linux/Documentation/ABI/testing/sysfs-bus-iio-meas-spec

What:           /sys/bus/iio/devices/iio:deviceX/battery_low
KernelVersion:  4.1.0
Contact:        [email protected]
Description:
                Reading returns either '1' or '0'. '1' means that the
                battery level supplied to sensor is below 2.25V.
                This ABI is available for tsys02d, htu21, ms8607