acpiec_bus_read
ACPI_STATUS acpiec_bus_read(device_t, u_int, ACPI_INTEGER *, int);
rv = acpiec_bus_read(sc->sc_ecdev, 0x84, &lo, 1);
rv = acpiec_bus_read(sc->sc_ecdev, 0x85, &hi, 1);
(void)acpiec_bus_read(sc->sc_ecdev, addr, val, width);