On Fri, 18 Mar 2011 10:56:19 +0800 "Wu, Hao" <[email protected]> wrote:
> >On Thu, 17 Mar 2011 09:00:48 -0700 > >Jacob Pan <[email protected]> wrote: > > > >> On Wed, 16 Mar 2011 17:42:36 +0800 > >> "Wu, Hao" <[email protected]> wrote: > >> > >> > langwell_otg_chrg_vbus() is mainly for SRP (Vbus pulse), I think > >> > the resistor is used to protect Vbus pulsing current as > >> > mentioned in OTG 1.3 Spec. So you can ignore this function for > >> > charging. > >> > > >> Based on the 2.0 OTG spec. 5.1.4, vbus pulsing is not supported > >> anymore, only data pulse is supported. Should we remove vbus > >> charging for this reason? > >> > >> Jacob > >Hao, > > > >Also, it seems we only do vbus discharge on Langwell but not on > >Penwell. Do you know what is the reason for it? > > Jacob, > > For Langwell, the transceiver driver still follows old USB OTG 1.3 > Spec, in OTG 1.3 Spec, VBus pulsing SRP must be supported.But for > Penwell, the transceiver driver follows USB OTG 2.0 Spec. There is no > vbus pulsing support in OTG 2.0. This is why we do not need vbus > discharge on penwell. Hi Hao, In terms of HW capability, I would assume Langwell can be made to be OTG 2.0 compliant, correct? Since in OTG 1.3, B-device is required to do both vbus and dataline pulsing SRP, Langwell can still support it. Thanks, Jacob (from Linux laptop) _______________________________________________ MeeGo-kernel mailing list [email protected] http://lists.meego.com/listinfo/meego-kernel
