reproduce:
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # https://github.com/ashyti/linux/commit/313d6aa4c64875ed8a10339a2db8766f49108efb
        git remote add ashyti https://github.com/ashyti/linux
        git fetch --no-tags ashyti test/i2c-host
        git checkout 313d6aa4c64875ed8a10339a2db8766f49108efb
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=arm olddefconfig
        ~/lkp-tests/kbuild/make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=arm SHELL=/bin/bash drivers/i2c/busses/