pcfiic_read
pcfiic_read(sc, PCF8584_S0);
r = pcfiic_read(sc, PCF8584_S0);
if (pcfiic_read(sc, PCF8584_S1) & PCF8584_STATUS_BBN)
*r = pcfiic_read(sc, PCF8584_S1);
u_int8_t pcfiic_read(struct pcfiic_softc *, bus_size_t);