diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index a9000b0ebe69..e82ed9d5c656 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -90,7 +90,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
 		op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
 
 	if (op->dummy.nbytes)
-		op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
+		op->dummy.buswidth = spi_nor_get_protocol_data_nbits(proto);
 
 	if (op->data.nbytes)
 		op->data.buswidth = spi_nor_get_protocol_data_nbits(proto);