Hi Ioana, I love your patch! Yet something to improve: [auto build test ERROR on net-next/master] url: https://github.com/0day-ci/linux/commits/Ioana-Ciornei/net-phy-add-Lynx-P... base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2 config: i386-allmodconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-13) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): ld: drivers/net/phy/mdio-lynx-pcs.o: in function `lynx_pcs_config': mdio-lynx-pcs.c:(.text+0x47): undefined reference to `mdiobus_write' ld: mdio-lynx-pcs.c:(.text+0xed): undefined reference to `mdiobus_write' ld: mdio-lynx-pcs.c:(.text+0xfe): undefined reference to `mdiobus_write' ld: drivers/net/phy/mdio-lynx-pcs.o: in function `lynx_pcs_an_restart': mdio-lynx-pcs.c:(.text+0x14d): undefined reference to `mdiobus_write' ld: drivers/net/phy/mdio-lynx-pcs.o: in function `lynx_pcs_link_up': mdio-lynx-pcs.c:(.text+0x262): undefined reference to `mdiobus_modify' ld: mdio-lynx-pcs.c:(.text+0x2a3): undefined reference to `mdiobus_write' ld: drivers/net/phy/mdio-lynx-pcs.o: in function `lynx_pcs_get_state': mdio-lynx-pcs.c:(.text+0x2f2): undefined reference to `phylink_mii_c22_pcs_get_state' ld: mdio-lynx-pcs.c:(.text+0x364): undefined reference to `mdiobus_read' ld: mdio-lynx-pcs.c:(.text+0x44c): undefined reference to `mdiobus_read' ld: mdio-lynx-pcs.c:(.text+0x45e): undefined reference to `mdiobus_read' --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org