>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.
Full OTG 2.0 compliant needs some new features for example, ADP which langwell does not support. For SRP, due to Langwell hardware limitation, only vbus SRP can be detected correctly as I remembered, so Vbus pulsing SRP is a must for back-to-back cases. Thanks Hao _______________________________________________ MeeGo-kernel mailing list [email protected] http://lists.meego.com/listinfo/meego-kernel
