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

From: Linus Walleij <linus.walleij@linaro.org>
To: Davide Ciminaghi <ciminaghi@gnudd.com>
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 15:32:25 +0200	[thread overview]
Message-ID: <CACRpkdZeAAZYqV3ccd-X=ZwdnfSwRUdXchGETB-WTkgSZQL=Pw@mail.gmail.com> (raw)
In-Reply-To: <Yw3DKCuDoPkCaqxE@arcana.i.gnudd.com>

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.

Today I think we would solve this by simply creating software nodes, which
are the same no matter if you're doing device tree or ACPI, so it would
have been much easier now, I think. :/

Yours,
Linus Walleij