linux-kernel - Re: [PATCHv2] drivers: bus: simple-pm-bus: Fix compatibility with simple-bus for auxdata

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Message-ID: <CAL_JsqJWPc4rt0NiaF=zS0XOy4b8pZKDCEaxCjp8rW+joMjvjQ@mail.gmail.com>
Date:   Tue, 19 Jan 2021 08:51:01 -0600
From:   Rob Herring <robh+dt@...nel.org>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Arnd Bergmann <arnd@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        DTML <devicetree@...r.kernel.org>,
        linux-omap <linux-omap@...r.kernel.org>
Subject: Re: [PATCHv2] drivers: bus: simple-pm-bus: Fix compatibility with
 simple-bus for auxdata

On Mon, Jan 18, 2021 at 2:41 AM Tony Lindgren <tony@...mide.com> wrote:
>
> * Arnd Bergmann <arnd@...nel.org> [210118 08:30]:
> > On Mon, Jan 18, 2021 at 8:33 AM Tony Lindgren <tony@...mide.com> wrote:
> > >
> > > After converting am335x to probe devices with simple-pm-bus I noticed
> > > that we are not passing auxdata for of_platform_populate() like we do
> > > with simple-bus.
> > >
> > > While device tree using SoCs should no longer need platform data, there
> > > are still quite a few drivers that still need it as can be seen with
> > > git grep OF_DEV_AUXDATA. We want to have simple-pm-bus be usable as a
> > > replacement for simple-bus also for cases where OF_DEV_AUXDATA is still
> > > needed.
> > >
> > > Let's fix the issue by passing auxdata as platform data to simple-pm-bus.
> > > That way the SoCs needing this can pass the auxdata with OF_DEV_AUXDATA.
> > > And let's pass the auxdata for omaps to fix the issue for am335x.
> > >
> > > As an alternative solution, adding simple-pm-bus handling directly to
> > > drivers/of/platform.c was considered, but we would still need simple-pm-bus
> > > device driver. So passing auxdata as platform data seems like the simplest
> > > solution.
> > >
> > > Fixes: 5a230524f879 ("ARM: dts: Use simple-pm-bus for genpd for am3 l4_wkup")
> > > Signed-off-by: Tony Lindgren <tony@...mide.com>
> > > ---
> > > Changes since v1: Updated description, added devicetree list to Cc
> >
> > This looks fine to me for now
> >
> > Acked-by: Arnd Bergmann <arnd@...db.de>
>
> Thanks for the review.
>
> > But I think we should take the time to discuss how to phase out auxdata
> > over time. There are still a number of users, but it's not that many in the
> > end. For some of them I see a clear solution, for other ones I do not:
>
> Yes agreed we should remove the auxdata use.
>
> > omap2: I'll leave these for Tony to comment
>
> The three hardest ones to update (because of PM dependencies):
>
> - PRM power managment interrupts that also pinctrl driver uses

I haven't looked at it, but can't one driver go find the other node
and the interrupts it needs? There's nothing wrong with a driver
looking outside 'its node' for information.

Rob