reproduce:
        # https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/commit/?id=220ae5d36dba278003d265aabd080ffa78553f5a
        git remote add soc https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git
        git fetch --no-tags soc zx/soc
        git checkout 220ae5d36dba278003d265aabd080ffa78553f5a
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs