Re: [RFC v2 5/6] drivers: boot_constraint: Add initial DT bindings

From: Rob Herring
Date: Mon Jul 17 2017 - 13:34:15 EST


On Thu, Jul 13, 2017 at 03:06:08PM +0530, Viresh Kumar wrote:
> On 12-07-17, 16:28, Rob Herring wrote:
> > Display is a pretty well known use case here. Do you have other
> > examples in mind?
>
> No, I don't.
>
> @Stephen: Do you have more cases like this for your Qcom products ?
>
> > Other cases I've seen are automotive with keeping
> > the backup camera going and CAN bus handling. Though my new car has a
> > flicker shortly after coming on, so I guess the handoff doesn't have
> > to be completely seemless. :)
>
> :)
>
> > [...]
> >
> > > + mmc: mmc@0x0 {
> > > + ...
> > > + ...
> > > + vmmc-supply = <&twl_reg1>;
> > > + vmmcaux-supply = <&twl_reg2>;
> > > + boot-constraint-supplies = "vmmc", "vmmcaux";
> > > + boot-constraint-uV = <1800000 2000000>, /* vmmc */
> > > + <2000000 2000000>; /* vmmcaux */
> >
> > No. I don't like how this is going to extend to all the other bindings
> > people are going to want constraints for. We don't need a parallel set
> > of properties for each type of binding.
>
> Fair enough.
>
> > I'm not convinced that we need a general solution for what's probably
> > a handful of things that need a handoff versus just re-initialize.
>
> What about keeping the first four patches (mostly) as it is and adding
> these constraints from a platform specific constraints driver ?
>
> Will that be acceptable ?

Meaning no DT binding? Then I don't care (from a DT perspective).

Rob