Cool, I think I have now the core of my async driver to interact with the bus of the lcd working.
 
I have a more general design question. The lcd requires a lot of configuration for each item typically two options, some of them can be changed after init.
 
Is there a common rust way to implement this? My Idea would be to use enums for each option and maybe use this builder pattern I read about. Or have defaults amd use methods to update the config. The api of the device requires to set multiple things with one command, so using independent methods for each setting alone wouldn't work.