Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/31813 )
Change subject: Fix up remaining boolean uses of CONFIG_XXX to CONFIG(XXX) ......................................................................
Patch Set 1:
Not sure if this is the way to go. The original intention of IS_ENABLED(), as I understood it, was to avoid problems with undefined CONFIG_* macros. For instance in CPP, an undefined CONFIG_ would be true for an #if, and one defined to 0 would be true for an #ifdef. IS_ENABLED() solved that very nicely.
In C, we have other issues. I would always prefer a plain `CONFIG_...` in C, simply because it results in a compile time error when the config is undefined.
I mean... I'm not sure how useful it is, but as far as I understood it, the expected code style is to use IS_ENABLED() (and now CONFIG()) everywhere, for all boolean Kconfigs, in both preprocessor and C. That's what I've always been told in reviews, and that's what I've then started telling other people.
If we think it's crap we can start a bigger discussion about whether we want to change it if you want, but for now I'm pretty sure that's what we've been doing and what the vast majority of our code already conforms to, so I was just trying to eliminate the last few stragglers here.