diff --git a/include/sms.h b/include/sms.h
index ce7fe133..e9260561 100644
--- a/include/sms.h
+++ b/include/sms.h
@@ -51,7 +51,7 @@ struct ofono_sms_driver {
 	void (*sca_set)(struct ofono_sms *sms,
 			const struct ofono_phone_number *sca,
 			ofono_sms_sca_set_cb_t cb, void *data);
-	void (*submit)(struct ofono_sms *sms, unsigned char *pdu,
+	void (*submit)(struct ofono_sms *sms, const unsigned char *pdu,
 			int pdu_len, int tpdu_len, int mms,
 			ofono_sms_submit_cb_t cb, void *data);
 	void (*bearer_query)(struct ofono_sms *sms,