This is a note to let you know that I've just added the patch titled

serial: imx: Update cached mctrl value when changing RTS

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: serial-imx-update-cached-mctrl-value-when-changing-rts.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Wed Dec 6 18:04:41 CET 2017

From: Ian Jamison ian.dev@arkver.com Date: Thu, 21 Sep 2017 10:13:12 +0200 Subject: serial: imx: Update cached mctrl value when changing RTS

From: Ian Jamison ian.dev@arkver.com

[ Upstream commit a0983c742a5885f82afb282166f83f1d3d8addf4 ]

UART core function uart_update_mctrl relies on a cached value of modem control lines. This was used but not updated by local RTS control functions within imx.c. These are used for RS485 line driver enable signalling. Having an out-of-date value in the cached mctrl can result in the transmitter being enabled when it shouldn't be.

Fix this by updating the mctrl value before applying it.

Signed-off-by: Ian Jamison ian.dev@arkver.com Origin: id:8195c96e674517b82a6ff7fe914c7ba0f86e702b.1505375165.git.ian.dev@arkver.com Acked-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Tested-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Tested-by: Clemens Gruber clemens.gruber@pqgruber.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/imx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -334,7 +334,8 @@ static void imx_port_rts_active(struct i { *ucr2 &= ~(UCR2_CTSC | UCR2_CTS);

- mctrl_gpio_set(sport->gpios, sport->port.mctrl | TIOCM_RTS); + sport->port.mctrl |= TIOCM_RTS; + mctrl_gpio_set(sport->gpios, sport->port.mctrl); }

static void imx_port_rts_inactive(struct imx_port *sport, unsigned long *ucr2) @@ -342,7 +343,8 @@ static void imx_port_rts_inactive(struct *ucr2 &= ~UCR2_CTSC; *ucr2 |= UCR2_CTS;

- mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS); + sport->port.mctrl &= ~TIOCM_RTS; + mctrl_gpio_set(sport->gpios, sport->port.mctrl); }

static void imx_port_rts_auto(struct imx_port *sport, unsigned long *ucr2)

Patches currently in stable-queue which might be from ian.dev@arkver.com are

queue-4.14/serial-imx-update-cached-mctrl-value-when-changing-rts.patch