tsllux_read2
if ((error = tsllux_read2(sc, TSL256x_REG_DATA0LOW, adc0valp)) == 0)
error = tsllux_read2(sc, TSL256x_REG_DATA1LOW, adc1valp);
static int tsllux_read2(struct tsllux_softc *, uint8_t, uint16_t *);