btw, i updated one HAL to e-h rc3 and implemented the APIs for another:
* https://github.com/stm32-rs/stm32f4xx-hal/pull/715/files
* https://github.com/Rahix/avr-hal/pull/470/files

the `&mut self` of `InputPin` was a bit painful due to the traits (see the diff in the PRs) because `rustc` started to pick other implementations than it did before (but that might also just be me not being good enough in dealing with this, so my solutions there might be ugly)