| /* 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) |
| { |
| device_remove_file(tdev->dev, &dev_attr_enable); |
| dev_set_drvdata(tdev->dev, NULL); |
| device_destroy(timed_output_class, MKDEV(0, tdev->index)); |
| } |
| 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"); |