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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
4 *
5 * Based on code by Randy Vinson <rvinson@mvista.com>,
6 * which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
7 *
8 * Copyright (C) 2014 Rose Technology
9 * Copyright (C) 2006-2007 Freescale Semiconductor
10 * Copyright (c) 2005 MontaVista Software, Inc.
11 */
12/*
13 * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
14 * recommended in .../Documentation/i2c/writing-clients.rst section
15 * "Sending and receiving", using SMBus level communication is preferred.
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 /* Time of Day */
38#define DS1374_REG_TOD1 0x01
39#define DS1374_REG_TOD2 0x02
40#define DS1374_REG_TOD3 0x03
41#define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */
42#define DS1374_REG_WDALM1 0x05
43#define DS1374_REG_WDALM2 0x06
44#define DS1374_REG_CR 0x07 /* Control */
45#define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
46#define DS1374_REG_CR_WDSTR 0x08 /* 1=INT, 0=RST */
47#define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
48#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
49#define DS1374_REG_SR 0x08 /* Status */
50#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
51#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
52#define DS1374_REG_TCR 0x09 /* Trickle Charge */
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 /* The mutex protects alarm operations, and prevents a race
76 * between the enable_irq() in the workqueue and the free_irq()
77 * in the remove function.
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 /* If the alarm is pending, clear it before requesting
147 * the interrupt, so an interrupt event isn't reported
148 * before everything is initialized.
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/* The ds1374 has a decrementer for an alarm, rather than a comparator.
182 * If the time of day is changed, then the alarm will need to be
183 * reset.
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 /* This can happen due to races, in addition to dates that are
243 * truly in the past. To avoid requiring the caller to check for
244 * races, dates in the past are assumed to be in the recent past
245 * (i.e. not something that we'd rather the caller know about via
246 * an error), and the alarm is set to go off as soon as possible.
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 /* Disable any existing alarm before setting the new one
260 * (or lack thereof). */
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 * Watchdog Driver
369 *
370 *****************************************************************************
371 */
372/* Default margin */
373#define TIMER_MARGIN_DEFAULT 32
374#define TIMER_MARGIN_MIN 1
375#define TIMER_MARGIN_MAX 4095 /* 24-bit value */
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 /* Disable any existing watchdog/alarm before setting the new one */
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 /* Set new watchdog time */
412 timeout = timeout * 4096;
413 ret = ds1374_write_rtc(client, timeout, DS1374_REG_WDALM0, 3);
414 if (ret)
415 return ret;
416
417 /* Enable watchdog timer */
418 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
419 cr &= ~DS1374_REG_CR_WDSTR;/* for RST PIN */
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 * Reload the watchdog timer. (ie, pat the watchdog)
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 /* Disable watchdog timer */
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 /*CONFIG_RTC_DRV_DS1374_WDT*/
463/*
464 *****************************************************************************
465 *
466 * Driver Interface
467 *
468 *****************************************************************************
469 */
470static int ds1374_probe(struct i2c_client *client)
471{
472 struct ds1374 *ds1374;
473 int ret;
474
475 ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
476 if (!ds1374)
477 return -ENOMEM;
478
479 ds1374->rtc = devm_rtc_allocate_device(&client->dev);
480 if (IS_ERR(ds1374->rtc))
481 return PTR_ERR(ds1374->rtc);
482
483 ds1374->client = client;
484 i2c_set_clientdata(client, ds1374);
485
486 INIT_WORK(&ds1374->work, ds1374_work);
487 mutex_init(&ds1374->mutex);
488
489 ret = ds1374_check_rtc_status(client);
490 if (ret)
491 return ret;
492
493 if (client->irq > 0) {
494 ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
495 "ds1374", client);
496 if (ret) {
497 dev_err(&client->dev, "unable to request IRQ\n");
498 return ret;
499 }
500
501 device_set_wakeup_capable(&client->dev, 1);
502 }
503
504 ds1374->rtc->ops = &ds1374_rtc_ops;
505 ds1374->rtc->range_max = U32_MAX;
506
507 ret = devm_rtc_register_device(ds1374->rtc);
508 if (ret)
509 return ret;
510
511#ifdef CONFIG_RTC_DRV_DS1374_WDT
512 ds1374->wdt.info = &ds1374_wdt_info;
513 ds1374->wdt.ops = &ds1374_wdt_ops;
514 ds1374->wdt.timeout = TIMER_MARGIN_DEFAULT;
515 ds1374->wdt.min_timeout = TIMER_MARGIN_MIN;
516 ds1374->wdt.max_timeout = TIMER_MARGIN_MAX;
517
518 watchdog_init_timeout(&ds1374->wdt, wdt_margin, &client->dev);
519 watchdog_set_nowayout(&ds1374->wdt, nowayout);
520 watchdog_stop_on_reboot(&ds1374->wdt);
521 watchdog_stop_on_unregister(&ds1374->wdt);
522 watchdog_set_drvdata(&ds1374->wdt, ds1374);
523 ds1374_wdt_settimeout(&ds1374->wdt, ds1374->wdt.timeout);
524
525 ret = devm_watchdog_register_device(&client->dev, &ds1374->wdt);
526 if (ret)
527 return ret;
528#endif
529
530 return 0;
531}
532
533static void ds1374_remove(struct i2c_client *client)
534{
535 struct ds1374 *ds1374 = i2c_get_clientdata(client);
536
537 if (client->irq > 0) {
538 mutex_lock(&ds1374->mutex);
539 ds1374->exiting = 1;
540 mutex_unlock(&ds1374->mutex);
541
542 devm_free_irq(&client->dev, client->irq, client);
543 cancel_work_sync(&ds1374->work);
544 }
545}
546
547#ifdef CONFIG_PM_SLEEP
548static int ds1374_suspend(struct device *dev)
549{
550 struct i2c_client *client = to_i2c_client(dev);
551
552 if (client->irq > 0 && device_may_wakeup(&client->dev))
553 enable_irq_wake(client->irq);
554 return 0;
555}
556
557static int ds1374_resume(struct device *dev)
558{
559 struct i2c_client *client = to_i2c_client(dev);
560
561 if (client->irq > 0 && device_may_wakeup(&client->dev))
562 disable_irq_wake(client->irq);
563 return 0;
564}
565#endif
566
567static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
568
569static struct i2c_driver ds1374_driver = {
570 .driver = {
571 .name = "rtc-ds1374",
572 .of_match_table = of_match_ptr(ds1374_of_match),
573 .pm = &ds1374_pm,
574 },
575 .probe = ds1374_probe,
576 .remove = ds1374_remove,
577 .id_table = ds1374_id,
578};
579
580module_i2c_driver(ds1374_driver);
581
582MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
583MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
584MODULE_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) 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");