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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#include <linux/slab.h>
19#include <linux/workqueue.h>
20
21#include "rtc-core.h"
22
23
24static DEFINE_IDA(rtc_ida);
25struct class *rtc_class;
26
27static void rtc_device_release(struct device *dev)
28{
29 struct rtc_device *rtc = to_rtc_device(dev);
30 ida_simple_remove(&rtc_ida, rtc->id);
31 kfree(rtc);
32}
33
34#if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
35
36/*
37 * On suspend(), measure the delta between one RTC and the
38 * system's wall clock; restore it on resume().
39 */
40
41static struct timespec old_rtc, old_system, old_delta;
42
43
44static int rtc_suspend(struct device *dev, pm_message_t mesg)
45{
46 struct rtc_device *rtc = to_rtc_device(dev);
47 struct rtc_time tm;
48 struct timespec delta, delta_delta;
49 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
50 return 0;
51
52 /* snapshot the current RTC and system time at suspend*/
53 rtc_read_time(rtc, &tm);
54 getnstimeofday(&old_system);
55 rtc_tm_to_time(&tm, &old_rtc.tv_sec);
56
57
58 /*
59 * To avoid drift caused by repeated suspend/resumes,
60 * which each can add ~1 second drift error,
61 * try to compensate so the difference in system time
62 * and rtc time stays close to constant.
63 */
64 delta = timespec_sub(old_system, old_rtc);
65 delta_delta = timespec_sub(delta, old_delta);
66 if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
67 /*
68 * if delta_delta is too large, assume time correction
69 * has occured and set old_delta to the current delta.
70 */
71 old_delta = delta;
72 } else {
73 /* Otherwise try to adjust old_system to compensate */
74 old_system = timespec_sub(old_system, delta_delta);
75 }
76
77 return 0;
78}
79
80static int rtc_resume(struct device *dev)
81{
82 struct rtc_device *rtc = to_rtc_device(dev);
83 struct rtc_time tm;
84 struct timespec new_system, new_rtc;
85 struct timespec sleep_time;
86
87 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
88 return 0;
89
90 /* snapshot the current rtc and system time at resume */
91 getnstimeofday(&new_system);
92 rtc_read_time(rtc, &tm);
93 if (rtc_valid_tm(&tm) != 0) {
94 pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev));
95 return 0;
96 }
97 rtc_tm_to_time(&tm, &new_rtc.tv_sec);
98 new_rtc.tv_nsec = 0;
99
100 if (new_rtc.tv_sec < old_rtc.tv_sec) {
101 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
102 return 0;
103 }
104
105 /* calculate the RTC time delta (sleep time)*/
106 sleep_time = timespec_sub(new_rtc, old_rtc);
107
108 /*
109 * Since these RTC suspend/resume handlers are not called
110 * at the very end of suspend or the start of resume,
111 * some run-time may pass on either sides of the sleep time
112 * so subtract kernel run-time between rtc_suspend to rtc_resume
113 * to keep things accurate.
114 */
115 sleep_time = timespec_sub(sleep_time,
116 timespec_sub(new_system, old_system));
117
118 if (sleep_time.tv_sec >= 0)
119 timekeeping_inject_sleeptime(&sleep_time);
120 return 0;
121}
122
123#else
124#define rtc_suspend NULL
125#define rtc_resume NULL
126#endif
127
128
129/**
130 * rtc_device_register - register w/ RTC class
131 * @dev: the device to register
132 *
133 * rtc_device_unregister() must be called when the class device is no
134 * longer needed.
135 *
136 * Returns the pointer to the new struct class device.
137 */
138struct rtc_device *rtc_device_register(const char *name, struct device *dev,
139 const struct rtc_class_ops *ops,
140 struct module *owner)
141{
142 struct rtc_device *rtc;
143 struct rtc_wkalrm alrm;
144 int id, err;
145
146 id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
147 if (id < 0) {
148 err = id;
149 goto exit;
150 }
151
152 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
153 if (rtc == NULL) {
154 err = -ENOMEM;
155 goto exit_ida;
156 }
157
158 rtc->id = id;
159 rtc->ops = ops;
160 rtc->owner = owner;
161 rtc->irq_freq = 1;
162 rtc->max_user_freq = 64;
163 rtc->dev.parent = dev;
164 rtc->dev.class = rtc_class;
165 rtc->dev.release = rtc_device_release;
166
167 mutex_init(&rtc->ops_lock);
168 spin_lock_init(&rtc->irq_lock);
169 spin_lock_init(&rtc->irq_task_lock);
170 init_waitqueue_head(&rtc->irq_queue);
171
172 /* Init timerqueue */
173 timerqueue_init_head(&rtc->timerqueue);
174 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
175 /* Init aie timer */
176 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
177 /* Init uie timer */
178 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
179 /* Init pie timer */
180 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
181 rtc->pie_timer.function = rtc_pie_update_irq;
182 rtc->pie_enabled = 0;
183
184 /* Check to see if there is an ALARM already set in hw */
185 err = __rtc_read_alarm(rtc, &alrm);
186
187 if (!err && !rtc_valid_tm(&alrm.time))
188 rtc_initialize_alarm(rtc, &alrm);
189
190 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
191 dev_set_name(&rtc->dev, "rtc%d", id);
192
193 rtc_dev_prepare(rtc);
194
195 err = device_register(&rtc->dev);
196 if (err) {
197 put_device(&rtc->dev);
198 goto exit_kfree;
199 }
200
201 rtc_dev_add_device(rtc);
202 rtc_sysfs_add_device(rtc);
203 rtc_proc_add_device(rtc);
204
205 dev_info(dev, "rtc core: registered %s as %s\n",
206 rtc->name, dev_name(&rtc->dev));
207
208 return rtc;
209
210exit_kfree:
211 kfree(rtc);
212
213exit_ida:
214 ida_simple_remove(&rtc_ida, id);
215
216exit:
217 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
218 name, err);
219 return ERR_PTR(err);
220}
221EXPORT_SYMBOL_GPL(rtc_device_register);
222
223
224/**
225 * rtc_device_unregister - removes the previously registered RTC class device
226 *
227 * @rtc: the RTC class device to destroy
228 */
229void rtc_device_unregister(struct rtc_device *rtc)
230{
231 if (get_device(&rtc->dev) != NULL) {
232 mutex_lock(&rtc->ops_lock);
233 /* remove innards of this RTC, then disable it, before
234 * letting any rtc_class_open() users access it again
235 */
236 rtc_sysfs_del_device(rtc);
237 rtc_dev_del_device(rtc);
238 rtc_proc_del_device(rtc);
239 device_unregister(&rtc->dev);
240 rtc->ops = NULL;
241 mutex_unlock(&rtc->ops_lock);
242 put_device(&rtc->dev);
243 }
244}
245EXPORT_SYMBOL_GPL(rtc_device_unregister);
246
247static int __init rtc_init(void)
248{
249 rtc_class = class_create(THIS_MODULE, "rtc");
250 if (IS_ERR(rtc_class)) {
251 printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
252 return PTR_ERR(rtc_class);
253 }
254 rtc_class->suspend = rtc_suspend;
255 rtc_class->resume = rtc_resume;
256 rtc_dev_init();
257 rtc_sysfs_init(rtc_class);
258 return 0;
259}
260
261static void __exit rtc_exit(void)
262{
263 rtc_dev_exit();
264 class_destroy(rtc_class);
265 ida_destroy(&rtc_ida);
266}
267
268subsys_initcall(rtc_init);
269module_exit(rtc_exit);
270
271MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
272MODULE_DESCRIPTION("RTC class support");
273MODULE_LICENSE("GPL");
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/module.h>
17#include <linux/of.h>
18#include <linux/rtc.h>
19#include <linux/kdev_t.h>
20#include <linux/idr.h>
21#include <linux/slab.h>
22#include <linux/workqueue.h>
23
24#include "rtc-core.h"
25
26
27static DEFINE_IDA(rtc_ida);
28struct class *rtc_class;
29
30static void rtc_device_release(struct device *dev)
31{
32 struct rtc_device *rtc = to_rtc_device(dev);
33 ida_simple_remove(&rtc_ida, rtc->id);
34 kfree(rtc);
35}
36
37#ifdef CONFIG_RTC_HCTOSYS_DEVICE
38/* Result of the last RTC to system clock attempt. */
39int rtc_hctosys_ret = -ENODEV;
40#endif
41
42#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
43/*
44 * On suspend(), measure the delta between one RTC and the
45 * system's wall clock; restore it on resume().
46 */
47
48static struct timespec old_rtc, old_system, old_delta;
49
50
51static int rtc_suspend(struct device *dev)
52{
53 struct rtc_device *rtc = to_rtc_device(dev);
54 struct rtc_time tm;
55 struct timespec delta, delta_delta;
56
57 if (has_persistent_clock())
58 return 0;
59
60 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
61 return 0;
62
63 /* snapshot the current RTC and system time at suspend*/
64 rtc_read_time(rtc, &tm);
65 getnstimeofday(&old_system);
66 rtc_tm_to_time(&tm, &old_rtc.tv_sec);
67
68
69 /*
70 * To avoid drift caused by repeated suspend/resumes,
71 * which each can add ~1 second drift error,
72 * try to compensate so the difference in system time
73 * and rtc time stays close to constant.
74 */
75 delta = timespec_sub(old_system, old_rtc);
76 delta_delta = timespec_sub(delta, old_delta);
77 if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
78 /*
79 * if delta_delta is too large, assume time correction
80 * has occured and set old_delta to the current delta.
81 */
82 old_delta = delta;
83 } else {
84 /* Otherwise try to adjust old_system to compensate */
85 old_system = timespec_sub(old_system, delta_delta);
86 }
87
88 return 0;
89}
90
91static int rtc_resume(struct device *dev)
92{
93 struct rtc_device *rtc = to_rtc_device(dev);
94 struct rtc_time tm;
95 struct timespec new_system, new_rtc;
96 struct timespec sleep_time;
97
98 if (has_persistent_clock())
99 return 0;
100
101 rtc_hctosys_ret = -ENODEV;
102 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
103 return 0;
104
105 /* snapshot the current rtc and system time at resume */
106 getnstimeofday(&new_system);
107 rtc_read_time(rtc, &tm);
108 if (rtc_valid_tm(&tm) != 0) {
109 pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev));
110 return 0;
111 }
112 rtc_tm_to_time(&tm, &new_rtc.tv_sec);
113 new_rtc.tv_nsec = 0;
114
115 if (new_rtc.tv_sec < old_rtc.tv_sec) {
116 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
117 return 0;
118 }
119
120 /* calculate the RTC time delta (sleep time)*/
121 sleep_time = timespec_sub(new_rtc, old_rtc);
122
123 /*
124 * Since these RTC suspend/resume handlers are not called
125 * at the very end of suspend or the start of resume,
126 * some run-time may pass on either sides of the sleep time
127 * so subtract kernel run-time between rtc_suspend to rtc_resume
128 * to keep things accurate.
129 */
130 sleep_time = timespec_sub(sleep_time,
131 timespec_sub(new_system, old_system));
132
133 if (sleep_time.tv_sec >= 0)
134 timekeeping_inject_sleeptime(&sleep_time);
135 rtc_hctosys_ret = 0;
136 return 0;
137}
138
139static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
140#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)
141#else
142#define RTC_CLASS_DEV_PM_OPS NULL
143#endif
144
145
146/**
147 * rtc_device_register - register w/ RTC class
148 * @dev: the device to register
149 *
150 * rtc_device_unregister() must be called when the class device is no
151 * longer needed.
152 *
153 * Returns the pointer to the new struct class device.
154 */
155struct rtc_device *rtc_device_register(const char *name, struct device *dev,
156 const struct rtc_class_ops *ops,
157 struct module *owner)
158{
159 struct rtc_device *rtc;
160 struct rtc_wkalrm alrm;
161 int of_id = -1, id = -1, err;
162
163 if (dev->of_node)
164 of_id = of_alias_get_id(dev->of_node, "rtc");
165 else if (dev->parent && dev->parent->of_node)
166 of_id = of_alias_get_id(dev->parent->of_node, "rtc");
167
168 if (of_id >= 0) {
169 id = ida_simple_get(&rtc_ida, of_id, of_id + 1,
170 GFP_KERNEL);
171 if (id < 0)
172 dev_warn(dev, "/aliases ID %d not available\n",
173 of_id);
174 }
175
176 if (id < 0) {
177 id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
178 if (id < 0) {
179 err = id;
180 goto exit;
181 }
182 }
183
184 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
185 if (rtc == NULL) {
186 err = -ENOMEM;
187 goto exit_ida;
188 }
189
190 rtc->id = id;
191 rtc->ops = ops;
192 rtc->owner = owner;
193 rtc->irq_freq = 1;
194 rtc->max_user_freq = 64;
195 rtc->dev.parent = dev;
196 rtc->dev.class = rtc_class;
197 rtc->dev.release = rtc_device_release;
198
199 mutex_init(&rtc->ops_lock);
200 spin_lock_init(&rtc->irq_lock);
201 spin_lock_init(&rtc->irq_task_lock);
202 init_waitqueue_head(&rtc->irq_queue);
203
204 /* Init timerqueue */
205 timerqueue_init_head(&rtc->timerqueue);
206 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
207 /* Init aie timer */
208 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
209 /* Init uie timer */
210 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
211 /* Init pie timer */
212 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
213 rtc->pie_timer.function = rtc_pie_update_irq;
214 rtc->pie_enabled = 0;
215
216 /* Check to see if there is an ALARM already set in hw */
217 err = __rtc_read_alarm(rtc, &alrm);
218
219 if (!err && !rtc_valid_tm(&alrm.time))
220 rtc_initialize_alarm(rtc, &alrm);
221
222 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
223 dev_set_name(&rtc->dev, "rtc%d", id);
224
225 rtc_dev_prepare(rtc);
226
227 err = device_register(&rtc->dev);
228 if (err) {
229 put_device(&rtc->dev);
230 goto exit_kfree;
231 }
232
233 rtc_dev_add_device(rtc);
234 rtc_sysfs_add_device(rtc);
235 rtc_proc_add_device(rtc);
236
237 dev_info(dev, "rtc core: registered %s as %s\n",
238 rtc->name, dev_name(&rtc->dev));
239
240 return rtc;
241
242exit_kfree:
243 kfree(rtc);
244
245exit_ida:
246 ida_simple_remove(&rtc_ida, id);
247
248exit:
249 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
250 name, err);
251 return ERR_PTR(err);
252}
253EXPORT_SYMBOL_GPL(rtc_device_register);
254
255
256/**
257 * rtc_device_unregister - removes the previously registered RTC class device
258 *
259 * @rtc: the RTC class device to destroy
260 */
261void rtc_device_unregister(struct rtc_device *rtc)
262{
263 if (get_device(&rtc->dev) != NULL) {
264 mutex_lock(&rtc->ops_lock);
265 /* remove innards of this RTC, then disable it, before
266 * letting any rtc_class_open() users access it again
267 */
268 rtc_sysfs_del_device(rtc);
269 rtc_dev_del_device(rtc);
270 rtc_proc_del_device(rtc);
271 device_unregister(&rtc->dev);
272 rtc->ops = NULL;
273 mutex_unlock(&rtc->ops_lock);
274 put_device(&rtc->dev);
275 }
276}
277EXPORT_SYMBOL_GPL(rtc_device_unregister);
278
279static void devm_rtc_device_release(struct device *dev, void *res)
280{
281 struct rtc_device *rtc = *(struct rtc_device **)res;
282
283 rtc_device_unregister(rtc);
284}
285
286static int devm_rtc_device_match(struct device *dev, void *res, void *data)
287{
288 struct rtc **r = res;
289
290 return *r == data;
291}
292
293/**
294 * devm_rtc_device_register - resource managed rtc_device_register()
295 * @dev: the device to register
296 * @name: the name of the device
297 * @ops: the rtc operations structure
298 * @owner: the module owner
299 *
300 * @return a struct rtc on success, or an ERR_PTR on error
301 *
302 * Managed rtc_device_register(). The rtc_device returned from this function
303 * are automatically freed on driver detach. See rtc_device_register()
304 * for more information.
305 */
306
307struct rtc_device *devm_rtc_device_register(struct device *dev,
308 const char *name,
309 const struct rtc_class_ops *ops,
310 struct module *owner)
311{
312 struct rtc_device **ptr, *rtc;
313
314 ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
315 if (!ptr)
316 return ERR_PTR(-ENOMEM);
317
318 rtc = rtc_device_register(name, dev, ops, owner);
319 if (!IS_ERR(rtc)) {
320 *ptr = rtc;
321 devres_add(dev, ptr);
322 } else {
323 devres_free(ptr);
324 }
325
326 return rtc;
327}
328EXPORT_SYMBOL_GPL(devm_rtc_device_register);
329
330/**
331 * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
332 * @dev: the device to unregister
333 * @rtc: the RTC class device to unregister
334 *
335 * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
336 * function will not need to be called and the resource management code will
337 * ensure that the resource is freed.
338 */
339void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc)
340{
341 int rc;
342
343 rc = devres_release(dev, devm_rtc_device_release,
344 devm_rtc_device_match, rtc);
345 WARN_ON(rc);
346}
347EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
348
349static int __init rtc_init(void)
350{
351 rtc_class = class_create(THIS_MODULE, "rtc");
352 if (IS_ERR(rtc_class)) {
353 pr_err("couldn't create class\n");
354 return PTR_ERR(rtc_class);
355 }
356 rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
357 rtc_dev_init();
358 rtc_sysfs_init(rtc_class);
359 return 0;
360}
361
362static void __exit rtc_exit(void)
363{
364 rtc_dev_exit();
365 class_destroy(rtc_class);
366 ida_destroy(&rtc_ida);
367}
368
369subsys_initcall(rtc_init);
370module_exit(rtc_exit);
371
372MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
373MODULE_DESCRIPTION("RTC class support");
374MODULE_LICENSE("GPL");