On Thu, Jun 09, 2016 at 10:24:44AM +0300, Roger Quadros wrote: > On 08/06/16 15:42, Peter Chen wrote: > > On Wed, Jun 08, 2016 at 01:12:10PM +0300, Roger Quadros wrote: > >> Hi, > >> > >> On 08/06/16 12:53, Peter Chen wrote: > >>> On Wed, Jun 08, 2016 at 12:03:40PM +0300, Roger Quadros wrote: > >>>> +int usb_otg_unregister(struct device *dev) > >>>> +{ > >>>> + struct usb_otg *otg; > >>>> + > >>>> + mutex_lock(&otg_list_mutex); > >>>> + otg = usb_otg_get_data(dev); > >>>> + if (!otg) { > >>>> + dev_err(dev, "otg: %s: device not in otg list\n", > >>>> + __func__); > >>>> + mutex_unlock(&otg_list_mutex); > >>>> + return -EINVAL; > >>>> + } > >>>> + > >>>> + /* prevent unregister till both host & gadget have unregistered */ > >>>> + if (otg->host || otg->gadget) { > >>>> + dev_err(dev, "otg: %s: host/gadget still registered\n", > >>>> + __func__); > >>> > >>> You need to call mutex_unlock here > >> > >> Indeed. good catch. > >>> > >>>> + > >>>> +int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready) > >>>> +{ > >>> > >>> What this API is for? Why need it in this version? > >> > >> we moved gadget to otg registration from udc_bind_to_driver() to usb_add_gadget_udc_release(). > >> This means there is a window when gadget function driver (e.g. g_zero) is not loaded. > >> We don't want to start the gadget controller in that window. > >> > >> usb_otg_gadget_ready() is used by gadget core to notify the otg core when the function driver > >> is ready or not-ready. > >> > > > > Why you need to move this from gadget's probe to udc's probe? Currently, > > the sequence of gadget and udc's probe is random, but udc_bind_to_driver > > is called when udc is ready. > > > Because we need to support -EPROBE_DEFER at udc probe. > At udc_bind_to_driver there is no scope for -EPROBE_DEFER. > Why udc_bind_to_driver can't return -EPROBE_DEFER if register to OTG is failed? > Another issue is that we need to register with otg and have otg->caps available > before driver->bind() is called in udc_bind_to_driver(). Else gadget function > will not have the correct OTG descriptor. > You can do register before calling driver->bind. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html