IBM_EC_BRIGHTNESS
status = ACPI_EC_READ(sc->ec_dev, IBM_EC_BRIGHTNESS, &val_ec, 1);
IBM_EC_BRIGHTNESS, i - step, 1);
return ACPI_EC_WRITE(sc->ec_dev, IBM_EC_BRIGHTNESS, arg, 1);
status = ACPI_EC_READ(sc->ec_dev, IBM_EC_BRIGHTNESS,
ACPI_EC_READ(sc->ec_dev, IBM_EC_BRIGHTNESS, &val_ec, 1);