add access to ACPI docking station UID

@@ -659,6 +659,23 @@
 }
 DEVICE_ATTR(undock, S_IWUSR, NULL, write_undock);
 
+/*
+ * show_dock_uid - read method for "uid" file in sysfs
+ */
+static ssize_t show_dock_uid(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	unsigned long lbuf;
+	acpi_status status = acpi_evaluate_integer(dock_station->handle, "_UID", 0, &lbuf);
+	if(ACPI_FAILURE(status)) {
+	    return 0;
+	}
+	return snprintf(buf, PAGE_SIZE, "%lx\n", lbuf);
+}
+DEVICE_ATTR(uid, S_IRUGO, show_dock_uid, NULL);
+
+
+
 /**
  * dock_add - add a new dock station
  * @handle: the dock station handle

@@ -707,6 +724,13 @@
 		kfree(dock_station);
 		return ret;
 	}
+	ret = device_create_file(&dock_device.dev, &dev_attr_uid);
+	if (ret) {
+		printk("Error %d adding sysfs file\n", ret);
+		platform_device_unregister(&dock_device);
+		kfree(dock_station);
+		return ret;
+	}
 
 	/* Find dependent devices */
 	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,