On 13/06/16 10:20, Peter Chen wrote: > On Mon, Jun 13, 2016 at 10:14:31AM +0300, Roger Quadros wrote: >> On 12/06/16 14:36, Peter Chen wrote: >>> On Fri, Jun 10, 2016 at 04:07:22PM +0300, Roger Quadros wrote: >>>> >>>> +/** >>>> + * usb_otg_add_gadget_udc - adds a new gadget to the udc class driver list >>>> + * @parent: the parent device to this udc. Usually the controller >>>> + * driver's device. >>> >>> It seems it should be udc device >> >> Parent and udc->dev are not the same right? > > Sure, udc's parent is otg device. > >> >> I guess i'll omit the second statement to avoid confusion. So. >> >> @parent: the parent device to this udc. > > Where you call below APIs? It seems to be a udc driver, right? > So, when you try to get "otg-controller" from the node, this node > should be udc. @parent is actually the device that represents the USB Device controller in the device tree. When you call usb_add_gadget_udc_release() a new udc->dev device is created as it's child. See explanation for the @parent argument in usb_add_gadget_udc_release(). As we want to keep the parent argument identical to that I will not make any changes then. > > /** > * usb_otg_add_gadget_udc - adds a new gadget to the udc class driver list > * @parent: the parent device to this udc. Usually the controller > * driver's device. > * @gadget: the gadget to be added to the list > * @otg_dev: the OTG controller device > * > * If otg_dev is NULL then device tree node is checked > * for OTG controller via the otg-controller property. > * Returns zero on success, negative errno otherwise. > */ > int usb_otg_add_gadget_udc(struct device *parent, struct usb_gadget *gadget, > struct device *otg_dev) > { > if (!otg_dev) { > gadget->otg_dev = of_usb_get_otg(parent->of_node); > if (!gadget->otg_dev) > return -ENODEV; > } else { > gadget->otg_dev = otg_dev; > } > > return usb_add_gadget_udc_release(parent, gadget, NULL); > } > EXPORT_SYMBOL_GPL(usb_otg_add_gadget_udc); > -- cheers, -roger -- 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