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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC subsystem, base class
4 *
5 * Copyright (C) 2005 Tower Technologies
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 *
8 * class skeleton from drivers/hwmon/hwmon.c
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/module.h>
14#include <linux/of.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
23static DEFINE_IDA(rtc_ida);
24struct class *rtc_class;
25
26static void rtc_device_release(struct device *dev)
27{
28 struct rtc_device *rtc = to_rtc_device(dev);
29
30 ida_simple_remove(&rtc_ida, rtc->id);
31 mutex_destroy(&rtc->ops_lock);
32 kfree(rtc);
33}
34
35#ifdef CONFIG_RTC_HCTOSYS_DEVICE
36/* Result of the last RTC to system clock attempt. */
37int rtc_hctosys_ret = -ENODEV;
38
39/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
40 * whether it stores the most close value or the value with partial
41 * seconds truncated. However, it is important that we use it to store
42 * the truncated value. This is because otherwise it is necessary,
43 * in an rtc sync function, to read both xtime.tv_sec and
44 * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
45 * of >32bits is not possible. So storing the most close value would
46 * slow down the sync API. So here we have the truncated value and
47 * the best guess is to add 0.5s.
48 */
49
50static void rtc_hctosys(struct rtc_device *rtc)
51{
52 int err;
53 struct rtc_time tm;
54 struct timespec64 tv64 = {
55 .tv_nsec = NSEC_PER_SEC >> 1,
56 };
57
58 err = rtc_read_time(rtc, &tm);
59 if (err) {
60 dev_err(rtc->dev.parent,
61 "hctosys: unable to read the hardware clock\n");
62 goto err_read;
63 }
64
65 tv64.tv_sec = rtc_tm_to_time64(&tm);
66
67#if BITS_PER_LONG == 32
68 if (tv64.tv_sec > INT_MAX) {
69 err = -ERANGE;
70 goto err_read;
71 }
72#endif
73
74 err = do_settimeofday64(&tv64);
75
76 dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
77 &tm, (long long)tv64.tv_sec);
78
79err_read:
80 rtc_hctosys_ret = err;
81}
82#endif
83
84#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
85/*
86 * On suspend(), measure the delta between one RTC and the
87 * system's wall clock; restore it on resume().
88 */
89
90static struct timespec64 old_rtc, old_system, old_delta;
91
92static int rtc_suspend(struct device *dev)
93{
94 struct rtc_device *rtc = to_rtc_device(dev);
95 struct rtc_time tm;
96 struct timespec64 delta, delta_delta;
97 int err;
98
99 if (timekeeping_rtc_skipsuspend())
100 return 0;
101
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 suspend*/
106 err = rtc_read_time(rtc, &tm);
107 if (err < 0) {
108 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
109 return 0;
110 }
111
112 ktime_get_real_ts64(&old_system);
113 old_rtc.tv_sec = rtc_tm_to_time64(&tm);
114
115 /*
116 * To avoid drift caused by repeated suspend/resumes,
117 * which each can add ~1 second drift error,
118 * try to compensate so the difference in system time
119 * and rtc time stays close to constant.
120 */
121 delta = timespec64_sub(old_system, old_rtc);
122 delta_delta = timespec64_sub(delta, old_delta);
123 if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
124 /*
125 * if delta_delta is too large, assume time correction
126 * has occurred and set old_delta to the current delta.
127 */
128 old_delta = delta;
129 } else {
130 /* Otherwise try to adjust old_system to compensate */
131 old_system = timespec64_sub(old_system, delta_delta);
132 }
133
134 return 0;
135}
136
137static int rtc_resume(struct device *dev)
138{
139 struct rtc_device *rtc = to_rtc_device(dev);
140 struct rtc_time tm;
141 struct timespec64 new_system, new_rtc;
142 struct timespec64 sleep_time;
143 int err;
144
145 if (timekeeping_rtc_skipresume())
146 return 0;
147
148 rtc_hctosys_ret = -ENODEV;
149 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
150 return 0;
151
152 /* snapshot the current rtc and system time at resume */
153 ktime_get_real_ts64(&new_system);
154 err = rtc_read_time(rtc, &tm);
155 if (err < 0) {
156 pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
157 return 0;
158 }
159
160 new_rtc.tv_sec = rtc_tm_to_time64(&tm);
161 new_rtc.tv_nsec = 0;
162
163 if (new_rtc.tv_sec < old_rtc.tv_sec) {
164 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
165 return 0;
166 }
167
168 /* calculate the RTC time delta (sleep time)*/
169 sleep_time = timespec64_sub(new_rtc, old_rtc);
170
171 /*
172 * Since these RTC suspend/resume handlers are not called
173 * at the very end of suspend or the start of resume,
174 * some run-time may pass on either sides of the sleep time
175 * so subtract kernel run-time between rtc_suspend to rtc_resume
176 * to keep things accurate.
177 */
178 sleep_time = timespec64_sub(sleep_time,
179 timespec64_sub(new_system, old_system));
180
181 if (sleep_time.tv_sec >= 0)
182 timekeeping_inject_sleeptime64(&sleep_time);
183 rtc_hctosys_ret = 0;
184 return 0;
185}
186
187static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
188#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)
189#else
190#define RTC_CLASS_DEV_PM_OPS NULL
191#endif
192
193/* Ensure the caller will set the id before releasing the device */
194static struct rtc_device *rtc_allocate_device(void)
195{
196 struct rtc_device *rtc;
197
198 rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
199 if (!rtc)
200 return NULL;
201
202 device_initialize(&rtc->dev);
203
204 /*
205 * Drivers can revise this default after allocating the device.
206 * The default is what most RTCs do: Increment seconds exactly one
207 * second after the write happened. This adds a default transport
208 * time of 5ms which is at least halfways close to reality.
209 */
210 rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC;
211
212 rtc->irq_freq = 1;
213 rtc->max_user_freq = 64;
214 rtc->dev.class = rtc_class;
215 rtc->dev.groups = rtc_get_dev_attribute_groups();
216 rtc->dev.release = rtc_device_release;
217
218 mutex_init(&rtc->ops_lock);
219 spin_lock_init(&rtc->irq_lock);
220 init_waitqueue_head(&rtc->irq_queue);
221
222 /* Init timerqueue */
223 timerqueue_init_head(&rtc->timerqueue);
224 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
225 /* Init aie timer */
226 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc);
227 /* Init uie timer */
228 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc);
229 /* Init pie timer */
230 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
231 rtc->pie_timer.function = rtc_pie_update_irq;
232 rtc->pie_enabled = 0;
233
234 set_bit(RTC_FEATURE_ALARM, rtc->features);
235
236 return rtc;
237}
238
239static int rtc_device_get_id(struct device *dev)
240{
241 int of_id = -1, id = -1;
242
243 if (dev->of_node)
244 of_id = of_alias_get_id(dev->of_node, "rtc");
245 else if (dev->parent && dev->parent->of_node)
246 of_id = of_alias_get_id(dev->parent->of_node, "rtc");
247
248 if (of_id >= 0) {
249 id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL);
250 if (id < 0)
251 dev_warn(dev, "/aliases ID %d not available\n", of_id);
252 }
253
254 if (id < 0)
255 id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
256
257 return id;
258}
259
260static void rtc_device_get_offset(struct rtc_device *rtc)
261{
262 time64_t range_secs;
263 u32 start_year;
264 int ret;
265
266 /*
267 * If RTC driver did not implement the range of RTC hardware device,
268 * then we can not expand the RTC range by adding or subtracting one
269 * offset.
270 */
271 if (rtc->range_min == rtc->range_max)
272 return;
273
274 ret = device_property_read_u32(rtc->dev.parent, "start-year",
275 &start_year);
276 if (!ret) {
277 rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0);
278 rtc->set_start_time = true;
279 }
280
281 /*
282 * If user did not implement the start time for RTC driver, then no
283 * need to expand the RTC range.
284 */
285 if (!rtc->set_start_time)
286 return;
287
288 range_secs = rtc->range_max - rtc->range_min + 1;
289
290 /*
291 * If the start_secs is larger than the maximum seconds (rtc->range_max)
292 * supported by RTC hardware or the maximum seconds of new expanded
293 * range (start_secs + rtc->range_max - rtc->range_min) is less than
294 * rtc->range_min, which means the minimum seconds (rtc->range_min) of
295 * RTC hardware will be mapped to start_secs by adding one offset, so
296 * the offset seconds calculation formula should be:
297 * rtc->offset_secs = rtc->start_secs - rtc->range_min;
298 *
299 * If the start_secs is larger than the minimum seconds (rtc->range_min)
300 * supported by RTC hardware, then there is one region is overlapped
301 * between the original RTC hardware range and the new expanded range,
302 * and this overlapped region do not need to be mapped into the new
303 * expanded range due to it is valid for RTC device. So the minimum
304 * seconds of RTC hardware (rtc->range_min) should be mapped to
305 * rtc->range_max + 1, then the offset seconds formula should be:
306 * rtc->offset_secs = rtc->range_max - rtc->range_min + 1;
307 *
308 * If the start_secs is less than the minimum seconds (rtc->range_min),
309 * which is similar to case 2. So the start_secs should be mapped to
310 * start_secs + rtc->range_max - rtc->range_min + 1, then the
311 * offset seconds formula should be:
312 * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1);
313 *
314 * Otherwise the offset seconds should be 0.
315 */
316 if (rtc->start_secs > rtc->range_max ||
317 rtc->start_secs + range_secs - 1 < rtc->range_min)
318 rtc->offset_secs = rtc->start_secs - rtc->range_min;
319 else if (rtc->start_secs > rtc->range_min)
320 rtc->offset_secs = range_secs;
321 else if (rtc->start_secs < rtc->range_min)
322 rtc->offset_secs = -range_secs;
323 else
324 rtc->offset_secs = 0;
325}
326
327static void devm_rtc_unregister_device(void *data)
328{
329 struct rtc_device *rtc = data;
330
331 mutex_lock(&rtc->ops_lock);
332 /*
333 * Remove innards of this RTC, then disable it, before
334 * letting any rtc_class_open() users access it again
335 */
336 rtc_proc_del_device(rtc);
337 cdev_device_del(&rtc->char_dev, &rtc->dev);
338 rtc->ops = NULL;
339 mutex_unlock(&rtc->ops_lock);
340}
341
342static void devm_rtc_release_device(void *res)
343{
344 struct rtc_device *rtc = res;
345
346 put_device(&rtc->dev);
347}
348
349struct rtc_device *devm_rtc_allocate_device(struct device *dev)
350{
351 struct rtc_device *rtc;
352 int id, err;
353
354 id = rtc_device_get_id(dev);
355 if (id < 0)
356 return ERR_PTR(id);
357
358 rtc = rtc_allocate_device();
359 if (!rtc) {
360 ida_simple_remove(&rtc_ida, id);
361 return ERR_PTR(-ENOMEM);
362 }
363
364 rtc->id = id;
365 rtc->dev.parent = dev;
366 dev_set_name(&rtc->dev, "rtc%d", id);
367
368 err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc);
369 if (err)
370 return ERR_PTR(err);
371
372 return rtc;
373}
374EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
375
376int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
377{
378 struct rtc_wkalrm alrm;
379 int err;
380
381 if (!rtc->ops) {
382 dev_dbg(&rtc->dev, "no ops set\n");
383 return -EINVAL;
384 }
385
386 if (!rtc->ops->set_alarm)
387 clear_bit(RTC_FEATURE_ALARM, rtc->features);
388
389 rtc->owner = owner;
390 rtc_device_get_offset(rtc);
391
392 /* Check to see if there is an ALARM already set in hw */
393 err = __rtc_read_alarm(rtc, &alrm);
394 if (!err && !rtc_valid_tm(&alrm.time))
395 rtc_initialize_alarm(rtc, &alrm);
396
397 rtc_dev_prepare(rtc);
398
399 err = cdev_device_add(&rtc->char_dev, &rtc->dev);
400 if (err)
401 dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
402 MAJOR(rtc->dev.devt), rtc->id);
403 else
404 dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
405 MAJOR(rtc->dev.devt), rtc->id);
406
407 rtc_proc_add_device(rtc);
408
409 dev_info(rtc->dev.parent, "registered as %s\n",
410 dev_name(&rtc->dev));
411
412#ifdef CONFIG_RTC_HCTOSYS_DEVICE
413 if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE))
414 rtc_hctosys(rtc);
415#endif
416
417 return devm_add_action_or_reset(rtc->dev.parent,
418 devm_rtc_unregister_device, rtc);
419}
420EXPORT_SYMBOL_GPL(__devm_rtc_register_device);
421
422/**
423 * devm_rtc_device_register - resource managed rtc_device_register()
424 * @dev: the device to register
425 * @name: the name of the device (unused)
426 * @ops: the rtc operations structure
427 * @owner: the module owner
428 *
429 * @return a struct rtc on success, or an ERR_PTR on error
430 *
431 * Managed rtc_device_register(). The rtc_device returned from this function
432 * are automatically freed on driver detach.
433 * This function is deprecated, use devm_rtc_allocate_device and
434 * rtc_register_device instead
435 */
436struct rtc_device *devm_rtc_device_register(struct device *dev,
437 const char *name,
438 const struct rtc_class_ops *ops,
439 struct module *owner)
440{
441 struct rtc_device *rtc;
442 int err;
443
444 rtc = devm_rtc_allocate_device(dev);
445 if (IS_ERR(rtc))
446 return rtc;
447
448 rtc->ops = ops;
449
450 err = __devm_rtc_register_device(owner, rtc);
451 if (err)
452 return ERR_PTR(err);
453
454 return rtc;
455}
456EXPORT_SYMBOL_GPL(devm_rtc_device_register);
457
458static int __init rtc_init(void)
459{
460 rtc_class = class_create(THIS_MODULE, "rtc");
461 if (IS_ERR(rtc_class)) {
462 pr_err("couldn't create class\n");
463 return PTR_ERR(rtc_class);
464 }
465 rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
466 rtc_dev_init();
467 return 0;
468}
469subsys_initcall(rtc_init);