From 38b1f0fb42f772b8c9aac53593883a18ff5eb9d7 Mon Sep 17 00:00:00 2001
From: Fabio Estevam <fabio.estevam@nxp.com>
Date: Thu, 4 Jan 2018 15:58:34 -0200
Subject: [PATCH] serial: imx: Only wakeup via RTSDEN bit if the system has RTS/CTS
Git-commit: 38b1f0fb42f772b8c9aac53593883a18ff5eb9d7
Patch-mainline: v4.16-rc1
References: bsc#1051510

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.estevam@nxp.com>
Reviewed-by: Martin Kaiser <martin@kaiser.cx>
Acked-by: Fugang Duan <fugang.duan@nxp.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 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
@@ -2282,12 +2282,14 @@ 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)