Hi William, I love your patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v5.7-rc6 next-20200519] [cannot apply to stm32/stm32-next linux/master] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/William-Breathitt-Gray/Introduce... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 12bf0b632ed090358cbf03e323e5342212d0b2e4 config: arm64-randconfig-r026-20200519 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 135b877874fae96b4372c8a3fbfaa8ff44ff86e3) reproduce: 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 # 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: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): int counter_chrdev_add(struct counter_device *const counter, ^ drivers/counter/counter-chrdev.c:632:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int counter_chrdev_add(struct counter_device *const counter, ^ static void counter_chrdev_free(struct counter_device *const counter) ^ drivers/counter/counter-chrdev.c:652:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void counter_chrdev_free(struct counter_device *const counter) ^ static 2 warnings generated. vim +/counter_chrdev_add +632 drivers/counter/counter-chrdev.c 631 633 const dev_t counter_devt) 634 { 635 struct device *const dev = &counter->dev; 636 struct cdev *const chrdev = &counter->chrdev; 637 638 /* Initialize Counter character device control selection */ 639 memset(counter->selection, 0, sizeof(counter->selection)); 640 641 /* Initialize Counter character device selected controls list */ 642 INIT_LIST_HEAD(&counter->control_list); 643 644 /* Initialize character device */ 645 cdev_init(chrdev, &counter_fops); 646 dev->devt = MKDEV(MAJOR(counter_devt), counter->id); 647 cdev_set_parent(chrdev, &dev->kobj); 648 649 return cdev_add(chrdev, dev->devt, 1); 650 } 651 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org