From: Sergey Organov <sorganov@gmail.com>
Date: Fri, 26 Jul 2019 21:52:39 +0300
Subject: serial: imx: set_termios(): do not enable autoRTS if RTS is unset
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Git-commit: a25aee902e666e8cc41e33754f13c69a979dd67f
Patch-mainline: v5.4-rc1
References: jsc#SLE-16106
Don't let receiver hardware automatically control RTS output if it
was requested to be inactive.
To ensure this, set_termios() shouldn't set UCR2_CTSC bit if UCR2_CTS
(=TIOCM_RTS) is cleared. Added corresponding check in imx_uart_rts_auto()
to fix this.
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1564167161-3972-2-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
drivers/tty/serial/imx.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 57d6e6ba556e..32f36d86a960 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -405,7 +405,12 @@ static void imx_uart_rts_inactive(struct imx_port *sport, u32 *ucr2)
/* called with port.lock taken and irqs caller dependent */
static void imx_uart_rts_auto(struct imx_port *sport, u32 *ucr2)
{
- *ucr2 |= UCR2_CTSC;
+ /*
+ * Only let receiver control RTS output if we were not requested to have
+ * RTS inactive (which then should take precedence).
+ */
+ if (*ucr2 & UCR2_CTS)
+ *ucr2 |= UCR2_CTSC;
}
/* called with port.lock taken and irqs off */