tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: c11d28ab4a691736e30b49813fb801847bd44e83 commit: be7bd03f0201b5a513ced98c08444a140eab92ea [3008/12102] ASoC: fsl_asrc: Move common definition to fsl_asrc_common config: x86_64-randconfig-a004-20200524 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3393cc4cebf9969db94dc424b7a2b6195589c33b) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout be7bd03f0201b5a513ced98c08444a140eab92ea # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 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 <<): sound/soc/fsl/fsl_asrc.c:157:5: warning: no previous prototype for function 'fsl_asrc_request_pair' [-Wmissing-prototypes] int fsl_asrc_request_pair(int channels, struct fsl_asrc_pair *pair) ^ sound/soc/fsl/fsl_asrc.c:157:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int fsl_asrc_request_pair(int channels, struct fsl_asrc_pair *pair) ^ static sound/soc/fsl/fsl_asrc.c:200:6: warning: no previous prototype for function 'fsl_asrc_release_pair' [-Wmissing-prototypes] void fsl_asrc_release_pair(struct fsl_asrc_pair *pair) ^ sound/soc/fsl/fsl_asrc.c:200:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void fsl_asrc_release_pair(struct fsl_asrc_pair *pair) ^ static struct dma_chan *fsl_asrc_get_dma_channel(struct fsl_asrc_pair *pair, bool dir) ^ sound/soc/fsl/fsl_asrc.c:557:1: note: declare 'static' if the function is not intended to be used outside of this translation unit struct dma_chan *fsl_asrc_get_dma_channel(struct fsl_asrc_pair *pair, bool dir) ^ static 3 warnings generated. vim +/fsl_asrc_get_dma_channel +557 sound/soc/fsl/fsl_asrc.c 3117bb3109dc223 Nicolin Chen 2014-07-29 553 3117bb3109dc223 Nicolin Chen 2014-07-29 554 /** 3117bb3109dc223 Nicolin Chen 2014-07-29 555 * Get DMA channel according to the pair and direction. 3117bb3109dc223 Nicolin Chen 2014-07-29 556 */ 3117bb3109dc223 Nicolin Chen 2014-07-29 @557 struct dma_chan *fsl_asrc_get_dma_channel(struct fsl_asrc_pair *pair, bool dir) 3117bb3109dc223 Nicolin Chen 2014-07-29 558 { 7470704d8b425c4 Shengjiu Wang 2020-04-16 559 struct fsl_asrc *asrc = pair->asrc; 3117bb3109dc223 Nicolin Chen 2014-07-29 560 enum asrc_pair_index index = pair->index; 3117bb3109dc223 Nicolin Chen 2014-07-29 561 char name[4]; 3117bb3109dc223 Nicolin Chen 2014-07-29 562 3117bb3109dc223 Nicolin Chen 2014-07-29 563 sprintf(name, "%cx%c", dir == IN ? 'r' : 't', index + 'a'); 3117bb3109dc223 Nicolin Chen 2014-07-29 564 7470704d8b425c4 Shengjiu Wang 2020-04-16 565 return dma_request_slave_channel(&asrc->pdev->dev, name); 3117bb3109dc223 Nicolin Chen 2014-07-29 566 } 3117bb3109dc223 Nicolin Chen 2014-07-29 567 EXPORT_SYMBOL_GPL(fsl_asrc_get_dma_channel); 3117bb3109dc223 Nicolin Chen 2014-07-29 568 :::::: The code at line 557 was first introduced by commit :::::: 3117bb3109dc223e186302f5dc8ce9ed04adca90 ASoC: fsl_asrc: Add ASRC ASoC CPU DAI and platform drivers :::::: TO: Nicolin Chen <nicoleotsuka(a)gmail.com&gt; :::::: CC: Mark Brown <broonie(a)linaro.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org