Re: [RFC 1/8] dt-bindings: usb: qcom,dwc3: Add bindings to enable runtime

[Caleb Connolly]

> Hi Caleb,
>
>    There are two types of platforms, some use extcon and some use 
> role-switch to deliver vbus/id notifications. Extcon targets already 
> have this qscratch modifications present today in vbus and id handlers. 
> But for role-switch based targets we don't have any way to get this 
> notification to dwc3-qcom. In this implementation, I wanted to get those 
> notications from core to glue and for this we implenented vendor hooks.
>
> The property added has been used to do two things:
>
> 1. Register glue's vendor hooks to core driver
> 2. Do runtime_allow for glue (and by default for core as the dt is not 
> flattened)
>
> In case of extcon, we don't want to register vendor hooks as 
> notifications are not necessary.

Could it just be enabled when role_switch is present then?
> For xhci, we opted to enable runtime from userspace.

> > >         HS/FS/LS modes are supported.
> > >       type: boolean
> > > +  qcom,enable-rt:
> > > +    description:
> > > +      If present, register vendor hooks to facilitate runtime 
> > > suspend/resume
> > > +    type: boolean
> >
> > A Krzysztof pointed out, properties should define the hardware 
> > behaviour, not tot the implementation details. For this case the 
> > hardware isn't wired up to vbus, so maybe something like "qcom,no-vbus"?
> > > +
>
> On all targets, vbus is not routed to hardware. This vbus toggle 
> indication is given to controller via qscratch only.
>
> Regards,
> Krishna,

--
// Caleb (they/them)