Ok, really add drivers/base/sys.c

drivers/base/sys.c

+/*
+ * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
+ *
+ * Copyright (c) 2002 Patrick Mochel
+ *              2002 Open Source Development Lab
+ * 
+ * This exports a 'system' bus type. 
+ * By default, a 'sys' bus gets added to the root of the system. There will
+ * always be core system devices. Devices can use register_sys_device() to
+ * add themselves as children of the system bus.
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+
+static struct device system_bus = {
+       name:           "System Bus",
+       bus_id:         "sys",
+};
+
+int register_sys_device(struct device * dev)
+{
+       int error = -EINVAL;
+
+       if (dev) {
+               if (!dev->parent)
+                       dev->parent = &system_bus;
+               error = device_register(dev);
+       }
+       return error;
+}
+
+void unregister_sys_device(struct device * dev)
+{
+       if (dev)
+               put_device(dev);
+}
+
+static int sys_bus_init(void)
+{
+       return device_register(&system_bus);
+}
+
+subsys_initcall(sys_bus_init);
+EXPORT_SYMBOL(register_sys_device);
+EXPORT_SYMBOL(unregister_sys_device);