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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
Jingoo Hanc100a5e2013-02-21 16:45:23 -080014#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080016#include <linux/module.h>
Stephen Warren9d2b7e52014-01-23 15:55:14 -080017#include <linux/of.h>
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080018#include <linux/rtc.h>
19#include <linux/kdev_t.h>
20#include <linux/idr.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/slab.h>
John Stultz6610e082010-09-23 15:07:34 -070022#include <linux/workqueue.h>
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080023
David Brownell5726fb22007-05-08 00:33:27 -070024#include "rtc-core.h"
25
26
Jonathan Cameron6d03d062011-11-02 13:37:49 -070027static DEFINE_IDA(rtc_ida);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080028struct class *rtc_class;
29
David Brownellcd966202007-05-08 00:33:40 -070030static void rtc_device_release(struct device *dev)
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080031{
David Brownellcd966202007-05-08 00:33:40 -070032 struct rtc_device *rtc = to_rtc_device(dev);
Jonathan Cameron6d03d062011-11-02 13:37:49 -070033 ida_simple_remove(&rtc_ida, rtc->id);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -080034 kfree(rtc);
35}
36
David Fries4c24e292012-10-04 17:14:12 -070037#ifdef CONFIG_RTC_HCTOSYS_DEVICE
38/* Result of the last RTC to system clock attempt. */
39int rtc_hctosys_ret = -ENODEV;
40#endif
David Brownell7ca1d482007-05-08 00:33:42 -070041
Shuah Khan92e7f042013-07-03 15:07:59 -070042#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
David Brownell7ca1d482007-05-08 00:33:42 -070043/*
44 * On suspend(), measure the delta between one RTC and the
45 * system's wall clock; restore it on resume().
46 */
47
John Stultzd4bda8f2014-11-20 21:06:12 -080048static struct timespec64 old_rtc, old_system, old_delta;
John Stultz3dcad5f2011-05-27 11:33:18 -070049
David Brownell7ca1d482007-05-08 00:33:42 -070050
Shuah Khan92e7f042013-07-03 15:07:59 -070051static int rtc_suspend(struct device *dev)
David Brownell7ca1d482007-05-08 00:33:42 -070052{
53 struct rtc_device *rtc = to_rtc_device(dev);
54 struct rtc_time tm;
John Stultzd4bda8f2014-11-20 21:06:12 -080055 struct timespec64 delta, delta_delta;
Hyogi Gime1d60092014-08-08 14:20:24 -070056 int err;
Feng Tang9ecf37e2013-01-16 00:09:48 +080057
Xunlei Pang0fa88cb2015-04-01 20:34:38 -070058 if (timekeeping_rtc_skipsuspend())
Feng Tang9ecf37e2013-01-16 00:09:48 +080059 return 0;
60
Kay Sieversd4afc762009-01-06 14:42:11 -080061 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
David Brownell7ca1d482007-05-08 00:33:42 -070062 return 0;
63
John Stultz3dcad5f2011-05-27 11:33:18 -070064 /* snapshot the current RTC and system time at suspend*/
Hyogi Gime1d60092014-08-08 14:20:24 -070065 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
John Stultzd4bda8f2014-11-20 21:06:12 -080071 getnstimeofday64(&old_system);
72 old_rtc.tv_sec = rtc_tm_to_time64(&tm);
John Stultz3dcad5f2011-05-27 11:33:18 -070073
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 */
John Stultzd4bda8f2014-11-20 21:06:12 -080081 delta = timespec64_sub(old_system, old_rtc);
82 delta_delta = timespec64_sub(delta, old_delta);
Arve Hjønnevåg6a8943d2011-11-22 18:24:51 -080083 if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
John Stultz3dcad5f2011-05-27 11:33:18 -070084 /*
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 */
John Stultzd4bda8f2014-11-20 21:06:12 -080091 old_system = timespec64_sub(old_system, delta_delta);
John Stultz3dcad5f2011-05-27 11:33:18 -070092 }
David Brownell7ca1d482007-05-08 00:33:42 -070093
David Brownell7ca1d482007-05-08 00:33:42 -070094 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;
John Stultzd4bda8f2014-11-20 21:06:12 -0800101 struct timespec64 new_system, new_rtc;
102 struct timespec64 sleep_time;
Hyogi Gime1d60092014-08-08 14:20:24 -0700103 int err;
David Brownell7ca1d482007-05-08 00:33:42 -0700104
Xunlei Pang0fa88cb2015-04-01 20:34:38 -0700105 if (timekeeping_rtc_skipresume())
Feng Tang9ecf37e2013-01-16 00:09:48 +0800106 return 0;
107
David Fries4c24e292012-10-04 17:14:12 -0700108 rtc_hctosys_ret = -ENODEV;
Kay Sieversd4afc762009-01-06 14:42:11 -0800109 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
David Brownell7ca1d482007-05-08 00:33:42 -0700110 return 0;
111
John Stultz3dcad5f2011-05-27 11:33:18 -0700112 /* snapshot the current rtc and system time at resume */
John Stultzd4bda8f2014-11-20 21:06:12 -0800113 getnstimeofday64(&new_system);
Hyogi Gime1d60092014-08-08 14:20:24 -0700114 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
John Stultzd4bda8f2014-11-20 21:06:12 -0800120 new_rtc.tv_sec = rtc_tm_to_time64(&tm);
John Stultz3dcad5f2011-05-27 11:33:18 -0700121 new_rtc.tv_nsec = 0;
122
Arve Hjønnevåg6a8943d2011-11-22 18:24:51 -0800123 if (new_rtc.tv_sec < old_rtc.tv_sec) {
124 pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
David Brownell7ca1d482007-05-08 00:33:42 -0700125 return 0;
126 }
127
John Stultz3dcad5f2011-05-27 11:33:18 -0700128 /* calculate the RTC time delta (sleep time)*/
John Stultzd4bda8f2014-11-20 21:06:12 -0800129 sleep_time = timespec64_sub(new_rtc, old_rtc);
David Brownell7ca1d482007-05-08 00:33:42 -0700130
John Stultz3dcad5f2011-05-27 11:33:18 -0700131 /*
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 */
John Stultzd4bda8f2014-11-20 21:06:12 -0800138 sleep_time = timespec64_sub(sleep_time,
139 timespec64_sub(new_system, old_system));
John Stultz3dcad5f2011-05-27 11:33:18 -0700140
Arve Hjønnevåg6a8943d2011-11-22 18:24:51 -0800141 if (sleep_time.tv_sec >= 0)
John Stultzd4bda8f2014-11-20 21:06:12 -0800142 timekeeping_inject_sleeptime64(&sleep_time);
David Fries4c24e292012-10-04 17:14:12 -0700143 rtc_hctosys_ret = 0;
David Brownell7ca1d482007-05-08 00:33:42 -0700144 return 0;
145}
146
Shuah Khan92e7f042013-07-03 15:07:59 -0700147static 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)
David Brownell7ca1d482007-05-08 00:33:42 -0700149#else
Shuah Khan92e7f042013-07-03 15:07:59 -0700150#define RTC_CLASS_DEV_PM_OPS NULL
David Brownell7ca1d482007-05-08 00:33:42 -0700151#endif
152
153
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800154/**
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,
David Brownellff8371a2006-09-30 23:28:17 -0700164 const struct rtc_class_ops *ops,
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800165 struct module *owner)
166{
167 struct rtc_device *rtc;
John Stultzf44f7f92011-02-21 22:58:51 -0800168 struct rtc_wkalrm alrm;
Stephen Warren9d2b7e52014-01-23 15:55:14 -0800169 int of_id = -1, id = -1, err;
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800170
Stephen Warren9d2b7e52014-01-23 15:55:14 -0800171 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
Jonathan Cameron6d03d062011-11-02 13:37:49 -0700184 if (id < 0) {
Stephen Warren9d2b7e52014-01-23 15:55:14 -0800185 id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
186 if (id < 0) {
187 err = id;
188 goto exit;
189 }
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800190 }
191
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800192 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
193 if (rtc == NULL) {
194 err = -ENOMEM;
Jonathan Cameron6d03d062011-11-02 13:37:49 -0700195 goto exit_ida;
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800196 }
197
198 rtc->id = id;
199 rtc->ops = ops;
200 rtc->owner = owner;
Marcelo Roberto Jimenez83a06bf2011-02-02 16:04:02 -0200201 rtc->irq_freq = 1;
Alessandro Zummo110d6932006-06-25 05:48:20 -0700202 rtc->max_user_freq = 64;
David Brownellcd966202007-05-08 00:33:40 -0700203 rtc->dev.parent = dev;
204 rtc->dev.class = rtc_class;
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700205 rtc->dev.groups = rtc_get_dev_attribute_groups();
David Brownellcd966202007-05-08 00:33:40 -0700206 rtc->dev.release = rtc_device_release;
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800207
208 mutex_init(&rtc->ops_lock);
209 spin_lock_init(&rtc->irq_lock);
210 spin_lock_init(&rtc->irq_task_lock);
Alessandro Zummod691eb92007-10-16 01:28:15 -0700211 init_waitqueue_head(&rtc->irq_queue);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800212
John Stultz6610e082010-09-23 15:07:34 -0700213 /* Init timerqueue */
214 timerqueue_init_head(&rtc->timerqueue);
Thomas Gleixner96c8f062010-12-13 22:45:48 +0100215 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
John Stultz6610e082010-09-23 15:07:34 -0700216 /* Init aie timer */
Thomas Gleixner96c8f062010-12-13 22:45:48 +0100217 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
John Stultz6610e082010-09-23 15:07:34 -0700218 /* Init uie timer */
Thomas Gleixner96c8f062010-12-13 22:45:48 +0100219 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
John Stultz6610e082010-09-23 15:07:34 -0700220 /* 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
Aaro Koskinen182683e2015-04-16 12:45:48 -0700225 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
226 dev_set_name(&rtc->dev, "rtc%d", id);
227
John Stultzf44f7f92011-02-21 22:58:51 -0800228 /* 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))
John Stultzf6d5b332011-03-29 18:00:27 -0700232 rtc_initialize_alarm(rtc, &alrm);
John Stultzf44f7f92011-02-21 22:58:51 -0800233
David Brownellcb3a58d2007-05-08 00:33:46 -0700234 rtc_dev_prepare(rtc);
235
David Brownellcd966202007-05-08 00:33:40 -0700236 err = device_register(&rtc->dev);
Vasiliy Kulikov59cca862010-10-27 15:33:04 -0700237 if (err) {
Dmitry Torokhov67066642015-07-20 16:02:49 -0700238 /* This will free both memory and the ID */
Vasiliy Kulikov59cca862010-10-27 15:33:04 -0700239 put_device(&rtc->dev);
Dmitry Torokhov67066642015-07-20 16:02:49 -0700240 goto exit;
Vasiliy Kulikov59cca862010-10-27 15:33:04 -0700241 }
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800242
David Brownell5726fb22007-05-08 00:33:27 -0700243 rtc_dev_add_device(rtc);
David Brownell7d9f99e2007-05-08 00:33:38 -0700244 rtc_proc_add_device(rtc);
David Brownell5726fb22007-05-08 00:33:27 -0700245
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800246 dev_info(dev, "rtc core: registered %s as %s\n",
Kay Sieversd4afc762009-01-06 14:42:11 -0800247 rtc->name, dev_name(&rtc->dev));
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800248
249 return rtc;
250
Jonathan Cameron6d03d062011-11-02 13:37:49 -0700251exit_ida:
252 ida_simple_remove(&rtc_ida, id);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800253
254exit:
Alessandro Zummod1d65b72006-04-10 22:54:45 -0700255 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
256 name, err);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800257 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{
Dmitry Torokhovc3b399a42015-07-20 16:02:50 -0700269 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 */
Dmitry Torokhovc3b399a42015-07-20 16:02:50 -0700274 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);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800280}
281EXPORT_SYMBOL_GPL(rtc_device_unregister);
282
Jingoo Han3e217b62013-04-29 16:18:27 -0700283static 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()
Jingoo Han3e217b62013-04-29 16:18:27 -0700299 * @dev: the device to register
Jingoo Han6636a992013-04-29 16:18:33 -0700300 * @name: the name of the device
Jingoo Han3e217b62013-04-29 16:18:27 -0700301 * @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
Jingoo Han6636a992013-04-29 16:18:33 -0700311struct rtc_device *devm_rtc_device_register(struct device *dev,
312 const char *name,
Jingoo Han3e217b62013-04-29 16:18:27 -0700313 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
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800353static int __init rtc_init(void)
354{
355 rtc_class = class_create(THIS_MODULE, "rtc");
356 if (IS_ERR(rtc_class)) {
Jingoo Hanc100a5e2013-02-21 16:45:23 -0800357 pr_err("couldn't create class\n");
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800358 return PTR_ERR(rtc_class);
359 }
Shuah Khan92e7f042013-07-03 15:07:59 -0700360 rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
David Brownell5726fb22007-05-08 00:33:27 -0700361 rtc_dev_init();
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800362 return 0;
363}
364
365static void __exit rtc_exit(void)
366{
David Brownell5726fb22007-05-08 00:33:27 -0700367 rtc_dev_exit();
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800368 class_destroy(rtc_class);
Jonathan Cameron6d03d062011-11-02 13:37:49 -0700369 ida_destroy(&rtc_ida);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800370}
371
David Brownell818a8672006-09-30 23:28:15 -0700372subsys_initcall(rtc_init);
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800373module_exit(rtc_exit);
374
David Brownell818a8672006-09-30 23:28:15 -0700375MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
Alessandro Zummo0c86edc2006-03-27 01:16:37 -0800376MODULE_DESCRIPTION("RTC class support");
377MODULE_LICENSE("GPL");