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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_IDR(rtc_idr);
25static DEFINE_MUTEX(idr_lock);
26struct class *rtc_class;
27
28static void rtc_device_release(struct device *dev)
29{
30 struct rtc_device *rtc = to_rtc_device(dev);
31 mutex_lock(&idr_lock);
32 idr_remove(&rtc_idr, rtc->id);
33 mutex_unlock(&idr_lock);
34 kfree(rtc);
35}
36
37#if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
38
39/*
40 * On suspend(), measure the delta between one RTC and the
41 * system's wall clock; restore it on resume().
42 */
43
44static struct timespec old_rtc, old_system, old_delta;
45
46
47static int rtc_suspend(struct device *dev, pm_message_t mesg)
48{
49 struct rtc_device *rtc = to_rtc_device(dev);
50 struct rtc_time tm;
51 struct timespec delta, delta_delta;
52 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
53 return 0;
54
55 /* snapshot the current RTC and system time at suspend*/
56 rtc_read_time(rtc, &tm);
57 getnstimeofday(&old_system);
58 rtc_tm_to_time(&tm, &old_rtc.tv_sec);
59
60
61 /*
62 * To avoid drift caused by repeated suspend/resumes,
63 * which each can add ~1 second drift error,
64 * try to compensate so the difference in system time
65 * and rtc time stays close to constant.
66 */
67 delta = timespec_sub(old_system, old_rtc);
68 delta_delta = timespec_sub(delta, old_delta);
69 if (abs(delta_delta.tv_sec) >= 2) {
70 /*
71 * if delta_delta is too large, assume time correction
72 * has occured and set old_delta to the current delta.
73 */
74 old_delta = delta;
75 } else {
76 /* Otherwise try to adjust old_system to compensate */
77 old_system = timespec_sub(old_system, delta_delta);
78 }
79
80 return 0;
81}
82
83static int rtc_resume(struct device *dev)
84{
85 struct rtc_device *rtc = to_rtc_device(dev);
86 struct rtc_time tm;
87 struct timespec new_system, new_rtc;
88 struct timespec sleep_time;
89
90 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
91 return 0;
92
93 /* snapshot the current rtc and system time at resume */
94 getnstimeofday(&new_system);
95 rtc_read_time(rtc, &tm);
96 if (rtc_valid_tm(&tm) != 0) {
97 pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev));
98 return 0;
99 }
100 rtc_tm_to_time(&tm, &new_rtc.tv_sec);
101 new_rtc.tv_nsec = 0;
102
103 if (new_rtc.tv_sec <= old_rtc.tv_sec) {
104 if (new_rtc.tv_sec < old_rtc.tv_sec)
105 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
106 return 0;
107 }
108
109 /* calculate the RTC time delta (sleep time)*/
110 sleep_time = timespec_sub(new_rtc, old_rtc);
111
112 /*
113 * Since these RTC suspend/resume handlers are not called
114 * at the very end of suspend or the start of resume,
115 * some run-time may pass on either sides of the sleep time
116 * so subtract kernel run-time between rtc_suspend to rtc_resume
117 * to keep things accurate.
118 */
119 sleep_time = timespec_sub(sleep_time,
120 timespec_sub(new_system, old_system));
121
122 timekeeping_inject_sleeptime(&sleep_time);
123 return 0;
124}
125
126#else
127#define rtc_suspend NULL
128#define rtc_resume NULL
129#endif
130
131
132/**
133 * rtc_device_register - register w/ RTC class
134 * @dev: the device to register
135 *
136 * rtc_device_unregister() must be called when the class device is no
137 * longer needed.
138 *
139 * Returns the pointer to the new struct class device.
140 */
141struct rtc_device *rtc_device_register(const char *name, struct device *dev,
142 const struct rtc_class_ops *ops,
143 struct module *owner)
144{
145 struct rtc_device *rtc;
146 struct rtc_wkalrm alrm;
147 int id, err;
148
149 if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
150 err = -ENOMEM;
151 goto exit;
152 }
153
154
155 mutex_lock(&idr_lock);
156 err = idr_get_new(&rtc_idr, NULL, &id);
157 mutex_unlock(&idr_lock);
158
159 if (err < 0)
160 goto exit;
161
162 id = id & MAX_ID_MASK;
163
164 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
165 if (rtc == NULL) {
166 err = -ENOMEM;
167 goto exit_idr;
168 }
169
170 rtc->id = id;
171 rtc->ops = ops;
172 rtc->owner = owner;
173 rtc->irq_freq = 1;
174 rtc->max_user_freq = 64;
175 rtc->dev.parent = dev;
176 rtc->dev.class = rtc_class;
177 rtc->dev.release = rtc_device_release;
178
179 mutex_init(&rtc->ops_lock);
180 spin_lock_init(&rtc->irq_lock);
181 spin_lock_init(&rtc->irq_task_lock);
182 init_waitqueue_head(&rtc->irq_queue);
183
184 /* Init timerqueue */
185 timerqueue_init_head(&rtc->timerqueue);
186 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
187 /* Init aie timer */
188 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
189 /* Init uie timer */
190 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
191 /* Init pie timer */
192 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
193 rtc->pie_timer.function = rtc_pie_update_irq;
194 rtc->pie_enabled = 0;
195
196 /* Check to see if there is an ALARM already set in hw */
197 err = __rtc_read_alarm(rtc, &alrm);
198
199 if (!err && !rtc_valid_tm(&alrm.time))
200 rtc_initialize_alarm(rtc, &alrm);
201
202 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
203 dev_set_name(&rtc->dev, "rtc%d", id);
204
205 rtc_dev_prepare(rtc);
206
207 err = device_register(&rtc->dev);
208 if (err) {
209 put_device(&rtc->dev);
210 goto exit_kfree;
211 }
212
213 rtc_dev_add_device(rtc);
214 rtc_sysfs_add_device(rtc);
215 rtc_proc_add_device(rtc);
216
217 dev_info(dev, "rtc core: registered %s as %s\n",
218 rtc->name, dev_name(&rtc->dev));
219
220 return rtc;
221
222exit_kfree:
223 kfree(rtc);
224
225exit_idr:
226 mutex_lock(&idr_lock);
227 idr_remove(&rtc_idr, id);
228 mutex_unlock(&idr_lock);
229
230exit:
231 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
232 name, err);
233 return ERR_PTR(err);
234}
235EXPORT_SYMBOL_GPL(rtc_device_register);
236
237
238/**
239 * rtc_device_unregister - removes the previously registered RTC class device
240 *
241 * @rtc: the RTC class device to destroy
242 */
243void rtc_device_unregister(struct rtc_device *rtc)
244{
245 if (get_device(&rtc->dev) != NULL) {
246 mutex_lock(&rtc->ops_lock);
247 /* remove innards of this RTC, then disable it, before
248 * letting any rtc_class_open() users access it again
249 */
250 rtc_sysfs_del_device(rtc);
251 rtc_dev_del_device(rtc);
252 rtc_proc_del_device(rtc);
253 device_unregister(&rtc->dev);
254 rtc->ops = NULL;
255 mutex_unlock(&rtc->ops_lock);
256 put_device(&rtc->dev);
257 }
258}
259EXPORT_SYMBOL_GPL(rtc_device_unregister);
260
261static int __init rtc_init(void)
262{
263 rtc_class = class_create(THIS_MODULE, "rtc");
264 if (IS_ERR(rtc_class)) {
265 printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
266 return PTR_ERR(rtc_class);
267 }
268 rtc_class->suspend = rtc_suspend;
269 rtc_class->resume = rtc_resume;
270 rtc_dev_init();
271 rtc_sysfs_init(rtc_class);
272 return 0;
273}
274
275static void __exit rtc_exit(void)
276{
277 rtc_dev_exit();
278 class_destroy(rtc_class);
279 idr_destroy(&rtc_idr);
280}
281
282subsys_initcall(rtc_init);
283module_exit(rtc_exit);
284
285MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
286MODULE_DESCRIPTION("RTC class support");
287MODULE_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");