usb: make usb port a real device

This patch turns each USB port on a hub into a new struct device. This
new device has the USB hub interface device as its parent. The port
devices are stored in a new structure (usb_port), and an array of
usb_ports are dynamically allocated once we know how many ports the USB
hub has.

Move the port_owner variable out of usb_hub and into this new structure.

A new file will be created in the hub interface sysfs directory, so
add documentation.

Acked-by: Alan Stern <[e-mail]>
Signed-off-by: Lan Tianyu <[e-mail]>
Signed-off-by: Sarah Sharp <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/sysfs-bus-usb

···
 		If the device doesn't support LTM, the file will read "no".
 		The file will be present for all speeds of USB devices, and will
 		always read "no" for USB 1.1 and USB 2.0 devices.
+
+What:		/sys/bus/usb/devices/.../(hub interface)/portX
+Date:		August 2012
+Contact:	Lan Tianyu <[e-mail]>
+Description:
+		The /sys/bus/usb/devices/.../(hub interface)/portX
+		is usb port device's sysfs directory.

drivers/usb/core/hub.c

···
 #endif
 #endif
 
+struct usb_port {
+	struct device dev;
+	struct dev_state *port_owner;
+};
+
 struct usb_hub {
 	struct device		*intfdev;	/* the "interface" device */
 	struct usb_device	*hdev;
···
 	u8			indicator[USB_MAXCHILDREN];
 	struct delayed_work	leds;
 	struct delayed_work	init_work;
-	struct dev_state	**port_owners;
+	struct usb_port		**ports;
 };
 
 static inline int hub_is_superspeed(struct usb_device *hdev)
···
 #define HUB_DEBOUNCE_STEP	  25
 #define HUB_DEBOUNCE_STABLE	 100
 
+#define to_usb_port(_dev) \
+	container_of(_dev, struct usb_port, dev)
 
 static int usb_reset_and_verify_device(struct usb_device *udev);
 
···
 	return 0;
 }
 
+static void usb_port_device_release(struct device *dev)
+{
+	struct usb_port *port_dev = to_usb_port(dev);
+
+	kfree(port_dev);
+}
+
+static void usb_hub_remove_port_device(struct usb_hub *hub,
+				       int port1)
+{
+	device_unregister(&hub->ports[port1 - 1]->dev);
+}
+
+struct device_type usb_port_device_type = {
+	.name =		"usb_port",
+	.release =	usb_port_device_release,
+};
+
+static int usb_hub_create_port_device(struct usb_hub *hub,
+				      int port1)
+{
+	struct usb_port *port_dev = NULL;
+	int retval;
+
+	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
+	if (!port_dev) {
+		retval = -ENOMEM;
+		goto exit;
+	}
+
+	hub->ports[port1 - 1] = port_dev;
+	port_dev->dev.parent = hub->intfdev;
+	port_dev->dev.type = &usb_port_device_type;
+	dev_set_name(&port_dev->dev, "port%d", port1);
+
+	retval = device_register(&port_dev->dev);
+	if (retval)
+		goto error_register;
+	return 0;
+
+error_register:
+	put_device(&port_dev->dev);
+exit:
+	return retval;
+}
+
 static int hub_configure(struct usb_hub *hub,
 	struct usb_endpoint_descriptor *endpoint)
 {
···
 	u16 hubstatus, hubchange;
 	u16 wHubCharacteristics;
 	unsigned int pipe;
-	int maxp, ret;
+	int maxp, ret, i;
 	char *message = "out of memory";
 
 	hub->buffer = kmalloc(sizeof(*hub->buffer), GFP_KERNEL);
···
 
 	hdev->children = kzalloc(hdev->maxchild *
 				sizeof(struct usb_device *), GFP_KERNEL);
-	hub->port_owners = kzalloc(hdev->maxchild * sizeof(struct dev_state *),
-				GFP_KERNEL);
-	if (!hdev->children || !hub->port_owners) {
+	hub->ports = kzalloc(hdev->maxchild * sizeof(struct usb_port *),
+			     GFP_KERNEL);
+	if (!hdev->children || !hub->ports) {
 		ret = -ENOMEM;
 		goto fail;
 	}
···
 	if (hub->has_indicators && blinkenlights)
 		hub->indicator [0] = INDICATOR_CYCLE;
 
+	for (i = 0; i < hdev->maxchild; i++)
+		if (usb_hub_create_port_device(hub, i + 1) < 0)
+			dev_err(hub->intfdev,
+				"couldn't create port%d device.\n", i + 1);
+
 	hub_activate(hub, HUB_INIT);
 	return 0;
 
···
 {
 	struct usb_hub *hub = usb_get_intfdata(intf);
 	struct usb_device *hdev = interface_to_usbdev(intf);
+	int i;
+
+	for (i = 0; i < hdev->maxchild; i++)
+		usb_hub_remove_port_device(hub, i + 1);
 
 	/* Take the hub off the event list and don't let it be added again */
 	spin_lock_irq(&hub_event_lock);
···
 
 	usb_free_urb(hub->urb);
 	kfree(hdev->children);
-	kfree(hub->port_owners);
+	kfree(hub->ports);
 	kfree(hub->descriptor);
 	kfree(hub->status);
 	kfree(hub->buffer);
···
 	/* This assumes that devices not managed by the hub driver
 	 * will always have maxchild equal to 0.
 	 */
-	*ppowner = &(hdev_to_hub(hdev)->port_owners[port1 - 1]);
+	*ppowner = &(hdev_to_hub(hdev)->ports[port1 - 1]->port_owner);
 	return 0;
 }
 
···
 
 void usb_hub_release_all_ports(struct usb_device *hdev, struct dev_state *owner)
 {
+	struct usb_hub *hub = hdev_to_hub(hdev);
 	int n;
-	struct dev_state **powner;
 
-	n = find_port_owner(hdev, 1, &powner);
-	if (n == 0) {
-		for (; n < hdev->maxchild; (++n, ++powner)) {
-			if (*powner == owner)
-				*powner = NULL;
-		}
+	for (n = 0; n < hdev->maxchild; n++) {
+		if (hub->ports[n]->port_owner == owner)
+			hub->ports[n]->port_owner = NULL;
 	}
+
 }
 
 /* The caller must hold udev's lock */
···
 	if (udev->state == USB_STATE_NOTATTACHED || !udev->parent)
 		return false;
 	hub = hdev_to_hub(udev->parent);
-	return !!hub->port_owners[udev->portnum - 1];
+	return !!hub->ports[udev->portnum - 1]->port_owner;
 }
-
 
 static void recursively_mark_NOTATTACHED(struct usb_device *udev)
 {