Hi Dmitry,
On Fri, May 02, 2008 at 03:20:48PM +0400, Dmitry Baryshkov wrote:
> Sometimes gpio line can generate jitter while transitioning from one state
> to another one. Implement a way to filter such noise during transitions.
>
I don't think we need to do both count and interval and you don't
really need to track state... What do you think about the patch below?
--
Dmitry
From: Dmitry Baryshkov <dbaryshkov@xxxxxxxxx>
Input: gpio-keys debouncing support
Signed-off-by: Dmitry Baryshkov <dbaryshkov@xxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
---
drivers/input/keyboard/gpio_keys.c | 88 ++++++++++++++++++++++++++++---------
include/linux/gpio_keys.h | 1
2 files changed, 69 insertions(+), 20 deletions(-)
Index: linux/drivers/input/keyboard/gpio_keys.c
===================================================================
--- linux.orig/drivers/input/keyboard/gpio_keys.c
+++ linux/drivers/input/keyboard/gpio_keys.c
@@ -26,23 +26,54 @@
#include <asm/gpio.h>
+struct gpio_button_data {
+ struct gpio_keys_button *button;
+ struct input_dev *input;
+ struct timer_list timer;
+};
+
+struct gpio_keys_drvdata {
+ struct input_dev *input;
+ struct gpio_button_data data[0];
+};
+
+static void gpio_keys_report_event(struct gpio_keys_button *button,
+ struct input_dev *input)
+{
+ 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);
+ input_sync(input);
+}
+
+static void gpio_check_button(unsigned long _data)
+{
+ struct gpio_button_data *data = (struct gpio_button_data *)_data;
+
+ gpio_keys_report_event(data->button, data->input);
+}
+
static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
{
- int i;
struct platform_device *pdev = dev_id;
struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
- struct input_dev *input = platform_get_drvdata(pdev);
+ struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
+ int i;
for (i = 0; i < pdata->nbuttons; i++) {
struct gpio_keys_button *button = &pdata->buttons[i];
- int gpio = button->gpio;
- if (irq == gpio_to_irq(gpio)) {
- unsigned int type = button->type ?: EV_KEY;
- int state = (gpio_get_value(gpio) ? 1 : 0) ^ button->active_low;
+ if (irq == gpio_to_irq(button->gpio)) {
+ struct gpio_button_data *bdata = &ddata->data[i];
+
+ if (button->debounce_interval)
+ mod_timer(&bdata->timer,
+ jiffies +
+ msecs_to_jiffies(button->debounce_interval));
+ else
+ gpio_keys_report_event(button, bdata->input);
- input_event(input, type, button->code, !!state);
- input_sync(input);
return IRQ_HANDLED;
}
}
@@ -53,17 +84,20 @@ static irqreturn_t gpio_keys_isr(int irq
static int __devinit gpio_keys_probe(struct platform_device *pdev)
{
struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+ struct gpio_keys_drvdata *ddata;
struct input_dev *input;
int i, error;
int wakeup = 0;
+ ddata = kcalloc(pdata->nbuttons, sizeof(struct gpio_keys_drvdata),
+ GFP_KERNEL);
input = input_allocate_device();
- if (!input)
- return -ENOMEM;
-
- platform_set_drvdata(pdev, input);
+ if (!ddata || !input) {
+ error = -ENOMEM;
+ goto fail1;
+ }
- input->evbit[0] = BIT_MASK(EV_KEY);
+ platform_set_drvdata(pdev, ddata);
input->name = pdev->name;
input->phys = "gpio-keys/input0";
@@ -74,16 +108,23 @@ static int __devinit gpio_keys_probe(str
input->id.product = 0x0001;
input->id.version = 0x0100;
+ ddata->input = input;
+
for (i = 0; i < pdata->nbuttons; i++) {
struct gpio_keys_button *button = &pdata->buttons[i];
+ struct gpio_button_data *bdata = &ddata->data[i];
int irq;
unsigned int type = button->type ?: EV_KEY;
+ bdata->input = input;
+ setup_timer(&bdata->timer,
+ gpio_check_button, (unsigned long)bdata);
+
error = gpio_request(button->gpio, button->desc ?: "gpio_keys");
if (error < 0) {
pr_err("gpio-keys: failed to request GPIO %d,"
" error %d\n", button->gpio, error);
- goto fail;
+ goto fail2;
}
error = gpio_direction_input(button->gpio);
@@ -92,7 +133,7 @@ static int __devinit gpio_keys_probe(str
" direction for GPIO %d, error %d\n",
button->gpio, error);
gpio_free(button->gpio);
- goto fail;
+ goto fail2;
}
irq = gpio_to_irq(button->gpio);
@@ -102,7 +143,7 @@ static int __devinit gpio_keys_probe(str
" for GPIO %d, error %d\n",
button->gpio, error);
gpio_free(button->gpio);
- goto fail;
+ goto fail2;
}
error = request_irq(irq, gpio_keys_isr,
@@ -114,7 +155,7 @@ static int __devinit gpio_keys_probe(str
pr_err("gpio-keys: Unable to claim irq %d; error %d\n",
irq, error);
gpio_free(button->gpio);
- goto fail;
+ goto fail2;
}
if (button->wakeup)
@@ -127,21 +168,25 @@ static int __devinit gpio_keys_probe(str
if (error) {
pr_err("gpio-keys: Unable to register input device, "
"error: %d\n", error);
- goto fail;
+ goto fail2;
}
device_init_wakeup(&pdev->dev, wakeup);
return 0;
- fail:
+ fail2:
while (--i >= 0) {
free_irq(gpio_to_irq(pdata->buttons[i].gpio), pdev);
+ if (pdata->buttons[i].debounce_interval)
+ del_timer_sync(&ddata->data[i].timer);
gpio_free(pdata->buttons[i].gpio);
}
platform_set_drvdata(pdev, NULL);
+ fail1:
input_free_device(input);
+ kfree(ddata);
return error;
}
@@ -149,7 +194,8 @@ static int __devinit gpio_keys_probe(str
static int __devexit gpio_keys_remove(struct platform_device *pdev)
{
struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
- struct input_dev *input = platform_get_drvdata(pdev);
+ struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
+ struct input_dev *input = ddata->input;
int i;
device_init_wakeup(&pdev->dev, 0);
@@ -157,6 +203,8 @@ static int __devexit gpio_keys_remove(st
for (i = 0; i < pdata->nbuttons; i++) {
int irq = gpio_to_irq(pdata->buttons[i].gpio);
free_irq(irq, pdev);
+ if (pdata->buttons[i].debounce_interval)
+ del_timer_sync(&ddata->data[i].timer);
gpio_free(pdata->buttons[i].gpio);
}
Index: linux/include/linux/gpio_keys.h
===================================================================
--- linux.orig/include/linux/gpio_keys.h
+++ linux/include/linux/gpio_keys.h
@@ -9,6 +9,7 @@ struct gpio_keys_button {
char *desc;
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 */
};
struct gpio_keys_platform_data {
--
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