diff --git a/drivers/mtd/nand/raw/fsl_upm.c b/drivers/mtd/nand/raw/fsl_upm.c
index 0864261..7366e85 100644
--- a/drivers/mtd/nand/raw/fsl_upm.c
+++ b/drivers/mtd/nand/raw/fsl_upm.c
@@ -135,7 +135,7 @@ static int fun_exec_op(struct nand_chip *chip, const struct nand_operation *op,
 	unsigned int i;
 	int ret;
 
-	if (op->cs > NAND_MAX_CHIPS)
+	if (op->cs >= NAND_MAX_CHIPS)
 		return -EINVAL;
 
 	if (check_only)