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355b0502 GKH |
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 | ||
c810a399 SK |
17 | #define pr_fmt(fmt) "timed_output: " fmt |
18 | ||
355b0502 GKH |
19 | #include <linux/module.h> |
20 | #include <linux/types.h> | |
21 | #include <linux/device.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/err.h> | |
24 | ||
25 | #include "timed_output.h" | |
26 | ||
27 | static struct class *timed_output_class; | |
28 | static atomic_t device_count; | |
29 | ||
30 | static ssize_t enable_show(struct device *dev, struct device_attribute *attr, | |
31 | char *buf) | |
32 | { | |
33 | struct timed_output_dev *tdev = dev_get_drvdata(dev); | |
34 | int remaining = tdev->get_time(tdev); | |
35 | ||
36 | return sprintf(buf, "%d\n", remaining); | |
37 | } | |
38 | ||
39 | static ssize_t enable_store( | |
40 | struct device *dev, struct device_attribute *attr, | |
41 | const char *buf, size_t size) | |
42 | { | |
43 | struct timed_output_dev *tdev = dev_get_drvdata(dev); | |
44 | int value; | |
45 | ||
8bfe15f3 ML |
46 | if (sscanf(buf, "%d", &value) != 1) |
47 | return -EINVAL; | |
48 | ||
355b0502 GKH |
49 | tdev->enable(tdev, value); |
50 | ||
51 | return size; | |
52 | } | |
53 | ||
54 | static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, enable_show, enable_store); | |
55 | ||
56 | static int create_timed_output_class(void) | |
57 | { | |
58 | if (!timed_output_class) { | |
59 | timed_output_class = class_create(THIS_MODULE, "timed_output"); | |
60 | if (IS_ERR(timed_output_class)) | |
61 | return PTR_ERR(timed_output_class); | |
62 | atomic_set(&device_count, 0); | |
63 | } | |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
68 | int timed_output_dev_register(struct timed_output_dev *tdev) | |
69 | { | |
70 | int ret; | |
71 | ||
72 | if (!tdev || !tdev->name || !tdev->enable || !tdev->get_time) | |
73 | return -EINVAL; | |
74 | ||
75 | ret = create_timed_output_class(); | |
76 | if (ret < 0) | |
77 | return ret; | |
78 | ||
79 | tdev->index = atomic_inc_return(&device_count); | |
80 | tdev->dev = device_create(timed_output_class, NULL, | |
81 | MKDEV(0, tdev->index), NULL, tdev->name); | |
82 | if (IS_ERR(tdev->dev)) | |
83 | return PTR_ERR(tdev->dev); | |
84 | ||
85 | ret = device_create_file(tdev->dev, &dev_attr_enable); | |
86 | if (ret < 0) | |
87 | goto err_create_file; | |
88 | ||
89 | dev_set_drvdata(tdev->dev, tdev); | |
90 | tdev->state = 0; | |
91 | return 0; | |
92 | ||
93 | err_create_file: | |
94 | device_destroy(timed_output_class, MKDEV(0, tdev->index)); | |
c810a399 | 95 | pr_err("failed to register driver %s\n", |
355b0502 GKH |
96 | tdev->name); |
97 | ||
98 | return ret; | |
99 | } | |
100 | EXPORT_SYMBOL_GPL(timed_output_dev_register); | |
101 | ||
102 | void timed_output_dev_unregister(struct timed_output_dev *tdev) | |
103 | { | |
d9a861d5 | 104 | tdev->enable(tdev, 0); |
355b0502 GKH |
105 | device_remove_file(tdev->dev, &dev_attr_enable); |
106 | device_destroy(timed_output_class, MKDEV(0, tdev->index)); | |
107 | dev_set_drvdata(tdev->dev, NULL); | |
108 | } | |
109 | EXPORT_SYMBOL_GPL(timed_output_dev_unregister); | |
110 | ||
111 | static int __init timed_output_init(void) | |
112 | { | |
113 | return create_timed_output_class(); | |
114 | } | |
115 | ||
116 | static void __exit timed_output_exit(void) | |
117 | { | |
118 | class_destroy(timed_output_class); | |
119 | } | |
120 | ||
121 | module_init(timed_output_init); | |
122 | module_exit(timed_output_exit); | |
123 | ||
124 | MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); | |
125 | MODULE_DESCRIPTION("timed output class driver"); | |
126 | MODULE_LICENSE("GPL"); |