diff --git a/sys/dev/adb/adb.h b/sys/dev/adb/adb.h
index 6b007c46959..c29a52dac62 100644
--- a/sys/dev/adb/adb.h
+++ b/sys/dev/adb/adb.h
@@ -74,7 +74,6 @@ size_t	adb_read_register(device_t dev, u_char reg, void *data);
 size_t	adb_write_register(device_t dev, u_char reg, size_t len, void *data);
 
 /* Bits for implementing ADB host bus adapters */
-extern devclass_t adb_devclass;
 extern driver_t adb_driver;
 
 #endif
diff --git a/sys/dev/adb/adb_bus.c b/sys/dev/adb/adb_bus.c
index 8c300c83df1..e5f858a2a22 100644
--- a/sys/dev/adb/adb_bus.c
+++ b/sys/dev/adb/adb_bus.c
@@ -78,8 +78,6 @@ driver_t adb_driver = {
 	sizeof(struct adb_softc),
 };
 
-devclass_t adb_devclass;
-
 static int
 adb_bus_probe(device_t dev)
 {
diff --git a/sys/powerpc/powermac/cuda.c b/sys/powerpc/powermac/cuda.c
index 3c17448187e..0feb197143f 100644
--- a/sys/powerpc/powermac/cuda.c
+++ b/sys/powerpc/powermac/cuda.c
@@ -116,7 +116,7 @@ static driver_t cuda_driver = {
 static devclass_t cuda_devclass;
 
 DRIVER_MODULE(cuda, macio, cuda_driver, cuda_devclass, 0, 0);
-DRIVER_MODULE(adb, cuda, adb_driver, adb_devclass, 0, 0);
+DRIVER_MODULE(adb, cuda, adb_driver, 0, 0);
 
 static void cuda_intr(void *arg);
 static uint8_t cuda_read_reg(struct cuda_softc *sc, u_int offset);
diff --git a/sys/powerpc/powermac/pmu.c b/sys/powerpc/powermac/pmu.c
index 642206fd4f7..56194d85e7b 100644
--- a/sys/powerpc/powermac/pmu.c
+++ b/sys/powerpc/powermac/pmu.c
@@ -158,7 +158,7 @@ static devclass_t pmu_devclass;
 
 EARLY_DRIVER_MODULE(pmu, macio, pmu_driver, pmu_devclass, 0, 0,
     BUS_PASS_RESOURCE);
-DRIVER_MODULE(adb, pmu, adb_driver, adb_devclass, 0, 0);
+DRIVER_MODULE(adb, pmu, adb_driver, 0, 0);
 
 static int	pmuextint_probe(device_t);
 static int	pmuextint_attach(device_t);