diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index cc83b772b7ca..7b868ea48ad5 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -967,7 +967,7 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv)
 			__func__);
 		return 0;
 	}
-	dma_sync_sg_for_device(port->dev, priv->sg_tx_p, nent, DMA_TO_DEVICE);
+	dma_sync_sg_for_device(port->dev, priv->sg_tx_p, num, DMA_TO_DEVICE);
 	priv->desc_tx = desc;
 	desc->callback = pch_dma_tx_complete;
 	desc->callback_param = priv;