linux/drivers/extcon/extcon-gpio.c
Mark Brown d0db2e7ae7 extcon: gpio: Use power efficient workqueue for debounce
The debounce timeout is generally quite long and the work not performance
critical so allow the scheduler to run the work anywhere rather than in
the normal per-CPU workqueue.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
2013-08-05 08:53:34 +09:00

165 lines
4.2 KiB
C

/*
* drivers/extcon/extcon_gpio.c
*
* Single-state GPIO extcon driver based on extcon class
*
* Copyright (C) 2008 Google, Inc.
* Author: Mike Lockwood <lockwood@android.com>
*
* Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
* (originally switch class is supported)
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/gpio.h>
#include <linux/extcon.h>
#include <linux/extcon/extcon-gpio.h>
struct gpio_extcon_data {
struct extcon_dev edev;
unsigned gpio;
const char *state_on;
const char *state_off;
int irq;
struct delayed_work work;
unsigned long debounce_jiffies;
};
static void gpio_extcon_work(struct work_struct *work)
{
int state;
struct gpio_extcon_data *data =
container_of(to_delayed_work(work), struct gpio_extcon_data,
work);
state = gpio_get_value(data->gpio);
extcon_set_state(&data->edev, state);
}
static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
{
struct gpio_extcon_data *extcon_data = dev_id;
queue_delayed_work(system_power_efficient_wq, &extcon_data->work,
extcon_data->debounce_jiffies);
return IRQ_HANDLED;
}
static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf)
{
struct gpio_extcon_data *extcon_data =
container_of(edev, struct gpio_extcon_data, edev);
const char *state;
if (extcon_get_state(edev))
state = extcon_data->state_on;
else
state = extcon_data->state_off;
if (state)
return sprintf(buf, "%s\n", state);
return -EINVAL;
}
static int gpio_extcon_probe(struct platform_device *pdev)
{
struct gpio_extcon_platform_data *pdata = pdev->dev.platform_data;
struct gpio_extcon_data *extcon_data;
int ret = 0;
if (!pdata)
return -EBUSY;
if (!pdata->irq_flags) {
dev_err(&pdev->dev, "IRQ flag is not specified.\n");
return -EINVAL;
}
extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
GFP_KERNEL);
if (!extcon_data)
return -ENOMEM;
extcon_data->edev.name = pdata->name;
extcon_data->gpio = pdata->gpio;
extcon_data->state_on = pdata->state_on;
extcon_data->state_off = pdata->state_off;
if (pdata->state_on && pdata->state_off)
extcon_data->edev.print_state = extcon_gpio_print_state;
extcon_data->debounce_jiffies = msecs_to_jiffies(pdata->debounce);
ret = extcon_dev_register(&extcon_data->edev, &pdev->dev);
if (ret < 0)
return ret;
ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
pdev->name);
if (ret < 0)
goto err;
INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
extcon_data->irq = gpio_to_irq(extcon_data->gpio);
if (extcon_data->irq < 0) {
ret = extcon_data->irq;
goto err;
}
ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler,
pdata->irq_flags, pdev->name,
extcon_data);
if (ret < 0)
goto err;
platform_set_drvdata(pdev, extcon_data);
/* Perform initial detection */
gpio_extcon_work(&extcon_data->work.work);
return 0;
err:
extcon_dev_unregister(&extcon_data->edev);
return ret;
}
static int gpio_extcon_remove(struct platform_device *pdev)
{
struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev);
cancel_delayed_work_sync(&extcon_data->work);
free_irq(extcon_data->irq, extcon_data);
extcon_dev_unregister(&extcon_data->edev);
return 0;
}
static struct platform_driver gpio_extcon_driver = {
.probe = gpio_extcon_probe,
.remove = gpio_extcon_remove,
.driver = {
.name = "extcon-gpio",
.owner = THIS_MODULE,
},
};
module_platform_driver(gpio_extcon_driver);
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_DESCRIPTION("GPIO extcon driver");
MODULE_LICENSE("GPL");