Re: [PATCH v1 1/1] Add driver for Mellanox BlueField-3 GPIO controller

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Tue, Sep 6, 2022 at 5:08 PM Asmaa Mnebhi <asmaa@xxxxxxxxxx> wrote:
> -----Original Message-----
> From: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Sent: Friday, September 2, 2022 5:55 PM
> On Fri, Sep 2, 2022 at 5:55 PM Asmaa Mnebhi <asmaa@xxxxxxxxxx> wrote:

...

> > I would like that to be controlled by the ACPI table only.
>
> I don't know if it is possible to restrict GPIOs to just be used from ACPI.

On Intel platforms that's done with HW assistance, i.e. firmware
configures special registers inside pin control / GPIO address space
that reflect ownership. The driver rejects any attempts to request
such GPIOs. As a workaround one may simply disable all user space
interfaces (as you already discussed in this thread).

-- 
With Best Regards,
Andy Shevchenko