linux-kernel - [PATCH 2/2] tty: serial: fsl_lpuart: writing a 1 and then a 0 to trigger a break character

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Message-Id: <20220715025944.11076-3-sherry.sun@nxp.com>
Date:   Fri, 15 Jul 2022 10:59:44 +0800
From:   Sherry Sun <sherry.sun@....com>
To:     gregkh@...uxfoundation.org, jirislaby@...nel.org, michael@...le.cc
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-imx@....com
Subject: [PATCH 2/2] tty: serial: fsl_lpuart: writing a 1 and then a 0 to trigger a break character

According to the lpuart reference manual, need to writing a 1 and then a
0 to the UARTCTRL_SBK field queues a break character in the transmit
data stream. Only writing a 1 cannot trigger the break character, so fix
it.

Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Signed-off-by: Sherry Sun <sherry.sun@....com>
---
 drivers/tty/serial/fsl_lpuart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index b6365566a460..8a4aae7dbd99 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1486,7 +1486,7 @@ static void lpuart32_break_ctl(struct uart_port *port, int break_state)
 	temp = lpuart32_read(port, UARTCTRL) & ~UARTCTRL_SBK;
 
 	if (break_state != 0)
-		temp |= UARTCTRL_SBK;
+		lpuart32_write(port, temp | UARTCTRL_SBK, UARTCTRL);
 
 	lpuart32_write(port, temp, UARTCTRL);
 }
-- 
2.17.1