pseye_getreg
static uint8_t pseye_getreg(struct pseye_softc *, uint16_t);
val = pseye_getreg(sc, 0x21);
val = pseye_getreg(sc, 0x23);
if (pseye_getreg(sc, reg) != val)
reg = pseye_getreg(sc, PSEYE_SCCB_STATUS);