There are GPIO controllers, that cannot be configured to produce
interrupts on both edges. To be able to meaningfully use these for
gpio-keys, add a polling option.
Signed-off-by: Guennadi Liakhovetski <lg@xxxxxxx>
---
I previously tried to solve this problem by reporting a release event
immediately after press, but this proved to be not very useful. This patch
adds a timer to poll for release events on such buttons. I so far set the
polling period to 50ms, don't know how good or bad this is, and whether we
want to have it configurable.
diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index ad67d76..2203fd0 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -29,10 +29,13 @@ struct gpio_button_data {
struct gpio_keys_button *button;
struct input_dev *input;
struct timer_list timer;
+ struct timer_list *release;
+ int state;
};
struct gpio_keys_drvdata {
struct input_dev *input;
+ struct timer_list release;
struct gpio_button_data data[0];
};
@@ -43,10 +46,41 @@ static void gpio_keys_report_event(struct gpio_button_data *bdata)
unsigned int type = button->type ?: EV_KEY;
int state = (gpio_get_value(button->gpio) ? 1 : 0) ^ button->active_low;
- input_event(input, type, button->code, !!state);
+ bdata->state = !!state;
+ input_event(input, type, button->code, bdata->state);
+ /* If the button only supports press events, poll for release */
+ if (state && button->irq_trigger != (IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING))
+ mod_timer(bdata->release, jiffies + msecs_to_jiffies(50));
+
input_sync(input);
}
+static void gpio_poll_button(unsigned long _data)
+{
+ struct platform_device *pdev = (struct platform_device *)_data;
+ struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+ struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
+ int i;
+
+ for (i = 0; i < pdata->nbuttons; i++) {
+ struct gpio_button_data *bdata = &ddata->data[i];
+ struct gpio_keys_button *button = bdata->button;
+
+ if (bdata->state && button->irq_trigger !=
+ (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)) {
+ int state = (gpio_get_value(button->gpio) ? 1 : 0) ^
+ button->active_low;
+
+ if (!state)
+ gpio_keys_report_event(bdata);
+ else
+ mod_timer(bdata->release, jiffies +
+ msecs_to_jiffies(50));
+ }
+ }
+}
+
static void gpio_check_button(unsigned long _data)
{
struct gpio_button_data *data = (struct gpio_button_data *)_data;
@@ -104,6 +138,9 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
ddata->input = input;
+ setup_timer(&ddata->release,
+ gpio_poll_button, (unsigned long)pdev);
+
for (i = 0; i < pdata->nbuttons; i++) {
struct gpio_keys_button *button = &pdata->buttons[i];
struct gpio_button_data *bdata = &ddata->data[i];
@@ -141,9 +178,19 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
goto fail2;
}
+ button->irq_trigger &= IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING;
+
+ if (!button->irq_trigger)
+ button->irq_trigger = IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING;
+
+ if (button->irq_trigger != (IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING))
+ bdata->release = &ddata->release;
+
error = request_irq(irq, gpio_keys_isr,
- IRQF_SAMPLE_RANDOM | IRQF_TRIGGER_RISING |
- IRQF_TRIGGER_FALLING,
+ IRQF_SAMPLE_RANDOM | button->irq_trigger,
button->desc ? button->desc : "gpio_keys",
bdata);
if (error) {
@@ -171,6 +218,7 @@ static int __devinit gpio_keys_probe(struct platform_device *pdev)
return 0;
fail2:
+ del_timer_sync(&ddata->release);
while (--i >= 0) {
free_irq(gpio_to_irq(pdata->buttons[i].gpio), &ddata->data[i]);
if (pdata->buttons[i].debounce_interval)
@@ -195,6 +243,8 @@ static int __devexit gpio_keys_remove(struct platform_device *pdev)
device_init_wakeup(&pdev->dev, 0);
+ del_timer_sync(&ddata->release);
+
for (i = 0; i < pdata->nbuttons; i++) {
int irq = gpio_to_irq(pdata->buttons[i].gpio);
free_irq(irq, &ddata->data[i]);
diff --git a/include/linux/gpio_keys.h b/include/linux/gpio_keys.h
index 1289fa7..d0bd8e2 100644
--- a/include/linux/gpio_keys.h
+++ b/include/linux/gpio_keys.h
@@ -10,6 +10,7 @@ struct gpio_keys_button {
int type; /* input event type (EV_KEY, EV_SW) */
int wakeup; /* configure the button as a wake-up source */
int debounce_interval; /* debounce ticks interval in msecs */
+ unsigned long irq_trigger; /* IRQF_TRIGGER_{RISING,FALLING} */
};
struct gpio_keys_platform_data {
--
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