emac_mdio_read
data->val_out = emac_mdio_read(ndev, dev->phy.address,
int ret = emac_mdio_read(bus->priv, addr, regnum);
dev->phy.mdio_read = emac_mdio_read;
r = emac_mdio_read(dev->ndev, i, MII_BMCR);
mii_bus->read = emac_mdio_read;