projects/linux·blob v4.13 · refs

474 lines · 11.1 KiB

1/*
2 * RTC subsystem, base class
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <[email protected]>
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/* Ensure the caller will set the id before releasing the device */
154static struct rtc_device *rtc_allocate_device(void)
155{
156 struct rtc_device *rtc;
157
158 rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
159 if (!rtc)
160 return NULL;
161
162 device_initialize(&rtc->dev);
163
164 rtc->irq_freq = 1;
165 rtc->max_user_freq = 64;
166 rtc->dev.class = rtc_class;
167 rtc->dev.groups = rtc_get_dev_attribute_groups();
168 rtc->dev.release = rtc_device_release;
169
170 mutex_init(&rtc->ops_lock);
171 spin_lock_init(&rtc->irq_lock);
172 spin_lock_init(&rtc->irq_task_lock);
173 init_waitqueue_head(&rtc->irq_queue);
174
175 /* Init timerqueue */
176 timerqueue_init_head(&rtc->timerqueue);
177 INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
178 /* Init aie timer */
179 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
180 /* Init uie timer */
181 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
182 /* Init pie timer */
183 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
184 rtc->pie_timer.function = rtc_pie_update_irq;
185 rtc->pie_enabled = 0;
186
187 return rtc;
188}
189
190static int rtc_device_get_id(struct device *dev)
191{
192 int of_id = -1, id = -1;
193
194 if (dev->of_node)
195 of_id = of_alias_get_id(dev->of_node, "rtc");
196 else if (dev->parent && dev->parent->of_node)
197 of_id = of_alias_get_id(dev->parent->of_node, "rtc");
198
199 if (of_id >= 0) {
200 id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL);
201 if (id < 0)
202 dev_warn(dev, "/aliases ID %d not available\n", of_id);
203 }
204
205 if (id < 0)
206 id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
207
208 return id;
209}
210
211/**
212 * rtc_device_register - register w/ RTC class
213 * @dev: the device to register
214 *
215 * rtc_device_unregister() must be called when the class device is no
216 * longer needed.
217 *
218 * Returns the pointer to the new struct class device.
219 */
220struct rtc_device *rtc_device_register(const char *name, struct device *dev,
221 const struct rtc_class_ops *ops,
222 struct module *owner)
223{
224 struct rtc_device *rtc;
225 struct rtc_wkalrm alrm;
226 int id, err;
227
228 id = rtc_device_get_id(dev);
229 if (id < 0) {
230 err = id;
231 goto exit;
232 }
233
234 rtc = rtc_allocate_device();
235 if (!rtc) {
236 err = -ENOMEM;
237 goto exit_ida;
238 }
239
240 rtc->id = id;
241 rtc->ops = ops;
242 rtc->owner = owner;
243 rtc->dev.parent = dev;
244
245 dev_set_name(&rtc->dev, "rtc%d", id);
246
247 /* Check to see if there is an ALARM already set in hw */
248 err = __rtc_read_alarm(rtc, &alrm);
249
250 if (!err && !rtc_valid_tm(&alrm.time))
251 rtc_initialize_alarm(rtc, &alrm);
252
253 rtc_dev_prepare(rtc);
254
255 err = cdev_device_add(&rtc->char_dev, &rtc->dev);
256 if (err) {
257 dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n",
258 name, MAJOR(rtc->dev.devt), rtc->id);
259
260 /* This will free both memory and the ID */
261 put_device(&rtc->dev);
262 goto exit;
263 } else {
264 dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", name,
265 MAJOR(rtc->dev.devt), rtc->id);
266 }
267
268 rtc_proc_add_device(rtc);
269
270 dev_info(dev, "rtc core: registered %s as %s\n",
271 name, dev_name(&rtc->dev));
272
273 return rtc;
274
275exit_ida:
276 ida_simple_remove(&rtc_ida, id);
277
278exit:
279 dev_err(dev, "rtc core: unable to register %s, err = %d\n",
280 name, err);
281 return ERR_PTR(err);
282}
283EXPORT_SYMBOL_GPL(rtc_device_register);
284
285
286/**
287 * rtc_device_unregister - removes the previously registered RTC class device
288 *
289 * @rtc: the RTC class device to destroy
290 */
291void rtc_device_unregister(struct rtc_device *rtc)
292{
293 rtc_nvmem_unregister(rtc);
294
295 mutex_lock(&rtc->ops_lock);
296 /*
297 * Remove innards of this RTC, then disable it, before
298 * letting any rtc_class_open() users access it again
299 */
300 rtc_proc_del_device(rtc);
301 cdev_device_del(&rtc->char_dev, &rtc->dev);
302 rtc->ops = NULL;
303 mutex_unlock(&rtc->ops_lock);
304 put_device(&rtc->dev);
305}
306EXPORT_SYMBOL_GPL(rtc_device_unregister);
307
308static void devm_rtc_device_release(struct device *dev, void *res)
309{
310 struct rtc_device *rtc = *(struct rtc_device **)res;
311
312 rtc_device_unregister(rtc);
313}
314
315static int devm_rtc_device_match(struct device *dev, void *res, void *data)
316{
317 struct rtc **r = res;
318
319 return *r == data;
320}
321
322/**
323 * devm_rtc_device_register - resource managed rtc_device_register()
324 * @dev: the device to register
325 * @name: the name of the device
326 * @ops: the rtc operations structure
327 * @owner: the module owner
328 *
329 * @return a struct rtc on success, or an ERR_PTR on error
330 *
331 * Managed rtc_device_register(). The rtc_device returned from this function
332 * are automatically freed on driver detach. See rtc_device_register()
333 * for more information.
334 */
335
336struct rtc_device *devm_rtc_device_register(struct device *dev,
337 const char *name,
338 const struct rtc_class_ops *ops,
339 struct module *owner)
340{
341 struct rtc_device **ptr, *rtc;
342
343 ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
344 if (!ptr)
345 return ERR_PTR(-ENOMEM);
346
347 rtc = rtc_device_register(name, dev, ops, owner);
348 if (!IS_ERR(rtc)) {
349 *ptr = rtc;
350 devres_add(dev, ptr);
351 } else {
352 devres_free(ptr);
353 }
354
355 return rtc;
356}
357EXPORT_SYMBOL_GPL(devm_rtc_device_register);
358
359/**
360 * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
361 * @dev: the device to unregister
362 * @rtc: the RTC class device to unregister
363 *
364 * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
365 * function will not need to be called and the resource management code will
366 * ensure that the resource is freed.
367 */
368void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc)
369{
370 int rc;
371
372 rc = devres_release(dev, devm_rtc_device_release,
373 devm_rtc_device_match, rtc);
374 WARN_ON(rc);
375}
376EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
377
378static void devm_rtc_release_device(struct device *dev, void *res)
379{
380 struct rtc_device *rtc = *(struct rtc_device **)res;
381
382 if (rtc->registered)
383 rtc_device_unregister(rtc);
384 else
385 put_device(&rtc->dev);
386}
387
388struct rtc_device *devm_rtc_allocate_device(struct device *dev)
389{
390 struct rtc_device **ptr, *rtc;
391 int id, err;
392
393 id = rtc_device_get_id(dev);
394 if (id < 0)
395 return ERR_PTR(id);
396
397 ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
398 if (!ptr) {
399 err = -ENOMEM;
400 goto exit_ida;
401 }
402
403 rtc = rtc_allocate_device();
404 if (!rtc) {
405 err = -ENOMEM;
406 goto exit_devres;
407 }
408
409 *ptr = rtc;
410 devres_add(dev, ptr);
411
412 rtc->id = id;
413 rtc->dev.parent = dev;
414 dev_set_name(&rtc->dev, "rtc%d", id);
415
416 return rtc;
417
418exit_devres:
419 devres_free(ptr);
420exit_ida:
421 ida_simple_remove(&rtc_ida, id);
422 return ERR_PTR(err);
423}
424EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
425
426int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
427{
428 struct rtc_wkalrm alrm;
429 int err;
430
431 if (!rtc->ops)
432 return -EINVAL;
433
434 rtc->owner = owner;
435
436 /* Check to see if there is an ALARM already set in hw */
437 err = __rtc_read_alarm(rtc, &alrm);
438 if (!err && !rtc_valid_tm(&alrm.time))
439 rtc_initialize_alarm(rtc, &alrm);
440
441 rtc_dev_prepare(rtc);
442
443 err = cdev_device_add(&rtc->char_dev, &rtc->dev);
444 if (err)
445 dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
446 MAJOR(rtc->dev.devt), rtc->id);
447 else
448 dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
449 MAJOR(rtc->dev.devt), rtc->id);
450
451 rtc_proc_add_device(rtc);
452
453 rtc_nvmem_register(rtc);
454
455 rtc->registered = true;
456 dev_info(rtc->dev.parent, "registered as %s\n",
457 dev_name(&rtc->dev));
458
459 return 0;
460}
461EXPORT_SYMBOL_GPL(__rtc_register_device);
462
463static int __init rtc_init(void)
464{
465 rtc_class = class_create(THIS_MODULE, "rtc");
466 if (IS_ERR(rtc_class)) {
467 pr_err("couldn't create class\n");
468 return PTR_ERR(rtc_class);
469 }
470 rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
471 rtc_dev_init();
472 return 0;
473}
474subsys_initcall(rtc_init);