I have had a look into the spec (USB PD), but it does not explicitly explain 
whether the negotiation is done in hardware (by dedicated charger chips) or 
driver software (which then assigns higher allowed current to the ports).

We are planning for new devices to be designed, where we want to support 
charging smartphones etc. and we want to know if there has to be done something 
for this in the USB drivers, and from which kernel on the PD will be supported.
Actually it seems that the negotiation is a job for the charger chips and they 
signal their state via GPIOs to CPU/SoC.

However, I think that the USB team should have an eye on the USB PD spec. and 
keep it in mind.

Thanks,
Carsten



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> -----Original Message-----
> From: Greg KH [mailto:gre...@linuxfoundation.org]
> Sent: Mittwoch, 25. Februar 2015 16:45
> To: Schmid, Carsten
> Cc: linux-usb@vger.kernel.org
> Subject: Re: USB driver support for high current charging
> 
> On Wed, Feb 25, 2015 at 08:39:49AM +0000, Schmid, Carsten wrote:
> > Hello,
> >
> > there is a spec from USB regarding high current charging (on top of USB3.0).
> > Do you know if there is any driver support required, and if so, when
> > will this be available with Linux?
> 
> I think the spec will answer the "is any driver support required"
> question, right?  Have you looked at it?
> 
> Do you have hardware with this feature that needs Linux support?
> 
> thanks,
> 
> greg k-h
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