Re: Using PTN5110 w/ USB Hub

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

Hi Adam,

On Tue, Apr 12, 2022 at 10:58:03AM -0500, Adam Ford wrote:
> On Tue, Apr 12, 2022 at 10:37 AM Jun Li <lijun.kernel@gmail.com> wrote:
> >
> > Adam Ford <aford173@gmail.com> 于2022年4月12日周二 08:24写道：
> > >
> > > I have a board with a dual role USB conttroller connected to a dual
> > > role hub
> >
> > Could you please explain more about what's "a dual role hub"?
> Thanks for responding.
> 
> 
> The datasheet is listed here:
> https://ww1.microchip.com/downloads/en/DeviceDoc/00002238D.pdf
> 
> I worded that poorly, sorry.  It supports DCP, CDP, SDP.
> 
> >From the datasheet:
> • USB Hub Feature Controller IC Hub with:- 1 USB 3.1 Gen 1 USB
> Type-CTM downstream port- 4 USB 3.1 Gen 1 legacy downstream ports- 1
> USB 2.0 downstream port- Legacy upstream port
> • USB-IF Battery Charger revision 1.2 support on up & downstream ports
> (DCP, CDP, SDP)
> 
> The hope was to have the PTN enable the SRC_EN when the USB-C cable is
> connected to the hub.
> 
> >
> > > connected to a PTN5110 for enabing power to the USB-C.
> > >
> > > SoC -> Hub -> PTN-> USB-C
> >
> > What signals of Hub chip connect to PTN5110 chip?
> 
> Technically, only the CC pins are connected between the USB-C
> connector and the PTN5110.  There isn't really a connection to the hub
> itself, but the output on the PTN enables a regulator which powers the
> USB-C which does connect to the hub.
> 
> >
> > >
> > > The hope was the PTN5110 would enable/disable the src_en pin when I
> > > connect a device that needs power.  Unfortunately, most of the
> > > examples I can see for the device trees on a PTN5110 show some sort of
> > > connection to a USB controller, but  I am going through a hub, not a
> > > controller.
> > >
> > > Is it possible to configure the PTN5110 to either not require
> > > connection to a USB controller or plumb it to a USB hub?
> >
> > My understanding PTN5110(TCPCI controller with PD PHY) is independent
> > with USB data path, for USB data path, I think it should be:
> > SoC -> Hub -> USB-C
> > PTN5110 should not care or know if there is a Hub between type-C connector
> > and USB controller.
> > If the type-C connector connects to a Hub, then it's a DFP only on data,
> > and from power point view, you also only power source role, right?
> 
> Yes.  We're basically trying to source power when a device is
> connected and power down the regulator when the USB-C device is
> disconnected. Unfortunately, the PTN5110 never enables power even when
> I specify it's source only with no sink.  The driver acts like it
> needs some sort of USB node, and when it doesn't find one, and the
> example device tree in the YAML file shows a refernce to the USB
> controller.  I assumed I needed to plumb it to the hub somehow.  If I
> am reading your response correctly, I should just add the node for the
> USB controller and forget the hub exists, is that correct?

Which driver are you talking about?

thanks,

-- 
heikki