4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Fabio Estevam <fabio.este...@nxp.com>

commit 38b1f0fb42f772b8c9aac53593883a18ff5eb9d7 upstream.

The wakeup mechanism via RTSDEN bit relies on the system using the RTS/CTS
lines, so only allow such wakeup method when the system actually has
RTS/CTS support.

Fixes: bc85734b126f ("serial: imx: allow waking up on RTSD")
Signed-off-by: Fabio Estevam <fabio.este...@nxp.com>
Reviewed-by: Martin Kaiser <mar...@kaiser.cx>
Acked-by: Fugang Duan <fugang.d...@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/tty/serial/imx.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2275,12 +2275,14 @@ static void serial_imx_enable_wakeup(str
                val &= ~UCR3_AWAKEN;
        writel(val, sport->port.membase + UCR3);
 
-       val = readl(sport->port.membase + UCR1);
-       if (on)
-               val |= UCR1_RTSDEN;
-       else
-               val &= ~UCR1_RTSDEN;
-       writel(val, sport->port.membase + UCR1);
+       if (sport->have_rtscts) {
+               val = readl(sport->port.membase + UCR1);
+               if (on)
+                       val |= UCR1_RTSDEN;
+               else
+                       val &= ~UCR1_RTSDEN;
+               writel(val, sport->port.membase + UCR1);
+       }
 }
 
 static int imx_serial_port_suspend_noirq(struct device *dev)


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