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/*
* drivers/switch/switch_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/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/switch.h>
#include <linux/workqueue.h>
#include <linux/gpio.h>
struct gpio_switch_data {
struct switch_dev sdev;
unsigned gpio;
const char *name_on;
const char *name_off;
const char *state_on;
const char *state_off;
int irq;
struct work_struct work;
};
static void gpio_switch_work(struct work_struct *work)
{
int state;
struct gpio_switch_data *data =
container_of(work, struct gpio_switch_data, work);
state = gpio_get_value(data->gpio);
switch_set_state(&data->sdev, state);
}
static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
{
struct gpio_switch_data *switch_data =
(struct gpio_switch_data *)dev_id;
schedule_work(&switch_data->work);
return IRQ_HANDLED;
}
static ssize_t switch_gpio_print_state(struct switch_dev *sdev, char *buf)
{
struct gpio_switch_data *switch_data =
container_of(sdev, struct gpio_switch_data, sdev);
const char *state;
if (switch_get_state(sdev))
state = switch_data->state_on;
else
state = switch_data->state_off;
if (state)
return sprintf(buf, "%s\n", state);
return -1;
}
static int gpio_switch_probe(struct platform_device *pdev)
{
struct gpio_switch_platform_data *pdata = pdev->dev.platform_data;
struct gpio_switch_data *switch_data;
int ret = 0;
if (!pdata)
return -EBUSY;
switch_data = kzalloc(sizeof(struct gpio_switch_data), GFP_KERNEL);
if (!switch_data)
return -ENOMEM;
switch_data->sdev.name = pdata->name;
switch_data->gpio = pdata->gpio;
switch_data->name_on = pdata->name_on;
switch_data->name_off = pdata->name_off;
switch_data->state_on = pdata->state_on;
switch_data->state_off = pdata->state_off;
switch_data->sdev.print_state = switch_gpio_print_state;
ret = switch_dev_register(&switch_data->sdev);
if (ret < 0)
goto err_switch_dev_register;
ret = gpio_request(switch_data->gpio, pdev->name);
if (ret < 0)
goto err_request_gpio;
ret = gpio_direction_input(switch_data->gpio);
if (ret < 0)
goto err_set_gpio_input;
INIT_WORK(&switch_data->work, gpio_switch_work);
switch_data->irq = gpio_to_irq(switch_data->gpio);
if (switch_data->irq < 0) {
ret = switch_data->irq;
goto err_detect_irq_num_failed;
}
ret = request_irq(switch_data->irq, gpio_irq_handler,
IRQF_TRIGGER_LOW, pdev->name, switch_data);
if (ret < 0)
goto err_request_irq;
/* Perform initial detection */
gpio_switch_work(&switch_data->work);
return 0;
err_request_irq:
err_detect_irq_num_failed:
err_set_gpio_input:
gpio_free(switch_data->gpio);
err_request_gpio:
switch_dev_unregister(&switch_data->sdev);
err_switch_dev_register:
kfree(switch_data);
return ret;
}
static int gpio_switch_remove(struct platform_device *pdev)
{
struct gpio_switch_data *switch_data = platform_get_drvdata(pdev);
cancel_work_sync(&switch_data->work);
gpio_free(switch_data->gpio);
switch_dev_unregister(&switch_data->sdev);
kfree(switch_data);
return 0;
}
static struct platform_driver gpio_switch_driver = {
.probe = gpio_switch_probe,
.remove = gpio_switch_remove,
.driver = {
.name = "switch-gpio",
.owner = THIS_MODULE,
},
};
static int __init gpio_switch_init(void)
{
return platform_driver_register(&gpio_switch_driver);
}
static void __exit gpio_switch_exit(void)
{
platform_driver_unregister(&gpio_switch_driver);
}
module_init(gpio_switch_init);
module_exit(gpio_switch_exit);
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_DESCRIPTION("GPIO Switch driver");
MODULE_LICENSE("GPL");
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