Hi Miquel, I love your patch! Perhaps something to improve: [auto build test WARNING on geert-renesas-devel/next] [also build test WARNING on geert-renesas-drivers/renesas-clk robh/for-next linus/master v5.17-rc4 next-20220217] [cannot apply to vkoul-dmaengine/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/Miquel-Raynal/RZN1-DMA-support/20220220-182519 base: https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-devel.git next config: arm-randconfig-r022-20220220 (https://download.01.org/0day-ci/archive/20220221/202202210355.JzDJ9Lyz-lkp@xxxxxxxxx/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e) 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/ed9b880ea7f2b23b42feeed7a6ed898cd09ae2f1 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Miquel-Raynal/RZN1-DMA-support/20220220-182519 git checkout ed9b880ea7f2b23b42feeed7a6ed898cd09ae2f1 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/clk/renesas/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): >> drivers/clk/renesas/r9a06g032-clocks.c:320:5: warning: no previous prototype for function 'r9a06g032_syscon_set_dmamux' [-Wmissing-prototypes] int r9a06g032_syscon_set_dmamux(u32 mask, u32 val) ^ drivers/clk/renesas/r9a06g032-clocks.c:320:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int r9a06g032_syscon_set_dmamux(u32 mask, u32 val) ^ static 1 warning generated. vim +/r9a06g032_syscon_set_dmamux +320 drivers/clk/renesas/r9a06g032-clocks.c 317 318 /* Exported helper to access the DMAMUX register */ 319 static struct r9a06g032_priv *syscon_priv; > 320 int r9a06g032_syscon_set_dmamux(u32 mask, u32 val) 321 { 322 u32 dmamux; 323 324 if (!syscon_priv) 325 return -EPROBE_DEFER; 326 327 spin_lock(&syscon_priv->lock); 328 329 dmamux = readl(syscon_priv->reg + R9A06G032_SYSCON_DMAMUX); 330 dmamux &= ~mask; 331 dmamux |= val & mask; 332 writel(dmamux, syscon_priv->reg + R9A06G032_SYSCON_DMAMUX); 333 334 spin_unlock(&syscon_priv->lock); 335 336 return 0; 337 } 338 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx