USB: add devpath sysfs attribute

This is not exported from the usb core, yet we rely on it to create
paths to interfaces for this device in sysfs.  Export it to make
userspace tools have an easier time to figure things out.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/sysfs.c

@@ -138,6 +138,16 @@ show_devnum(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR(devnum, S_IRUGO, show_devnum, NULL);
 
+static ssize_t
+show_devpath(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct usb_device *udev;
+
+	udev = to_usb_device(dev);
+	return sprintf(buf, "%s\n", udev->devpath);
+}
+static DEVICE_ATTR(devpath, S_IRUGO, show_devpath, NULL);
+
 static ssize_t
 show_version(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -538,8 +548,8 @@ static struct attribute *dev_attrs[] = {
 	&dev_attr_bConfigurationValue.attr,
 	&dev_attr_bmAttributes.attr,
 	&dev_attr_bMaxPower.attr,
-	&dev_attr_urbnum.attr,
 	/* device attributes */
+	&dev_attr_urbnum.attr,
 	&dev_attr_idVendor.attr,
 	&dev_attr_idProduct.attr,
 	&dev_attr_bcdDevice.attr,
@@ -551,6 +561,7 @@ static struct attribute *dev_attrs[] = {
 	&dev_attr_speed.attr,
 	&dev_attr_busnum.attr,
 	&dev_attr_devnum.attr,
+	&dev_attr_devpath.attr,
 	&dev_attr_version.attr,
 	&dev_attr_maxchild.attr,
 	&dev_attr_quirks.attr,