gadget_release
void gadget_release(struct device *pdev);
void (*release)(struct device *dev) = udc->gadget_release;
udc->gadget_release = gadget->dev.release;
gadget->dev.release = udc->gadget_release;
void (*gadget_release)(struct device *dev);
gadget_release);
usb_initialize_gadget(&pdev->dev, &dev->gadget, gadget_release);
EXPORT_SYMBOL_GPL(gadget_release);
gadget_release);