LAN887X_MIS_DLL_CFG_REG1
rxc = phy_read_mmd(phydev, MDIO_MMD_VEND1, LAN887X_MIS_DLL_CFG_REG1);
ret = phy_modify_mmd(phydev, MDIO_MMD_VEND1, LAN887X_MIS_DLL_CFG_REG1,