This looks like a prime candidate for a HAVE_RTC config variable
So you do:
config RTC
tristate "Enhanced Real Time Clock Support"
+ depends on HAVE_RTC && !RTC_DEV_CMOS
config HAVE_RTC
bool
(No "depends on" allowed!)
And then the architectures that do support the RTC Framework do an:
(arch/x86/Kconfig as an example):
config X86
+ select HAVE_RTC
So when PPC suddenly supports it they add this single
select statement and no more Kconfig magic needed.
See Documentation/kbuild/kconfig-language.txt for a bit more elaborate
description.
Sam
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