diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 7122efd..e488cf9 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -352,6 +352,8 @@
 					 u_char *buf)
 {
 	*retlen = 0;
+	if (!mtd->read_fact_prot_reg)
+		return -EOPNOTSUPP;
 	return mtd->read_fact_prot_reg(mtd, from, len, retlen, buf);
 }
 
@@ -369,6 +371,8 @@
 					 u_char *buf)
 {
 	*retlen = 0;
+	if (!mtd->read_user_prot_reg)
+		return -EOPNOTSUPP;
 	return mtd->read_user_prot_reg(mtd, from, len, retlen, buf);
 }