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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 | 50 | |
d4afc76c | 51 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
52 | return 0; |
53 | ||
54 | rtc_read_time(rtc, &tm); | |
55 | rtc_tm_to_time(&tm, &oldtime); | |
56 | ||
57 | /* RTC precision is 1 second; adjust delta for avg 1/2 sec err */ | |
58 | set_normalized_timespec(&delta, | |
2c6b47de JS |
59 | ts.tv_sec - oldtime, |
60 | ts.tv_nsec - (NSEC_PER_SEC >> 1)); | |
7ca1d488 DB |
61 | |
62 | return 0; | |
63 | } | |
64 | ||
65 | static int rtc_resume(struct device *dev) | |
66 | { | |
67 | struct rtc_device *rtc = to_rtc_device(dev); | |
68 | struct rtc_time tm; | |
69 | time_t newtime; | |
70 | struct timespec time; | |
71 | ||
d4afc76c | 72 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
73 | return 0; |
74 | ||
75 | rtc_read_time(rtc, &tm); | |
76 | if (rtc_valid_tm(&tm) != 0) { | |
d4afc76c | 77 | pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev)); |
7ca1d488 DB |
78 | return 0; |
79 | } | |
80 | rtc_tm_to_time(&tm, &newtime); | |
81 | if (newtime <= oldtime) { | |
82 | if (newtime < oldtime) | |
d4afc76c | 83 | pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); |
7ca1d488 DB |
84 | return 0; |
85 | } | |
86 | ||
87 | /* restore wall clock using delta against this RTC; | |
88 | * adjust again for avg 1/2 second RTC sampling error | |
89 | */ | |
90 | set_normalized_timespec(&time, | |
91 | newtime + delta.tv_sec, | |
92 | (NSEC_PER_SEC >> 1) + delta.tv_nsec); | |
93 | do_settimeofday(&time); | |
94 | ||
95 | return 0; | |
96 | } | |
97 | ||
98 | #else | |
99 | #define rtc_suspend NULL | |
100 | #define rtc_resume NULL | |
101 | #endif | |
102 | ||
103 | ||
0c86edc0 AZ |
104 | /** |
105 | * rtc_device_register - register w/ RTC class | |
106 | * @dev: the device to register | |
107 | * | |
108 | * rtc_device_unregister() must be called when the class device is no | |
109 | * longer needed. | |
110 | * | |
111 | * Returns the pointer to the new struct class device. | |
112 | */ | |
113 | struct rtc_device *rtc_device_register(const char *name, struct device *dev, | |
ff8371ac | 114 | const struct rtc_class_ops *ops, |
0c86edc0 AZ |
115 | struct module *owner) |
116 | { | |
117 | struct rtc_device *rtc; | |
118 | int id, err; | |
119 | ||
120 | if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) { | |
121 | err = -ENOMEM; | |
122 | goto exit; | |
123 | } | |
124 | ||
125 | ||
126 | mutex_lock(&idr_lock); | |
127 | err = idr_get_new(&rtc_idr, NULL, &id); | |
128 | mutex_unlock(&idr_lock); | |
129 | ||
130 | if (err < 0) | |
131 | goto exit; | |
132 | ||
133 | id = id & MAX_ID_MASK; | |
134 | ||
135 | rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL); | |
136 | if (rtc == NULL) { | |
137 | err = -ENOMEM; | |
138 | goto exit_idr; | |
139 | } | |
140 | ||
141 | rtc->id = id; | |
142 | rtc->ops = ops; | |
143 | rtc->owner = owner; | |
110d693d | 144 | rtc->max_user_freq = 64; |
cd966209 DB |
145 | rtc->dev.parent = dev; |
146 | rtc->dev.class = rtc_class; | |
147 | rtc->dev.release = rtc_device_release; | |
0c86edc0 AZ |
148 | |
149 | mutex_init(&rtc->ops_lock); | |
150 | spin_lock_init(&rtc->irq_lock); | |
151 | spin_lock_init(&rtc->irq_task_lock); | |
d691eb90 | 152 | init_waitqueue_head(&rtc->irq_queue); |
0c86edc0 AZ |
153 | |
154 | strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE); | |
d4afc76c | 155 | dev_set_name(&rtc->dev, "rtc%d", id); |
0c86edc0 | 156 | |
cb3a58d2 DB |
157 | rtc_dev_prepare(rtc); |
158 | ||
cd966209 | 159 | err = device_register(&rtc->dev); |
0c86edc0 AZ |
160 | if (err) |
161 | goto exit_kfree; | |
162 | ||
5726fb20 | 163 | rtc_dev_add_device(rtc); |
446ecbd9 | 164 | rtc_sysfs_add_device(rtc); |
7d9f99ec | 165 | rtc_proc_add_device(rtc); |
5726fb20 | 166 | |
0c86edc0 | 167 | dev_info(dev, "rtc core: registered %s as %s\n", |
d4afc76c | 168 | rtc->name, dev_name(&rtc->dev)); |
0c86edc0 AZ |
169 | |
170 | return rtc; | |
171 | ||
172 | exit_kfree: | |
173 | kfree(rtc); | |
174 | ||
175 | exit_idr: | |
6ac12dfe | 176 | mutex_lock(&idr_lock); |
0c86edc0 | 177 | idr_remove(&rtc_idr, id); |
6ac12dfe | 178 | mutex_unlock(&idr_lock); |
0c86edc0 AZ |
179 | |
180 | exit: | |
d1d65b77 AZ |
181 | dev_err(dev, "rtc core: unable to register %s, err = %d\n", |
182 | name, err); | |
0c86edc0 AZ |
183 | return ERR_PTR(err); |
184 | } | |
185 | EXPORT_SYMBOL_GPL(rtc_device_register); | |
186 | ||
187 | ||
188 | /** | |
189 | * rtc_device_unregister - removes the previously registered RTC class device | |
190 | * | |
191 | * @rtc: the RTC class device to destroy | |
192 | */ | |
193 | void rtc_device_unregister(struct rtc_device *rtc) | |
194 | { | |
cd966209 | 195 | if (get_device(&rtc->dev) != NULL) { |
e109ebd1 DB |
196 | mutex_lock(&rtc->ops_lock); |
197 | /* remove innards of this RTC, then disable it, before | |
198 | * letting any rtc_class_open() users access it again | |
199 | */ | |
446ecbd9 | 200 | rtc_sysfs_del_device(rtc); |
5726fb20 | 201 | rtc_dev_del_device(rtc); |
7d9f99ec | 202 | rtc_proc_del_device(rtc); |
cd966209 | 203 | device_unregister(&rtc->dev); |
e109ebd1 DB |
204 | rtc->ops = NULL; |
205 | mutex_unlock(&rtc->ops_lock); | |
cd966209 | 206 | put_device(&rtc->dev); |
e109ebd1 | 207 | } |
0c86edc0 AZ |
208 | } |
209 | EXPORT_SYMBOL_GPL(rtc_device_unregister); | |
210 | ||
0c86edc0 AZ |
211 | static int __init rtc_init(void) |
212 | { | |
213 | rtc_class = class_create(THIS_MODULE, "rtc"); | |
214 | if (IS_ERR(rtc_class)) { | |
215 | printk(KERN_ERR "%s: couldn't create class\n", __FILE__); | |
216 | return PTR_ERR(rtc_class); | |
217 | } | |
7ca1d488 DB |
218 | rtc_class->suspend = rtc_suspend; |
219 | rtc_class->resume = rtc_resume; | |
5726fb20 | 220 | rtc_dev_init(); |
446ecbd9 | 221 | rtc_sysfs_init(rtc_class); |
0c86edc0 AZ |
222 | return 0; |
223 | } | |
224 | ||
225 | static void __exit rtc_exit(void) | |
226 | { | |
5726fb20 | 227 | rtc_dev_exit(); |
0c86edc0 AZ |
228 | class_destroy(rtc_class); |
229 | } | |
230 | ||
818a8674 | 231 | subsys_initcall(rtc_init); |
0c86edc0 AZ |
232 | module_exit(rtc_exit); |
233 | ||
818a8674 | 234 | MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); |
0c86edc0 AZ |
235 | MODULE_DESCRIPTION("RTC class support"); |
236 | MODULE_LICENSE("GPL"); |