Hi Sam, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on robh/for-next] [also build test WARNING on tty/tty-testing linus/master v5.14-rc3 next-20210730] [cannot apply to pinctrl-samsung/for-next] [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/Sam-Protsenko/Add-minimal-support-for-Exynos850-SoC/20210730-225138 base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next config: s390-randconfig-r002-20210730 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 4f71f59bf3d9914188a11d0c41bedbb339d36ff5) 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 s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://github.com/0day-ci/linux/commit/738bb76f03b05dc8cde2c11eebe2e49187e98b2e git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Sam-Protsenko/Add-minimal-support-for-Exynos850-SoC/20210730-225138 git checkout 738bb76f03b05dc8cde2c11eebe2e49187e98b2e # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from drivers/clk/samsung/clk-exynos850.c:13: In file included from include/linux/of_address.h:7: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:36:59: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) ^ In file included from drivers/clk/samsung/clk-exynos850.c:13: In file included from include/linux/of_address.h:7: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) ^ In file included from drivers/clk/samsung/clk-exynos850.c:13: In file included from include/linux/of_address.h:7: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ >> drivers/clk/samsung/clk-exynos850.c:36:13: warning: no previous prototype for function 'exynos850_clk_init' [-Wmissing-prototypes] void __init exynos850_clk_init(struct device_node *np) ^ drivers/clk/samsung/clk-exynos850.c:36:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init exynos850_clk_init(struct device_node *np) ^ static 13 warnings generated. vim +/exynos850_clk_init +36 drivers/clk/samsung/clk-exynos850.c 35 > 36 void __init exynos850_clk_init(struct device_node *np) 37 { 38 void __iomem *reg_base; 39 struct samsung_clk_provider *ctx; 40 41 if (!np) 42 panic("%s: unable to determine soc\n", __func__); 43 44 reg_base = of_iomap(np, 0); 45 if (!reg_base) 46 panic("%s: failed to map registers\n", __func__); 47 48 ctx = samsung_clk_init(np, reg_base, CLK_NR_CLKS); 49 if (!ctx) 50 panic("%s: unable to allocate ctx\n", __func__); 51 52 samsung_clk_of_register_fixed_ext(ctx, 53 exynos850_fixed_rate_ext_clks, 54 ARRAY_SIZE(exynos850_fixed_rate_ext_clks), 55 ext_clk_match); 56 57 samsung_clk_register_fixed_rate(ctx, exynos850_peri_clks, 58 ARRAY_SIZE(exynos850_peri_clks)); 59 60 samsung_clk_of_add_provider(np, ctx); 61 } 62 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org