config_default vs subtargets having their own config_<ver>?

[Tim Harvey]

Greetings,

I'm working on cortexa53 support for target/linux/imx for imx8 support
and am not quite clear how best to take care of kernel config. There
is a lot of differences in kernel config for
cortexa7/cortexa9/cortexa53 with regards to IMX SoC's.

I see some targets have config_default files in the subtarget dirs and
others have config_<kver>.

What is the recommended way of defining kernel config per subtarget
and how is it recommended to come up with those split up config files?

Best Regards,

Tim