IER
ki2c_writereg(sc, IER, 0);
ki2c_writereg(sc, IER,I2C_INT_DATA|I2C_INT_ADDR|I2C_INT_STOP);
ki2c_writereg(sc, IER, I2C_INT_DATA | I2C_INT_ADDR| I2C_INT_STOP);
OUTP(IER, 0);
CSR_WRITE(sc, IER, 0x7f); /* all but MSR */
UART_WRITE(base, IER, 0x00); /* make sure INT disabled */
IER = IE_ALL; /* すべての割り込みを許可 */