usb: gadget: udc-core: allow udc class register gadget device

Currently all UDC drivers are calling
device_register() before calling
usb_add_gadget_udc(). In order to avoid
code duplication, we can allow udc-core.c
register that device.

However that would become a really large patch,
so to cope with the meanwhile and allow us
to write bite-sized patches, we're adding
a flag which will be set by UDC driver once
it removes the code for registering the
gadget device.

Once all are converted, the new flag will
be removed.

Reviewed-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/udc-core.c

@@ -173,14 +173,22 @@ int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
 	if (!udc)
 		goto err1;
 
+	if (gadget->register_my_device) {
+		dev_set_name(&gadget->dev, "gadget");
+
+		ret = device_register(&gadget->dev);
+		if (ret)
+			goto err2;
+	}
+
 	device_initialize(&udc->dev);
 	udc->dev.release = usb_udc_release;
 	udc->dev.class = udc_class;
 	udc->dev.groups = usb_udc_attr_groups;
 	udc->dev.parent = parent;
 	ret = dev_set_name(&udc->dev, "%s", kobject_name(&parent->kobj));
 	if (ret)
-		goto err2;
+		goto err3;
 
 	udc->gadget = gadget;
 
@@ -189,18 +197,22 @@ int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
 
 	ret = device_add(&udc->dev);
 	if (ret)
-		goto err3;
+		goto err4;
 
 	mutex_unlock(&udc_lock);
 
 	return 0;
-err3:
+
+err4:
 	list_del(&udc->list);
 	mutex_unlock(&udc_lock);
 
-err2:
+err3:
 	put_device(&udc->dev);
 
+err2:
+	if (gadget->register_my_device)
+		put_device(&gadget->dev);
 err1:
 	return ret;
 }
@@ -254,6 +266,9 @@ void usb_del_gadget_udc(struct usb_gadget *gadget)
 
 	kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
 	device_unregister(&udc->dev);
+
+	if (gadget->register_my_device)
+		device_unregister(&gadget->dev);
 }
 EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
 

include/linux/usb/gadget.h

@@ -494,6 +494,9 @@ struct usb_gadget_ops {
  *	only supports HNP on a different root port.
  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
  *	enabled HNP support.
+ * @register_my_device: Flag telling udc-core that UDC driver didn't
+ *	register the gadget device to the driver model. Temporary until
+ *	all UDC drivers are fixed up properly.
  * @name: Identifies the controller hardware type.  Used in diagnostics
  *	and sometimes configuration.
  * @dev: Driver model state for this abstract device.
@@ -531,6 +534,7 @@ struct usb_gadget {
 	unsigned			b_hnp_enable:1;
 	unsigned			a_hnp_support:1;
 	unsigned			a_alt_hnp_support:1;
+	unsigned			register_my_device:1;
 	const char			*name;
 	struct device			dev;
 	unsigned			out_epnum;