Hi Geert, I love your patch! Yet something to improve: [auto build test ERROR on robh/for-next] [also build test ERROR on staging/staging-testing linus/master v5.14-rc1 next-20210714] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Geert-Uytterhoeven/auxdisplay-ht... base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next config: arm-randconfig-r036-20210714 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 8d69635ed9ecf36fd0ca85906bfde17949671cbe) 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 arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://github.com/0day-ci/linux/commit/a8d991401542b45f91eb59e1cdf24fd6c... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Geert-Uytterhoeven/auxdisplay-ht16k33-Add-character-display-support/20210714-231351 git checkout a8d991401542b45f91eb59e1cdf24fd6c419360e # save the attached .config to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=arm SHELL=/bin/bash 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 >>): --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org