Re: [RFC 02/10] property: add fwnode_get_match_data()

Andy Shevchenko
2022-02-22T09:24:54Z

On Tue, Feb 22, 2022 at 9:47 AM Clément Léger <clement.leger@bootlin.com> wrote:
> Le Tue, 22 Feb 2022 09:33:32 +0100,
> Andy Shevchenko <andy.shevchenko@gmail.com> a écrit :
> > On Tue, Feb 22, 2022 at 9:24 AM Clément Léger <clement.leger@bootlin.com> wrote:
> > > Le Mon, 21 Feb 2022 19:46:12 +0200,
> > > Andy Shevchenko <andriy.shevchenko@linux.intel.com> a écrit :

...

> > > The idea is to allow device with a software_node description to match
> > > with the content of the of_match_table. Without this, we would need a
> > > new type of match table that would probably duplicates part of the
> > > of_match_table to be able to match software_node against a driver.
> > > I did not found an other way to do it without modifying drivers
> > > individually to support software_nodes.
> >
> > software nodes should not be used as a replacement of the real
> > firmware nodes. The idea behind is to fill the gaps in the cases when
> > firmware doesn't provide enough information to the OS. I think Heikki
> > can confirm or correct me.
>
> Yes, the documentation states that:
>
> NOTE! The primary hardware description should always come from either
> ACPI tables or DT. Describing an entire system with software nodes,
> though possible, is not acceptable! The software nodes should only
> complement the primary hardware description.
>
> > If you want to use the device on an ACPI based platform, you need to
> > describe it in ACPI as much as possible. The rest we may discuss.
>
> Agreed but the PCIe card might also be plugged in a system using a
> device-tree description (ARM for instance). I should I do that without
> duplicating the description both in DT and ACPI ?

Why is it (duplication) a problem?
Each platform has its own kind of description, so one needs to provide
it in the format the platform accepts.

--
With Best Regards,
Andy Shevchenko