IBCR_MSSL
reg = (IBCR_MSSL | IBCR_NOACK | IBCR_IBIE | IBCR_TXRX);
if ((READ1(sc, I2C_IBCR) & IBCR_MSSL) != 0)
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | IBCR_NOACK);
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL);
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | IBCR_NOACK);