diff --git a/drivers/nfc/pn533/i2c.c b/drivers/nfc/pn533/i2c.c
index 2c2fb9cfe10a..8f60ce039b0d 100644
--- a/drivers/nfc/pn533/i2c.c
+++ b/drivers/nfc/pn533/i2c.c
@@ -51,7 +51,7 @@ static int pn533_i2c_send_ack(struct pn533 *dev, gfp_t flags)
 {
 	struct pn533_i2c_phy *phy = dev->phy;
 	struct i2c_client *client = phy->i2c_dev;
-	u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
+	static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
 	/* spec 6.2.1.3:  Preamble, SoPC (2), ACK Code (2), Postamble */
 	int rc;
 
diff --git a/drivers/nfc/pn533/usb.c b/drivers/nfc/pn533/usb.c
index 000159ea9c5f..8ed203ea21ea 100644
--- a/drivers/nfc/pn533/usb.c
+++ b/drivers/nfc/pn533/usb.c
@@ -148,11 +148,11 @@ static int pn533_submit_urb_for_ack(struct pn533_usb_phy *phy, gfp_t flags)
 static int pn533_usb_send_ack(struct pn533 *dev, gfp_t flags)
 {
 	struct pn533_usb_phy *phy = dev->phy;
-	u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
+	static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
 	/* spec 7.1.1.3:  Preamble, SoPC (2), ACK Code (2), Postamble */
 	int rc;
 
-	phy->out_urb->transfer_buffer = ack;
+	phy->out_urb->transfer_buffer = (u8 *)ack;
 	phy->out_urb->transfer_buffer_length = sizeof(ack);
 	rc = usb_submit_urb(phy->out_urb, flags);