diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index bf4be4b53b44..a366233d8ac2 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -811,6 +811,7 @@ static void __init pmu_i2c_probe(void)
 		bus->hostdata = bus + 1;
 		bus->xfer = pmu_i2c_xfer;
 		mutex_init(&bus->mutex);
+		lockdep_register_key(&bus->lock_key);
 		lockdep_set_class(&bus->mutex, &bus->lock_key);
 		bus->flags = pmac_i2c_multibus;
 		list_add(&bus->link, &pmac_i2c_busses);
@@ -934,6 +935,7 @@ static void __init smu_i2c_probe(void)
 		bus->hostdata = bus + 1;
 		bus->xfer = smu_i2c_xfer;
 		mutex_init(&bus->mutex);
+		lockdep_register_key(&bus->lock_key);
 		lockdep_set_class(&bus->mutex, &bus->lock_key);
 		bus->flags = 0;
 		list_add(&bus->link, &pmac_i2c_busses);