diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index 09bfe4b..df89d91 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -582,6 +582,7 @@ static void __init kw_i2c_add(struct pmac_i2c_host_kw *host,
 	bus->close = kw_i2c_close;
 	bus->xfer = kw_i2c_xfer;
 	mutex_init(&bus->mutex);
+	lockdep_register_key(&bus->lock_key);
 	lockdep_set_class(&bus->mutex, &bus->lock_key);
 	if (controller == busnode)
 		bus->flags = pmac_i2c_multibus;