Re: [PATCH] docs: kconfig: Mention IS_REACHABLE as way for optional dependency

From: Krzysztof Kozlowski
Date: Sat Feb 15 2025 - 07:44:22 EST


On 15/02/2025 12:42, Krzysztof Kozlowski wrote:
> @@ -580,10 +582,15 @@ Some drivers are able to optionally use a feature from another module
> or build cleanly with that module disabled, but cause a link failure
> when trying to use that loadable module from a built-in driver.
>
> -The most common way to express this optional dependency in Kconfig logic
> -uses the slightly counterintuitive::
> +There are two ways to express this optional dependency:
>
> - config FOO
> +1. If pre-processor can discard entire optional code or module FOO does not
> + provide !FOO stubs then in the C code :ref:`IS_REACHABLE<is_reachable>`
> +
> +2. Otherwise (and module FOO must provide all !FOO stubs) use the slightly

Obviously this should be "module BAR", similarly above.

I will send a v2.

> + counterintuitive Kconfig syntax::
> +
> + config FOO
> tristate "Support for foo hardware"
> depends on BAR || !BAR
>


Best regards,
Krzysztof