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1 | /* drivers/misc/timed_output.c |
2 | * | |
3 | * Copyright (C) 2009 Google, Inc. | |
4 | * Author: Mike Lockwood <lockwood@android.com> | |
5 | * | |
6 | * This software is licensed under the terms of the GNU General Public | |
7 | * License version 2, as published by the Free Software Foundation, and | |
8 | * may be copied, distributed, and modified under those terms. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | */ | |
16 | ||
17 | #include <linux/module.h> | |
18 | #include <linux/types.h> | |
19 | #include <linux/device.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/err.h> | |
22 | ||
23 | #include "timed_output.h" | |
24 | ||
25 | static struct class *timed_output_class; | |
26 | static atomic_t device_count; | |
27 | ||
28 | static ssize_t enable_show(struct device *dev, struct device_attribute *attr, | |
29 | char *buf) | |
30 | { | |
31 | struct timed_output_dev *tdev = dev_get_drvdata(dev); | |
32 | int remaining = tdev->get_time(tdev); | |
33 | ||
34 | return sprintf(buf, "%d\n", remaining); | |
35 | } | |
36 | ||
37 | static ssize_t enable_store( | |
38 | struct device *dev, struct device_attribute *attr, | |
39 | const char *buf, size_t size) | |
40 | { | |
41 | struct timed_output_dev *tdev = dev_get_drvdata(dev); | |
42 | int value; | |
43 | ||
44 | sscanf(buf, "%d", &value); | |
45 | tdev->enable(tdev, value); | |
46 | ||
47 | return size; | |
48 | } | |
49 | ||
50 | static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, enable_show, enable_store); | |
51 | ||
52 | static int create_timed_output_class(void) | |
53 | { | |
54 | if (!timed_output_class) { | |
55 | timed_output_class = class_create(THIS_MODULE, "timed_output"); | |
56 | if (IS_ERR(timed_output_class)) | |
57 | return PTR_ERR(timed_output_class); | |
58 | atomic_set(&device_count, 0); | |
59 | } | |
60 | ||
61 | return 0; | |
62 | } | |
63 | ||
64 | int timed_output_dev_register(struct timed_output_dev *tdev) | |
65 | { | |
66 | int ret; | |
67 | ||
68 | if (!tdev || !tdev->name || !tdev->enable || !tdev->get_time) | |
69 | return -EINVAL; | |
70 | ||
71 | ret = create_timed_output_class(); | |
72 | if (ret < 0) | |
73 | return ret; | |
74 | ||
75 | tdev->index = atomic_inc_return(&device_count); | |
76 | tdev->dev = device_create(timed_output_class, NULL, | |
77 | MKDEV(0, tdev->index), NULL, tdev->name); | |
78 | if (IS_ERR(tdev->dev)) | |
79 | return PTR_ERR(tdev->dev); | |
80 | ||
81 | ret = device_create_file(tdev->dev, &dev_attr_enable); | |
82 | if (ret < 0) | |
83 | goto err_create_file; | |
84 | ||
85 | dev_set_drvdata(tdev->dev, tdev); | |
86 | tdev->state = 0; | |
87 | return 0; | |
88 | ||
89 | err_create_file: | |
90 | device_destroy(timed_output_class, MKDEV(0, tdev->index)); | |
91 | printk(KERN_ERR "timed_output: Failed to register driver %s\n", | |
92 | tdev->name); | |
93 | ||
94 | return ret; | |
95 | } | |
96 | EXPORT_SYMBOL_GPL(timed_output_dev_register); | |
97 | ||
98 | void timed_output_dev_unregister(struct timed_output_dev *tdev) | |
99 | { | |
100 | device_remove_file(tdev->dev, &dev_attr_enable); | |
101 | device_destroy(timed_output_class, MKDEV(0, tdev->index)); | |
102 | dev_set_drvdata(tdev->dev, NULL); | |
103 | } | |
104 | EXPORT_SYMBOL_GPL(timed_output_dev_unregister); | |
105 | ||
106 | static int __init timed_output_init(void) | |
107 | { | |
108 | return create_timed_output_class(); | |
109 | } | |
110 | ||
111 | static void __exit timed_output_exit(void) | |
112 | { | |
113 | class_destroy(timed_output_class); | |
114 | } | |
115 | ||
116 | module_init(timed_output_init); | |
117 | module_exit(timed_output_exit); | |
118 | ||
119 | MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); | |
120 | MODULE_DESCRIPTION("timed output class driver"); | |
121 | MODULE_LICENSE("GPL"); |