diff --git a/drivers/isdn/hardware/mISDN/netjet.c b/drivers/isdn/hardware/mISDN/netjet.c
index f8945eddb957..df34512675d0 100644
--- a/drivers/isdn/hardware/mISDN/netjet.c
+++ b/drivers/isdn/hardware/mISDN/netjet.c
@@ -970,7 +970,7 @@ nj_release(struct tiger_hw *card)
 	}
 	if (card->irq > 0)
 		free_irq(card->irq, card);
-	if (card->isac.dch.dev.dev.class)
+	if (device_is_registered(&card->isac.dch.dev.dev))
 		mISDN_unregister_device(&card->isac.dch.dev);
 
 	for (i = 0; i < 2; i++) {