Hi Angelo, I love your patch! Perhaps something to improve: [auto build test WARNING on usb-serial/usb-next] [also build test WARNING on peter.chen-usb/ci-for-usb-next balbi-usb/testing/next usb/usb-testing v5.8-rc4 next-20200708] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Angelo-Dureghello/USB-serial-add... base: https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial.git usb-next config: s390-allyesconfig (attached as .config) compiler: s390-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 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=s390 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 >>): 71 | #define PARITY_NONE 0 | In file included from include/uapi/linux/if.h:37, from include/linux/compat.h:16, from arch/s390/include/asm/elf.h:132, from include/linux/elf.h:6, from include/linux/module.h:18, from drivers/usb/serial/xr21v1412.c:11: include/uapi/linux/hdlc/ioctl.h:24: note: this is the location of the previous definition 24 | #define PARITY_NONE 1 /* No parity */ | vim +/PARITY_NONE +71 drivers/usb/serial/xr21v1412.c 70 72 #define PARITY_ODD 1 73 #define PARITY_EVEN 2 74 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org