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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 15 Nov 2021 14:13:43 +0200
Message-ID: <CAHp75VeemaMFCLncFAF24RU6kEbj=9F3w5LWjA-o-uky=pO=5w@mail.gmail.com>
Subject: Re: [PATCH v8 2/4] iio: adc: Add Xilinx AMS driver
To:     Anand Ashok Dumbre <ANANDASH@xilinx.com>
Cc:     Jonathan Cameron <jic23@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        linux-iio <linux-iio@vger.kernel.org>, git <git@xilinx.com>,
        Michal Simek <michals@xilinx.com>,
        Peter Meerwald <pmeerw@pmeerw.net>,
        devicetree <devicetree@vger.kernel.org>,
        Manish Narani <MNARANI@xilinx.com>
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On Mon, Nov 15, 2021 at 1:59 PM Anand Ashok Dumbre <ANANDASH@xilinx.com> wrote:

...

> > > > +             ams->pl_base = of_iomap(node, 0);
> > >
> > > Hmm. So of_iomap() leaves us dependent on dt specific calls. Whilst it
> > > doesn't exactly look hard to create a generic version covering at
> > > least dt and acpi I don' think there is an equivalent acpi function currently
> > defined.
> > >
> > > Andy, do you think this is a good thing to add to the generic firmware
> > > node handling?  It's a bit specialist as most of the time this will be
> > > wrapped up in the platform device handling or similar rather than being in a
> > child node like this.
> >
> > I saw this issue previously somewhere else and we can do something about
> > it.
> > But first (before going to ACPI guts) we may indeed introduce a basic
> > skeleton under fwnode API for this.
> >
> > Something like
> >
> > void __iomem *fwnode_iomap(...)
> > {
> >   if (is_of_node(fwnode))
> >     return of_iomap();
> >   return NULL;
> > }
> > EXPORT_SYMBOL_GPL(fwnode_iomap);
> >
> > At least it will allow drivers to make them property provider agnostic.
> >
> > Okay, I checked the current version of the ACPI specification and the
> > proposed DTS here. With above API and something like
> >
> > Device (AMS0) {
> >   Name (_CRS, ...)
> >   ...
> >   Device (PLMN) {
> >     Name (_CRS, ...)
> >   }
> >   Device (PSMN) {
> >     Name (_CRS, ...)
> >   }
> > }
> >
> > we may get the resource from the corresponding fwnode's _CRS object
>
> Just to be sure, do I need to do anything for this in this iteration?

Can you provide a helper to drivers/base/property.h for the X-node
iomap() to be agnostic?

(X - SW, FW, ...)

-- 
With Best Regards,
Andy Shevchenko