reproduce (this is a W=1 build):
        # https://github.com/AsahiLinux/linux/commit/fff9f4467d52393012e4d98dd77d390299a98173
        git remote add asahilinux https://github.com/AsahiLinux/linux
        git fetch --no-tags asahilinux sven/smc-v4
        git checkout fff9f4467d52393012e4d98dd77d390299a98173
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/mfd/