Hi Krzysztof, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: f40ddce88593482919761f74910f42f4b84c004b commit: 91687c1926bcd6b80d669375d57331b7bf80bf99 usb: phy: Enable compile testing for some of drivers date: 1 year, 2 months ago config: mips-randconfig-r015-20210216 (attached as .config) compiler: mipsel-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 91687c1926bcd6b80d669375d57331b7bf80bf99 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=mips 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 >>): mipsel-linux-ld: drivers/spi/spi-mt65xx.o: in function `mtk_spi_probe': spi-mt65xx.c:(.text+0x59c): undefined reference to `clk_set_parent' mipsel-linux-ld: drivers/usb/phy/phy-tegra-usb.o: in function `tegra_usb_phy_probe': Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for PHY_DA8XX_USB Depends on ARCH_DAVINCI_DA8XX Selected by - USB_OHCI_HCD_DAVINCI && USB_SUPPORT && USB && (ARCH_DAVINCI_DA8XX || COMPILE_TEST && USB_OHCI_HCD --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org