From: Sherry Sun <sherry.sun@nxp.com>
Date: Fri, 25 Nov 2022 18:19:53 +0800
Subject: [PATCH] tty: serial: fsl_lpuart: clear LPUART Status Register in
 lpuart32_shutdown()
References: bsc#1012628
Patch-mainline: 6.2.3
Git-commit: 4029dfc034febb54f6dd8ea83568accc943bc088

[ Upstream commit 4029dfc034febb54f6dd8ea83568accc943bc088 ]

The LPUART Status Register needs to be cleared when closing the uart
port to get a clean environment when reopening the uart.

Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221125101953.18753-4-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/serial/fsl_lpuart.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 5d1c28e0..986ec832 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1796,6 +1796,10 @@ static void lpuart32_shutdown(struct uart_port *port)
 
 	spin_lock_irqsave(&port->lock, flags);
 
+	/* clear status */
+	temp = lpuart32_read(&sport->port, UARTSTAT);
+	lpuart32_write(&sport->port, temp, UARTSTAT);
+
 	/* disable Rx/Tx DMA */
 	temp = lpuart32_read(port, UARTBAUD);
 	temp &= ~(UARTBAUD_TDMAE | UARTBAUD_RDMAE);
-- 
2.35.3