E1000_MMDAAD
ret_val = hw->phy.ops.write_reg(hw, E1000_MMDAAD, address);
ret_val = hw->phy.ops.read_reg(hw, E1000_MMDAAD, data);
ret_val = hw->phy.ops.write_reg(hw, E1000_MMDAAD, *data);