Hi Michal,

FYI, the error/warning still remains.

tree:   https://github.com/Xilinx/linux-xlnx xlnx_rebase_v5.4
head:   2f686fa6c0bf7fa168dc45dd7ce1359217212911
commit: 3d600fd776cbda29abdea084f7437f7d9102b2a5 [904/1765] usb: dwc3: Add support for removing vbus when suspended
config: x86_64-randconfig-r013-20210720 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 87039c048c0cbc3d8cbba86187269b006bf2f373)
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
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/Xilinx/linux-xlnx/commit/3d600fd776cbda29abdea084f7437f7d9102b2a5
        git remote add xlnx https://github.com/Xilinx/linux-xlnx
        git fetch --no-tags xlnx xlnx_rebase_v5.4
        git checkout 3d600fd776cbda29abdea084f7437f7d9102b2a5
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=x86_64 SHELL=/bin/bash M=drivers/usb/dwc3

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All error/warnings (new ones prefixed by >>):

   In file included from drivers/usb/dwc3/core.c:35:
   drivers/usb/dwc3/core.h:1419:6: warning: no previous prototype for function 'dwc3_simple_wakeup_capable' [-Wmissing-prototypes]
   void dwc3_simple_wakeup_capable(struct device *dev, bool wakeup)
        ^
   drivers/usb/dwc3/core.h:1419:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void dwc3_simple_wakeup_capable(struct device *dev, bool wakeup)
   ^
   static 
>> drivers/usb/dwc3/core.h:1421:6: warning: no previous prototype for function 'dwc3_set_simple_data' [-Wmissing-prototypes]
   void dwc3_set_simple_data(struct dwc3 *dwc)
        ^
   drivers/usb/dwc3/core.h:1421:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void dwc3_set_simple_data(struct dwc3 *dwc)
   ^
   static 
   2 warnings generated.
--
>> ld.lld: error: duplicate symbol: dwc3_set_simple_data
   >>> defined at core.c
   >>> drivers/usb/dwc3/core.o:(dwc3_set_simple_data)
   >>> defined at host.c
   >>> drivers/usb/dwc3/host.o:(.text+0x10)
--
>> ld.lld: error: duplicate symbol: dwc3_set_simple_data
   >>> defined at core.c
   >>> drivers/usb/dwc3/core.o:(dwc3_set_simple_data)
   >>> defined at debugfs.c
   >>> drivers/usb/dwc3/debugfs.o:(.text+0x10)

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org