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Alessandro Zummo0c86edc2006-03-27 01:16:37 -08001/*
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
David Brownell5726fb22007-05-08 00:33:27 -070019#include "rtc-core.h"
20
21
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080022static DEFINE_IDR(rtc_idr);
23static DEFINE_MUTEX(idr_lock);
24struct class *rtc_class;
25
David Brownellcd966202007-05-08 00:33:40 -070026static void rtc_device_release(struct device *dev)
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080027{
David Brownellcd966202007-05-08 00:33:40 -070028 struct rtc_device *rtc = to_rtc_device(dev);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080029 mutex_lock(&idr_lock);
30 idr_remove(&rtc_idr, rtc->id);
31 mutex_unlock(&idr_lock);
32 kfree(rtc);
33}
34
David Brownell7ca1d482007-05-08 00:33:42 -070035#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
42static struct timespec delta;
43static time_t oldtime;
44
45static 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;
49
50 if (strncmp(rtc->dev.bus_id,
51 CONFIG_RTC_HCTOSYS_DEVICE,
52 BUS_ID_SIZE) != 0)
53 return 0;
54
55 rtc_read_time(rtc, &tm);
56 rtc_tm_to_time(&tm, &oldtime);
57
58 /* RTC precision is 1 second; adjust delta for avg 1/2 sec err */
59 set_normalized_timespec(&delta,
60 xtime.tv_sec - oldtime,
61 xtime.tv_nsec - (NSEC_PER_SEC >> 1));
62
63 return 0;
64}
65
66static int rtc_resume(struct device *dev)
67{
68 struct rtc_device *rtc = to_rtc_device(dev);
69 struct rtc_time tm;
70 time_t newtime;
71 struct timespec time;
72
73 if (strncmp(rtc->dev.bus_id,
74 CONFIG_RTC_HCTOSYS_DEVICE,
75 BUS_ID_SIZE) != 0)
76 return 0;
77
78 rtc_read_time(rtc, &tm);
79 if (rtc_valid_tm(&tm) != 0) {
80 pr_debug("%s: bogus resume time\n", rtc->dev.bus_id);
81 return 0;
82 }
83 rtc_tm_to_time(&tm, &newtime);
84 if (newtime <= oldtime) {
85 if (newtime < oldtime)
86 pr_debug("%s: time travel!\n", rtc->dev.bus_id);
87 return 0;
88 }
89
90 /* restore wall clock using delta against this RTC;
91 * adjust again for avg 1/2 second RTC sampling error
92 */
93 set_normalized_timespec(&time,
94 newtime + delta.tv_sec,
95 (NSEC_PER_SEC >> 1) + delta.tv_nsec);
96 do_settimeofday(&time);
97
98 return 0;
99}
100
101#else
102#define rtc_suspend NULL
103#define rtc_resume NULL
104#endif
105
106
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800107/**
108 * rtc_device_register - register w/ RTC class
109 * @dev: the device to register
110 *
111 * rtc_device_unregister() must be called when the class device is no
112 * longer needed.
113 *
114 * Returns the pointer to the new struct class device.
115 */
116struct rtc_device *rtc_device_register(const char *name, struct device *dev,
David Brownellff8371a2006-09-30 23:28:17 -0700117 const struct rtc_class_ops *ops,
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800118 struct module *owner)
119{
120 struct rtc_device *rtc;
121 int id, err;
122
123 if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
124 err = -ENOMEM;
125 goto exit;
126 }
127
128
129 mutex_lock(&idr_lock);
130 err = idr_get_new(&rtc_idr, NULL, &id);
131 mutex_unlock(&idr_lock);
132
133 if (err < 0)
134 goto exit;
135
136 id = id & MAX_ID_MASK;
137
138 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
139 if (rtc == NULL) {
140 err = -ENOMEM;
141 goto exit_idr;
142 }
143
144 rtc->id = id;
145 rtc->ops = ops;
146 rtc->owner = owner;
Alessandro Zummo110d6932006-06-25 05:48:20 -0700147 rtc->max_user_freq = 64;
David Brownellcd966202007-05-08 00:33:40 -0700148 rtc->dev.parent = dev;
149 rtc->dev.class = rtc_class;
150 rtc->dev.release = rtc_device_release;
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800151
152 mutex_init(&rtc->ops_lock);
153 spin_lock_init(&rtc->irq_lock);
154 spin_lock_init(&rtc->irq_task_lock);
155
156 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
David Brownellcd966202007-05-08 00:33:40 -0700157 snprintf(rtc->dev.bus_id, BUS_ID_SIZE, "rtc%d", id);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800158
David Brownellcd966202007-05-08 00:33:40 -0700159 err = device_register(&rtc->dev);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800160 if (err)
161 goto exit_kfree;
162
David Brownell5726fb22007-05-08 00:33:27 -0700163 rtc_dev_add_device(rtc);
David Brownell446ecbd2007-05-08 00:33:33 -0700164 rtc_sysfs_add_device(rtc);
David Brownell7d9f99e2007-05-08 00:33:38 -0700165 rtc_proc_add_device(rtc);
David Brownell5726fb22007-05-08 00:33:27 -0700166
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800167 dev_info(dev, "rtc core: registered %s as %s\n",
David Brownellcd966202007-05-08 00:33:40 -0700168 rtc->name, rtc->dev.bus_id);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800169
170 return rtc;
171
172exit_kfree:
173 kfree(rtc);
174
175exit_idr:
Sonny Rao6ac12df2006-06-27 02:54:06 -0700176 mutex_lock(&idr_lock);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800177 idr_remove(&rtc_idr, id);
Sonny Rao6ac12df2006-06-27 02:54:06 -0700178 mutex_unlock(&idr_lock);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800179
180exit:
Alessandro Zummod1d65b72006-04-10 22:54:45 -0700181 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
182 name, err);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800183 return ERR_PTR(err);
184}
185EXPORT_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 */
193void rtc_device_unregister(struct rtc_device *rtc)
194{
David Brownellcd966202007-05-08 00:33:40 -0700195 if (get_device(&rtc->dev) != NULL) {
David Brownelle109ebd2007-02-28 20:12:40 -0800196 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 */
David Brownell446ecbd2007-05-08 00:33:33 -0700200 rtc_sysfs_del_device(rtc);
David Brownell5726fb22007-05-08 00:33:27 -0700201 rtc_dev_del_device(rtc);
David Brownell7d9f99e2007-05-08 00:33:38 -0700202 rtc_proc_del_device(rtc);
David Brownellcd966202007-05-08 00:33:40 -0700203 device_unregister(&rtc->dev);
David Brownelle109ebd2007-02-28 20:12:40 -0800204 rtc->ops = NULL;
205 mutex_unlock(&rtc->ops_lock);
David Brownellcd966202007-05-08 00:33:40 -0700206 put_device(&rtc->dev);
David Brownelle109ebd2007-02-28 20:12:40 -0800207 }
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800208}
209EXPORT_SYMBOL_GPL(rtc_device_unregister);
210
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800211static 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 }
David Brownell7ca1d482007-05-08 00:33:42 -0700218 rtc_class->suspend = rtc_suspend;
219 rtc_class->resume = rtc_resume;
David Brownell5726fb22007-05-08 00:33:27 -0700220 rtc_dev_init();
David Brownell446ecbd2007-05-08 00:33:33 -0700221 rtc_sysfs_init(rtc_class);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800222 return 0;
223}
224
225static void __exit rtc_exit(void)
226{
David Brownell5726fb22007-05-08 00:33:27 -0700227 rtc_dev_exit();
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800228 class_destroy(rtc_class);
229}
230
David Brownell818a8672006-09-30 23:28:15 -0700231subsys_initcall(rtc_init);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800232module_exit(rtc_exit);
233
David Brownell818a8672006-09-30 23:28:15 -0700234MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800235MODULE_DESCRIPTION("RTC class support");
236MODULE_LICENSE("GPL");