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0c86edc0 AZ |
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 | ||
c100a5e0 JH |
14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
15 | ||
0c86edc0 | 16 | #include <linux/module.h> |
9d2b7e53 | 17 | #include <linux/of.h> |
0c86edc0 AZ |
18 | #include <linux/rtc.h> |
19 | #include <linux/kdev_t.h> | |
20 | #include <linux/idr.h> | |
5a0e3ad6 | 21 | #include <linux/slab.h> |
6610e089 | 22 | #include <linux/workqueue.h> |
0c86edc0 | 23 | |
5726fb20 DB |
24 | #include "rtc-core.h" |
25 | ||
26 | ||
6d03d06d | 27 | static DEFINE_IDA(rtc_ida); |
0c86edc0 AZ |
28 | struct class *rtc_class; |
29 | ||
cd966209 | 30 | static void rtc_device_release(struct device *dev) |
0c86edc0 | 31 | { |
cd966209 | 32 | struct rtc_device *rtc = to_rtc_device(dev); |
6d03d06d | 33 | ida_simple_remove(&rtc_ida, rtc->id); |
0c86edc0 AZ |
34 | kfree(rtc); |
35 | } | |
36 | ||
4c24e29e DF |
37 | #ifdef CONFIG_RTC_HCTOSYS_DEVICE |
38 | /* Result of the last RTC to system clock attempt. */ | |
39 | int rtc_hctosys_ret = -ENODEV; | |
40 | #endif | |
7ca1d488 | 41 | |
92e7f04a | 42 | #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE) |
7ca1d488 DB |
43 | /* |
44 | * On suspend(), measure the delta between one RTC and the | |
45 | * system's wall clock; restore it on resume(). | |
46 | */ | |
47 | ||
d4bda8f8 | 48 | static struct timespec64 old_rtc, old_system, old_delta; |
3dcad5ff | 49 | |
7ca1d488 | 50 | |
92e7f04a | 51 | static int rtc_suspend(struct device *dev) |
7ca1d488 DB |
52 | { |
53 | struct rtc_device *rtc = to_rtc_device(dev); | |
54 | struct rtc_time tm; | |
d4bda8f8 | 55 | struct timespec64 delta, delta_delta; |
e1d60093 | 56 | int err; |
9ecf37eb | 57 | |
0fa88cb4 | 58 | if (timekeeping_rtc_skipsuspend()) |
9ecf37eb FT |
59 | return 0; |
60 | ||
d4afc76c | 61 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
62 | return 0; |
63 | ||
3dcad5ff | 64 | /* snapshot the current RTC and system time at suspend*/ |
e1d60093 HG |
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 | ||
d4bda8f8 JS |
71 | getnstimeofday64(&old_system); |
72 | old_rtc.tv_sec = rtc_tm_to_time64(&tm); | |
3dcad5ff JS |
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 | */ | |
d4bda8f8 JS |
81 | delta = timespec64_sub(old_system, old_rtc); |
82 | delta_delta = timespec64_sub(delta, old_delta); | |
6a8943d9 | 83 | if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) { |
3dcad5ff JS |
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 */ | |
d4bda8f8 | 91 | old_system = timespec64_sub(old_system, delta_delta); |
3dcad5ff | 92 | } |
7ca1d488 | 93 | |
7ca1d488 DB |
94 | return 0; |
95 | } | |
96 | ||
97 | static int rtc_resume(struct device *dev) | |
98 | { | |
99 | struct rtc_device *rtc = to_rtc_device(dev); | |
100 | struct rtc_time tm; | |
d4bda8f8 JS |
101 | struct timespec64 new_system, new_rtc; |
102 | struct timespec64 sleep_time; | |
e1d60093 | 103 | int err; |
7ca1d488 | 104 | |
0fa88cb4 | 105 | if (timekeeping_rtc_skipresume()) |
9ecf37eb FT |
106 | return 0; |
107 | ||
4c24e29e | 108 | rtc_hctosys_ret = -ENODEV; |
d4afc76c | 109 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
110 | return 0; |
111 | ||
3dcad5ff | 112 | /* snapshot the current rtc and system time at resume */ |
d4bda8f8 | 113 | getnstimeofday64(&new_system); |
e1d60093 HG |
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 | ||
d4bda8f8 | 120 | new_rtc.tv_sec = rtc_tm_to_time64(&tm); |
3dcad5ff JS |
121 | new_rtc.tv_nsec = 0; |
122 | ||
6a8943d9 AH |
123 | if (new_rtc.tv_sec < old_rtc.tv_sec) { |
124 | pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); | |
7ca1d488 DB |
125 | return 0; |
126 | } | |
127 | ||
3dcad5ff | 128 | /* calculate the RTC time delta (sleep time)*/ |
d4bda8f8 | 129 | sleep_time = timespec64_sub(new_rtc, old_rtc); |
3dcad5ff JS |
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 | */ | |
d4bda8f8 JS |
138 | sleep_time = timespec64_sub(sleep_time, |
139 | timespec64_sub(new_system, old_system)); | |
7ca1d488 | 140 | |
6a8943d9 | 141 | if (sleep_time.tv_sec >= 0) |
d4bda8f8 | 142 | timekeeping_inject_sleeptime64(&sleep_time); |
4c24e29e | 143 | rtc_hctosys_ret = 0; |
7ca1d488 DB |
144 | return 0; |
145 | } | |
146 | ||
92e7f04a SK |
147 | static 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) | |
7ca1d488 | 149 | #else |
92e7f04a | 150 | #define RTC_CLASS_DEV_PM_OPS NULL |
7ca1d488 DB |
151 | #endif |
152 | ||
153 | ||
0c86edc0 AZ |
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 | */ | |
163 | struct rtc_device *rtc_device_register(const char *name, struct device *dev, | |
ff8371ac | 164 | const struct rtc_class_ops *ops, |
0c86edc0 AZ |
165 | struct module *owner) |
166 | { | |
167 | struct rtc_device *rtc; | |
f44f7f96 | 168 | struct rtc_wkalrm alrm; |
9d2b7e53 SW |
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 | } | |
0c86edc0 | 183 | |
6d03d06d | 184 | if (id < 0) { |
9d2b7e53 SW |
185 | id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL); |
186 | if (id < 0) { | |
187 | err = id; | |
188 | goto exit; | |
189 | } | |
0c86edc0 AZ |
190 | } |
191 | ||
0c86edc0 AZ |
192 | rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL); |
193 | if (rtc == NULL) { | |
194 | err = -ENOMEM; | |
6d03d06d | 195 | goto exit_ida; |
0c86edc0 AZ |
196 | } |
197 | ||
d5ed9177 LG |
198 | device_initialize(&rtc->dev); |
199 | ||
0c86edc0 AZ |
200 | rtc->id = id; |
201 | rtc->ops = ops; | |
202 | rtc->owner = owner; | |
83a06bf5 | 203 | rtc->irq_freq = 1; |
110d693d | 204 | rtc->max_user_freq = 64; |
cd966209 DB |
205 | rtc->dev.parent = dev; |
206 | rtc->dev.class = rtc_class; | |
3ee2c40b | 207 | rtc->dev.groups = rtc_get_dev_attribute_groups(); |
cd966209 | 208 | rtc->dev.release = rtc_device_release; |
0c86edc0 AZ |
209 | |
210 | mutex_init(&rtc->ops_lock); | |
211 | spin_lock_init(&rtc->irq_lock); | |
212 | spin_lock_init(&rtc->irq_task_lock); | |
d691eb90 | 213 | init_waitqueue_head(&rtc->irq_queue); |
0c86edc0 | 214 | |
6610e089 JS |
215 | /* Init timerqueue */ |
216 | timerqueue_init_head(&rtc->timerqueue); | |
96c8f06a | 217 | INIT_WORK(&rtc->irqwork, rtc_timer_do_work); |
6610e089 | 218 | /* Init aie timer */ |
96c8f06a | 219 | rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc); |
6610e089 | 220 | /* Init uie timer */ |
96c8f06a | 221 | rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc); |
6610e089 JS |
222 | /* Init pie timer */ |
223 | hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
224 | rtc->pie_timer.function = rtc_pie_update_irq; | |
225 | rtc->pie_enabled = 0; | |
226 | ||
182683e9 AK |
227 | strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE); |
228 | dev_set_name(&rtc->dev, "rtc%d", id); | |
229 | ||
f44f7f96 JS |
230 | /* Check to see if there is an ALARM already set in hw */ |
231 | err = __rtc_read_alarm(rtc, &alrm); | |
232 | ||
233 | if (!err && !rtc_valid_tm(&alrm.time)) | |
f6d5b331 | 234 | rtc_initialize_alarm(rtc, &alrm); |
f44f7f96 | 235 | |
cb3a58d2 DB |
236 | rtc_dev_prepare(rtc); |
237 | ||
d5ed9177 | 238 | err = cdev_device_add(&rtc->char_dev, &rtc->dev); |
59cca865 | 239 | if (err) { |
d5ed9177 LG |
240 | dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n", |
241 | rtc->name, MAJOR(rtc->dev.devt), rtc->id); | |
242 | ||
6706664d | 243 | /* This will free both memory and the ID */ |
59cca865 | 244 | put_device(&rtc->dev); |
6706664d | 245 | goto exit; |
d5ed9177 LG |
246 | } else { |
247 | dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name, | |
248 | MAJOR(rtc->dev.devt), rtc->id); | |
59cca865 | 249 | } |
0c86edc0 | 250 | |
7d9f99ec | 251 | rtc_proc_add_device(rtc); |
5726fb20 | 252 | |
0c86edc0 | 253 | dev_info(dev, "rtc core: registered %s as %s\n", |
d4afc76c | 254 | rtc->name, dev_name(&rtc->dev)); |
0c86edc0 AZ |
255 | |
256 | return rtc; | |
257 | ||
6d03d06d JC |
258 | exit_ida: |
259 | ida_simple_remove(&rtc_ida, id); | |
0c86edc0 AZ |
260 | |
261 | exit: | |
d1d65b77 AZ |
262 | dev_err(dev, "rtc core: unable to register %s, err = %d\n", |
263 | name, err); | |
0c86edc0 AZ |
264 | return ERR_PTR(err); |
265 | } | |
266 | EXPORT_SYMBOL_GPL(rtc_device_register); | |
267 | ||
268 | ||
269 | /** | |
270 | * rtc_device_unregister - removes the previously registered RTC class device | |
271 | * | |
272 | * @rtc: the RTC class device to destroy | |
273 | */ | |
274 | void rtc_device_unregister(struct rtc_device *rtc) | |
275 | { | |
c3b399a4 DT |
276 | mutex_lock(&rtc->ops_lock); |
277 | /* | |
278 | * Remove innards of this RTC, then disable it, before | |
279 | * letting any rtc_class_open() users access it again | |
280 | */ | |
c3b399a4 | 281 | rtc_proc_del_device(rtc); |
d5ed9177 | 282 | cdev_device_del(&rtc->char_dev, &rtc->dev); |
c3b399a4 DT |
283 | rtc->ops = NULL; |
284 | mutex_unlock(&rtc->ops_lock); | |
285 | put_device(&rtc->dev); | |
0c86edc0 AZ |
286 | } |
287 | EXPORT_SYMBOL_GPL(rtc_device_unregister); | |
288 | ||
3e217b66 JH |
289 | static void devm_rtc_device_release(struct device *dev, void *res) |
290 | { | |
291 | struct rtc_device *rtc = *(struct rtc_device **)res; | |
292 | ||
293 | rtc_device_unregister(rtc); | |
294 | } | |
295 | ||
296 | static int devm_rtc_device_match(struct device *dev, void *res, void *data) | |
297 | { | |
298 | struct rtc **r = res; | |
299 | ||
300 | return *r == data; | |
301 | } | |
302 | ||
303 | /** | |
304 | * devm_rtc_device_register - resource managed rtc_device_register() | |
3e217b66 | 305 | * @dev: the device to register |
6636a994 | 306 | * @name: the name of the device |
3e217b66 JH |
307 | * @ops: the rtc operations structure |
308 | * @owner: the module owner | |
309 | * | |
310 | * @return a struct rtc on success, or an ERR_PTR on error | |
311 | * | |
312 | * Managed rtc_device_register(). The rtc_device returned from this function | |
313 | * are automatically freed on driver detach. See rtc_device_register() | |
314 | * for more information. | |
315 | */ | |
316 | ||
6636a994 JH |
317 | struct rtc_device *devm_rtc_device_register(struct device *dev, |
318 | const char *name, | |
3e217b66 JH |
319 | const struct rtc_class_ops *ops, |
320 | struct module *owner) | |
321 | { | |
322 | struct rtc_device **ptr, *rtc; | |
323 | ||
324 | ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL); | |
325 | if (!ptr) | |
326 | return ERR_PTR(-ENOMEM); | |
327 | ||
328 | rtc = rtc_device_register(name, dev, ops, owner); | |
329 | if (!IS_ERR(rtc)) { | |
330 | *ptr = rtc; | |
331 | devres_add(dev, ptr); | |
332 | } else { | |
333 | devres_free(ptr); | |
334 | } | |
335 | ||
336 | return rtc; | |
337 | } | |
338 | EXPORT_SYMBOL_GPL(devm_rtc_device_register); | |
339 | ||
340 | /** | |
341 | * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister() | |
342 | * @dev: the device to unregister | |
343 | * @rtc: the RTC class device to unregister | |
344 | * | |
345 | * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this | |
346 | * function will not need to be called and the resource management code will | |
347 | * ensure that the resource is freed. | |
348 | */ | |
349 | void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc) | |
350 | { | |
351 | int rc; | |
352 | ||
353 | rc = devres_release(dev, devm_rtc_device_release, | |
354 | devm_rtc_device_match, rtc); | |
355 | WARN_ON(rc); | |
356 | } | |
357 | EXPORT_SYMBOL_GPL(devm_rtc_device_unregister); | |
358 | ||
0c86edc0 AZ |
359 | static int __init rtc_init(void) |
360 | { | |
361 | rtc_class = class_create(THIS_MODULE, "rtc"); | |
362 | if (IS_ERR(rtc_class)) { | |
c100a5e0 | 363 | pr_err("couldn't create class\n"); |
0c86edc0 AZ |
364 | return PTR_ERR(rtc_class); |
365 | } | |
92e7f04a | 366 | rtc_class->pm = RTC_CLASS_DEV_PM_OPS; |
5726fb20 | 367 | rtc_dev_init(); |
0c86edc0 AZ |
368 | return 0; |
369 | } | |
818a8674 | 370 | subsys_initcall(rtc_init); |