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0c86edc0 AZ |
1 | /* |
2 | * RTC subsystem, base class | |
3 | * | |
4 | * Copyright (C) 2005 Tower Technologies | |
5 | * Author: Alessandro Zummo <a.zummo@towertech.it> | |
6 | * | |
7 | * class skeleton from drivers/hwmon/hwmon.c | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/rtc.h> | |
16 | #include <linux/kdev_t.h> | |
17 | #include <linux/idr.h> | |
18 | ||
5726fb20 DB |
19 | #include "rtc-core.h" |
20 | ||
21 | ||
0c86edc0 AZ |
22 | static DEFINE_IDR(rtc_idr); |
23 | static DEFINE_MUTEX(idr_lock); | |
24 | struct class *rtc_class; | |
25 | ||
cd966209 | 26 | static void rtc_device_release(struct device *dev) |
0c86edc0 | 27 | { |
cd966209 | 28 | struct rtc_device *rtc = to_rtc_device(dev); |
0c86edc0 AZ |
29 | mutex_lock(&idr_lock); |
30 | idr_remove(&rtc_idr, rtc->id); | |
31 | mutex_unlock(&idr_lock); | |
32 | kfree(rtc); | |
33 | } | |
34 | ||
7ca1d488 DB |
35 | #if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE) |
36 | ||
37 | /* | |
38 | * On suspend(), measure the delta between one RTC and the | |
39 | * system's wall clock; restore it on resume(). | |
40 | */ | |
41 | ||
42 | static struct timespec delta; | |
43 | static time_t oldtime; | |
44 | ||
45 | static int rtc_suspend(struct device *dev, pm_message_t mesg) | |
46 | { | |
47 | struct rtc_device *rtc = to_rtc_device(dev); | |
48 | struct rtc_time tm; | |
2c6b47de | 49 | struct timespec ts = current_kernel_time(); |
7ca1d488 DB |
50 | |
51 | if (strncmp(rtc->dev.bus_id, | |
52 | CONFIG_RTC_HCTOSYS_DEVICE, | |
53 | BUS_ID_SIZE) != 0) | |
54 | return 0; | |
55 | ||
56 | rtc_read_time(rtc, &tm); | |
57 | rtc_tm_to_time(&tm, &oldtime); | |
58 | ||
59 | /* RTC precision is 1 second; adjust delta for avg 1/2 sec err */ | |
60 | set_normalized_timespec(&delta, | |
2c6b47de | 61 | ts.tv_sec - oldtime, |
62 | ts.tv_nsec - (NSEC_PER_SEC >> 1)); | |
7ca1d488 DB |
63 | |
64 | return 0; | |
65 | } | |
66 | ||
67 | static int rtc_resume(struct device *dev) | |
68 | { | |
69 | struct rtc_device *rtc = to_rtc_device(dev); | |
70 | struct rtc_time tm; | |
71 | time_t newtime; | |
72 | struct timespec time; | |
73 | ||
74 | if (strncmp(rtc->dev.bus_id, | |
75 | CONFIG_RTC_HCTOSYS_DEVICE, | |
76 | BUS_ID_SIZE) != 0) | |
77 | return 0; | |
78 | ||
79 | rtc_read_time(rtc, &tm); | |
80 | if (rtc_valid_tm(&tm) != 0) { | |
81 | pr_debug("%s: bogus resume time\n", rtc->dev.bus_id); | |
82 | return 0; | |
83 | } | |
84 | rtc_tm_to_time(&tm, &newtime); | |
85 | if (newtime <= oldtime) { | |
86 | if (newtime < oldtime) | |
87 | pr_debug("%s: time travel!\n", rtc->dev.bus_id); | |
88 | return 0; | |
89 | } | |
90 | ||
91 | /* restore wall clock using delta against this RTC; | |
92 | * adjust again for avg 1/2 second RTC sampling error | |
93 | */ | |
94 | set_normalized_timespec(&time, | |
95 | newtime + delta.tv_sec, | |
96 | (NSEC_PER_SEC >> 1) + delta.tv_nsec); | |
97 | do_settimeofday(&time); | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | #else | |
103 | #define rtc_suspend NULL | |
104 | #define rtc_resume NULL | |
105 | #endif | |
106 | ||
107 | ||
0c86edc0 AZ |
108 | /** |
109 | * rtc_device_register - register w/ RTC class | |
110 | * @dev: the device to register | |
111 | * | |
112 | * rtc_device_unregister() must be called when the class device is no | |
113 | * longer needed. | |
114 | * | |
115 | * Returns the pointer to the new struct class device. | |
116 | */ | |
117 | struct rtc_device *rtc_device_register(const char *name, struct device *dev, | |
ff8371ac | 118 | const struct rtc_class_ops *ops, |
0c86edc0 AZ |
119 | struct module *owner) |
120 | { | |
121 | struct rtc_device *rtc; | |
122 | int id, err; | |
123 | ||
124 | if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) { | |
125 | err = -ENOMEM; | |
126 | goto exit; | |
127 | } | |
128 | ||
129 | ||
130 | mutex_lock(&idr_lock); | |
131 | err = idr_get_new(&rtc_idr, NULL, &id); | |
132 | mutex_unlock(&idr_lock); | |
133 | ||
134 | if (err < 0) | |
135 | goto exit; | |
136 | ||
137 | id = id & MAX_ID_MASK; | |
138 | ||
139 | rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL); | |
140 | if (rtc == NULL) { | |
141 | err = -ENOMEM; | |
142 | goto exit_idr; | |
143 | } | |
144 | ||
145 | rtc->id = id; | |
146 | rtc->ops = ops; | |
147 | rtc->owner = owner; | |
110d693d | 148 | rtc->max_user_freq = 64; |
cd966209 DB |
149 | rtc->dev.parent = dev; |
150 | rtc->dev.class = rtc_class; | |
151 | rtc->dev.release = rtc_device_release; | |
0c86edc0 AZ |
152 | |
153 | mutex_init(&rtc->ops_lock); | |
154 | spin_lock_init(&rtc->irq_lock); | |
155 | spin_lock_init(&rtc->irq_task_lock); | |
d691eb90 | 156 | init_waitqueue_head(&rtc->irq_queue); |
0c86edc0 AZ |
157 | |
158 | strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE); | |
cd966209 | 159 | snprintf(rtc->dev.bus_id, BUS_ID_SIZE, "rtc%d", id); |
0c86edc0 | 160 | |
cb3a58d2 DB |
161 | rtc_dev_prepare(rtc); |
162 | ||
cd966209 | 163 | err = device_register(&rtc->dev); |
0c86edc0 AZ |
164 | if (err) |
165 | goto exit_kfree; | |
166 | ||
5726fb20 | 167 | rtc_dev_add_device(rtc); |
446ecbd9 | 168 | rtc_sysfs_add_device(rtc); |
7d9f99ec | 169 | rtc_proc_add_device(rtc); |
5726fb20 | 170 | |
0c86edc0 | 171 | dev_info(dev, "rtc core: registered %s as %s\n", |
cd966209 | 172 | rtc->name, rtc->dev.bus_id); |
0c86edc0 AZ |
173 | |
174 | return rtc; | |
175 | ||
176 | exit_kfree: | |
177 | kfree(rtc); | |
178 | ||
179 | exit_idr: | |
6ac12dfe | 180 | mutex_lock(&idr_lock); |
0c86edc0 | 181 | idr_remove(&rtc_idr, id); |
6ac12dfe | 182 | mutex_unlock(&idr_lock); |
0c86edc0 AZ |
183 | |
184 | exit: | |
d1d65b77 AZ |
185 | dev_err(dev, "rtc core: unable to register %s, err = %d\n", |
186 | name, err); | |
0c86edc0 AZ |
187 | return ERR_PTR(err); |
188 | } | |
189 | EXPORT_SYMBOL_GPL(rtc_device_register); | |
190 | ||
191 | ||
192 | /** | |
193 | * rtc_device_unregister - removes the previously registered RTC class device | |
194 | * | |
195 | * @rtc: the RTC class device to destroy | |
196 | */ | |
197 | void rtc_device_unregister(struct rtc_device *rtc) | |
198 | { | |
cd966209 | 199 | if (get_device(&rtc->dev) != NULL) { |
e109ebd1 DB |
200 | mutex_lock(&rtc->ops_lock); |
201 | /* remove innards of this RTC, then disable it, before | |
202 | * letting any rtc_class_open() users access it again | |
203 | */ | |
446ecbd9 | 204 | rtc_sysfs_del_device(rtc); |
5726fb20 | 205 | rtc_dev_del_device(rtc); |
7d9f99ec | 206 | rtc_proc_del_device(rtc); |
cd966209 | 207 | device_unregister(&rtc->dev); |
e109ebd1 DB |
208 | rtc->ops = NULL; |
209 | mutex_unlock(&rtc->ops_lock); | |
cd966209 | 210 | put_device(&rtc->dev); |
e109ebd1 | 211 | } |
0c86edc0 AZ |
212 | } |
213 | EXPORT_SYMBOL_GPL(rtc_device_unregister); | |
214 | ||
0c86edc0 AZ |
215 | static int __init rtc_init(void) |
216 | { | |
217 | rtc_class = class_create(THIS_MODULE, "rtc"); | |
218 | if (IS_ERR(rtc_class)) { | |
219 | printk(KERN_ERR "%s: couldn't create class\n", __FILE__); | |
220 | return PTR_ERR(rtc_class); | |
221 | } | |
7ca1d488 DB |
222 | rtc_class->suspend = rtc_suspend; |
223 | rtc_class->resume = rtc_resume; | |
5726fb20 | 224 | rtc_dev_init(); |
446ecbd9 | 225 | rtc_sysfs_init(rtc_class); |
0c86edc0 AZ |
226 | return 0; |
227 | } | |
228 | ||
229 | static void __exit rtc_exit(void) | |
230 | { | |
5726fb20 | 231 | rtc_dev_exit(); |
0c86edc0 AZ |
232 | class_destroy(rtc_class); |
233 | } | |
234 | ||
818a8674 | 235 | subsys_initcall(rtc_init); |
0c86edc0 AZ |
236 | module_exit(rtc_exit); |
237 | ||
818a8674 | 238 | MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); |
0c86edc0 AZ |
239 | MODULE_DESCRIPTION("RTC class support"); |
240 | MODULE_LICENSE("GPL"); |