__phy_write_mmd
__phy_write_mmd(phydev, MDIO_MMD_VEND2, 0xb87c, parm);
EXPORT_SYMBOL(__phy_write_mmd);
ret = __phy_write_mmd(phydev, devad, regnum, val);
ret = __phy_write_mmd(phydev, devad, regnum, new);
int __phy_write_mmd(struct phy_device *phydev, int devad, u32 regnum, u16 val);