On Wed, Jan 28, 2015 at 09:08:56AM +0200, Alexander Shishkin wrote:
> Peter Chen <peter.chen@xxxxxxxxxxxxx> writes:
>
> > During this API, the deactivation count will be update, and it
> > will try to connect or disconnect gadget. It can be used to
> > enable functions for gadget.
>
> It's up to Felipe, but I'd like to see answers to the following
> questions in this commit message:
>
> * what is a deactivation, when does happen and why?
> * what is the problem that it solves?
> * who is the intended user of this api?
> * what are the constraints of using this api?
>
> It'd also be nice to mention some of these in the code.
In fact, some of these questions are answered by comments at code,
I will add more comments both at commit log and code.
>
> > /**
> > + * usb_udc_activation_handler - updates udc's deactivation count and
> > + * try to connect or disconnect
> > + *
> > + * @gadget: The gadget which the function is at
> > + * @active: the function needs to be active or not
> > + *
> > + * The composite core calls it when it wants to activate or deactivate
> > + * function.
> > + */
> > +void usb_udc_activation_handler(struct usb_gadget *gadget, bool active)
> > +{
> > + struct usb_udc *udc = usb_gadget_find_udc(gadget);
> > +
> > + if (udc) {
> > + if (active)
> > + udc->deactivations--;
> > + else
> > + udc->deactivations++;
> > + usb_udc_connect_control(udc);
> > + }
> > +}
> > +EXPORT_SYMBOL_GPL(usb_udc_activation_handler);
>
> Since this is exported to the drivers, does it make sense to guard
> against deactivations going negative and/or print a warning?
>
I will add a WARN_ON for that, thanks.
--
Best Regards,
Peter Chen
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