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1/*
2 * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
3 *
4 * Based on code by Randy Vinson <rvinson@mvista.com>,
5 * which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
6 *
7 * Copyright (C) 2014 Rose Technology
8 * Copyright (C) 2006-2007 Freescale Semiconductor
9 *
10 * 2005 (c) MontaVista Software, Inc. This file is licensed under
11 * the terms of the GNU General Public License version 2. This program
12 * is licensed "as is" without any warranty of any kind, whether express
13 * or implied.
14 */
15/*
16 * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
17 * recommended in .../Documentation/i2c/writing-clients.rst section
18 * "Sending and receiving", using SMBus level communication is preferred.
19 */
20
21#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/interrupt.h>
26#include <linux/i2c.h>
27#include <linux/rtc.h>
28#include <linux/bcd.h>
29#include <linux/workqueue.h>
30#include <linux/slab.h>
31#include <linux/pm.h>
32#ifdef CONFIG_RTC_DRV_DS1374_WDT
33#include <linux/fs.h>
34#include <linux/ioctl.h>
35#include <linux/miscdevice.h>
36#include <linux/reboot.h>
37#include <linux/watchdog.h>
38#endif
39
40#define DS1374_REG_TOD0 0x00 /* Time of Day */
41#define DS1374_REG_TOD1 0x01
42#define DS1374_REG_TOD2 0x02
43#define DS1374_REG_TOD3 0x03
44#define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */
45#define DS1374_REG_WDALM1 0x05
46#define DS1374_REG_WDALM2 0x06
47#define DS1374_REG_CR 0x07 /* Control */
48#define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
49#define DS1374_REG_CR_WDSTR 0x08 /* 1=INT, 0=RST */
50#define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
51#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
52#define DS1374_REG_SR 0x08 /* Status */
53#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
54#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
55#define DS1374_REG_TCR 0x09 /* Trickle Charge */
56
57static const struct i2c_device_id ds1374_id[] = {
58 { "ds1374", 0 },
59 { }
60};
61MODULE_DEVICE_TABLE(i2c, ds1374_id);
62
63#ifdef CONFIG_OF
64static const struct of_device_id ds1374_of_match[] = {
65 { .compatible = "dallas,ds1374" },
66 { }
67};
68MODULE_DEVICE_TABLE(of, ds1374_of_match);
69#endif
70
71struct ds1374 {
72 struct i2c_client *client;
73 struct rtc_device *rtc;
74 struct work_struct work;
75#ifdef CONFIG_RTC_DRV_DS1374_WDT
76 struct watchdog_device wdt;
77#endif
78 /* The mutex protects alarm operations, and prevents a race
79 * between the enable_irq() in the workqueue and the free_irq()
80 * in the remove function.
81 */
82 struct mutex mutex;
83 int exiting;
84};
85
86static struct i2c_driver ds1374_driver;
87
88static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
89 int reg, int nbytes)
90{
91 u8 buf[4];
92 int ret;
93 int i;
94
95 if (WARN_ON(nbytes > 4))
96 return -EINVAL;
97
98 ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
99
100 if (ret < 0)
101 return ret;
102 if (ret < nbytes)
103 return -EIO;
104
105 for (i = nbytes - 1, *time = 0; i >= 0; i--)
106 *time = (*time << 8) | buf[i];
107
108 return 0;
109}
110
111static int ds1374_write_rtc(struct i2c_client *client, u32 time,
112 int reg, int nbytes)
113{
114 u8 buf[4];
115 int i;
116
117 if (nbytes > 4) {
118 WARN_ON(1);
119 return -EINVAL;
120 }
121
122 for (i = 0; i < nbytes; i++) {
123 buf[i] = time & 0xff;
124 time >>= 8;
125 }
126
127 return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
128}
129
130static int ds1374_check_rtc_status(struct i2c_client *client)
131{
132 int ret = 0;
133 int control, stat;
134
135 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
136 if (stat < 0)
137 return stat;
138
139 if (stat & DS1374_REG_SR_OSF)
140 dev_warn(&client->dev,
141 "oscillator discontinuity flagged, time unreliable\n");
142
143 stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);
144
145 ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
146 if (ret < 0)
147 return ret;
148
149 /* If the alarm is pending, clear it before requesting
150 * the interrupt, so an interrupt event isn't reported
151 * before everything is initialized.
152 */
153
154 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
155 if (control < 0)
156 return control;
157
158 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
159 return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
160}
161
162static int ds1374_read_time(struct device *dev, struct rtc_time *time)
163{
164 struct i2c_client *client = to_i2c_client(dev);
165 u32 itime;
166 int ret;
167
168 ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
169 if (!ret)
170 rtc_time64_to_tm(itime, time);
171
172 return ret;
173}
174
175static int ds1374_set_time(struct device *dev, struct rtc_time *time)
176{
177 struct i2c_client *client = to_i2c_client(dev);
178 unsigned long itime = rtc_tm_to_time64(time);
179
180 return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
181}
182
183#ifndef CONFIG_RTC_DRV_DS1374_WDT
184/* The ds1374 has a decrementer for an alarm, rather than a comparator.
185 * If the time of day is changed, then the alarm will need to be
186 * reset.
187 */
188static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
189{
190 struct i2c_client *client = to_i2c_client(dev);
191 struct ds1374 *ds1374 = i2c_get_clientdata(client);
192 u32 now, cur_alarm;
193 int cr, sr;
194 int ret = 0;
195
196 if (client->irq <= 0)
197 return -EINVAL;
198
199 mutex_lock(&ds1374->mutex);
200
201 cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
202 if (ret < 0)
203 goto out;
204
205 sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
206 if (ret < 0)
207 goto out;
208
209 ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
210 if (ret)
211 goto out;
212
213 ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
214 if (ret)
215 goto out;
216
217 rtc_time64_to_tm(now + cur_alarm, &alarm->time);
218 alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
219 alarm->pending = !!(sr & DS1374_REG_SR_AF);
220
221out:
222 mutex_unlock(&ds1374->mutex);
223 return ret;
224}
225
226static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
227{
228 struct i2c_client *client = to_i2c_client(dev);
229 struct ds1374 *ds1374 = i2c_get_clientdata(client);
230 struct rtc_time now;
231 unsigned long new_alarm, itime;
232 int cr;
233 int ret = 0;
234
235 if (client->irq <= 0)
236 return -EINVAL;
237
238 ret = ds1374_read_time(dev, &now);
239 if (ret < 0)
240 return ret;
241
242 new_alarm = rtc_tm_to_time64(&alarm->time);
243 itime = rtc_tm_to_time64(&now);
244
245 /* This can happen due to races, in addition to dates that are
246 * truly in the past. To avoid requiring the caller to check for
247 * races, dates in the past are assumed to be in the recent past
248 * (i.e. not something that we'd rather the caller know about via
249 * an error), and the alarm is set to go off as soon as possible.
250 */
251 if (time_before_eq(new_alarm, itime))
252 new_alarm = 1;
253 else
254 new_alarm -= itime;
255
256 mutex_lock(&ds1374->mutex);
257
258 ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
259 if (ret < 0)
260 goto out;
261
262 /* Disable any existing alarm before setting the new one
263 * (or lack thereof). */
264 cr &= ~DS1374_REG_CR_WACE;
265
266 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
267 if (ret < 0)
268 goto out;
269
270 ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
271 if (ret)
272 goto out;
273
274 if (alarm->enabled) {
275 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
276 cr &= ~DS1374_REG_CR_WDALM;
277
278 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
279 }
280
281out:
282 mutex_unlock(&ds1374->mutex);
283 return ret;
284}
285#endif
286
287static irqreturn_t ds1374_irq(int irq, void *dev_id)
288{
289 struct i2c_client *client = dev_id;
290 struct ds1374 *ds1374 = i2c_get_clientdata(client);
291
292 disable_irq_nosync(irq);
293 schedule_work(&ds1374->work);
294 return IRQ_HANDLED;
295}
296
297static void ds1374_work(struct work_struct *work)
298{
299 struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
300 struct i2c_client *client = ds1374->client;
301 int stat, control;
302
303 mutex_lock(&ds1374->mutex);
304
305 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
306 if (stat < 0)
307 goto unlock;
308
309 if (stat & DS1374_REG_SR_AF) {
310 stat &= ~DS1374_REG_SR_AF;
311 i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
312
313 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
314 if (control < 0)
315 goto out;
316
317 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
318 i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
319
320 rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
321 }
322
323out:
324 if (!ds1374->exiting)
325 enable_irq(client->irq);
326unlock:
327 mutex_unlock(&ds1374->mutex);
328}
329
330#ifndef CONFIG_RTC_DRV_DS1374_WDT
331static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
332{
333 struct i2c_client *client = to_i2c_client(dev);
334 struct ds1374 *ds1374 = i2c_get_clientdata(client);
335 int ret;
336
337 mutex_lock(&ds1374->mutex);
338
339 ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
340 if (ret < 0)
341 goto out;
342
343 if (enabled) {
344 ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
345 ret &= ~DS1374_REG_CR_WDALM;
346 } else {
347 ret &= ~DS1374_REG_CR_WACE;
348 }
349 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
350
351out:
352 mutex_unlock(&ds1374->mutex);
353 return ret;
354}
355#endif
356
357static const struct rtc_class_ops ds1374_rtc_ops = {
358 .read_time = ds1374_read_time,
359 .set_time = ds1374_set_time,
360#ifndef CONFIG_RTC_DRV_DS1374_WDT
361 .read_alarm = ds1374_read_alarm,
362 .set_alarm = ds1374_set_alarm,
363 .alarm_irq_enable = ds1374_alarm_irq_enable,
364#endif
365};
366
367#ifdef CONFIG_RTC_DRV_DS1374_WDT
368/*
369 *****************************************************************************
370 *
371 * Watchdog Driver
372 *
373 *****************************************************************************
374 */
375/* Default margin */
376#define TIMER_MARGIN_DEFAULT 32
377#define TIMER_MARGIN_MIN 1
378#define TIMER_MARGIN_MAX 4095 /* 24-bit value */
379
380static int wdt_margin;
381module_param(wdt_margin, int, 0);
382MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
383
384static bool nowayout = WATCHDOG_NOWAYOUT;
385module_param(nowayout, bool, 0);
386MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default ="
387 __MODULE_STRING(WATCHDOG_NOWAYOUT)")");
388
389static const struct watchdog_info ds1374_wdt_info = {
390 .identity = "DS1374 Watchdog",
391 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
392 WDIOF_MAGICCLOSE,
393};
394
395static int ds1374_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
396{
397 struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
398 struct i2c_client *client = ds1374->client;
399 int ret, cr;
400
401 wdt->timeout = timeout;
402
403 cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
404 if (cr < 0)
405 return cr;
406
407 /* Disable any existing watchdog/alarm before setting the new one */
408 cr &= ~DS1374_REG_CR_WACE;
409
410 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
411 if (ret < 0)
412 return ret;
413
414 /* Set new watchdog time */
415 timeout = timeout * 4096;
416 ret = ds1374_write_rtc(client, timeout, DS1374_REG_WDALM0, 3);
417 if (ret)
418 return ret;
419
420 /* Enable watchdog timer */
421 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
422 cr &= ~DS1374_REG_CR_WDSTR;/* for RST PIN */
423 cr &= ~DS1374_REG_CR_AIE;
424
425 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
426 if (ret < 0)
427 return ret;
428
429 return 0;
430}
431
432/*
433 * Reload the watchdog timer. (ie, pat the watchdog)
434 */
435static int ds1374_wdt_start(struct watchdog_device *wdt)
436{
437 struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
438 u32 val;
439
440 return ds1374_read_rtc(ds1374->client, &val, DS1374_REG_WDALM0, 3);
441}
442
443static int ds1374_wdt_stop(struct watchdog_device *wdt)
444{
445 struct ds1374 *ds1374 = watchdog_get_drvdata(wdt);
446 struct i2c_client *client = ds1374->client;
447 int cr;
448
449 cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
450 if (cr < 0)
451 return cr;
452
453 /* Disable watchdog timer */
454 cr &= ~DS1374_REG_CR_WACE;
455
456 return i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
457}
458
459static const struct watchdog_ops ds1374_wdt_ops = {
460 .owner = THIS_MODULE,
461 .start = ds1374_wdt_start,
462 .stop = ds1374_wdt_stop,
463 .set_timeout = ds1374_wdt_settimeout,
464};
465#endif /*CONFIG_RTC_DRV_DS1374_WDT*/
466/*
467 *****************************************************************************
468 *
469 * Driver Interface
470 *
471 *****************************************************************************
472 */
473static int ds1374_probe(struct i2c_client *client,
474 const struct i2c_device_id *id)
475{
476 struct ds1374 *ds1374;
477 int ret;
478
479 ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
480 if (!ds1374)
481 return -ENOMEM;
482
483 ds1374->rtc = devm_rtc_allocate_device(&client->dev);
484 if (IS_ERR(ds1374->rtc))
485 return PTR_ERR(ds1374->rtc);
486
487 ds1374->client = client;
488 i2c_set_clientdata(client, ds1374);
489
490 INIT_WORK(&ds1374->work, ds1374_work);
491 mutex_init(&ds1374->mutex);
492
493 ret = ds1374_check_rtc_status(client);
494 if (ret)
495 return ret;
496
497 if (client->irq > 0) {
498 ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
499 "ds1374", client);
500 if (ret) {
501 dev_err(&client->dev, "unable to request IRQ\n");
502 return ret;
503 }
504
505 device_set_wakeup_capable(&client->dev, 1);
506 }
507
508 ds1374->rtc->ops = &ds1374_rtc_ops;
509 ds1374->rtc->range_max = U32_MAX;
510
511 ret = rtc_register_device(ds1374->rtc);
512 if (ret)
513 return ret;
514
515#ifdef CONFIG_RTC_DRV_DS1374_WDT
516 ds1374->wdt.info = &ds1374_wdt_info;
517 ds1374->wdt.ops = &ds1374_wdt_ops;
518 ds1374->wdt.timeout = TIMER_MARGIN_DEFAULT;
519 ds1374->wdt.min_timeout = TIMER_MARGIN_MIN;
520 ds1374->wdt.max_timeout = TIMER_MARGIN_MAX;
521
522 watchdog_init_timeout(&ds1374->wdt, wdt_margin, &client->dev);
523 watchdog_set_nowayout(&ds1374->wdt, nowayout);
524 watchdog_stop_on_reboot(&ds1374->wdt);
525 watchdog_stop_on_unregister(&ds1374->wdt);
526 watchdog_set_drvdata(&ds1374->wdt, ds1374);
527 ds1374_wdt_settimeout(&ds1374->wdt, ds1374->wdt.timeout);
528
529 ret = devm_watchdog_register_device(&client->dev, &ds1374->wdt);
530 if (ret)
531 return ret;
532#endif
533
534 return 0;
535}
536
537static int ds1374_remove(struct i2c_client *client)
538{
539 struct ds1374 *ds1374 = i2c_get_clientdata(client);
540
541 if (client->irq > 0) {
542 mutex_lock(&ds1374->mutex);
543 ds1374->exiting = 1;
544 mutex_unlock(&ds1374->mutex);
545
546 devm_free_irq(&client->dev, client->irq, client);
547 cancel_work_sync(&ds1374->work);
548 }
549
550 return 0;
551}
552
553#ifdef CONFIG_PM_SLEEP
554static int ds1374_suspend(struct device *dev)
555{
556 struct i2c_client *client = to_i2c_client(dev);
557
558 if (client->irq > 0 && device_may_wakeup(&client->dev))
559 enable_irq_wake(client->irq);
560 return 0;
561}
562
563static int ds1374_resume(struct device *dev)
564{
565 struct i2c_client *client = to_i2c_client(dev);
566
567 if (client->irq > 0 && device_may_wakeup(&client->dev))
568 disable_irq_wake(client->irq);
569 return 0;
570}
571#endif
572
573static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
574
575static struct i2c_driver ds1374_driver = {
576 .driver = {
577 .name = "rtc-ds1374",
578 .of_match_table = of_match_ptr(ds1374_of_match),
579 .pm = &ds1374_pm,
580 },
581 .probe = ds1374_probe,
582 .remove = ds1374_remove,
583 .id_table = ds1374_id,
584};
585
586module_i2c_driver(ds1374_driver);
587
588MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
589MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
590MODULE_LICENSE("GPL");
1/*
2 * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
3 *
4 * Based on code by Randy Vinson <rvinson@mvista.com>,
5 * which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
6 *
7 * Copyright (C) 2006-2007 Freescale Semiconductor
8 *
9 * 2005 (c) MontaVista Software, Inc. This file is licensed under
10 * the terms of the GNU General Public License version 2. This program
11 * is licensed "as is" without any warranty of any kind, whether express
12 * or implied.
13 */
14/*
15 * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
16 * recommened in .../Documentation/i2c/writing-clients section
17 * "Sending and receiving", using SMBus level communication is preferred.
18 */
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
30#define DS1374_REG_TOD0 0x00 /* Time of Day */
31#define DS1374_REG_TOD1 0x01
32#define DS1374_REG_TOD2 0x02
33#define DS1374_REG_TOD3 0x03
34#define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */
35#define DS1374_REG_WDALM1 0x05
36#define DS1374_REG_WDALM2 0x06
37#define DS1374_REG_CR 0x07 /* Control */
38#define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
39#define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
40#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
41#define DS1374_REG_SR 0x08 /* Status */
42#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
43#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
44#define DS1374_REG_TCR 0x09 /* Trickle Charge */
45
46static const struct i2c_device_id ds1374_id[] = {
47 { "ds1374", 0 },
48 { }
49};
50MODULE_DEVICE_TABLE(i2c, ds1374_id);
51
52struct ds1374 {
53 struct i2c_client *client;
54 struct rtc_device *rtc;
55 struct work_struct work;
56
57 /* The mutex protects alarm operations, and prevents a race
58 * between the enable_irq() in the workqueue and the free_irq()
59 * in the remove function.
60 */
61 struct mutex mutex;
62 int exiting;
63};
64
65static struct i2c_driver ds1374_driver;
66
67static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
68 int reg, int nbytes)
69{
70 u8 buf[4];
71 int ret;
72 int i;
73
74 if (nbytes > 4) {
75 WARN_ON(1);
76 return -EINVAL;
77 }
78
79 ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
80
81 if (ret < 0)
82 return ret;
83 if (ret < nbytes)
84 return -EIO;
85
86 for (i = nbytes - 1, *time = 0; i >= 0; i--)
87 *time = (*time << 8) | buf[i];
88
89 return 0;
90}
91
92static int ds1374_write_rtc(struct i2c_client *client, u32 time,
93 int reg, int nbytes)
94{
95 u8 buf[4];
96 int i;
97
98 if (nbytes > 4) {
99 WARN_ON(1);
100 return -EINVAL;
101 }
102
103 for (i = 0; i < nbytes; i++) {
104 buf[i] = time & 0xff;
105 time >>= 8;
106 }
107
108 return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
109}
110
111static int ds1374_check_rtc_status(struct i2c_client *client)
112{
113 int ret = 0;
114 int control, stat;
115
116 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
117 if (stat < 0)
118 return stat;
119
120 if (stat & DS1374_REG_SR_OSF)
121 dev_warn(&client->dev,
122 "oscillator discontinuity flagged, time unreliable\n");
123
124 stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);
125
126 ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
127 if (ret < 0)
128 return ret;
129
130 /* If the alarm is pending, clear it before requesting
131 * the interrupt, so an interrupt event isn't reported
132 * before everything is initialized.
133 */
134
135 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
136 if (control < 0)
137 return control;
138
139 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
140 return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
141}
142
143static int ds1374_read_time(struct device *dev, struct rtc_time *time)
144{
145 struct i2c_client *client = to_i2c_client(dev);
146 u32 itime;
147 int ret;
148
149 ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
150 if (!ret)
151 rtc_time_to_tm(itime, time);
152
153 return ret;
154}
155
156static int ds1374_set_time(struct device *dev, struct rtc_time *time)
157{
158 struct i2c_client *client = to_i2c_client(dev);
159 unsigned long itime;
160
161 rtc_tm_to_time(time, &itime);
162 return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
163}
164
165/* The ds1374 has a decrementer for an alarm, rather than a comparator.
166 * If the time of day is changed, then the alarm will need to be
167 * reset.
168 */
169static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
170{
171 struct i2c_client *client = to_i2c_client(dev);
172 struct ds1374 *ds1374 = i2c_get_clientdata(client);
173 u32 now, cur_alarm;
174 int cr, sr;
175 int ret = 0;
176
177 if (client->irq <= 0)
178 return -EINVAL;
179
180 mutex_lock(&ds1374->mutex);
181
182 cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
183 if (ret < 0)
184 goto out;
185
186 sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
187 if (ret < 0)
188 goto out;
189
190 ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
191 if (ret)
192 goto out;
193
194 ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
195 if (ret)
196 goto out;
197
198 rtc_time_to_tm(now + cur_alarm, &alarm->time);
199 alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
200 alarm->pending = !!(sr & DS1374_REG_SR_AF);
201
202out:
203 mutex_unlock(&ds1374->mutex);
204 return ret;
205}
206
207static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
208{
209 struct i2c_client *client = to_i2c_client(dev);
210 struct ds1374 *ds1374 = i2c_get_clientdata(client);
211 struct rtc_time now;
212 unsigned long new_alarm, itime;
213 int cr;
214 int ret = 0;
215
216 if (client->irq <= 0)
217 return -EINVAL;
218
219 ret = ds1374_read_time(dev, &now);
220 if (ret < 0)
221 return ret;
222
223 rtc_tm_to_time(&alarm->time, &new_alarm);
224 rtc_tm_to_time(&now, &itime);
225
226 /* This can happen due to races, in addition to dates that are
227 * truly in the past. To avoid requiring the caller to check for
228 * races, dates in the past are assumed to be in the recent past
229 * (i.e. not something that we'd rather the caller know about via
230 * an error), and the alarm is set to go off as soon as possible.
231 */
232 if (time_before_eq(new_alarm, itime))
233 new_alarm = 1;
234 else
235 new_alarm -= itime;
236
237 mutex_lock(&ds1374->mutex);
238
239 ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
240 if (ret < 0)
241 goto out;
242
243 /* Disable any existing alarm before setting the new one
244 * (or lack thereof). */
245 cr &= ~DS1374_REG_CR_WACE;
246
247 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
248 if (ret < 0)
249 goto out;
250
251 ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
252 if (ret)
253 goto out;
254
255 if (alarm->enabled) {
256 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
257 cr &= ~DS1374_REG_CR_WDALM;
258
259 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
260 }
261
262out:
263 mutex_unlock(&ds1374->mutex);
264 return ret;
265}
266
267static irqreturn_t ds1374_irq(int irq, void *dev_id)
268{
269 struct i2c_client *client = dev_id;
270 struct ds1374 *ds1374 = i2c_get_clientdata(client);
271
272 disable_irq_nosync(irq);
273 schedule_work(&ds1374->work);
274 return IRQ_HANDLED;
275}
276
277static void ds1374_work(struct work_struct *work)
278{
279 struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
280 struct i2c_client *client = ds1374->client;
281 int stat, control;
282
283 mutex_lock(&ds1374->mutex);
284
285 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
286 if (stat < 0)
287 goto unlock;
288
289 if (stat & DS1374_REG_SR_AF) {
290 stat &= ~DS1374_REG_SR_AF;
291 i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
292
293 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
294 if (control < 0)
295 goto out;
296
297 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
298 i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
299
300 rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
301 }
302
303out:
304 if (!ds1374->exiting)
305 enable_irq(client->irq);
306unlock:
307 mutex_unlock(&ds1374->mutex);
308}
309
310static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
311{
312 struct i2c_client *client = to_i2c_client(dev);
313 struct ds1374 *ds1374 = i2c_get_clientdata(client);
314 int ret;
315
316 mutex_lock(&ds1374->mutex);
317
318 ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
319 if (ret < 0)
320 goto out;
321
322 if (enabled) {
323 ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
324 ret &= ~DS1374_REG_CR_WDALM;
325 } else {
326 ret &= ~DS1374_REG_CR_WACE;
327 }
328 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
329
330out:
331 mutex_unlock(&ds1374->mutex);
332 return ret;
333}
334
335static const struct rtc_class_ops ds1374_rtc_ops = {
336 .read_time = ds1374_read_time,
337 .set_time = ds1374_set_time,
338 .read_alarm = ds1374_read_alarm,
339 .set_alarm = ds1374_set_alarm,
340 .alarm_irq_enable = ds1374_alarm_irq_enable,
341};
342
343static int ds1374_probe(struct i2c_client *client,
344 const struct i2c_device_id *id)
345{
346 struct ds1374 *ds1374;
347 int ret;
348
349 ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
350 if (!ds1374)
351 return -ENOMEM;
352
353 ds1374->client = client;
354 i2c_set_clientdata(client, ds1374);
355
356 INIT_WORK(&ds1374->work, ds1374_work);
357 mutex_init(&ds1374->mutex);
358
359 ret = ds1374_check_rtc_status(client);
360 if (ret)
361 return ret;
362
363 if (client->irq > 0) {
364 ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
365 "ds1374", client);
366 if (ret) {
367 dev_err(&client->dev, "unable to request IRQ\n");
368 return ret;
369 }
370
371 device_set_wakeup_capable(&client->dev, 1);
372 }
373
374 ds1374->rtc = devm_rtc_device_register(&client->dev, client->name,
375 &ds1374_rtc_ops, THIS_MODULE);
376 if (IS_ERR(ds1374->rtc)) {
377 dev_err(&client->dev, "unable to register the class device\n");
378 return PTR_ERR(ds1374->rtc);
379 }
380
381 return 0;
382}
383
384static int ds1374_remove(struct i2c_client *client)
385{
386 struct ds1374 *ds1374 = i2c_get_clientdata(client);
387
388 if (client->irq > 0) {
389 mutex_lock(&ds1374->mutex);
390 ds1374->exiting = 1;
391 mutex_unlock(&ds1374->mutex);
392
393 devm_free_irq(&client->dev, client->irq, client);
394 cancel_work_sync(&ds1374->work);
395 }
396
397 return 0;
398}
399
400#ifdef CONFIG_PM_SLEEP
401static int ds1374_suspend(struct device *dev)
402{
403 struct i2c_client *client = to_i2c_client(dev);
404
405 if (client->irq >= 0 && device_may_wakeup(&client->dev))
406 enable_irq_wake(client->irq);
407 return 0;
408}
409
410static int ds1374_resume(struct device *dev)
411{
412 struct i2c_client *client = to_i2c_client(dev);
413
414 if (client->irq >= 0 && device_may_wakeup(&client->dev))
415 disable_irq_wake(client->irq);
416 return 0;
417}
418#endif
419
420static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
421
422static struct i2c_driver ds1374_driver = {
423 .driver = {
424 .name = "rtc-ds1374",
425 .owner = THIS_MODULE,
426 .pm = &ds1374_pm,
427 },
428 .probe = ds1374_probe,
429 .remove = ds1374_remove,
430 .id_table = ds1374_id,
431};
432
433module_i2c_driver(ds1374_driver);
434
435MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
436MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
437MODULE_LICENSE("GPL");