diff --git a/kernel/chips/matorb.c b/kernel/chips/matorb.c
index da335eb4..0184d17d 100644
--- a/kernel/chips/matorb.c
+++ b/kernel/chips/matorb.c
@@ -171,7 +171,7 @@ int matorb_detect(struct i2c_adapter *adapter, int address, int kind)
   matorb_list[i] = new_client;
   new_client->id = i;
   data->valid = 0;
-  data->update_lock = MUTEX;
+  init_MUTEX(&data->update_lock);
     
   /* Tell the I2C layer a new client has arrived */
   if ((err = i2c_attach_client(new_client)))