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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Thu, 1 Sep 2022 00:07:26 +0300
Message-ID: <CAHp75Vff0GUQXD8zstEFwXNcnbxKEc7Gqahoo_kZp69MyKWskg@mail.gmail.com>
Subject: Re: [PATCH] gpio: Allow user to customise maximum number of GPIOs
To:     Davide Ciminaghi <ciminaghi@gnudd.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Alexandre Courbot <gnurou@gmail.com>,
        Alexandre Courbot <acourbot@nvidia.com>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        Jonathan Corbet <corbet@lwn.net>,
        Russell King <linux@armlinux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        "moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
        "open list:GENERIC INCLUDE/ASM HEADER FILES" 
        <linux-arch@vger.kernel.org>, Alessandro Rubini <rubini@gnudd.com>
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On Wed, Aug 31, 2022 at 5:14 PM Davide Ciminaghi <ciminaghi@gnudd.com> wrote:
> On Wed, Aug 31, 2022 at 03:32:25PM +0200, Linus Walleij wrote:
> > On Tue, Aug 30, 2022 at 9:58 AM Davide Ciminaghi <ciminaghi@gnudd.com> wrote:
> >
> > > the sta2x11 was a chip containing AMBA peripherals and a PCIe to AMBA bridge
> > > (it is still in production as far as I know, but deprecated for new designs).
> > > It would typically be installed on x86 machines, so you needed to build and
> > > run AMBA drivers in an x86 environment. The original drivers we started from
> > > had platform data, but then we were told to switch to DTS.
> >
> > For the record I think that was bad advice, I hope it wasn't me.
> > But the world was different back then I suppose.
> > Adding DTS to x86 which is inherently ACPI is not a good idea.
> > Especially if you look at how SBSA ACPI UARTS were done
> > in drivers/tty/serial/amba-pl011.c.
> >
> now that I think of it, ACPI was also listed as a possible choice, but the
> problem was that we didn't know much about ACPI, and took the DTS way.
> So there was no bad advice, just fear of the unknown :-)

Feel free to ask, we have experts in the mailing list(s).

-- 
With Best Regards,
Andy Shevchenko