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path: root/target/linux/generic/patches-3.10/820-usb_add_usb_find_device_by_name.patch
blob: 720b740c352a203cebaccd35b691db0a870aa949 (plain)
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--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -645,6 +645,71 @@ int __usb_get_extra_descriptor(char *buf
 }
 EXPORT_SYMBOL_GPL(__usb_get_extra_descriptor);
 
+static struct usb_device *match_device_name(struct usb_device *dev,
+					    const char *name)
+{
+	struct usb_device *ret_dev = NULL;
+	struct usb_device *childdev = NULL;
+	int child;
+
+	dev_dbg(&dev->dev, "check for name %s ...\n", name);
+
+	/* see if this device matches */
+	if (strcmp(dev_name(&dev->dev), name) == 0 ) {
+		dev_dbg(&dev->dev, "matched this device!\n");
+		ret_dev = usb_get_dev(dev);
+		goto exit;
+	}
+	/* look through all of the children of this device */
+	usb_hub_for_each_child(dev, child, childdev) {
+		if (childdev) {
+			usb_lock_device(childdev);
+			ret_dev = match_device_name(childdev, name);
+			usb_unlock_device(childdev);
+			if (ret_dev)
+				goto exit;
+		}
+	}
+exit:
+	return ret_dev;
+}
+
+/**
+ * usb_find_device_by_name - find a specific usb device in the system
+ * @name: the name of the device to find
+ *
+ * Returns a pointer to a struct usb_device if such a specified usb
+ * device is present in the system currently.  The usage count of the
+ * device will be incremented if a device is found.  Make sure to call
+ * usb_put_dev() when the caller is finished with the device.
+ *
+ * If a device with the specified bus id is not found, NULL is returned.
+ */
+struct usb_device *usb_find_device_by_name(const char *name)
+{
+	struct list_head *buslist;
+	struct usb_bus *bus;
+	struct usb_device *dev = NULL;
+
+	mutex_lock(&usb_bus_list_lock);
+	for (buslist = usb_bus_list.next;
+	     buslist != &usb_bus_list;
+	     buslist = buslist->next) {
+		bus = container_of(buslist, struct usb_bus, bus_list);
+		if (!bus->root_hub)
+			continue;
+		usb_lock_device(bus->root_hub);
+		dev = match_device_name(bus->root_hub, name);
+		usb_unlock_device(bus->root_hub);
+		if (dev)
+			goto exit;
+	}
+exit:
+	mutex_unlock(&usb_bus_list_lock);
+	return dev;
+}
+EXPORT_SYMBOL_GPL(usb_find_device_by_name);
+
 /**
  * usb_alloc_coherent - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
  * @dev: device the buffer will be used with
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -675,6 +675,7 @@ static inline bool usb_device_supports_l
 	return udev->bos->ss_cap->bmAttributes & USB_LTM_SUPPORT;
 }
 
+extern struct usb_device *usb_find_device_by_name(const char *name);
 
 /*-------------------------------------------------------------------------*/