Hi Liam, kernel test robot noticed the following build warnings: [auto build test WARNING on a5e505a99ca748583dbe558b691be1b26f05d678] url: https://github.com/intel-lab-lkp/linux/commits/Liam-Beguin/dt-bindings-iio-adc-add-lltc-ltc2309-bindings/20230826-022412 base: a5e505a99ca748583dbe558b691be1b26f05d678 patch link: https://lore.kernel.org/r/20230825-ltc2309-v2-2-6d75f2b3fb50%40gmail.com patch subject: [PATCH v2 2/2] iio: adc: add ltc2309 support config: sparc-allyesconfig (https://download.01.org/0day-ci/archive/20230826/202308260324.RYZ1IVWw-lkp@xxxxxxxxx/config) compiler: sparc64-linux-gcc (GCC) 13.2.0 reproduce: (https://download.01.org/0day-ci/archive/20230826/202308260324.RYZ1IVWw-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202308260324.RYZ1IVWw-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> drivers/iio/adc/ltc2309.c:163:6: warning: no previous prototype for 'ltc2309_regulator_disable' [-Wmissing-prototypes] 163 | void ltc2309_regulator_disable(void *regulator) | ^~~~~~~~~~~~~~~~~~~~~~~~~ vim +/ltc2309_regulator_disable +163 drivers/iio/adc/ltc2309.c 162 > 163 void ltc2309_regulator_disable(void *regulator) 164 { 165 struct regulator *r = (struct regulator *)regulator; 166 167 regulator_disable(r); 168 } 169 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki