ISR
val = CSR_READ_1(l, ISR);
CSR_WRITE_1(l, ISR, ~0);
CSR_WRITE_1(l, ISR, ISR_PTM); /* clear ISR Tx complete bit */
val = CSR_READ_1(l, ISR);
CSR_WRITE_1(l, ISR, ISR_PRS); /* clear ISR Rx complete bit */
ki2c_writereg(sc, ISR, 0);
isr = ki2c_readreg(sc, ISR);
ki2c_writereg(sc, ISR, isr);
if (ki2c_readreg(sc, ISR))
isr = bus_space_read_1(sc->sc_iot, sc->sc_ioh, ISR);