diff --git a/drivers/mailbox/omap-mbox.h b/drivers/mailbox/omap-mbox.h
index 6cd38fc68599..86d7518cd13b 100644
--- a/drivers/mailbox/omap-mbox.h
+++ b/drivers/mailbox/omap-mbox.h
@@ -52,7 +52,7 @@ struct omap_mbox_queue {
 
 struct omap_mbox {
 	const char		*name;
-	unsigned int		irq;
+	int			irq;
 	struct omap_mbox_queue	*txq, *rxq;
 	struct omap_mbox_ops	*ops;
 	struct device		*dev;