FIFO_IRQEN
writew(tmp & ~FIFO_IRQEN, &i2c->regs->tx_fifo.stat_ctrl);
writew(readw(&i2c->regs->tx_fifo.stat_ctrl) | FIFO_IRQEN,
writew(readw(&i2c->regs->rx_fifo.stat_ctrl) | FIFO_IRQEN,
writew(FIFO_IRQEN | readw(&i2c->regs->rx_fifo.stat_ctrl),
writew(tmp & ~FIFO_IRQEN, &i2c->regs->rx_fifo.stat_ctrl);