Hi Stefan, Thank you for the patch! Yet something to improve: [auto build test ERROR on next-20220120] [also build test ERROR on v5.16] [cannot apply to broonie-spi/for-next rafael-pm/linux-next tiwai-sound/for-next linus/master v5.16 v5.16-rc8 v5.16-rc7] [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/Stefan-Binding/Support-Spi-in-i2... base: 7fc5253f5a13271e9df35d6b936ff97b74540a59 config: arc-randconfig-r043-20220120 (https://download.01.org/0day-ci/archive/20220121/202201210121.LFkpILul-lk...) compiler: arc-elf-gcc (GCC) 11.2.0 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/0day-ci/linux/commit/aedf84002ec1568907471591915e28bed... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Stefan-Binding/Support-Spi-in-i2c-multi-instantiate-driver/20220120-214608 git checkout aedf84002ec1568907471591915e28bed40e8f9a # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash drivers/media/i2c/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from include/media/v4l2-common.h:270, from include/media/v4l2-subdev.h:15, from include/media/v4l2-device.h:13, from drivers/media/i2c/tvaudio.c:40: 769 | { | ^ include/linux/spi/spi.h:767:34: warning: 'acpi_spi_device_alloc' declared 'static' but never defined [-Wunused-function] 767 | static inline struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, | ^~~~~~~~~~~~~~~~~~~~~ vim +769 include/linux/spi/spi.h 762 763 #if IS_ENABLED(CONFIG_ACPI) 764 extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, 765 struct acpi_device *adev); 766 #else 767 static inline struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, 768 struct acpi_device *adev); 770 return ERR_PTR(-EOPNOTSUPP); 771 } 772 #endif 773 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org