Kconfig rules (depends, imply)
rdunlap at infradead.org
Tue May 31 16:25:52 EDT 2022
On 5/31/22 05:14, Muni Sekhar wrote:
> Hi all,
> menuconfig SOUNDWIRE
> tristate "SoundWire support"
> depends on ACPI || OF
> "depends on ACPI || OF" mean, SOUNDWIRE depends on both ACPI and OF modules?
"||" is logical OR, so SOUNDWIRE depends on either ACPI or OF (or both
of them can be enabled).
> config SOUNDWIRE_QCOM
> tristate "Qualcomm SoundWire Master driver"
> imply SLIMBUS
> What does "imply SLIMBUS" mean?
- weak reverse dependencies: "imply" <symbol> ["if" <expr>]
This is similar to "select" as it enforces a lower limit on another
symbol except that the "implied" symbol's value may still be set to n
from a direct dependency or with a visible prompt.
So (in your example) SLIMBUS is desired but not required.
That means that the code that is built for SOUNDWIRE_QCOM
probably needs to use IS_REACHABLE(CONFIG_SLIMBUS) to
see if that SLIMBUS code is available at build time.
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