Hi Oliver, FYI, the error/warning still remains. tree: https://github.com/Freescale/linux-fslc pr/288 head: 26c3698b94fe22823c8dcefb548326265c708b5c commit: 53ecae250dd9e334787ede9eb40e0555b7fd0c00 [15436/17591] MLK-24911-1: soc: imx: Add support to get iMX8mp LDO trim fuse value config: arm64-randconfig-r034-20210312 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 7b153b43d3a14d76975039408c4b922beb576735) 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 arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://github.com/Freescale/linux-fslc/commit/53ecae250dd9e334787ede9eb4... git remote add freescale-fslc https://github.com/Freescale/linux-fslc git fetch --no-tags freescale-fslc pr/288 git checkout 53ecae250dd9e334787ede9eb40e0555b7fd0c00 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/soc/imx/soc-imx8.c:324:5: warning: no previous prototype for function 'check_m4_enabled' [-Wmissing-prototypes] int check_m4_enabled(void) ^ drivers/soc/imx/soc-imx8.c:324:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int check_m4_enabled(void) ^ static int imx8mp_get_ldo_trim(int ldo) ^ drivers/soc/imx/soc-imx8.c:339:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int imx8mp_get_ldo_trim(int ldo) ^ static 2 warnings generated. vim +/imx8mp_get_ldo_trim +339 drivers/soc/imx/soc-imx8.c 338 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org