[PATCH v7 1/3] serial: imx: set_termios(): do not enable autoRTS if RTS is unset

[Sergey Organov <sorganov@gmail.com>]

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>
---
 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 57d6e6b..32f36d8 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 */
-- 
2.10.0.1.g57b01a3


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