Re: [PATCH] gpio: Allow user to customise maximum number of GPIOs

From: Davide Ciminaghi <ciminaghi@gnudd.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: 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>
Subject: Re: [PATCH] gpio: Allow user to customise maximum number of GPIOs
Date: Wed, 31 Aug 2022 16:12:36 +0200	[thread overview]
Message-ID: <Yw9sVCNtaLUjZH/F@arcana.i.gnudd.com> (raw)
In-Reply-To: <CACRpkdZeAAZYqV3ccd-X=ZwdnfSwRUdXchGETB-WTkgSZQL=Pw@mail.gmail.com>

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 :-)

Thanks
Davide