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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_new = 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 * recommened in .../Documentation/i2c/writing-clients 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_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
50#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
51#define DS1374_REG_SR 0x08 /* Status */
52#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
53#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
54#define DS1374_REG_TCR 0x09 /* Trickle Charge */
55
56static const struct i2c_device_id ds1374_id[] = {
57 { "ds1374", 0 },
58 { }
59};
60MODULE_DEVICE_TABLE(i2c, ds1374_id);
61
62#ifdef CONFIG_OF
63static const struct of_device_id ds1374_of_match[] = {
64 { .compatible = "dallas,ds1374" },
65 { }
66};
67MODULE_DEVICE_TABLE(of, ds1374_of_match);
68#endif
69
70struct ds1374 {
71 struct i2c_client *client;
72 struct rtc_device *rtc;
73 struct work_struct work;
74
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_time_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;
176
177 rtc_tm_to_time(time, &itime);
178 return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
179}
180
181#ifndef CONFIG_RTC_DRV_DS1374_WDT
182/* The ds1374 has a decrementer for an alarm, rather than a comparator.
183 * If the time of day is changed, then the alarm will need to be
184 * reset.
185 */
186static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
187{
188 struct i2c_client *client = to_i2c_client(dev);
189 struct ds1374 *ds1374 = i2c_get_clientdata(client);
190 u32 now, cur_alarm;
191 int cr, sr;
192 int ret = 0;
193
194 if (client->irq <= 0)
195 return -EINVAL;
196
197 mutex_lock(&ds1374->mutex);
198
199 cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
200 if (ret < 0)
201 goto out;
202
203 sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
204 if (ret < 0)
205 goto out;
206
207 ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
208 if (ret)
209 goto out;
210
211 ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
212 if (ret)
213 goto out;
214
215 rtc_time_to_tm(now + cur_alarm, &alarm->time);
216 alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
217 alarm->pending = !!(sr & DS1374_REG_SR_AF);
218
219out:
220 mutex_unlock(&ds1374->mutex);
221 return ret;
222}
223
224static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
225{
226 struct i2c_client *client = to_i2c_client(dev);
227 struct ds1374 *ds1374 = i2c_get_clientdata(client);
228 struct rtc_time now;
229 unsigned long new_alarm, itime;
230 int cr;
231 int ret = 0;
232
233 if (client->irq <= 0)
234 return -EINVAL;
235
236 ret = ds1374_read_time(dev, &now);
237 if (ret < 0)
238 return ret;
239
240 rtc_tm_to_time(&alarm->time, &new_alarm);
241 rtc_tm_to_time(&now, &itime);
242
243 /* This can happen due to races, in addition to dates that are
244 * truly in the past. To avoid requiring the caller to check for
245 * races, dates in the past are assumed to be in the recent past
246 * (i.e. not something that we'd rather the caller know about via
247 * an error), and the alarm is set to go off as soon as possible.
248 */
249 if (time_before_eq(new_alarm, itime))
250 new_alarm = 1;
251 else
252 new_alarm -= itime;
253
254 mutex_lock(&ds1374->mutex);
255
256 ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
257 if (ret < 0)
258 goto out;
259
260 /* Disable any existing alarm before setting the new one
261 * (or lack thereof). */
262 cr &= ~DS1374_REG_CR_WACE;
263
264 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
265 if (ret < 0)
266 goto out;
267
268 ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
269 if (ret)
270 goto out;
271
272 if (alarm->enabled) {
273 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
274 cr &= ~DS1374_REG_CR_WDALM;
275
276 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
277 }
278
279out:
280 mutex_unlock(&ds1374->mutex);
281 return ret;
282}
283#endif
284
285static irqreturn_t ds1374_irq(int irq, void *dev_id)
286{
287 struct i2c_client *client = dev_id;
288 struct ds1374 *ds1374 = i2c_get_clientdata(client);
289
290 disable_irq_nosync(irq);
291 schedule_work(&ds1374->work);
292 return IRQ_HANDLED;
293}
294
295static void ds1374_work(struct work_struct *work)
296{
297 struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
298 struct i2c_client *client = ds1374->client;
299 int stat, control;
300
301 mutex_lock(&ds1374->mutex);
302
303 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
304 if (stat < 0)
305 goto unlock;
306
307 if (stat & DS1374_REG_SR_AF) {
308 stat &= ~DS1374_REG_SR_AF;
309 i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
310
311 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
312 if (control < 0)
313 goto out;
314
315 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
316 i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
317
318 rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
319 }
320
321out:
322 if (!ds1374->exiting)
323 enable_irq(client->irq);
324unlock:
325 mutex_unlock(&ds1374->mutex);
326}
327
328#ifndef CONFIG_RTC_DRV_DS1374_WDT
329static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
330{
331 struct i2c_client *client = to_i2c_client(dev);
332 struct ds1374 *ds1374 = i2c_get_clientdata(client);
333 int ret;
334
335 mutex_lock(&ds1374->mutex);
336
337 ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
338 if (ret < 0)
339 goto out;
340
341 if (enabled) {
342 ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
343 ret &= ~DS1374_REG_CR_WDALM;
344 } else {
345 ret &= ~DS1374_REG_CR_WACE;
346 }
347 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
348
349out:
350 mutex_unlock(&ds1374->mutex);
351 return ret;
352}
353#endif
354
355static const struct rtc_class_ops ds1374_rtc_ops = {
356 .read_time = ds1374_read_time,
357 .set_time = ds1374_set_time,
358#ifndef CONFIG_RTC_DRV_DS1374_WDT
359 .read_alarm = ds1374_read_alarm,
360 .set_alarm = ds1374_set_alarm,
361 .alarm_irq_enable = ds1374_alarm_irq_enable,
362#endif
363};
364
365#ifdef CONFIG_RTC_DRV_DS1374_WDT
366/*
367 *****************************************************************************
368 *
369 * Watchdog Driver
370 *
371 *****************************************************************************
372 */
373static struct i2c_client *save_client;
374/* Default margin */
375#define WD_TIMO 131762
376
377#define DRV_NAME "DS1374 Watchdog"
378
379static int wdt_margin = WD_TIMO;
380static unsigned long wdt_is_open;
381module_param(wdt_margin, int, 0);
382MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
383
384static const struct watchdog_info ds1374_wdt_info = {
385 .identity = "DS1374 WTD",
386 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
387 WDIOF_MAGICCLOSE,
388};
389
390static int ds1374_wdt_settimeout(unsigned int timeout)
391{
392 int ret = -ENOIOCTLCMD;
393 int cr;
394
395 ret = cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
396 if (ret < 0)
397 goto out;
398
399 /* Disable any existing watchdog/alarm before setting the new one */
400 cr &= ~DS1374_REG_CR_WACE;
401
402 ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
403 if (ret < 0)
404 goto out;
405
406 /* Set new watchdog time */
407 ret = ds1374_write_rtc(save_client, timeout, DS1374_REG_WDALM0, 3);
408 if (ret) {
409 pr_info("couldn't set new watchdog time\n");
410 goto out;
411 }
412
413 /* Enable watchdog timer */
414 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
415 cr &= ~DS1374_REG_CR_AIE;
416
417 ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
418 if (ret < 0)
419 goto out;
420
421 return 0;
422out:
423 return ret;
424}
425
426
427/*
428 * Reload the watchdog timer. (ie, pat the watchdog)
429 */
430static void ds1374_wdt_ping(void)
431{
432 u32 val;
433 int ret = 0;
434
435 ret = ds1374_read_rtc(save_client, &val, DS1374_REG_WDALM0, 3);
436 if (ret)
437 pr_info("WD TICK FAIL!!!!!!!!!! %i\n", ret);
438}
439
440static void ds1374_wdt_disable(void)
441{
442 int ret = -ENOIOCTLCMD;
443 int cr;
444
445 cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
446 /* Disable watchdog timer */
447 cr &= ~DS1374_REG_CR_WACE;
448
449 ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
450}
451
452/*
453 * Watchdog device is opened, and watchdog starts running.
454 */
455static int ds1374_wdt_open(struct inode *inode, struct file *file)
456{
457 struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
458
459 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
460 mutex_lock(&ds1374->mutex);
461 if (test_and_set_bit(0, &wdt_is_open)) {
462 mutex_unlock(&ds1374->mutex);
463 return -EBUSY;
464 }
465 /*
466 * Activate
467 */
468 wdt_is_open = 1;
469 mutex_unlock(&ds1374->mutex);
470 return nonseekable_open(inode, file);
471 }
472 return -ENODEV;
473}
474
475/*
476 * Close the watchdog device.
477 */
478static int ds1374_wdt_release(struct inode *inode, struct file *file)
479{
480 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
481 clear_bit(0, &wdt_is_open);
482
483 return 0;
484}
485
486/*
487 * Pat the watchdog whenever device is written to.
488 */
489static ssize_t ds1374_wdt_write(struct file *file, const char __user *data,
490 size_t len, loff_t *ppos)
491{
492 if (len) {
493 ds1374_wdt_ping();
494 return 1;
495 }
496 return 0;
497}
498
499static ssize_t ds1374_wdt_read(struct file *file, char __user *data,
500 size_t len, loff_t *ppos)
501{
502 return 0;
503}
504
505/*
506 * Handle commands from user-space.
507 */
508static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd,
509 unsigned long arg)
510{
511 int new_margin, options;
512
513 switch (cmd) {
514 case WDIOC_GETSUPPORT:
515 return copy_to_user((struct watchdog_info __user *)arg,
516 &ds1374_wdt_info, sizeof(ds1374_wdt_info)) ? -EFAULT : 0;
517
518 case WDIOC_GETSTATUS:
519 case WDIOC_GETBOOTSTATUS:
520 return put_user(0, (int __user *)arg);
521 case WDIOC_KEEPALIVE:
522 ds1374_wdt_ping();
523 return 0;
524 case WDIOC_SETTIMEOUT:
525 if (get_user(new_margin, (int __user *)arg))
526 return -EFAULT;
527
528 /* the hardware's tick rate is 4096 Hz, so
529 * the counter value needs to be scaled accordingly
530 */
531 new_margin <<= 12;
532 if (new_margin < 1 || new_margin > 16777216)
533 return -EINVAL;
534
535 wdt_margin = new_margin;
536 ds1374_wdt_settimeout(new_margin);
537 ds1374_wdt_ping();
538 /* fallthrough */
539 case WDIOC_GETTIMEOUT:
540 /* when returning ... inverse is true */
541 return put_user((wdt_margin >> 12), (int __user *)arg);
542 case WDIOC_SETOPTIONS:
543 if (copy_from_user(&options, (int __user *)arg, sizeof(int)))
544 return -EFAULT;
545
546 if (options & WDIOS_DISABLECARD) {
547 pr_info("disable watchdog\n");
548 ds1374_wdt_disable();
549 return 0;
550 }
551
552 if (options & WDIOS_ENABLECARD) {
553 pr_info("enable watchdog\n");
554 ds1374_wdt_settimeout(wdt_margin);
555 ds1374_wdt_ping();
556 return 0;
557 }
558 return -EINVAL;
559 }
560 return -ENOTTY;
561}
562
563static long ds1374_wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
564 unsigned long arg)
565{
566 int ret;
567 struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
568
569 mutex_lock(&ds1374->mutex);
570 ret = ds1374_wdt_ioctl(file, cmd, arg);
571 mutex_unlock(&ds1374->mutex);
572
573 return ret;
574}
575
576static int ds1374_wdt_notify_sys(struct notifier_block *this,
577 unsigned long code, void *unused)
578{
579 if (code == SYS_DOWN || code == SYS_HALT)
580 /* Disable Watchdog */
581 ds1374_wdt_disable();
582 return NOTIFY_DONE;
583}
584
585static const struct file_operations ds1374_wdt_fops = {
586 .owner = THIS_MODULE,
587 .read = ds1374_wdt_read,
588 .unlocked_ioctl = ds1374_wdt_unlocked_ioctl,
589 .write = ds1374_wdt_write,
590 .open = ds1374_wdt_open,
591 .release = ds1374_wdt_release,
592 .llseek = no_llseek,
593};
594
595static struct miscdevice ds1374_miscdev = {
596 .minor = WATCHDOG_MINOR,
597 .name = "watchdog",
598 .fops = &ds1374_wdt_fops,
599};
600
601static struct notifier_block ds1374_wdt_notifier = {
602 .notifier_call = ds1374_wdt_notify_sys,
603};
604
605#endif /*CONFIG_RTC_DRV_DS1374_WDT*/
606/*
607 *****************************************************************************
608 *
609 * Driver Interface
610 *
611 *****************************************************************************
612 */
613static int ds1374_probe(struct i2c_client *client,
614 const struct i2c_device_id *id)
615{
616 struct ds1374 *ds1374;
617 int ret;
618
619 ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
620 if (!ds1374)
621 return -ENOMEM;
622
623 ds1374->client = client;
624 i2c_set_clientdata(client, ds1374);
625
626 INIT_WORK(&ds1374->work, ds1374_work);
627 mutex_init(&ds1374->mutex);
628
629 ret = ds1374_check_rtc_status(client);
630 if (ret)
631 return ret;
632
633 if (client->irq > 0) {
634 ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
635 "ds1374", client);
636 if (ret) {
637 dev_err(&client->dev, "unable to request IRQ\n");
638 return ret;
639 }
640
641 device_set_wakeup_capable(&client->dev, 1);
642 }
643
644 ds1374->rtc = devm_rtc_device_register(&client->dev, client->name,
645 &ds1374_rtc_ops, THIS_MODULE);
646 if (IS_ERR(ds1374->rtc)) {
647 dev_err(&client->dev, "unable to register the class device\n");
648 return PTR_ERR(ds1374->rtc);
649 }
650
651#ifdef CONFIG_RTC_DRV_DS1374_WDT
652 save_client = client;
653 ret = misc_register(&ds1374_miscdev);
654 if (ret)
655 return ret;
656 ret = register_reboot_notifier(&ds1374_wdt_notifier);
657 if (ret) {
658 misc_deregister(&ds1374_miscdev);
659 return ret;
660 }
661 ds1374_wdt_settimeout(131072);
662#endif
663
664 return 0;
665}
666
667static int ds1374_remove(struct i2c_client *client)
668{
669 struct ds1374 *ds1374 = i2c_get_clientdata(client);
670#ifdef CONFIG_RTC_DRV_DS1374_WDT
671 misc_deregister(&ds1374_miscdev);
672 ds1374_miscdev.parent = NULL;
673 unregister_reboot_notifier(&ds1374_wdt_notifier);
674#endif
675
676 if (client->irq > 0) {
677 mutex_lock(&ds1374->mutex);
678 ds1374->exiting = 1;
679 mutex_unlock(&ds1374->mutex);
680
681 devm_free_irq(&client->dev, client->irq, client);
682 cancel_work_sync(&ds1374->work);
683 }
684
685 return 0;
686}
687
688#ifdef CONFIG_PM_SLEEP
689static int ds1374_suspend(struct device *dev)
690{
691 struct i2c_client *client = to_i2c_client(dev);
692
693 if (client->irq > 0 && device_may_wakeup(&client->dev))
694 enable_irq_wake(client->irq);
695 return 0;
696}
697
698static int ds1374_resume(struct device *dev)
699{
700 struct i2c_client *client = to_i2c_client(dev);
701
702 if (client->irq > 0 && device_may_wakeup(&client->dev))
703 disable_irq_wake(client->irq);
704 return 0;
705}
706#endif
707
708static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
709
710static struct i2c_driver ds1374_driver = {
711 .driver = {
712 .name = "rtc-ds1374",
713 .of_match_table = of_match_ptr(ds1374_of_match),
714 .pm = &ds1374_pm,
715 },
716 .probe = ds1374_probe,
717 .remove = ds1374_remove,
718 .id_table = ds1374_id,
719};
720
721module_i2c_driver(ds1374_driver);
722
723MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
724MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
725MODULE_LICENSE("GPL");