diff --git a/drivers/mailbox/omap-mbox.h b/drivers/mailbox/omap-mbox.h
index 6cd38fc685994b025c74689e324481bcf7b2b6b1..86d7518cd13b2c07b27b6931042e1d3c7b10529d 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;