i2c_start
i2c_start(dev);
ret = i2c_start(bus);
i2c_start(adap);
i2c_start(adap);
i2c_start(adap);
i2c_start(adap);
i2c_if->i2c_start = xgbe_i2c_start;
ret = pdata->i2c_if.i2c_start(pdata);
int (*i2c_start)(struct xgbe_prv_data *);