Possibility to share device trees and how various OSes have their different copies

[orangecms]

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The Device Tree spec is quite freeform, not requiring much in terms of naming of nodes and properties, or what properties to have, but very few. However, Linux is where DTs are mainly developed, and then copied over to other projects, such as U-Boot and BSDs.

See e.g. https://gist.github.com/orangecms/b8146e5dc35662cc4caddd2e4d5a90c8 comparing Broadcom arm64 device trees in NetBSD vs Linux.

This shows how the two OSes sometimes use different compat strings, which could be worked around by having all possible strings in the respective driver. Node names are a bit tougher. Some properties may or may not exist in either OS though, and the respective driver is coupled with it.

Document why this is the case, and if OSes can ever use common device trees, including across versions of the same OS.