keys: notify system preparing to force reset if resetkey is defined

On flo/deb hardware platform, the power key button is able to reset
whole system forcely via predefined timer at PMIC side. Add notifying
call chains to let registered drivers have a chance to prepare data
backup before power is cut off by PMIC firmware.

Change-Id: I25fe00020950f0d4208caffda172f46396082a4d
Signed-off-by: paris_yeh <paris_yeh@asus.com>

drivers/input/keyboard/gpio_keys.c

@@ -40,6 +40,9 @@ struct gpio_button_data {
 	spinlock_t lock;
 	bool disabled;
 	bool key_pressed;
+	struct work_struct reset_work;
+	struct timer_list reset_timer;
+	unsigned int timer_hwreset;	/* in msecs */
 };
 
 struct gpio_keys_drvdata {
@@ -332,6 +335,28 @@ static char *key_descriptions[] = {
 };
 #endif
 
+/* Routines for resetkey-transition notifications */
+static BLOCKING_NOTIFIER_HEAD(resetkey_chain_head);
+
+int register_resetkey_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&resetkey_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(register_resetkey_notifier);
+
+int unregister_resetkey_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&resetkey_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_resetkey_notifier);
+
+int resetkey_notifier_call_chain(unsigned long val)
+{
+	int ret = blocking_notifier_call_chain(&resetkey_chain_head, val, NULL);
+
+	return notifier_to_errno(ret);
+}
+
 static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
 {
 	const struct gpio_keys_button *button = bdata->button;
@@ -363,6 +388,13 @@ static void gpio_keys_gpio_work_func(struct work_struct *work)
 		pr_info("gpio_keys: %s %s\n", state ? "Pressed" : "Released",
 			key_descriptions[button->code - KEY_VOLUMEDOWN]);
 #endif
+	if (button->can_reset) {
+		if (state)
+			mod_timer(&bdata->reset_timer,
+				jiffies + msecs_to_jiffies(bdata->timer_hwreset));
+		else
+			del_timer_sync(&bdata->reset_timer);
+	}
 	gpio_keys_gpio_report_event(bdata);
 }
 
@@ -373,6 +405,19 @@ static void gpio_keys_gpio_timer(unsigned long _data)
 	schedule_work(&bdata->work);
 }
 
+static void reset_keys_work_func(struct work_struct *work)
+{
+	pr_info("gpio_keys: notify listeners pmic preparing to reset\n");
+	resetkey_notifier_call_chain(RESETKEY_PREPARE_HWREST);
+}
+
+static void powerkey_gpio_timer(unsigned long _data)
+{
+	struct gpio_button_data *bdata = (struct gpio_button_data *)_data;
+
+	schedule_work(&bdata->reset_work);
+}
+
 static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
 {
 	struct gpio_button_data *bdata = dev_id;
@@ -493,6 +538,13 @@ static int __devinit gpio_keys_setup_key(struct platform_device *pdev,
 		isr = gpio_keys_gpio_isr;
 		irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
 
+		if (button->can_reset) {
+			INIT_WORK(&bdata->reset_work, reset_keys_work_func);
+			bdata->timer_hwreset = button->reset_interval;
+			setup_timer(&bdata->reset_timer, powerkey_gpio_timer,
+					(unsigned long)bdata);
+		}
+
 	} else {
 		if (!button->irq) {
 			dev_err(dev, "No IRQ specified\n");

include/linux/gpio_keys.h

@@ -15,6 +15,8 @@ struct gpio_keys_button {
 	bool can_disable;
 	int value;		/* axis value for EV_ABS */
 	unsigned int irq;	/* Irq number in case of interrupt keys */
+	bool can_reset;		/* key is able to reset system */
+	int reset_interval;	/* reset key interval in msec */
 };
 
 struct gpio_keys_platform_data {
@@ -28,4 +30,12 @@ struct gpio_keys_platform_data {
 	const char *name;		/* input device name */
 };
 
+
+#define RESETKEY_PRESS			0x0001 /* power key is pressed */
+#define RESETKEY_RELEASE		0x0002 /* power key is released */
+#define RESETKEY_PREPARE_HWREST		0x0003 /* Going to reset whole system by pmic*/
+
+extern int register_resetkey_notifier(struct notifier_block *nb);
+extern int unregister_resetkey_notifier(struct notifier_block *nb);
+
 #endif