1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/interrupt.h>
23#include <linux/i2c.h>
24#include <linux/rtc.h>
25#include <linux/bcd.h>
26#include <linux/workqueue.h>
27#include <linux/slab.h>
28#include <linux/pm.h>
29#ifdef CONFIG_RTC_DRV_DS1374_WDT
30#include <linux/fs.h>
31#include <linux/ioctl.h>
32#include <linux/miscdevice.h>
33#include <linux/reboot.h>
34#include <linux/watchdog.h>
35#endif
36
37#define DS1374_REG_TOD0 0x00
38#define DS1374_REG_TOD1 0x01
39#define DS1374_REG_TOD2 0x02
40#define DS1374_REG_TOD3 0x03
41#define DS1374_REG_WDALM0 0x04
42#define DS1374_REG_WDALM1 0x05
43#define DS1374_REG_WDALM2 0x06
44#define DS1374_REG_CR 0x07
45#define DS1374_REG_CR_AIE 0x01
46#define DS1374_REG_CR_WDSTR 0x08
47#define DS1374_REG_CR_WDALM 0x20
48#define DS1374_REG_CR_WACE 0x40
49#define DS1374_REG_SR 0x08
50#define DS1374_REG_SR_OSF 0x80
51#define DS1374_REG_SR_AF 0x01
52#define DS1374_REG_TCR 0x09
53
54static const struct i2c_device_id ds1374_id[] = {
55 { "ds1374", 0 },
56 { }
57};
58MODULE_DEVICE_TABLE(i2c, ds1374_id);
59
60#ifdef CONFIG_OF
61static const struct of_device_id ds1374_of_match[] = {
62 { .compatible = "dallas,ds1374" },
63 { }
64};
65MODULE_DEVICE_TABLE(of, ds1374_of_match);
66#endif
67
68struct ds1374 {
69 struct i2c_client *client;
70 struct rtc_device *rtc;
71 struct work_struct work;
72#ifdef CONFIG_RTC_DRV_DS1374_WDT
73 struct watchdog_device wdt;
74#endif
75
76
77
78
79 struct mutex mutex;
80 int exiting;
81};
82
83static struct i2c_driver ds1374_driver;
84
85static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
86 int reg, int nbytes)
87{
88 u8 buf[4];
89 int ret;
90 int i;
91
92 if (WARN_ON(nbytes > 4))
93 return -EINVAL;
94
95 ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
96
97 if (ret < 0)
98 return ret;
99 if (ret < nbytes)
100 return -EIO;
101
102 for (i = nbytes - 1, *time = 0; i >= 0; i--)
103 *time = (*time << 8) | buf[i];
104
105 return 0;
106}
107
108static int ds1374_write_rtc(struct i2c_client *client, u32 time,
109 int reg, int nbytes)
110{
111 u8 buf[4];
112 int i;
113
114 if (nbytes > 4) {
115 WARN_ON(1);
116 return -EINVAL;
117 }
118
119 for (i = 0; i < nbytes; i++) {
120 buf[i] = time & 0xff;
121 time >>= 8;
122 }
123
124 return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
125}
126
127static int ds1374_check_rtc_status(struct i2c_client *client)
128{
129 int ret = 0;
130 int control, stat;
131
132 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
133 if (stat < 0)
134 return stat;
135
136 if (stat & DS1374_REG_SR_OSF)
137 dev_warn(&client->dev,
138 "oscillator discontinuity flagged, time unreliable\n");
139
140 stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);
141
142 ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
143 if (ret < 0)
144 return ret;
145
146
147
148
149
150
151 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
152 if (control < 0)
153 return control;
154
155 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
156 return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
157}
158
159static int ds1374_read_time(struct device *dev, struct rtc_time *time)
160{
161 struct i2c_client *client = to_i2c_client(dev);
162 u32 itime;
163 int ret;
164
165 ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
166 if (!ret)
167 rtc_time64_to_tm(itime, time);
168
169 return ret;
170}
171
172static int ds1374_set_time(struct device *dev, struct rtc_time *time)
173{
174 struct i2c_client *client = to_i2c_client(dev);
175 unsigned long itime = rtc_tm_to_time64(time);
176
177 return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
178}
179
180#ifndef CONFIG_RTC_DRV_DS1374_WDT
181
182
183
184
185static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
186{
187 struct i2c_client *client = to_i2c_client(dev);
188 struct ds1374 *ds1374 = i2c_get_clientdata(client);
189 u32 now, cur_alarm;
190 int cr, sr;
191 int ret = 0;
192
193 if (client->irq <= 0)
194 return -EINVAL;
195
196 mutex_lock(&ds1374->mutex);
197
198 cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
199 if (ret < 0)
200 goto out;
201
202 sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
203 if (ret < 0)
204 goto out;
205
206 ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
207 if (ret)
208 goto out;
209
210 ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
211 if (ret)
212 goto out;
213
214 rtc_time64_to_tm(now + cur_alarm, &alarm->time);
215 alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
216 alarm->pending = !!(sr & DS1374_REG_SR_AF);
217
218out:
219 mutex_unlock(&ds1374->mutex);
220 return ret;
221}
222
223static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
224{
225 struct i2c_client *client = to_i2c_client(dev);
226 struct ds1374 *ds1374 = i2c_get_clientdata(client);
227 struct rtc_time now;
228 unsigned long new_alarm, itime;
229 int cr;
230 int ret = 0;
231
232 if (client->irq <= 0)
233 return -EINVAL;
234
235 ret = ds1374_read_time(dev, &now);
236 if (ret < 0)
237 return ret;
238
239 new_alarm = rtc_tm_to_time64(&alarm->time);
240 itime = rtc_tm_to_time64(&now);
241
242
243
244
245
246
247
248 if (time_before_eq(new_alarm, itime))
249 new_alarm = 1;
250 else
251 new_alarm -= itime;
252
253 mutex_lock(&ds1374->mutex);
254
255 ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
256 if (ret < 0)
257 goto out;
258
259
260
261 cr &= ~DS1374_REG_CR_WACE;
262
263 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
264 if (ret < 0)
265 goto out;
266
267 ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
268 if (ret)
269 goto out;
270
271 if (alarm->enabled) {
272 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
273 cr &= ~DS1374_REG_CR_WDALM;
274
275 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
276 }
277
278out:
279 mutex_unlock(&ds1374->mutex);
280 return ret;
281}
282#endif
283
284static irqreturn_t ds1374_irq(int irq, void *dev_id)
285{
286 struct i2c_client *client = dev_id;
287 struct ds1374 *ds1374 = i2c_get_clientdata(client);
288
289 disable_irq_nosync(irq);
290 schedule_work(&ds1374->work);
291 return IRQ_HANDLED;
292}
293
294static void ds1374_work(struct work_struct *work)
295{
296 struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
297 struct i2c_client *client = ds1374->client;
298 int stat, control;
299
300 mutex_lock(&ds1374->mutex);
301
302 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
303 if (stat < 0)
304 goto unlock;
305
306 if (stat & DS1374_REG_SR_AF) {
307 stat &= ~DS1374_REG_SR_AF;
308 i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
309
310 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
311 if (control < 0)
312 goto out;
313
314 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
315 i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
316
317 rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
318 }
319
320out:
321 if (!ds1374->exiting)
322 enable_irq(client->irq);
323unlock:
324 mutex_unlock(&ds1374->mutex);
325}
326
327#ifndef CONFIG_RTC_DRV_DS1374_WDT
328static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
329{
330 struct i2c_client *client = to_i2c_client(dev);
331 struct ds1374 *ds1374 = i2c_get_clientdata(client);
332 int ret;
333
334 mutex_lock(&ds1374->mutex);
335
336 ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
337 if (ret < 0)
338 goto out;
339
340 if (enabled) {
341 ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
342 ret &= ~DS1374_REG_CR_WDALM;
343 } else {
344 ret &= ~DS1374_REG_CR_WACE;
345 }
346 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
347
348out:
349 mutex_unlock(&ds1374->mutex);
350 return ret;
351}
352#endif
353
354static const struct rtc_class_ops ds1374_rtc_ops = {
355 .read_time = ds1374_read_time,
356 .set_time = ds1374_set_time,
357#ifndef CONFIG_RTC_DRV_DS1374_WDT
358 .read_alarm = ds1374_read_alarm,
359 .set_alarm = ds1374_set_alarm,
360 .alarm_irq_enable = ds1374_alarm_irq_enable,
361#endif
362};
363
364#ifdef CONFIG_RTC_DRV_DS1374_WDT
365
366
367
368
369
370
371
372
373#define TIMER_MARGIN_DEFAULT 32
374#define TIMER_MARGIN_MIN 1
375#define TIMER_MARGIN_MAX 4095
376
377static int wdt_margin;
378module_param(wdt_margin, int, 0);
379MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
380
381static bool nowayout = WATCHDOG_NOWAYOUT;
382module_param(nowayout, bool, 0);
383MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default ="
384 __MODULE_STRING(WATCHDOG_NOWAYOUT)")");
385
386static const struct watchdog_info ds1374_wdt_info = {
387 .identity = "DS1374 Watchdog",
388 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
389 WDIOF_MAGICCLOSE,
390};
391
392static int ds1374_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
393{
394 struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
395 struct i2c_client *client = ds1374->client;
396 int ret, cr;
397
398 wdt->timeout = timeout;
399
400 cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
401 if (cr < 0)
402 return cr;
403
404
405 cr &= ~DS1374_REG_CR_WACE;
406
407 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
408 if (ret < 0)
409 return ret;
410
411
412 timeout = timeout * 4096;
413 ret = ds1374_write_rtc(client, timeout, DS1374_REG_WDALM0, 3);
414 if (ret)
415 return ret;
416
417
418 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
419 cr &= ~DS1374_REG_CR_WDSTR;
420 cr &= ~DS1374_REG_CR_AIE;
421
422 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
423 if (ret < 0)
424 return ret;
425
426 return 0;
427}
428
429
430
431
432static int ds1374_wdt_start(struct watchdog_device *wdt)
433{
434 struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
435 u32 val;
436
437 return ds1374_read_rtc(ds1374->client, &val, DS1374_REG_WDALM0, 3);
438}
439
440static int ds1374_wdt_stop(struct watchdog_device *wdt)
441{
442 struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
443 struct i2c_client *client = ds1374->client;
444 int cr;
445
446 cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
447 if (cr < 0)
448 return cr;
449
450
451 cr &= ~DS1374_REG_CR_WACE;
452
453 return i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
454}
455
456static const struct watchdog_ops ds1374_wdt_ops = {
457 .owner = THIS_MODULE,
458 .start = ds1374_wdt_start,
459 .stop = ds1374_wdt_stop,
460 .set_timeout = ds1374_wdt_settimeout,
461};
462#endif
463
464
465
466
467
468
469
470static int ds1374_probe(struct i2c_client *client,
471 const struct i2c_device_id *id)
472{
473 struct ds1374 *ds1374;
474 int ret;
475
476 ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
477 if (!ds1374)
478 return -ENOMEM;
479
480 ds1374->rtc = devm_rtc_allocate_device(&client->dev);
481 if (IS_ERR(ds1374->rtc))
482 return PTR_ERR(ds1374->rtc);
483
484 ds1374->client = client;
485 i2c_set_clientdata(client, ds1374);
486
487 INIT_WORK(&ds1374->work, ds1374_work);
488 mutex_init(&ds1374->mutex);
489
490 ret = ds1374_check_rtc_status(client);
491 if (ret)
492 return ret;
493
494 if (client->irq > 0) {
495 ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
496 "ds1374", client);
497 if (ret) {
498 dev_err(&client->dev, "unable to request IRQ\n");
499 return ret;
500 }
501
502 device_set_wakeup_capable(&client->dev, 1);
503 }
504
505 ds1374->rtc->ops = &ds1374_rtc_ops;
506 ds1374->rtc->range_max = U32_MAX;
507
508 ret = devm_rtc_register_device(ds1374->rtc);
509 if (ret)
510 return ret;
511
512#ifdef CONFIG_RTC_DRV_DS1374_WDT
513 ds1374->wdt.info = &ds1374_wdt_info;
514 ds1374->wdt.ops = &ds1374_wdt_ops;
515 ds1374->wdt.timeout = TIMER_MARGIN_DEFAULT;
516 ds1374->wdt.min_timeout = TIMER_MARGIN_MIN;
517 ds1374->wdt.max_timeout = TIMER_MARGIN_MAX;
518
519 watchdog_init_timeout(&ds1374->wdt, wdt_margin, &client->dev);
520 watchdog_set_nowayout(&ds1374->wdt, nowayout);
521 watchdog_stop_on_reboot(&ds1374->wdt);
522 watchdog_stop_on_unregister(&ds1374->wdt);
523 watchdog_set_drvdata(&ds1374->wdt, ds1374);
524 ds1374_wdt_settimeout(&ds1374->wdt, ds1374->wdt.timeout);
525
526 ret = devm_watchdog_register_device(&client->dev, &ds1374->wdt);
527 if (ret)
528 return ret;
529#endif
530
531 return 0;
532}
533
534static int ds1374_remove(struct i2c_client *client)
535{
536 struct ds1374 *ds1374 = i2c_get_clientdata(client);
537
538 if (client->irq > 0) {
539 mutex_lock(&ds1374->mutex);
540 ds1374->exiting = 1;
541 mutex_unlock(&ds1374->mutex);
542
543 devm_free_irq(&client->dev, client->irq, client);
544 cancel_work_sync(&ds1374->work);
545 }
546
547 return 0;
548}
549
550#ifdef CONFIG_PM_SLEEP
551static int ds1374_suspend(struct device *dev)
552{
553 struct i2c_client *client = to_i2c_client(dev);
554
555 if (client->irq > 0 && device_may_wakeup(&client->dev))
556 enable_irq_wake(client->irq);
557 return 0;
558}
559
560static int ds1374_resume(struct device *dev)
561{
562 struct i2c_client *client = to_i2c_client(dev);
563
564 if (client->irq > 0 && device_may_wakeup(&client->dev))
565 disable_irq_wake(client->irq);
566 return 0;
567}
568#endif
569
570static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
571
572static struct i2c_driver ds1374_driver = {
573 .driver = {
574 .name = "rtc-ds1374",
575 .of_match_table = of_match_ptr(ds1374_of_match),
576 .pm = &ds1374_pm,
577 },
578 .probe = ds1374_probe,
579 .remove = ds1374_remove,
580 .id_table = ds1374_id,
581};
582
583module_i2c_driver(ds1374_driver);
584
585MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
586MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
587MODULE_LICENSE("GPL");
588