linux-kernel - Re: [RFC PATCH 0/2] Add software node support to regulator framework

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Date:   Mon, 12 Jul 2021 16:01:05 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Daniel Scally <djrscally@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <mgross@...ux.intel.com>,
        Maximilian Luz <luzmaximilian@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        kieran.bingham@...asonboard.com
Subject: Re: [RFC PATCH 0/2] Add software node support to regulator framework

On Mon, Jul 12, 2021 at 3:42 PM Mark Brown <broonie@...nel.org> wrote:
> On Sun, Jul 11, 2021 at 12:37:03PM +0300, Andy Shevchenko wrote:
> > On Fri, Jul 9, 2021 at 8:05 PM Mark Brown <broonie@...nel.org> wrote:
> > > On Thu, Jul 08, 2021 at 11:42:24PM +0100, Daniel Scally wrote:
>
> > > What is a software node and why would we want to use one here?
>
> > Software node is a representation of (missed and / or quirked)
> > firmware nodes in the code.
>
> > > Why are we not just using board files, what does this new abstraction
> > > solve?
>
> > Software node _is_ a board file part. The idea behind that is that the
> > driver, which requires any additional / necessary property that has
> > been missed in the firmware nodes, wouldn't need special treatment if
> > that property comes from a board file rather than firmware.
>
> This doesn't seem to correspond with what these patches are doing,
> they're creating something which bears no relation to any firmware
> interface and the code is specifically looking for swnodes.

Okay, this seems like a different story.
The software nodes shouldn't appear on its own in the generic code.
When we use software nodes API in it, it means that we have tried
other providers _explicitly_ and haven't found what we are looking for
and hence we have to check if software nodes are providing the same.
For example, here it's done that way:
https://elixir.bootlin.com/linux/v5.14-rc1/source/kernel/irq/irqdomain.c#L178.

In all other cases it shouldn't be called explicitly.

-- 
With Best Regards,
Andy Shevchenko