tree: https://github.com/Freescale/linux-fslc 5.4-2.3.x-imx head: 0b75fb32ce4bed3f44bd0e2e78c4f08521fac3c8 commit: a67139eb8d9bae8fd86fbf1ab05ad2fd2ec2ca9c [14409/18037] MA-17787 ASoC: rpmsg_wm8960: Separate i2c driver to individual file config: mips-randconfig-r025-20210408 (attached as .config) compiler: mips64el-linux-gcc (GCC) 9.3.0 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 # https://github.com/Freescale/linux-fslc/commit/a67139eb8d9bae8fd86fbf1ab0... git remote add freescale-fslc https://github.com/Freescale/linux-fslc git fetch --no-tags freescale-fslc 5.4-2.3.x-imx git checkout a67139eb8d9bae8fd86fbf1ab05ad2fd2ec2ca9c # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>): 153 | module_i2c_driver(rpmsg_wm8960_i2c_driver); | ^~~~~~~~~~~~~~~~~ sound/soc/codecs/rpmsg_wm8960_i2c.c:143:26: warning: 'rpmsg_wm8960_i2c_driver' defined but not used [-Wunused-variable] 143 | static struct i2c_driver rpmsg_wm8960_i2c_driver = { | ^~~~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +153 sound/soc/codecs/rpmsg_wm8960_i2c.c 152 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org