Re: [PATCH v4 1/9] driver core: add a faux bus for use when a simple device/bus is needed

Lyude Paul
2025-02-11T20:06:05Z

On Mon, 2025-02-10 at 10:52 -0500, Kurt Borja wrote:
> > Modules usually don't need to do the probe callback at all.  I show one
> > example in this series (the regulator dummy driver), but it can be
> > easily rewritten to not need that at all.
>
> This is a good point, but from a developer standpoint I would always try
> to use the probe callback. This API seems to suggest that's the
> appropiate use.
>
> Also it would be amazing if the probe could reside in an __init section.

IMO I think it is fine without the probe callback, plus we're the ones making
the API - it can say whatever we want :).

To be clear though, generally I'm fairly sure the only reason for drivers to
be using probe() at all is because you want a driver-callback the kernel is
responsible for executing in response to a new device being added on a bus.
This doesn't really make sense for a virtual bus, since we're in control of
adding devices - and thus probe() would just be an unnecessary layer for work
that can already easily be done from the same call site that added the device.
So I think it's fine for this to be a special case imo.

--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat

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