kernel-rk3328-gpio-poweroff.patch

diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
index 1c5af2fef..09ba6f8c6 100644
--- a/drivers/power/reset/gpio-poweroff.c
+++ b/drivers/power/reset/gpio-poweroff.c
@@ -24,6 +24,7 @@ static struct gpio_desc *reset_gpio;
 static u32 timeout = DEFAULT_TIMEOUT_MS;
 static u32 active_delay = 100;
 static u32 inactive_delay = 100;
+static void (*old_power_off)(void);
 
 static void gpio_poweroff_do_poweroff(void)
 {
@@ -43,6 +44,9 @@ static void gpio_poweroff_do_poweroff(void)
 	/* give it some time */
 	mdelay(timeout);
 
+	if (old_power_off)
+		old_power_off();
+
 	WARN_ON(1);
 }
 
@@ -50,14 +54,29 @@ static int gpio_poweroff_probe(struct platform_device *pdev)
 {
 	bool input = false;
 	enum gpiod_flags flags;
+	bool force = false;
+	bool export = false;
 
 	/* If a pm_power_off function has already been added, leave it alone */
-	if (pm_power_off != NULL) {
+	force = of_property_read_bool(pdev->dev.of_node, "force");
+	if (!force && (pm_power_off != NULL)) {
 		dev_err(&pdev->dev,
 			"%s: pm_power_off function already registered\n",
 		       __func__);
 		return -EBUSY;
 	}
+	if (pm_power_off != NULL) {
+		if (force) {
+			dev_err(&pdev->dev,
+				 "%s: pm_power_off function replaced",
+				 __func__);
+		} else {
+			dev_err(&pdev->dev,
+				"%s: pm_power_off function already registered",
+				__func__);
+			return -EBUSY;
+		}
+	}
 
 	input = device_property_read_bool(&pdev->dev, "input");
 	if (input)
@@ -74,6 +93,13 @@ static int gpio_poweroff_probe(struct platform_device *pdev)
 	if (IS_ERR(reset_gpio))
 		return PTR_ERR(reset_gpio);
 
+	export = of_property_read_bool(pdev->dev.of_node, "export");
+	if (export) {
+		gpiod_export(reset_gpio, false);
+		gpiod_export_link(&pdev->dev, "poweroff-gpio", reset_gpio);
+	}
+
+	old_power_off = pm_power_off;
 	pm_power_off = &gpio_poweroff_do_poweroff;
 	return 0;
 }
@@ -81,7 +107,9 @@ static int gpio_poweroff_probe(struct platform_device *pdev)
 static int gpio_poweroff_remove(struct platform_device *pdev)
 {
 	if (pm_power_off == &gpio_poweroff_do_poweroff)
-		pm_power_off = NULL;
+		pm_power_off = old_power_off;
+
+	gpiod_unexport(reset_gpio);
 
 	return 0;
 }