ICRXTX
rcar_i2c_write(priv, ICRXTX, msg->buf[priv->pos]);
u8 data = rcar_i2c_read(priv, ICRXTX);
rcar_i2c_write(priv, ICRXTX, value);
rcar_i2c_read(priv, ICRXTX); /* dummy read */
value = rcar_i2c_read(priv, ICRXTX);
rcar_i2c_write(priv, ICRXTX, value);
chan = rcar_i2c_request_dma_chan(dev, dir, priv->res->start + ICRXTX);