serial: imx: introduce serial_imx_enable_wakeup()

This change is a code reorganization. Here we introduce
serial_imx_enable_wakeup() helper function to do
the job of configuring and preparing wakeup sources
on imx serial device. The idea is to allow other
parts of the code to call this function whenever
the device is known to go to idle.

Cc: Fabio Estevam <festevam@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm/boot/dts/Makefile

@@ -326,6 +326,7 @@ dtb-$(CONFIG_SOC_IMX6Q) += \
 	imx6q-wandboard-revb1.dtb
 dtb-$(CONFIG_SOC_IMX6SL) += \
 	imx6sl-evk.dtb \
+	imx6sl-fox-p1.dtb \
 	imx6sl-warp.dtb
 dtb-$(CONFIG_SOC_IMX6SX) += \
 	imx6sx-sabreauto.dtb \

drivers/tty/serial/imx.c

@@ -1972,6 +1972,18 @@ static int serial_imx_remove(struct platform_device *pdev)
 	return uart_remove_one_port(&imx_reg, &sport->port);
 }
 
+static void serial_imx_enable_wakeup(struct imx_port *sport, bool on)
+{
+	unsigned int val;
+
+	val = readl(sport->port.membase + UCR3);
+	if (on)
+		val |= UCR3_AWAKEN;
+	else
+		val &= ~UCR3_AWAKEN;
+	writel(val, sport->port.membase + UCR3);
+}
+
 static int imx_serial_port_suspend_noirq(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
@@ -2029,12 +2041,9 @@ static int imx_serial_port_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct imx_port *sport = platform_get_drvdata(pdev);
-	unsigned int val;
 
 	/* enable wakeup from i.MX UART */
-	val = readl(sport->port.membase + UCR3);
-	val |= UCR3_AWAKEN;
-	writel(val, sport->port.membase + UCR3);
+	serial_imx_enable_wakeup(sport, true);
 
 	uart_suspend_port(&imx_reg, &sport->port);
 
@@ -2045,12 +2054,9 @@ static int imx_serial_port_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct imx_port *sport = platform_get_drvdata(pdev);
-	unsigned int val;
 
 	/* disable wakeup from i.MX UART */
-	val = readl(sport->port.membase + UCR3);
-	val &= ~UCR3_AWAKEN;
-	writel(val, sport->port.membase + UCR3);
+	serial_imx_enable_wakeup(sport, false);
 
 	uart_resume_port(&imx_reg, &sport->port);