Re: [PATCH 1/2] dt-bindings: usb: qcom,pmic-typec: drop port description
From: Rob Herring
Date: Fri Mar 22 2024 - 14:36:23 EST
On Fri, Mar 22, 2024 at 05:49:00PM +0200, Dmitry Baryshkov wrote:
> On Fri, 22 Mar 2024 at 17:23, Bryan O'Donoghue
> <bryan.odonoghue@xxxxxxxxxx> wrote:
> >
> > On 22/03/2024 15:09, neil.armstrong@xxxxxxxxxx wrote:
> > >> TBH I think we should drop this HS, SS stuff from the connector
> > >> definition - there's nothing to say in a h/w definition anywhere HS
> > >> must be a port or indeed SS - not all hardware knows or cares about
> > >> different HS/SS signalling.
> > >
> > > It matches the USB-C connector electrical characteristics, which by spec
> > > has, at least:
> > > - High-Speed USB Line
> > > - up to 4 differential high-speed lanes that can be switched to DP, USB2
> > > or PCIe
> > > - SideBand line (SBU)
> > >
> > > And those 3 components can be handled by 3 different HW in the SoC, so
> > > each one has a dedicated port.
> > >
> > > Remember DT describes the HW, not the SW implementation.
> > >
> > > Neil
> >
> > Yes, you're right about that.
> >
> > I suppose
> >
> > 1. Orientation switches should be defined as coming from a port on the
> > connector associated with the CC pins.
> > port@3:
> > orientation-switch port name goes here
> >
> > 2. Data-role switches...
> > Again the CC pins
> >
> > https://community.silabs.com/s/article/what-s-the-role-of-cc-pin-in-type-c-solution?language=en_US
> >
> > Maybe the right-thing-to-do is to add another port for the CC pins -
> > which would still describe the hardware characteristics but would
> > _accurately_ name the thing which does the data-role/orientation switching
>
> It's true that we don't describe CC lines. However In most of the
> cases CC lines are handled by the Type-C port manager directly. So
> there will be a connection from usb-c-connector to the pmic-typec
> itself (which looks pretty redundant).
The thought at the time this was designed was that would be the parent
node of the connector. That's perhaps too simple.
Rob