Hi Rafał,

I love your patch! Yet something to improve:

[auto build test ERROR on mtd/mtd/next]
[also build test ERROR on mtd/mtd/fixes robh/for-next linus/master v6.1-rc1 next-20221021]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Rafa-Mi-ecki/dt-bindings-mtd-partitions-support-marking-rootfs-partition/20221021-140227
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next
patch link:    https://lore.kernel.org/r/20221021060051.2508-2-zajec5%40gmail.com
patch subject: [PATCH V2 2/2] mtd: core: set ROOT_DEV for partitions marked as rootfs in DT
config: i386-randconfig-a015-20221017
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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/intel-lab-lkp/linux/commit/354cb0f2c01431932e04ea678765941b3fac1c8a
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Rafa-Mi-ecki/dt-bindings-mtd-partitions-support-marking-rootfs-partition/20221021-140227
        git checkout 354cb0f2c01431932e04ea678765941b3fac1c8a
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "ROOT_DEV" [drivers/mtd/mtd.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp