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

From: Andy Shevchenko
Date: Mon Jul 12 2021 - 08:09:47 EST

On Mon, Jul 12, 2021 at 2:35 PM Henning Schild
<henning.schild@xxxxxxxxxxx> 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