i2c_start
static int i2c_start(device_t, u_char, int);
DEVMETHOD(iicbus_start, i2c_start),
i2c_if->i2c_start = xgbe_i2c_start;
ret = pdata->i2c_if.i2c_start(pdata);
int (*i2c_start)(struct xgbe_prv_data *);
static int i2c_start(device_t, u_char, int);
DEVMETHOD(iicbus_start, i2c_start),
i2c_start(ptr, ctrl);
DEVMETHOD(iicbus_start, i2c_start),
static int i2c_start(device_t dev, u_char slave, int timeout);