Re: [RFC PATCH v2 07/16] gpio: Add support for unified device properties interface

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Darren Hart <dvhart@infradead.org>,
	Len Brown <Len.Brown@intel.com>, Arnd Bergmann <arnd@arndb.de>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	David Woodhouse <david.woodhouse@intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Grant Likely <grant.likely@linaro.org>,
	Mark Rutland <mark.rutland@arm.com>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alexandre Courbot <gnurou@gmail.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Bryan Wu <cooloney@gmail.com>, Lee Jones <lee.jones@linaro.org>,
	Aaron Lu <aaron.lu@intel.com>
Subject: Re: [RFC PATCH v2 07/16] gpio: Add support for unified device properties interface
Date: Tue, 07 Oct 2014 18:37:46 +0300	[thread overview]
Message-ID: <1412696266.7701.5.camel@linux.intel.com> (raw)
In-Reply-To: <CACRpkdbehhsDxikCV1bJjBm581MCcu2DRSmiQQXHG09EmjLNBQ@mail.gmail.com>

On Tue, 2014-10-07 at 15:37 +0200, Linus Walleij wrote:
> On Fri, Sep 26, 2014 at 5:21 AM, Darren Hart <dvhart@infradead.org> wrote:
> > On Wed, Sep 24, 2014 at 11:12:36AM +0200, Arnd Bergmann wrote:
> 
> > So as Mika has pointed out, LEDs aren't the only ones affected. Several drivers
> > will need to walk through non-device child nodes, and it seems to me that having
> > a firmware-independent mechanism to do so benefits the drivers by both making
> > them smaller and by increasing the reusability of new drivers and drivers
> > updated to use the new API across platforms.
> 
> In a recent round of reviews, for the OF case, that led to drivers
> which used device_initcall() without being a module, getting a match
> and handle to the parent device, and then walking over the nodes
> and instantiating child objects (Linux devices usually) in the process.
> 
> It was done as a response to the remark from Rob Herring that
> we were modeling things in the device tree as devices when they
> really weren't, we were just doing it that way because it fits the
> Linux device model and it's easier.
> 
> So we have that case too.
> 
> The question is if it's anything close to generalizable.
> 
> > Grant, Linus W? Thoughts?
> 
> I'm uncertain on the whole subject, I called on the others
> because of that...
> 
> For a while I had Andy Schevenko patch the GPIO and
> SFI core too, but it timed out due to no response from Len
> Brown. (Maybe I should just merge that stuff!) Do you (Intel) also
> want to unify the Medfield SFI thing into this or have you
> given up on it?

I think SFI is quite outdated stuff, though I have still Medfield device
close to me.

I don't think there will be any new platform with SFI (on the other hand
we never know :-) ). Thus, my opinion you may go ahead without worrying
about SFI.

-- 
Andy Shevchenko <andriy.shevchenko@intel.com>
Intel Finland Oy