Re: [net-next PATCH v3 09/15] device property: Introduce fwnode_get_id()

From: Saravana Kannan <saravanak@google.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	Calvin Johnson <calvin.johnson@oss.nxp.com>,
	Grant Likely <grant.likely@arm.com>,
	Jeremy Linton <jeremy.linton@arm.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	Cristi Sovaiala <cristian.sovaiala@nxp.com>,
	Florin Laurentiu Chiculita <florinlaurentiu.chiculita@nxp.com>,
	Ioana Ciornei <ioana.ciornei@nxp.com>,
	Madalin Bucur <madalin.bucur@oss.nxp.com>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Marcin Wojtas <mw@semihalf.com>,
	Pieter Jansen Van Vuuren <pieter.jansenvv@bamboosystems.io>,
	Jon <jon@solid-run.com>,
	Diana Madalina Craciun <diana.craciun@nxp.com>,
	LKML <linux-kernel@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	"linux.cj" <linux.cj@gmail.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
	Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [net-next PATCH v3 09/15] device property: Introduce fwnode_get_id()
Date: Fri, 22 Jan 2021 13:07:29 -0800	[thread overview]
Message-ID: <CAGETcx-CFPa6hckV6RjWfOcYnrfoU1_vYYpLZtV_LgxNSDzthQ@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VcVNj0+KZiLEsPgfz=fZoLr9g1=6ikeUo7FZ1rd4FKpWQ@mail.gmail.com>

On Fri, Jan 22, 2021 at 1:05 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Fri, Jan 22, 2021 at 10:59 PM Saravana Kannan <saravanak@google.com> wrote:
> > On Fri, Jan 22, 2021 at 8:34 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
> > > On Wed, Jan 20, 2021 at 9:01 PM Saravana Kannan <saravanak@google.com> wrote:
> > > > On Wed, Jan 20, 2021 at 11:15 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
>
> > > > I'd rather this new function be an ops instead of a bunch of #ifdef or
> > > > if (acpi) checks. Thoughts?
> > >
> > > Well, it looks more like a helper function than like an op and I'm not
> > > even sure how many potential users of it will expect that _ADR should
> > > be evaluated in the absence of the "reg" property.
> > >
> > > It's just that the "reg" property happens to be kind of an _ADR
> > > equivalent in this particular binding AFAICS.
> >
> > I agree it is not clear how useful this helper function is going to be.
> >
> > But in general, to me, any time the wrapper/helper functions in
> > drivers/base/property.c need to do something like this:
> >
> > if (ACPI)
> >    ACPI specific code
> > if (OF)
> >    OF specific code
> >
> > I think the code should be pushed to the fwnode ops. That's one of the
> > main point of fwnode. So that firmware specific stuff is done by
> > firmware specific code. Also, when adding support for new firmware,
> > it's pretty clear what support the firmware needs to implement.
> > Instead of having to go fix up a bunch of code all over the place.
>
> Wishful thinking.
> In the very case of GPIO it's related to framework using headers local
> to framework. Are you suggesting to open its guts to the entire wild
> world?

What are you even talking about? How is whatever you are saying
remotely related to getting an "id" for a fwnode?

> I don't think it's a good idea. You see, here we have different
> layering POD types,

POD?

> which are natural and quite low level that ops
> suits best for them and quite different resource types like GPIO. And
> the latter is closer to certain framework rather than to POD handling
> cases.
>

-Saravana