serial: imx: disable UCR4_OREN on shutdown

UCR4_OREN is (depending on the configuration) enabled in startup,
but is never disabled. Fix this by disabling it in shutdown.

Reported-by: Nandor Han <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
Acked-by: Uwe Kleine-König <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: sre

drivers/tty/serial/imx.c

@@ -1422,7 +1422,7 @@ static void imx_uart_shutdown(struct uart_port *port)
 {
 	struct imx_port *sport = (struct imx_port *)port;
 	unsigned long flags;
-	u32 ucr1, ucr2;
+	u32 ucr1, ucr2, ucr4;
 
 	if (sport->dma_is_enabled) {
 		dmaengine_terminate_sync(sport->dma_chan_tx);
@@ -1452,6 +1452,10 @@ static void imx_uart_shutdown(struct uart_port *port)
 	ucr2 = imx_uart_readl(sport, UCR2);
 	ucr2 &= ~(UCR2_TXEN | UCR2_ATEN);
 	imx_uart_writel(sport, ucr2, UCR2);
+
+	ucr4 = imx_uart_readl(sport, UCR4);
+	ucr4 &= ~UCR4_OREN;
+	imx_uart_writel(sport, ucr4, UCR4);
 	spin_unlock_irqrestore(&sport->port.lock, flags);
 
 	/*