+
+#if defined(CONFIG_USB_PERSIST) || defined(CONFIG_USB_SUSPEND)
+static const char power_group[] = "power";
+#endif
+
+#ifdef CONFIG_USB_PERSIST
+
+static ssize_t
+show_persist(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct usb_device *udev = to_usb_device(dev);
+
+ return sprintf(buf, "%d\n", udev->persist_enabled);
+}
+
+static ssize_t
+set_persist(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct usb_device *udev = to_usb_device(dev);
+ int value;
+
+ /* Hubs are always enabled for USB_PERSIST */
+ if (udev->descriptor.bDeviceClass == USB_CLASS_HUB)
+ return -EPERM;
+
+ if (sscanf(buf, "%d", &value) != 1)
+ return -EINVAL;
+ usb_pm_lock(udev);
+ udev->persist_enabled = !!value;
+ usb_pm_unlock(udev);
+ return count;
+}
+
+static DEVICE_ATTR(persist, S_IRUGO | S_IWUSR, show_persist, set_persist);
+
+static int add_persist_attributes(struct device *dev)
+{
+ int rc = 0;
+
+ if (is_usb_device(dev)) {
+ struct usb_device *udev = to_usb_device(dev);
+
+ /* Hubs are automatically enabled for USB_PERSIST */
+ if (udev->descriptor.bDeviceClass == USB_CLASS_HUB)
+ udev->persist_enabled = 1;
+ rc = sysfs_add_file_to_group(&dev->kobj,
+ &dev_attr_persist.attr,
+ power_group);
+ }
+ return rc;
+}
+
+static void remove_persist_attributes(struct device *dev)
+{
+ sysfs_remove_file_from_group(&dev->kobj,
+ &dev_attr_persist.attr,
+ power_group);
+}
+
+#else
+
+#define add_persist_attributes(dev) 0
+#define remove_persist_attributes(dev) do {} while (0)
+
+#endif /* CONFIG_USB_PERSIST */
+