tree: https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-nomadik.git ux500-janice-v5.10-rc1 head: e2561a704fc03cbda012da31198333381b72386d commit: 757460dad8873d91c4b243b47fbf39514b86b92a [38/51] iio: magnetometer: Add driver for Yamaha YAS530 config: powerpc64-randconfig-r024-20201213 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 84c09ab44599ece409e4e19761288ddf796fceec) 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 powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-nomadik.git/... git remote add nomadik https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-nomadik.git git fetch --no-tags nomadik ux500-janice-v5.10-rc1 git checkout 757460dad8873d91c4b243b47fbf39514b86b92a # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): default: ^~~~~~~ drivers/iio/magnetometer/yamaha-yas530.c:299:47: note: uninitialized use occurs here (yas5xx->hard_offsets[axis] - c->r[axis]) * coef; ^~~~ drivers/iio/magnetometer/yamaha-yas530.c:269:10: note: initialize the variable 'coef' to silence this warning s32 coef; ^ = 0 void yas5xx_dump_calibration(struct yas5xx *yas5xx) ^ drivers/iio/magnetometer/yamaha-yas530.c:674:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void yas5xx_dump_calibration(struct yas5xx *yas5xx) ^ static 2 warnings generated. vim +/coef +286 drivers/iio/magnetometer/yamaha-yas530.c 260 261 static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis) 262 { 263 struct yas5xx_calibration *c = &yas5xx->calibration; 264 static const s32 yas532ac_coef[] = { 265 YAS532_VERSION_AC_COEF_X, 266 YAS532_VERSION_AC_COEF_Y1, 267 YAS532_VERSION_AC_COEF_Y2, 268 }; 269 s32 coef; 270 271 /* Select coefficients */ 272 switch (yas5xx->devid) { 273 case YAS530_DEVICE_ID: 274 if (yas5xx->version == YAS530_VERSION_A) 275 coef = YAS530_VERSION_A_COEF; 276 else 277 coef = YAS530_VERSION_B_COEF; 278 break; 279 case YAS532_DEVICE_ID: 280 if (yas5xx->version == YAS532_VERSION_AB) 281 coef = YAS532_VERSION_AB_COEF; 282 else 283 /* Elaborate coefficients */ 284 coef = yas532ac_coef[axis]; 285 break; 287 dev_err(yas5xx->dev, "unknown device type\n"); 288 break; 289 } 290 /* 291 * Linearization formula: 292 * 293 * x' = x - (3721 + 50 * f) + (xoffset - r) * c 294 * 295 * Where f and r are calibration values, c is a per-device 296 * and sometimes per-axis coefficient. 297 */ 298 return val - (3721 + 50 * c->f[axis]) + 300 } 301 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org