After adding proximity sensor-support to #iio-sensor-proxy (https://gitlab.freedesktop.org/hadess/iio-sensor-proxy/merge_requests/298) and adding runtime-pm support for the chip used in the #librem5 (and it's devkit) (https://lore.kernel.org/linux-iio/cover.1580721204.git.agx@sigxcpu.org/) we can now wire it up to #phosh to fade the screen and prevent keyboard input: