What's the easiest way to make a device easier to port?

After researching why current consumer and embedded ARM (and, to a lesser extent, embedded RISC-V) devices are difficult to port to, the primary reason appears to be device discovery and driver support.

Obviously, extracting proprietary drivers from a potentially outdated AOSP-based OS version with a probably quite outdated kernel and getting that to run in mainline is a lot of work.

However, getting device trees shouldn't be, and really shouldn't be necessary, since they're not something that a manufacturer would hope close to their chest, unlike complex driver software.

Consequently, I would like to request to Fairphone – considering their mission statement – that they provide device trees and enumerable busses (if they don't) but would like to verify here that I wouldn't look like a moron asking for the wrong thing.

I hope this makes sense.