Re: [PATCH v3 8/8] Documentation: usb: chipidea: Update test procedure for HNP polling

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On Thu, Mar 19, 2015 at 08:00:35AM +0800, Peter Chen wrote:
> On Wed, Mar 18, 2015 at 05:57:32PM +0800, Li Jun wrote:
> > On Wed, Mar 18, 2015 at 01:54:40PM +0800, Peter Chen wrote:
> > > On Tue, Mar 17, 2015 at 10:37:52PM +0800, Li Jun wrote:
> > > > From: Li Jun <b47624@xxxxxxxxxxxxx>
> > > > 
> > > > Update HNP test procedure as HNP polling is supported.
> > > > 
> > > > Signed-off-by: Li Jun <jun.li@xxxxxxxxxxxxx>
> > > > ---
> > > >  Documentation/usb/chipidea.txt |    9 ++++-----
> > > >  1 file changed, 4 insertions(+), 5 deletions(-)
> > > > 
> > > > diff --git a/Documentation/usb/chipidea.txt b/Documentation/usb/chipidea.txt
> > > > index 3f848c1..95d9170 100644
> > > > --- a/Documentation/usb/chipidea.txt
> > > > +++ b/Documentation/usb/chipidea.txt
> > > > @@ -26,14 +26,13 @@ cat /sys/kernel/debug/ci_hdrc.0/registers
> > > >     On B-device:
> > > >     echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
> > > >  
> > > > -   if HNP polling is not supported, also need:
> > > > -   On A-device:
> > > > -   echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
> > > > -
> > > >     B-device should take host role and enumrate A-device.
> > > >  
> > > >  4) A-device switch back to host.
> > > > -   On B-device:
> > > > +   On A-device:
> > > > +   echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
> > > > +
> > > > +   or, on B-device:
> > > 
> > > Would you explain how it affect by introducing HNP polling and add
> > > to comment, I have not found it at OTG A-device with HNP State Diagram
> > > at otg 2.0 spec.
> > > 
> > 
> > By introducing HNP polling, B-Host can know when A-peripheral wish to be host
> > role, so this role switch also can be trigged in A-peripheral side by answering
> > the polling from B-Host; w/o HNP polling, this role switch only can be started
> > by B-Host release host role.
> 
> Get it, maybe you can add this to comment that A-peripheral can issue
> HNP after hnp polling introduce.
> 

Okay, I will add this comment, and send out whole series.

Li Jun
> > HNP polling does not impact the HNP states flow, by this mechanism OTG device
> > just have a way to do negotiation, otherwise this kind of negotiation need to
> > be done by user space application.
> > 
> > Li Jun
> > > >     echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
> > > >  
> > > >     A-device should switch back to host and enumrate B-device.
> > > > -- 
> > > > 1.7.9.5
> > > > 
> > > 
> > > -- 
> > > 
> > > Best Regards,
> > > Peter Chen
> 
> -- 
> 
> Best Regards,
> Peter Chen
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