[PATCH 1/4] usb: gadget: core: change udc class to gadget bus

[Peter Chen <peter.chen@xxxxxxxxxxxxx>]

The udc will be the device at gadget bus, and the gadget driver
will be the driver at this bus.

With gadget bus, we can support below features:
- udc driver is loaded later than gadget driver
- Binding udc and gadget driver manually

Signed-off-by: Peter Chen <peter.chen@xxxxxxxxxxxxx>
---
 drivers/usb/gadget/udc-core.c |   41 ++++++++++++++++++++++-------------------
 1 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/drivers/usb/gadget/udc-core.c b/drivers/usb/gadget/udc-core.c
index 27768a7..582b1eb 100644
--- a/drivers/usb/gadget/udc-core.c
+++ b/drivers/usb/gadget/udc-core.c
@@ -30,12 +30,12 @@
 
 /**
  * struct usb_udc - describes one usb device controller
- * @driver - the gadget driver pointer. For use by the class code
+ * @driver - the gadget driver pointer. For use by gadget bus
  * @dev - the child device to the actual controller
- * @gadget - the gadget. For use by the class code
- * @list - for use by the udc class driver
+ * @gadget - the gadget. For use by the gadget bus code
+ * @list - for use by the gadget bus code
  *
- * This represents the internal data structure which is used by the UDC-class
+ * This represents the internal data structure which is used by the gadget bus
  * to hold information about udc driver and gadget together.
  */
 struct usb_udc {
@@ -45,7 +45,7 @@ struct usb_udc {
 	struct list_head		list;
 };
 
-static struct class *udc_class;
+static struct bus_type gadget_bus_type;
 static LIST_HEAD(udc_list);
 static DEFINE_MUTEX(udc_lock);
 
@@ -128,7 +128,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_set_state);
  * @gadget: The gadget we want to get started
  * @driver: The driver we want to bind to @gadget
  *
- * This call is issued by the UDC Class driver when it's about
+ * This call is issued by the gadget bus driver when it's about
  * to register a gadget driver to the device controller, before
  * calling gadget driver's bind() method.
  *
@@ -148,7 +148,7 @@ static inline int usb_gadget_udc_start(struct usb_gadget *gadget,
  * @gadget: The device we want to stop activity
  * @driver: The driver to unbind from @gadget
  *
- * This call is issued by the UDC Class driver after calling
+ * This call is issued by the gadget bus driver after calling
  * gadget driver's unbind() method.
  *
  * The details are implementation specific, but it can go as
@@ -185,7 +185,7 @@ static void usb_udc_nop_release(struct device *dev)
 }
 
 /**
- * usb_add_gadget_udc_release - adds a new gadget to the udc class driver list
+ * usb_add_gadget_udc_release - adds a new gadget to the udc framework
  * @parent: the parent device to this udc. Usually the controller driver's
  * device.
  * @gadget: the gadget to be added to the list.
@@ -224,7 +224,7 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
 
 	device_initialize(&udc->dev);
 	udc->dev.release = usb_udc_release;
-	udc->dev.class = udc_class;
+	udc->dev.bus = &gadget_bus_type;
 	udc->dev.groups = usb_udc_attr_groups;
 	udc->dev.parent = parent;
 	ret = dev_set_name(&udc->dev, "%s", kobject_name(&parent->kobj));
@@ -263,7 +263,7 @@ err1:
 EXPORT_SYMBOL_GPL(usb_add_gadget_udc_release);
 
 /**
- * usb_add_gadget_udc - adds a new gadget to the udc class driver list
+ * usb_add_gadget_udc - adds a new gadget to the udc framework
  * @parent: the parent device to this udc. Usually the controller
  * driver's device.
  * @gadget: the gadget to be added to the list
@@ -558,23 +558,26 @@ static int usb_udc_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
+static struct bus_type gadget_bus_type = {
+	.name =		"usb_gadget",
+	.uevent =	usb_udc_uevent,
+};
+
 static int __init usb_udc_init(void)
 {
-	udc_class = class_create(THIS_MODULE, "udc");
-	if (IS_ERR(udc_class)) {
-		pr_err("failed to create udc class --> %ld\n",
-				PTR_ERR(udc_class));
-		return PTR_ERR(udc_class);
-	}
+	int ret = bus_register(&gadget_bus_type);
+
+	if (ret)
+		pr_err("failed to register gadget bus: %d\n", ret);
+
+	return ret;
 
-	udc_class->dev_uevent = usb_udc_uevent;
-	return 0;
 }
 subsys_initcall(usb_udc_init);
 
 static void __exit usb_udc_exit(void)
 {
-	class_destroy(udc_class);
+	bus_unregister(&gadget_bus_type);
 }
 module_exit(usb_udc_exit);
 
-- 
1.7.8

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