Re: [PATCH v3 0/4] add device drivers for Siemens Industrial PCs

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Henning Schild <henning.schild@siemens.com>
Cc: Hans de Goede <hdegoede@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux LED Subsystem <linux-leds@vger.kernel.org>,
	Platform Driver <platform-driver-x86@vger.kernel.org>,
	linux-watchdog@vger.kernel.org,
	Srikanth Krishnakar <skrishnakar@gmail.com>,
	Jan Kiszka <jan.kiszka@siemens.com>,
	Gerd Haeussler <gerd.haeussler.ext@siemens.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Wim Van Sebroeck <wim@linux-watchdog.org>,
	Mark Gross <mgross@linux.intel.com>, Pavel Machek <pavel@ucw.cz>,
	Enrico Weigelt <lkml@metux.net>
Subject: Re: [PATCH v3 0/4] add device drivers for Siemens Industrial PCs
Date: Mon, 12 Jul 2021 15:09:04 +0300	[thread overview]
Message-ID: <CAHp75VfvVD20pZng_BG-ptZiYo9VBfHFe2OABo8VmtYcarfcSw@mail.gmail.com> (raw)
In-Reply-To: <20210712133543.074aad80@md1za8fc.ad001.siemens.net>

On Mon, Jul 12, 2021 at 2:35 PM Henning Schild
<henning.schild@siemens.com> wrote:
>
> This series is basically stuck because people rightfully want me to use
> the GPIO subsystem for the LEDs and the watchdog bits that are
> connected to GPIO.
>
> Problem is that the GPIO subsystem does not initialize on the machines
> in question. It is a combination of hidden P2SB and missing ACPI table
> entries. The GPIO subsystem (intel pinctrl) needs either P2SB or ACPI do
> come up ...
>
> Andy proposed some patches for initializing the intel pinctrl stuff for
> one of the machines by falling back to SoC detection in case there is
> no ACPI or visible P2SB. While that works it would need to be done for
> any Intel SoC to be consistent and discussions seem to go nowhere.
>
> I would be willing to port over to "intel pintctl" and help with
> testing, but not so much with actual coding. Andy is that moving at all?
>
> Since my drivers do reserve the mmio regions properly and the intel
> pinctrl will never come up anyways, i do not see a conflict merging my
> proposed drivers in the current codebase. The wish to use the pinctrl
> infrastructure can not be fulfilled if that infra is not in place. Once
> intel pinctrl works, we can change those drivers to work with that.
>
> I do not want to take shortcuts ... but also do not want to get stuck
> here. So maybe one way to serialize the merge is to allow my changes
> like proposed and rebase on intel pinctrl once that subsystem actually
> initializes on these machines. We could even have two code paths ... if
> region can not be reserved, try gpio ... or the other way around.

Bjorn suggested exercising the IORESOURCE_PCI_FIXED on top of the
early PCI quirk that unhides P2SB for the entire run time. But I have
had no time to actually patch the kernel this way. Have tried the
proposed approach on your side?

-- 
With Best Regards,
Andy Shevchenko