2015-05-19 16:50 GMT+02:00 Russell King - ARM Linux [off-list ref]:

config CLKSRC_STM32
        bool "Clocksource for STM32 SoCs" if COMPILE_TEST
        depends on OF
        select CLKSRC_MMIO

This permits CLKSRC_STM32 to be selected by STM32 (provided OF is enabled,
it's always going to be for that case, right?) while allowing the option
to be visible when both OF!=n and COMPILE_TEST!=n.

Yes OF is always enabled when STM32.

So it fits our needs, as we only want the option to be visible when
both OF!=n and COMPILE_TEST!=n.

Remember,

        bool "string" if <condition-affects-visibility-of-string>
        depends on <condition-affects-config-symbol-availability>

The former merely hides the option from the user _if_ the condition fails.
The latter _disables_ the option completely (except if you try and select
it, at which point you end up with a Kconfig warning about that.)

Thanks for the reminder!
Maxime