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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 timespec64 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 timespec64 delta, delta_delta;
56 int err;
57
58 if (timekeeping_rtc_skipsuspend())
59 return 0;
60
61 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
62 return 0;
63
64 /* snapshot the current RTC and system time at suspend*/
65 err = rtc_read_time(rtc, &tm);
66 if (err < 0) {
67 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
68 return 0;
69 }
70
71 getnstimeofday64(&old_system);
72 old_rtc.tv_sec = rtc_tm_to_time64(&tm);
73
74
75 /*
76 * To avoid drift caused by repeated suspend/resumes,
77 * which each can add ~1 second drift error,
78 * try to compensate so the difference in system time
79 * and rtc time stays close to constant.
80 */
81 delta = timespec64_sub(old_system, old_rtc);
82 delta_delta = timespec64_sub(delta, old_delta);
83 if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
84 /*
85 * if delta_delta is too large, assume time correction
86 * has occured and set old_delta to the current delta.
87 */
88 old_delta = delta;
89 } else {
90 /* Otherwise try to adjust old_system to compensate */
91 old_system = timespec64_sub(old_system, delta_delta);
92 }
93
94 return 0;
95}
96
97static int rtc_resume(struct device *dev)
98{
99 struct rtc_device *rtc = to_rtc_device(dev);
100 struct rtc_time tm;
101 struct timespec64 new_system, new_rtc;
102 struct timespec64 sleep_time;
103 int err;
104
105 if (timekeeping_rtc_skipresume())
106 return 0;
107
108 rtc_hctosys_ret = -ENODEV;
109 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
110 return 0;
111
112 /* snapshot the current rtc and system time at resume */
113 getnstimeofday64(&new_system);
114 err = rtc_read_time(rtc, &tm);
115 if (err < 0) {
116 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
117 return 0;
118 }
119
120 new_rtc.tv_sec = rtc_tm_to_time64(&tm);
121 new_rtc.tv_nsec = 0;
122
123 if (new_rtc.tv_sec < old_rtc.tv_sec) {
124 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
125 return 0;
126 }
127
128 /* calculate the RTC time delta (sleep time)*/
129 sleep_time = timespec64_sub(new_rtc, old_rtc);
130
131 /*
132 * Since these RTC suspend/resume handlers are not called
133 * at the very end of suspend or the start of resume,
134 * some run-time may pass on either sides of the sleep time
135 * so subtract kernel run-time between rtc_suspend to rtc_resume
136 * to keep things accurate.
137 */
138 sleep_time = timespec64_sub(sleep_time,
139 timespec64_sub(new_system, old_system));
140
141 if (sleep_time.tv_sec >= 0)
142 timekeeping_inject_sleeptime64(&sleep_time);
143 rtc_hctosys_ret = 0;
144 return 0;
145}
146
147static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
148#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)
149#else
150#define RTC_CLASS_DEV_PM_OPS NULL
151#endif
152
153
154/**
155 * rtc_device_register - register w/ RTC class
156 * @dev: the device to register
157 *
158 * rtc_device_unregister() must be called when the class device is no
159 * longer needed.
160 *
161 * Returns the pointer to the new struct class device.
162 */
163struct rtc_device *rtc_device_register(const char *name, struct device *dev,
164 const struct rtc_class_ops *ops,
165 struct module *owner)
166{
167 struct rtc_device *rtc;
168 struct rtc_wkalrm alrm;
169 int of_id = -1, id = -1, err;
170
171 if (dev->of_node)
172 of_id = of_alias_get_id(dev->of_node, "rtc");
173 else if (dev->parent && dev->parent->of_node)
174 of_id = of_alias_get_id(dev->parent->of_node, "rtc");
175
176 if (of_id >= 0) {
177 id = ida_simple_get(&rtc_ida, of_id, of_id + 1,
178 GFP_KERNEL);
179 if (id < 0)
180 dev_warn(dev, "/aliases ID %d not available\n",
181 of_id);
182 }
183
184 if (id < 0) {
185 id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
186 if (id < 0) {
187 err = id;
188 goto exit;
189 }
190 }
191
192 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
193 if (rtc == NULL) {
194 err = -ENOMEM;
195 goto exit_ida;
196 }
197
198 rtc->id = id;
199 rtc->ops = ops;
200 rtc->owner = owner;
201 rtc->irq_freq = 1;
202 rtc->max_user_freq = 64;
203 rtc->dev.parent = dev;
204 rtc->dev.class = rtc_class;
205 rtc->dev.groups = rtc_get_dev_attribute_groups();
206 rtc->dev.release = rtc_device_release;
207
208 mutex_init(&rtc->ops_lock);
209 spin_lock_init(&rtc->irq_lock);
210 spin_lock_init(&rtc->irq_task_lock);
211 init_waitqueue_head(&rtc->irq_queue);
212
213 /* Init timerqueue */
214 timerqueue_init_head(&rtc->timerqueue);
215 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
216 /* Init aie timer */
217 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
218 /* Init uie timer */
219 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
220 /* Init pie timer */
221 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
222 rtc->pie_timer.function = rtc_pie_update_irq;
223 rtc->pie_enabled = 0;
224
225 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
226 dev_set_name(&rtc->dev, "rtc%d", id);
227
228 /* Check to see if there is an ALARM already set in hw */
229 err = __rtc_read_alarm(rtc, &alrm);
230
231 if (!err && !rtc_valid_tm(&alrm.time))
232 rtc_initialize_alarm(rtc, &alrm);
233
234 rtc_dev_prepare(rtc);
235
236 err = device_register(&rtc->dev);
237 if (err) {
238 /* This will free both memory and the ID */
239 put_device(&rtc->dev);
240 goto exit;
241 }
242
243 rtc_dev_add_device(rtc);
244 rtc_proc_add_device(rtc);
245
246 dev_info(dev, "rtc core: registered %s as %s\n",
247 rtc->name, dev_name(&rtc->dev));
248
249 return rtc;
250
251exit_ida:
252 ida_simple_remove(&rtc_ida, id);
253
254exit:
255 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
256 name, err);
257 return ERR_PTR(err);
258}
259EXPORT_SYMBOL_GPL(rtc_device_register);
260
261
262/**
263 * rtc_device_unregister - removes the previously registered RTC class device
264 *
265 * @rtc: the RTC class device to destroy
266 */
267void rtc_device_unregister(struct rtc_device *rtc)
268{
269 mutex_lock(&rtc->ops_lock);
270 /*
271 * Remove innards of this RTC, then disable it, before
272 * letting any rtc_class_open() users access it again
273 */
274 rtc_dev_del_device(rtc);
275 rtc_proc_del_device(rtc);
276 device_del(&rtc->dev);
277 rtc->ops = NULL;
278 mutex_unlock(&rtc->ops_lock);
279 put_device(&rtc->dev);
280}
281EXPORT_SYMBOL_GPL(rtc_device_unregister);
282
283static void devm_rtc_device_release(struct device *dev, void *res)
284{
285 struct rtc_device *rtc = *(struct rtc_device **)res;
286
287 rtc_device_unregister(rtc);
288}
289
290static int devm_rtc_device_match(struct device *dev, void *res, void *data)
291{
292 struct rtc **r = res;
293
294 return *r == data;
295}
296
297/**
298 * devm_rtc_device_register - resource managed rtc_device_register()
299 * @dev: the device to register
300 * @name: the name of the device
301 * @ops: the rtc operations structure
302 * @owner: the module owner
303 *
304 * @return a struct rtc on success, or an ERR_PTR on error
305 *
306 * Managed rtc_device_register(). The rtc_device returned from this function
307 * are automatically freed on driver detach. See rtc_device_register()
308 * for more information.
309 */
310
311struct rtc_device *devm_rtc_device_register(struct device *dev,
312 const char *name,
313 const struct rtc_class_ops *ops,
314 struct module *owner)
315{
316 struct rtc_device **ptr, *rtc;
317
318 ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
319 if (!ptr)
320 return ERR_PTR(-ENOMEM);
321
322 rtc = rtc_device_register(name, dev, ops, owner);
323 if (!IS_ERR(rtc)) {
324 *ptr = rtc;
325 devres_add(dev, ptr);
326 } else {
327 devres_free(ptr);
328 }
329
330 return rtc;
331}
332EXPORT_SYMBOL_GPL(devm_rtc_device_register);
333
334/**
335 * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
336 * @dev: the device to unregister
337 * @rtc: the RTC class device to unregister
338 *
339 * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
340 * function will not need to be called and the resource management code will
341 * ensure that the resource is freed.
342 */
343void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc)
344{
345 int rc;
346
347 rc = devres_release(dev, devm_rtc_device_release,
348 devm_rtc_device_match, rtc);
349 WARN_ON(rc);
350}
351EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
352
353static int __init rtc_init(void)
354{
355 rtc_class = class_create(THIS_MODULE, "rtc");
356 if (IS_ERR(rtc_class)) {
357 pr_err("couldn't create class\n");
358 return PTR_ERR(rtc_class);
359 }
360 rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
361 rtc_dev_init();
362 return 0;
363}
364subsys_initcall(rtc_init);