diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index 35d7a4d40d9a..80407a4679fa 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -492,7 +492,7 @@ static ssize_t pin_assignment_show(struct device *dev,
 
 	assignments = get_current_pin_assignments(dp);
 
-	for (i = 0; assignments; assignments >>= 1, i++) {
+	for (i = 0; assignments && i < DP_PIN_ASSIGN_MAX; assignments >>= 1, i++) {
 		if (assignments & 1) {
 			if (i == cur)
 				len += sprintf(buf + len, "[%s] ",
diff --git a/include/linux/usb/typec_dp.h b/include/linux/usb/typec_dp.h
index 296909ea04f2..afb73b3e0b80 100644
--- a/include/linux/usb/typec_dp.h
+++ b/include/linux/usb/typec_dp.h
@@ -56,6 +56,7 @@ enum {
 	DP_PIN_ASSIGN_D,
 	DP_PIN_ASSIGN_E,
 	DP_PIN_ASSIGN_F, /* Not supported after v1.0b */
+	DP_PIN_ASSIGN_MAX,
 };
 
 /* DisplayPort alt mode specific commands */