Re: [PATCH v3 04/15] ACPI: Document ACPI device specific properties

Rafael J. Wysocki
2014-10-03T14:18:53Z

On Friday, October 03, 2014 02:58:26 PM Mark Rutland wrote:
> On Fri, Oct 03, 2014 at 03:03:51AM +0100, Rafael J. Wysocki wrote:
> > On Thursday, October 02, 2014 04:36:54 PM Mika Westerberg wrote:
> > > On Thu, Oct 02, 2014 at 02:46:30PM +0200, Arnd Bergmann wrote:
> > > > On Thursday 02 October 2014 15:15:08 Mika Westerberg wrote:
> >
> > [cut]
> >
> > >
> > > Putting everything to a single package results this:
> > >
> > > Package () { "pwms", Package () {"led-red", ^PWM0, 0, 10, "led-green", ^PWM0, 1, 10 }}
> > >
> > > But I think the below looks better:
> >
> > I agree.
> >
> > > Package () { "pwms", Package () {^PWM0, 0, 10, ^PWM0, 1, 10 }}
> > > Package () { "pwm-names", Package () {"led-red", "led-green"}}
> > >
> > > and it is trivial to match with the corresponding DT fragment.
> > >
> > > > }
> > > >
> > > > vs.
> > > >
> > > > pwm-slave {
> > > > pwms = <&pwm0 0 10>, <&pwm1 1 20>;
> > > > pwm-names = "led-red", "led-green";
> > > > };
> > > >
> > >
> > > I don't have strong feelings which way it should be. The current
> > > implementation limits references so that you can have only integer
> > > arguments, like {ref0, int, int, ref1, int} but if people think it is
> > > better to allow strings there as well, it can be changed.
> > >
> > > I would like to get comments from Darren and Rafael about this, though.
> >
> > In my opinion there needs to be a "canonical" representation of the
> > binding that people always can expect to work. It seems reasonable to
> > use the one exactly matching the DT representation for that.
>
> I don't follow. The two forms would share the same high-level accessors,
> but the binary representation is already different. Why should we choose
> the inferior layout given they are already different binary formats?

Well, why is it inferior in the first place? It represents the same information
and I'm not sure why the binary formats matter here?

If I'm to create a _DSD with that information and have a DT template, it
surely is easier to copy it exactly than to figure out how to resolve it
to represent something I can actually put in there.

--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.