linux-kernel - Re: [PATCH v11 2/6] gpiolib: allow to specify the firmware node in struct gpio

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Date:   Wed, 1 Dec 2021 16:28:19 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Kent Gibson <warthog618@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Shuah Khan <shuah@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v11 2/6] gpiolib: allow to specify the firmware node in
 struct gpio_chip

On Wed, Dec 01, 2021 at 02:53:42PM +0100, Bartosz Golaszewski wrote:
> On Wed, Dec 1, 2021 at 2:40 PM Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> > On Wed, Dec 01, 2021 at 02:11:28PM +0100, Bartosz Golaszewski wrote:
> > > On Tue, Nov 30, 2021 at 10:04 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:

...

> > > Let me maybe rephrase the problem: currently, for GPIO devices
> > > instantiating multiple banks created outside of the OF or ACPI
> > > frameworks (e.g. instantiated manually and configured using a
> > > hierarchy of software nodes with a single parent swnode and a number
> > > of child swnodes representing the children), it is impossible to
> > > assign firmware nodes other than the one representing the top GPIO
> > > device to the gpiochip child devices.
> > >
> > > In fact if we want to drop the OF APIs entirely from gpiolib - this
> > > would be the right first step as for gpio-sim it actually replaces the
> > > gc->of_node = some_of_node; assignment that OF-based drivers do for
> > > sub-nodes defining banks and it does work with device-tree (I verified
> > > that too) thanks to the fwnode abstraction layer.
> >
> > I still don't see how you set up hierarchy of primary/secondary fwnodes.
> >
> > And I don't like this change. It seems it band-aids some issue with fwnode
> > usage. What the easiest way to reproduce the issue with your series applied
> > (without this change)?
> 
> Drop this patch and drop the line where the fwnode is assigned in
> gpio-sim.c. Then probe the device and print the addresses of the
> parent and child swnodes. See how they are the same and don't match
> the swnode hierarchy we created. You can then apply this patch and see
> how it becomes correct.

Thanks. I will give a spin.

Note, it seems I have to revert your older code first...

-- 
With Best Regards,
Andy Shevchenko