blob: 565562ba6ac9dacc7d8aa4842c7ddedb29de074d [file] [log] [blame]
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090018#include <linux/slab.h>
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080019
David Brownell5726fb22007-05-08 00:33:27 -070020#include "rtc-core.h"
21
22
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080023static DEFINE_IDR(rtc_idr);
24static DEFINE_MUTEX(idr_lock);
25struct class *rtc_class;
26
David Brownellcd966202007-05-08 00:33:40 -070027static void rtc_device_release(struct device *dev)
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080028{
David Brownellcd966202007-05-08 00:33:40 -070029 struct rtc_device *rtc = to_rtc_device(dev);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080030 mutex_lock(&idr_lock);
31 idr_remove(&rtc_idr, rtc->id);
32 mutex_unlock(&idr_lock);
33 kfree(rtc);
34}
35
David Brownell7ca1d482007-05-08 00:33:42 -070036#if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
37
38/*
39 * On suspend(), measure the delta between one RTC and the
40 * system's wall clock; restore it on resume().
41 */
42
43static struct timespec delta;
44static time_t oldtime;
45
46static int rtc_suspend(struct device *dev, pm_message_t mesg)
47{
48 struct rtc_device *rtc = to_rtc_device(dev);
49 struct rtc_time tm;
john stultz2c6b47d2007-07-24 17:47:43 -070050 struct timespec ts = current_kernel_time();
David Brownell7ca1d482007-05-08 00:33:42 -070051
Kay Sieversd4afc762009-01-06 14:42:11 -080052 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
David Brownell7ca1d482007-05-08 00:33:42 -070053 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,
john stultz2c6b47d2007-07-24 17:47:43 -070060 ts.tv_sec - oldtime,
61 ts.tv_nsec - (NSEC_PER_SEC >> 1));
David Brownell7ca1d482007-05-08 00:33:42 -070062
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
Kay Sieversd4afc762009-01-06 14:42:11 -080073 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
David Brownell7ca1d482007-05-08 00:33:42 -070074 return 0;
75
76 rtc_read_time(rtc, &tm);
77 if (rtc_valid_tm(&tm) != 0) {
Kay Sieversd4afc762009-01-06 14:42:11 -080078 pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev));
David Brownell7ca1d482007-05-08 00:33:42 -070079 return 0;
80 }
81 rtc_tm_to_time(&tm, &newtime);
82 if (newtime <= oldtime) {
83 if (newtime < oldtime)
Kay Sieversd4afc762009-01-06 14:42:11 -080084 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
David Brownell7ca1d482007-05-08 00:33:42 -070085 return 0;
86 }
87
88 /* restore wall clock using delta against this RTC;
89 * adjust again for avg 1/2 second RTC sampling error
90 */
91 set_normalized_timespec(&time,
92 newtime + delta.tv_sec,
93 (NSEC_PER_SEC >> 1) + delta.tv_nsec);
94 do_settimeofday(&time);
95
96 return 0;
97}
98
99#else
100#define rtc_suspend NULL
101#define rtc_resume NULL
102#endif
103
104
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800105/**
106 * rtc_device_register - register w/ RTC class
107 * @dev: the device to register
108 *
109 * rtc_device_unregister() must be called when the class device is no
110 * longer needed.
111 *
112 * Returns the pointer to the new struct class device.
113 */
114struct rtc_device *rtc_device_register(const char *name, struct device *dev,
David Brownellff8371a2006-09-30 23:28:17 -0700115 const struct rtc_class_ops *ops,
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800116 struct module *owner)
117{
118 struct rtc_device *rtc;
119 int id, err;
120
121 if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
122 err = -ENOMEM;
123 goto exit;
124 }
125
126
127 mutex_lock(&idr_lock);
128 err = idr_get_new(&rtc_idr, NULL, &id);
129 mutex_unlock(&idr_lock);
130
131 if (err < 0)
132 goto exit;
133
134 id = id & MAX_ID_MASK;
135
136 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
137 if (rtc == NULL) {
138 err = -ENOMEM;
139 goto exit_idr;
140 }
141
142 rtc->id = id;
143 rtc->ops = ops;
144 rtc->owner = owner;
Alessandro Zummo110d6932006-06-25 05:48:20 -0700145 rtc->max_user_freq = 64;
David Brownellcd966202007-05-08 00:33:40 -0700146 rtc->dev.parent = dev;
147 rtc->dev.class = rtc_class;
148 rtc->dev.release = rtc_device_release;
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800149
150 mutex_init(&rtc->ops_lock);
151 spin_lock_init(&rtc->irq_lock);
152 spin_lock_init(&rtc->irq_task_lock);
Alessandro Zummod691eb92007-10-16 01:28:15 -0700153 init_waitqueue_head(&rtc->irq_queue);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800154
155 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
Kay Sieversd4afc762009-01-06 14:42:11 -0800156 dev_set_name(&rtc->dev, "rtc%d", id);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800157
David Brownellcb3a58d2007-05-08 00:33:46 -0700158 rtc_dev_prepare(rtc);
159
David Brownellcd966202007-05-08 00:33:40 -0700160 err = device_register(&rtc->dev);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800161 if (err)
162 goto exit_kfree;
163
David Brownell5726fb22007-05-08 00:33:27 -0700164 rtc_dev_add_device(rtc);
David Brownell446ecbd2007-05-08 00:33:33 -0700165 rtc_sysfs_add_device(rtc);
David Brownell7d9f99e2007-05-08 00:33:38 -0700166 rtc_proc_add_device(rtc);
David Brownell5726fb22007-05-08 00:33:27 -0700167
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800168 dev_info(dev, "rtc core: registered %s as %s\n",
Kay Sieversd4afc762009-01-06 14:42:11 -0800169 rtc->name, dev_name(&rtc->dev));
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800170
171 return rtc;
172
173exit_kfree:
174 kfree(rtc);
175
176exit_idr:
Sonny Rao6ac12df2006-06-27 02:54:06 -0700177 mutex_lock(&idr_lock);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800178 idr_remove(&rtc_idr, id);
Sonny Rao6ac12df2006-06-27 02:54:06 -0700179 mutex_unlock(&idr_lock);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800180
181exit:
Alessandro Zummod1d65b72006-04-10 22:54:45 -0700182 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
183 name, err);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800184 return ERR_PTR(err);
185}
186EXPORT_SYMBOL_GPL(rtc_device_register);
187
188
189/**
190 * rtc_device_unregister - removes the previously registered RTC class device
191 *
192 * @rtc: the RTC class device to destroy
193 */
194void rtc_device_unregister(struct rtc_device *rtc)
195{
David Brownellcd966202007-05-08 00:33:40 -0700196 if (get_device(&rtc->dev) != NULL) {
David Brownelle109ebd2007-02-28 20:12:40 -0800197 mutex_lock(&rtc->ops_lock);
198 /* remove innards of this RTC, then disable it, before
199 * letting any rtc_class_open() users access it again
200 */
David Brownell446ecbd2007-05-08 00:33:33 -0700201 rtc_sysfs_del_device(rtc);
David Brownell5726fb22007-05-08 00:33:27 -0700202 rtc_dev_del_device(rtc);
David Brownell7d9f99e2007-05-08 00:33:38 -0700203 rtc_proc_del_device(rtc);
David Brownellcd966202007-05-08 00:33:40 -0700204 device_unregister(&rtc->dev);
David Brownelle109ebd2007-02-28 20:12:40 -0800205 rtc->ops = NULL;
206 mutex_unlock(&rtc->ops_lock);
David Brownellcd966202007-05-08 00:33:40 -0700207 put_device(&rtc->dev);
David Brownelle109ebd2007-02-28 20:12:40 -0800208 }
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800209}
210EXPORT_SYMBOL_GPL(rtc_device_unregister);
211
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800212static int __init rtc_init(void)
213{
214 rtc_class = class_create(THIS_MODULE, "rtc");
215 if (IS_ERR(rtc_class)) {
216 printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
217 return PTR_ERR(rtc_class);
218 }
David Brownell7ca1d482007-05-08 00:33:42 -0700219 rtc_class->suspend = rtc_suspend;
220 rtc_class->resume = rtc_resume;
David Brownell5726fb22007-05-08 00:33:27 -0700221 rtc_dev_init();
David Brownell446ecbd2007-05-08 00:33:33 -0700222 rtc_sysfs_init(rtc_class);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800223 return 0;
224}
225
226static void __exit rtc_exit(void)
227{
David Brownell5726fb22007-05-08 00:33:27 -0700228 rtc_dev_exit();
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800229 class_destroy(rtc_class);
Aaro Koskinen2a7a06a2010-03-05 13:44:24 -0800230 idr_destroy(&rtc_idr);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800231}
232
David Brownell818a8672006-09-30 23:28:15 -0700233subsys_initcall(rtc_init);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800234module_exit(rtc_exit);
235
David Brownell818a8672006-09-30 23:28:15 -0700236MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800237MODULE_DESCRIPTION("RTC class support");
238MODULE_LICENSE("GPL");