From 02b823a4d28ffb5fde5192799abd934d9de95630 Mon Sep 17 00:00:00 2001

From: Hans de Goede <hdegoede@redhat.com>

Date: Fri, 6 Jan 2017 20:08:11 +0100

Subject: [PATCH 12/16] Input: gpio_keys - Do not report wake button presses as

 evdev events

If a button is a wake button, it may still be bouncing from the press

to wakeup the device by the time the gpio interrupts get enabled again

and / or the gpio_keys_report_state call from gpio_keys_resume may

find the button still pressed and report this as a new press.

This is undesirable, esp. since the powerbutton on tablets is typically

a wakeup source and uses the gpio_keys driver on some tablets, leading

to userspace immediately re-suspending the tablet after the powerbutton

is pressed, due to it seeing a powerbutton press.

This commit ignores wakeup button presses for the first 1 second after

resume (and while resumed, as the workqueue may run before the resume

function runs), avoiding this problem.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

---

Note: maybe we should make WAKE_DEBOUNCE part of gpio_keys_button and

only do this when drivers / platform-data set this to a non-zero value ?

---

 drivers/input/keyboard/gpio_keys.c | 49 ++++++++++++++++++++++++++++++++++++--

 1 file changed, 47 insertions(+), 2 deletions(-)

diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c

index da3d362f21b1..e1488b534e7d 100644

--- a/drivers/input/keyboard/gpio_keys.c

+++ b/drivers/input/keyboard/gpio_keys.c

@@ -31,6 +31,8 @@

 #include <linux/of_irq.h>

 #include <linux/spinlock.h>

+#define WAKE_DEBOUNCE msecs_to_jiffies(1000)

+

 struct gpio_button_data {

 	const struct gpio_keys_button *button;

 	struct input_dev *input;

@@ -44,10 +46,14 @@ struct gpio_button_data {

 	struct delayed_work work;

 	unsigned int software_debounce;	/* in msecs, for GPIO-driven buttons */

+	unsigned long resume_time;	/* in jiffies, for wakeup buttons */

+

 	unsigned int irq;

 	spinlock_t lock;

 	bool disabled;

 	bool key_pressed;

+	bool suspended;

+	bool resume_time_valid;

 };

 struct gpio_keys_drvdata {

@@ -356,6 +362,27 @@ static struct attribute_group gpio_keys_attr_group = {

 	.attrs = gpio_keys_attrs,

 };

+static bool gpio_keys_ignore_wakeup_button_press(struct gpio_button_data *bdata)

+{

+	unsigned long flags;

+	bool ret = false;

+

+	if (!bdata->button->wakeup)

+		return ret;

+

+	spin_lock_irqsave(&bdata->lock, flags);

+

+	if (bdata->suspended)

+		ret = true; /* Our resume method did not run yet */

+	else if (bdata->resume_time_valid &&

+		 time_before(jiffies, bdata->resume_time + WAKE_DEBOUNCE))

+		ret = true; /* Assume this is a wakeup press and ignore */

+

+	spin_unlock_irqrestore(&bdata->lock, flags);

+

+	return ret;

+}

+

 static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)

 {

 	const struct gpio_keys_button *button = bdata->button;

@@ -370,6 +397,9 @@ static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)

 		return;

 	}

+	if (state && gpio_keys_ignore_wakeup_button_press(bdata))

+		return;

+

 	if (type == EV_ABS) {

 		if (state)

 			input_event(input, type, button->code, button->value);

@@ -429,6 +459,9 @@ static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)

 	BUG_ON(irq != bdata->irq);

+	if (gpio_keys_ignore_wakeup_button_press(bdata))

+		return IRQ_HANDLED;

+

 	spin_lock_irqsave(&bdata->lock, flags);

 	if (!bdata->key_pressed) {

@@ -848,13 +881,18 @@ static int __maybe_unused gpio_keys_suspend(struct device *dev)

 {

 	struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);

 	struct input_dev *input = ddata->input;

+	unsigned long flags;

 	int i;

 	if (device_may_wakeup(dev)) {

 		for (i = 0; i < ddata->pdata->nbuttons; i++) {

 			struct gpio_button_data *bdata = &ddata->data[i];

-			if (bdata->button->wakeup)

+			if (bdata->button->wakeup) {

+				spin_lock_irqsave(&bdata->lock, flags);

+				bdata->suspended = true;

+				spin_unlock_irqrestore(&bdata->lock, flags);

 				enable_irq_wake(bdata->irq);

+			}

 		}

 	} else {

 		mutex_lock(&input->mutex);

@@ -870,14 +908,21 @@ static int __maybe_unused gpio_keys_resume(struct device *dev)

 {

 	struct gpio_keys_drvdata *ddata = dev_get_drvdata(dev);

 	struct input_dev *input = ddata->input;

+	unsigned long flags;

 	int error = 0;

 	int i;

 	if (device_may_wakeup(dev)) {

 		for (i = 0; i < ddata->pdata->nbuttons; i++) {

 			struct gpio_button_data *bdata = &ddata->data[i];

-			if (bdata->button->wakeup)

+			if (bdata->button->wakeup) {

 				disable_irq_wake(bdata->irq);

+				spin_lock_irqsave(&bdata->lock, flags);

+				bdata->resume_time = jiffies;

+				bdata->resume_time_valid = true;

+				bdata->suspended = false;

+				spin_unlock_irqrestore(&bdata->lock, flags);

+			}

 		}

 	} else {

 		mutex_lock(&input->mutex);

-- 

2.13.0