Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface

From: Peter Chen
Date: Thu Feb 18 2016 - 04:11:25 EST


On Wed, Feb 17, 2016 at 04:28:16PM +0200, Heikki Krogerus wrote:
> On Wed, Feb 17, 2016 at 03:36:46PM +0200, Felipe Balbi wrote:
> >
> > Hi,
> >
>
> > IIRC mode and role negotiation goes via CC pins using the power delivery
> > protocol. If I misunderstand anything, let me know.
>
> The data role swap with USB Type-C connectors is in no way tied to USB
> Power Delivery. The USB Type-C spec defines that when USB PD is
> available, DR_Swap USB PD function is used to swap the role, otherwise
> emulated disconnect will do the trick.
>

I am interested in how you design role swap on the fly without USB PD.
Do you follow the spec like USB OTG 3.0 RSP (Role Swap Protocol) or
just echo the /sys to give up current role, and swap to another?

--

Best Regards,
Peter Chen