On Wed, 13 Aug 2014, Paul Zimmerman wrote:

> > > The UDC driver ought to know when Vbus turns on or off, without
> > > polling.  It should get an interrupt when that happens, or its
> > > ops->vbus_session routine should be called.  So at that time, the UDC
> > > driver could invoke a new usb_gadget_driver callback.  Let's also call
> > > it vbus_session.
> > >
> > > Since composite.c defines a usb_gadget_driver structure, it can have a
> > > composite_vbus_session() callback.  When this routine is called, it
> > > will check to see whether all the functions are activated.  If they are
> > > and Vbus is now on, it will call usb_gadget_connect(); otherwise it
> > > will call usb_gadget_disconnect().
> 
> Is there a difference between a VBus on/off and a connect/disconnect?
> Because AFAIK the Synopsys USB 3.0 controller (unless it is configured
> for OTG mode) does not have a way to detect when VBus is enabled/
> disabled, other than by a connect/disconnect interrupt.

That's an excellent point; it completely slipped my mind.  So we 
already have all the callbacks we need.

Alan Stern

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

Reply via email to