is:

abs(acceleration - reference) > magnitude

Add a new event type that makes this behavior clear.

Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220214073810.781016-3-cosmin.tanislav@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index c551301..41c1e3e 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -1213,6 +1213,32 @@ Description:
                number or direction is not specified, applies to all channels of
                this type.
 
+What:          /sys/.../iio:deviceX/events/in_accel_mag_referenced_en
+What:          /sys/.../iio:deviceX/events/in_accel_mag_referenced_rising_en
+What:          /sys/.../iio:deviceX/events/in_accel_mag_referenced_falling_en
+What:          /sys/.../iio:deviceX/events/in_accel_y_mag_referenced_en
+What:          /sys/.../iio:deviceX/events/in_accel_y_mag_referenced_rising_en
+What:          /sys/.../iio:deviceX/events/in_accel_y_mag_referenced_falling_en
+KernelVersion: 5.18
+Contact:       linux-iio@vger.kernel.org
+Description:
+               Similar to in_accel_mag[_y][_rising|_falling]_en, but the event
+               value is relative to a reference magnitude. The reference magnitude
+               includes the graviational acceleration.
+
+What:          /sys/.../iio:deviceX/events/in_accel_mag_referenced_value
+What:          /sys/.../iio:deviceX/events/in_accel_mag_referenced_rising_value
+What:          /sys/.../iio:deviceX/events/in_accel_mag_referenced_falling_value
+What:          /sys/.../iio:deviceX/events/in_accel_y_mag_referenced_value
+What:          /sys/.../iio:deviceX/events/in_accel_y_mag_referenced_rising_value
+What:          /sys/.../iio:deviceX/events/in_accel_y_mag_referenced_falling_value
+KernelVersion: 5.18
+Contact:       linux-iio@vger.kernel.org
+Description:
+               The value to which the reference magnitude of the channel is
+               compared. If the axis is not specified, it applies to all channels
+               of this type.
+
 What:          /sys/.../events/in_steps_change_en
 KernelVersion: 4.0
 Contact:       linux-iio@vger.kernel.org