diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index eb5d7b3d1860..aad7076ae020 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -2155,7 +2155,8 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
 	spi_nor_spimem_setup_op(nor, &op, read->proto);
 
 	/* convert the dummy cycles to the number of bytes */
-	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
+	op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) *
+			  op.dummy.buswidth / 8;
 	if (spi_nor_protocol_is_dtr(nor->read_proto))
 		op.dummy.nbytes *= 2;