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/* drivers/misc/timed_output.c
*
* Copyright (C) 2009 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/types.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/err.h>
#include "timed_output.h"
static struct class *timed_output_class;
static atomic_t device_count;
static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct timed_output_dev *tdev = dev_get_drvdata(dev);
int remaining = tdev->get_time(tdev);
return sprintf(buf, "%d\n", remaining);
}
static ssize_t enable_store(
struct device *dev, struct device_attribute *attr,
const char *buf, size_t size)
{
struct timed_output_dev *tdev = dev_get_drvdata(dev);
int value;
if (sscanf(buf, "%d", &value) != 1)
return -EINVAL;
tdev->enable(tdev, value);
return size;
}
static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, enable_show, enable_store);
static int create_timed_output_class(void)
{
if (!timed_output_class) {
timed_output_class = class_create(THIS_MODULE, "timed_output");
if (IS_ERR(timed_output_class))
return PTR_ERR(timed_output_class);
atomic_set(&device_count, 0);
}
return 0;
}
int timed_output_dev_register(struct timed_output_dev *tdev)
{
int ret;
if (!tdev || !tdev->name || !tdev->enable || !tdev->get_time)
return -EINVAL;
ret = create_timed_output_class();
if (ret < 0)
return ret;
tdev->index = atomic_inc_return(&device_count);
tdev->dev = device_create(timed_output_class, NULL,
MKDEV(0, tdev->index), NULL, tdev->name);
if (IS_ERR(tdev->dev))
return PTR_ERR(tdev->dev);
ret = device_create_file(tdev->dev, &dev_attr_enable);
if (ret < 0)
goto err_create_file;
dev_set_drvdata(tdev->dev, tdev);
tdev->state = 0;
return 0;
err_create_file:
device_destroy(timed_output_class, MKDEV(0, tdev->index));
printk(KERN_ERR "timed_output: Failed to register driver %s\n",
tdev->name);
return ret;
}
EXPORT_SYMBOL_GPL(timed_output_dev_register);
void timed_output_dev_unregister(struct timed_output_dev *tdev)
{
tdev->enable(tdev, 0);
device_remove_file(tdev->dev, &dev_attr_enable);
device_destroy(timed_output_class, MKDEV(0, tdev->index));
dev_set_drvdata(tdev->dev, NULL);
}
EXPORT_SYMBOL_GPL(timed_output_dev_unregister);
static int __init timed_output_init(void)
{
return create_timed_output_class();
}
static void __exit timed_output_exit(void)
{
class_destroy(timed_output_class);
}
module_init(timed_output_init);
module_exit(timed_output_exit);
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_DESCRIPTION("timed output class driver");
MODULE_LICENSE("GPL");
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