Questions on adapt yocto to a custom board

[<andrea@perpic.it>]

Hello everybody,

It's some day that I'm surfing the net looking for the answer to my
question, I don't find any useful information because it looks to me
that all the solutions in in some way tricks and not clean solutions.

My case:
I have an IMX53 custom board that is similar to loco but I added some
gpio and other function due to my application needs. (I think this
situation is common for everybody that produces dedicated hardware also
for other processors.)

For adding complexity... All the documentation I can see on the net is
related OR to LTIB OR to IMX6 that uses a different kernel version so
files are in different locations or with different names.

Finally my question:
What is the best way for deal with a new hardware?
Adapt all the file from (u-boot / kernel) of the more similar board for
adapt to my needs or create a new board?

case 1: I think it's simples because what is already working continue to
work but I expect less flexibility because if I need to have a variant
of that board I need to manage two different layers depends on the board
I need to compile.

case 2: create a new u-boot / kernel configuration for my board.
I expect more difficult at the beginning, find the right files to copy,
build the new versions of the firmware etc. Also every new changes on
the original board will be lost if I don't change them in my new files

What do you usually do?
What do you think are the problems with case 1 and case 2?

Are you aware of any guide that I can follow for case 1 and / or case 2?
I am thinking about... iomux, flexcan initialization...

Any input will be appreciated
thank you for reading the long post
best regards
Andrea