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. 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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
