The below compile time error can be seen when PHYLIB is configured as a module. ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_read': pcs-xpcs.c:(.text+0x29): undefined reference to `mdiobus_read' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_soft_reset.constprop.7': pcs-xpcs.c:(.text+0x80): undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.o: in function `xpcs_config_aneg': pcs-xpcs.c:(.text+0x318): undefined reference to `mdiobus_write' ld: pcs-xpcs.c:(.text+0x38e): undefined reference to `mdiobus_write' ld: pcs-xpcs.c:(.text+0x3eb): undefined reference to `mdiobus_write' ld: pcs-xpcs.c:(.text+0x437): undefined reference to `mdiobus_write' ld: drivers/net/pcs/pcs-xpcs.o:pcs-xpcs.c:(.text+0xb1e): more undefined references to `mdiobus_write' follow PHYLIB being a module leads to MDIO_BUS being a module as well while the XPCS is still built-in. What should happen in this configuration is that PCS_XPCS should be forced to build as module. However, that select only acts in the opposite way so we should turn it into a depends. Fix this up by explicitly depending on MDIO_BUS. Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested Fixes: 2fa4e4b799e1 ("net: pcs: Move XPCS into new PCS subdirectory") Signed-off-by: Ioana Ciornei <ioana.ciornei@xxxxxxx> --- drivers/net/pcs/Kconfig | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/pcs/Kconfig b/drivers/net/pcs/Kconfig index 074fb3f5db18..22ba7b0b476d 100644 --- a/drivers/net/pcs/Kconfig +++ b/drivers/net/pcs/Kconfig @@ -7,8 +7,7 @@ menu "PCS device drivers" config PCS_XPCS tristate "Synopsys DesignWare XPCS controller" - select MDIO_BUS - depends on MDIO_DEVICE + depends on MDIO_DEVICE && MDIO_BUS help This module provides helper functions for Synopsys DesignWare XPCS controllers. -- 2.17.1