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/* drivers/misc/timed_gpio.c
*
* Copyright (C) 2008 Google, Inc.
* Author: Mike Lockwood <lockwood@android.com>
*
* 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/platform_device.h>
#include <linux/slab.h>
#include <linux/hrtimer.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include "timed_output.h"
#include "timed_gpio.h"
struct timed_gpio_data {
struct timed_output_dev dev;
struct hrtimer timer;
spinlock_t lock;
unsigned gpio;
int max_timeout;
u8 active_low;
};
static enum hrtimer_restart gpio_timer_func(struct hrtimer *timer)
{
struct timed_gpio_data *data =
container_of(timer, struct timed_gpio_data, timer);
gpio_direction_output(data->gpio, data->active_low ? 1 : 0);
return HRTIMER_NORESTART;
}
static int gpio_get_time(struct timed_output_dev *dev)
{
struct timed_gpio_data *data =
container_of(dev, struct timed_gpio_data, dev);
if (hrtimer_active(&data->timer)) {
ktime_t r = hrtimer_get_remaining(&data->timer);
struct timeval t = ktime_to_timeval(r);
return t.tv_sec * 1000 + t.tv_usec / 1000;
} else
return 0;
}
static void gpio_enable(struct timed_output_dev *dev, int value)
{
struct timed_gpio_data *data =
container_of(dev, struct timed_gpio_data, dev);
unsigned long flags;
spin_lock_irqsave(&data->lock, flags);
/* cancel previous timer and set GPIO according to value */
hrtimer_cancel(&data->timer);
gpio_direction_output(data->gpio, data->active_low ? !value : !!value);
if (value > 0) {
if (value > data->max_timeout)
value = data->max_timeout;
hrtimer_start(&data->timer,
ktime_set(value / 1000, (value % 1000) * 1000000),
HRTIMER_MODE_REL);
}
spin_unlock_irqrestore(&data->lock, flags);
}
static int timed_gpio_probe(struct platform_device *pdev)
{
struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
struct timed_gpio *cur_gpio;
struct timed_gpio_data *gpio_data, *gpio_dat;
int i, ret;
if (!pdata)
return -EBUSY;
gpio_data = kzalloc(sizeof(struct timed_gpio_data) * pdata->num_gpios,
GFP_KERNEL);
if (!gpio_data)
return -ENOMEM;
for (i = 0; i < pdata->num_gpios; i++) {
cur_gpio = &pdata->gpios[i];
gpio_dat = &gpio_data[i];
hrtimer_init(&gpio_dat->timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
gpio_dat->timer.function = gpio_timer_func;
spin_lock_init(&gpio_dat->lock);
gpio_dat->dev.name = cur_gpio->name;
gpio_dat->dev.get_time = gpio_get_time;
gpio_dat->dev.enable = gpio_enable;
ret = gpio_request(cur_gpio->gpio, cur_gpio->name);
if (ret < 0)
goto err_out;
ret = timed_output_dev_register(&gpio_dat->dev);
if (ret < 0) {
gpio_free(cur_gpio->gpio);
goto err_out;
}
gpio_dat->gpio = cur_gpio->gpio;
gpio_dat->max_timeout = cur_gpio->max_timeout;
gpio_dat->active_low = cur_gpio->active_low;
gpio_direction_output(gpio_dat->gpio, gpio_dat->active_low);
}
platform_set_drvdata(pdev, gpio_data);
return 0;
err_out:
while (--i >= 0) {
timed_output_dev_unregister(&gpio_data[i].dev);
gpio_free(gpio_data[i].gpio);
}
kfree(gpio_data);
return ret;
}
static int timed_gpio_remove(struct platform_device *pdev)
{
struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
struct timed_gpio_data *gpio_data = platform_get_drvdata(pdev);
int i;
for (i = 0; i < pdata->num_gpios; i++) {
timed_output_dev_unregister(&gpio_data[i].dev);
gpio_free(gpio_data[i].gpio);
}
kfree(gpio_data);
return 0;
}
static struct platform_driver timed_gpio_driver = {
.probe = timed_gpio_probe,
.remove = timed_gpio_remove,
.driver = {
.name = TIMED_GPIO_NAME,
.owner = THIS_MODULE,
},
};
static int __init timed_gpio_init(void)
{
return platform_driver_register(&timed_gpio_driver);
}
static void __exit timed_gpio_exit(void)
{
platform_driver_unregister(&timed_gpio_driver);
}
module_init(timed_gpio_init);
module_exit(timed_gpio_exit);
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_DESCRIPTION("timed gpio driver");
MODULE_LICENSE("GPL");
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