diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index c8c217b7dd33..f627c9fd7b48 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -90,6 +90,7 @@ struct pmac_i2c_bus
 	int			opened;
 	int			polled;		/* open mode */
 	struct platform_device	*platform_dev;
+	struct lock_class_key   lock_key;
 
 	/* ops */
 	int (*open)(struct pmac_i2c_bus *bus);
@@ -587,6 +588,7 @@ 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_set_class(&bus->mutex, &bus->lock_key);
 	if (controller == busnode)
 		bus->flags = pmac_i2c_multibus;
 	list_add(&bus->link, &pmac_i2c_busses);
@@ -815,6 +817,7 @@ static void __init pmu_i2c_probe(void)
 		bus->hostdata = bus + 1;
 		bus->xfer = pmu_i2c_xfer;
 		mutex_init(&bus->mutex);
+		lockdep_set_class(&bus->mutex, &bus->lock_key);
 		bus->flags = pmac_i2c_multibus;
 		list_add(&bus->link, &pmac_i2c_busses);
 
@@ -938,6 +941,7 @@ static void __init smu_i2c_probe(void)
 		bus->hostdata = bus + 1;
 		bus->xfer = smu_i2c_xfer;
 		mutex_init(&bus->mutex);
+		lockdep_set_class(&bus->mutex, &bus->lock_key);
 		bus->flags = 0;
 		list_add(&bus->link, &pmac_i2c_busses);