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Roy Zangc03675f2010-08-10 18:02:20 -07001/*
2 * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
3 *
Lei Xua2d6d2f2011-02-25 14:44:23 -08004 * Copyright (C) 2009-2011 Freescale Semiconductor.
Lan Chunhe-B25806f46418c2010-10-27 15:33:12 -07005 * Author: Jack Lan <jack.lan@freescale.com>
Roy Zangc03675f2010-08-10 18:02:20 -07006 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
11 */
12/*
13 * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
14 * recommened in .../Documentation/i2c/writing-clients section
15 * "Sending and receiving", using SMBus level communication is preferred.
16 */
17
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/interrupt.h>
21#include <linux/i2c.h>
22#include <linux/rtc.h>
23#include <linux/bcd.h>
24#include <linux/workqueue.h>
25#include <linux/slab.h>
26
27#define DS3232_REG_SECONDS 0x00
28#define DS3232_REG_MINUTES 0x01
29#define DS3232_REG_HOURS 0x02
30#define DS3232_REG_AMPM 0x02
31#define DS3232_REG_DAY 0x03
32#define DS3232_REG_DATE 0x04
33#define DS3232_REG_MONTH 0x05
34#define DS3232_REG_CENTURY 0x05
35#define DS3232_REG_YEAR 0x06
36#define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */
37#define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */
38#define DS3232_REG_CR 0x0E /* Control register */
39# define DS3232_REG_CR_nEOSC 0x80
40# define DS3232_REG_CR_INTCN 0x04
41# define DS3232_REG_CR_A2IE 0x02
42# define DS3232_REG_CR_A1IE 0x01
43
44#define DS3232_REG_SR 0x0F /* control/status register */
45# define DS3232_REG_SR_OSF 0x80
46# define DS3232_REG_SR_BSY 0x04
47# define DS3232_REG_SR_A2F 0x02
48# define DS3232_REG_SR_A1F 0x01
49
50struct ds3232 {
51 struct i2c_client *client;
52 struct rtc_device *rtc;
53 struct work_struct work;
54
55 /* The mutex protects alarm operations, and prevents a race
56 * between the enable_irq() in the workqueue and the free_irq()
57 * in the remove function.
58 */
59 struct mutex mutex;
Wang Dongshengc93a3ae2014-04-03 14:50:08 -070060 bool suspended;
Roy Zangc03675f2010-08-10 18:02:20 -070061 int exiting;
62};
63
64static struct i2c_driver ds3232_driver;
65
66static int ds3232_check_rtc_status(struct i2c_client *client)
67{
68 int ret = 0;
69 int control, stat;
70
71 stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
72 if (stat < 0)
73 return stat;
74
75 if (stat & DS3232_REG_SR_OSF)
76 dev_warn(&client->dev,
77 "oscillator discontinuity flagged, "
78 "time unreliable\n");
79
80 stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
81
82 ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
83 if (ret < 0)
84 return ret;
85
86 /* If the alarm is pending, clear it before requesting
87 * the interrupt, so an interrupt event isn't reported
88 * before everything is initialized.
89 */
90
91 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
92 if (control < 0)
93 return control;
94
95 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
96 control |= DS3232_REG_CR_INTCN;
97
98 return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
99}
100
101static int ds3232_read_time(struct device *dev, struct rtc_time *time)
102{
103 struct i2c_client *client = to_i2c_client(dev);
104 int ret;
105 u8 buf[7];
106 unsigned int year, month, day, hour, minute, second;
107 unsigned int week, twelve_hr, am_pm;
108 unsigned int century, add_century = 0;
109
110 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf);
111
112 if (ret < 0)
113 return ret;
114 if (ret < 7)
115 return -EIO;
116
117 second = buf[0];
118 minute = buf[1];
119 hour = buf[2];
120 week = buf[3];
121 day = buf[4];
122 month = buf[5];
123 year = buf[6];
124
125 /* Extract additional information for AM/PM and century */
126
127 twelve_hr = hour & 0x40;
128 am_pm = hour & 0x20;
129 century = month & 0x80;
130
131 /* Write to rtc_time structure */
132
133 time->tm_sec = bcd2bin(second);
134 time->tm_min = bcd2bin(minute);
135 if (twelve_hr) {
136 /* Convert to 24 hr */
137 if (am_pm)
138 time->tm_hour = bcd2bin(hour & 0x1F) + 12;
139 else
140 time->tm_hour = bcd2bin(hour & 0x1F);
141 } else {
142 time->tm_hour = bcd2bin(hour);
143 }
144
Lei Xua2d6d2f2011-02-25 14:44:23 -0800145 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
146 time->tm_wday = bcd2bin(week) - 1;
Roy Zangc03675f2010-08-10 18:02:20 -0700147 time->tm_mday = bcd2bin(day);
Lei Xua2d6d2f2011-02-25 14:44:23 -0800148 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
149 time->tm_mon = bcd2bin(month & 0x7F) - 1;
Roy Zangc03675f2010-08-10 18:02:20 -0700150 if (century)
151 add_century = 100;
152
153 time->tm_year = bcd2bin(year) + add_century;
154
155 return rtc_valid_tm(time);
156}
157
158static int ds3232_set_time(struct device *dev, struct rtc_time *time)
159{
160 struct i2c_client *client = to_i2c_client(dev);
161 u8 buf[7];
162
163 /* Extract time from rtc_time and load into ds3232*/
164
165 buf[0] = bin2bcd(time->tm_sec);
166 buf[1] = bin2bcd(time->tm_min);
167 buf[2] = bin2bcd(time->tm_hour);
Lei Xua2d6d2f2011-02-25 14:44:23 -0800168 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
169 buf[3] = bin2bcd(time->tm_wday + 1);
Roy Zangc03675f2010-08-10 18:02:20 -0700170 buf[4] = bin2bcd(time->tm_mday); /* Date */
Lei Xua2d6d2f2011-02-25 14:44:23 -0800171 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
172 buf[5] = bin2bcd(time->tm_mon + 1);
Roy Zangc03675f2010-08-10 18:02:20 -0700173 if (time->tm_year >= 100) {
174 buf[5] |= 0x80;
175 buf[6] = bin2bcd(time->tm_year - 100);
176 } else {
177 buf[6] = bin2bcd(time->tm_year);
178 }
179
180 return i2c_smbus_write_i2c_block_data(client,
181 DS3232_REG_SECONDS, 7, buf);
182}
183
Lan Chunhe-B25806f46418c2010-10-27 15:33:12 -0700184/*
185 * DS3232 has two alarm, we only use alarm1
186 * According to linux specification, only support one-shot alarm
187 * no periodic alarm mode
188 */
189static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
190{
191 struct i2c_client *client = to_i2c_client(dev);
192 struct ds3232 *ds3232 = i2c_get_clientdata(client);
193 int control, stat;
194 int ret;
195 u8 buf[4];
196
197 mutex_lock(&ds3232->mutex);
198
199 ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
200 if (ret < 0)
201 goto out;
202 stat = ret;
203 ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
204 if (ret < 0)
205 goto out;
206 control = ret;
207 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
208 if (ret < 0)
209 goto out;
210
211 alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
212 alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
213 alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
214 alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
215
216 alarm->time.tm_mon = -1;
217 alarm->time.tm_year = -1;
218 alarm->time.tm_wday = -1;
219 alarm->time.tm_yday = -1;
220 alarm->time.tm_isdst = -1;
221
222 alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
223 alarm->pending = !!(stat & DS3232_REG_SR_A1F);
224
225 ret = 0;
226out:
227 mutex_unlock(&ds3232->mutex);
228 return ret;
229}
230
231/*
232 * linux rtc-module does not support wday alarm
233 * and only 24h time mode supported indeed
234 */
235static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
236{
237 struct i2c_client *client = to_i2c_client(dev);
238 struct ds3232 *ds3232 = i2c_get_clientdata(client);
239 int control, stat;
240 int ret;
241 u8 buf[4];
242
243 if (client->irq <= 0)
244 return -EINVAL;
245
246 mutex_lock(&ds3232->mutex);
247
248 buf[0] = bin2bcd(alarm->time.tm_sec);
249 buf[1] = bin2bcd(alarm->time.tm_min);
250 buf[2] = bin2bcd(alarm->time.tm_hour);
251 buf[3] = bin2bcd(alarm->time.tm_mday);
252
253 /* clear alarm interrupt enable bit */
254 ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
255 if (ret < 0)
256 goto out;
257 control = ret;
258 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
259 ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
260 if (ret < 0)
261 goto out;
262
263 /* clear any pending alarm flag */
264 ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
265 if (ret < 0)
266 goto out;
267 stat = ret;
268 stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
269 ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
270 if (ret < 0)
271 goto out;
272
273 ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
274
275 if (alarm->enabled) {
276 control |= DS3232_REG_CR_A1IE;
277 ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
278 }
279out:
280 mutex_unlock(&ds3232->mutex);
281 return ret;
282}
283
284static void ds3232_update_alarm(struct i2c_client *client)
285{
286 struct ds3232 *ds3232 = i2c_get_clientdata(client);
287 int control;
288 int ret;
289 u8 buf[4];
290
291 mutex_lock(&ds3232->mutex);
292
293 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
294 if (ret < 0)
295 goto unlock;
296
297 buf[0] = bcd2bin(buf[0]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
298 0x80 : buf[0];
299 buf[1] = bcd2bin(buf[1]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
300 0x80 : buf[1];
301 buf[2] = bcd2bin(buf[2]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
302 0x80 : buf[2];
303 buf[3] = bcd2bin(buf[3]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
304 0x80 : buf[3];
305
306 ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
307 if (ret < 0)
308 goto unlock;
309
310 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
311 if (control < 0)
312 goto unlock;
313
314 if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF))
315 /* enable alarm1 interrupt */
316 control |= DS3232_REG_CR_A1IE;
317 else
318 /* disable alarm1 interrupt */
319 control &= ~(DS3232_REG_CR_A1IE);
320 i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
321
322unlock:
323 mutex_unlock(&ds3232->mutex);
324}
325
326static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
327{
328 struct i2c_client *client = to_i2c_client(dev);
329 struct ds3232 *ds3232 = i2c_get_clientdata(client);
330
331 if (client->irq <= 0)
332 return -EINVAL;
333
334 if (enabled)
335 ds3232->rtc->irq_data |= RTC_AF;
336 else
337 ds3232->rtc->irq_data &= ~RTC_AF;
338
339 ds3232_update_alarm(client);
340 return 0;
341}
342
Roy Zangc03675f2010-08-10 18:02:20 -0700343static irqreturn_t ds3232_irq(int irq, void *dev_id)
344{
345 struct i2c_client *client = dev_id;
346 struct ds3232 *ds3232 = i2c_get_clientdata(client);
347
348 disable_irq_nosync(irq);
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700349
350 /*
351 * If rtc as a wakeup source, can't schedule the work
352 * at system resume flow, because at this time the i2c bus
353 * has not been resumed.
354 */
355 if (!ds3232->suspended)
356 schedule_work(&ds3232->work);
357
Roy Zangc03675f2010-08-10 18:02:20 -0700358 return IRQ_HANDLED;
359}
360
361static void ds3232_work(struct work_struct *work)
362{
363 struct ds3232 *ds3232 = container_of(work, struct ds3232, work);
364 struct i2c_client *client = ds3232->client;
365 int stat, control;
366
367 mutex_lock(&ds3232->mutex);
368
369 stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
370 if (stat < 0)
371 goto unlock;
372
373 if (stat & DS3232_REG_SR_A1F) {
374 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700375 if (control < 0) {
376 pr_warn("Read DS3232 Control Register error."
377 "Disable IRQ%d.\n", client->irq);
378 } else {
379 /* disable alarm1 interrupt */
380 control &= ~(DS3232_REG_CR_A1IE);
381 i2c_smbus_write_byte_data(client, DS3232_REG_CR,
382 control);
Roy Zangc03675f2010-08-10 18:02:20 -0700383
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700384 /* clear the alarm pend flag */
385 stat &= ~DS3232_REG_SR_A1F;
386 i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
Roy Zangc03675f2010-08-10 18:02:20 -0700387
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700388 rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
389
390 if (!ds3232->exiting)
391 enable_irq(client->irq);
392 }
Roy Zangc03675f2010-08-10 18:02:20 -0700393 }
394
Roy Zangc03675f2010-08-10 18:02:20 -0700395unlock:
396 mutex_unlock(&ds3232->mutex);
397}
398
399static const struct rtc_class_ops ds3232_rtc_ops = {
400 .read_time = ds3232_read_time,
401 .set_time = ds3232_set_time,
Lan Chunhe-B25806f46418c2010-10-27 15:33:12 -0700402 .read_alarm = ds3232_read_alarm,
403 .set_alarm = ds3232_set_alarm,
404 .alarm_irq_enable = ds3232_alarm_irq_enable,
Roy Zangc03675f2010-08-10 18:02:20 -0700405};
406
Greg Kroah-Hartman5a167f42012-12-21 13:09:38 -0800407static int ds3232_probe(struct i2c_client *client,
408 const struct i2c_device_id *id)
Roy Zangc03675f2010-08-10 18:02:20 -0700409{
410 struct ds3232 *ds3232;
411 int ret;
412
Sachin Kamat66714612013-04-29 16:20:31 -0700413 ds3232 = devm_kzalloc(&client->dev, sizeof(struct ds3232), GFP_KERNEL);
Roy Zangc03675f2010-08-10 18:02:20 -0700414 if (!ds3232)
415 return -ENOMEM;
416
417 ds3232->client = client;
418 i2c_set_clientdata(client, ds3232);
419
420 INIT_WORK(&ds3232->work, ds3232_work);
421 mutex_init(&ds3232->mutex);
422
423 ret = ds3232_check_rtc_status(client);
424 if (ret)
Sachin Kamat66714612013-04-29 16:20:31 -0700425 return ret;
Roy Zangc03675f2010-08-10 18:02:20 -0700426
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700427 if (client->irq > 0) {
Bharat Bhushana8a15eb2014-04-03 14:50:04 -0700428 ret = devm_request_irq(&client->dev, client->irq, ds3232_irq,
429 IRQF_SHARED, "ds3232", client);
Roy Zangc03675f2010-08-10 18:02:20 -0700430 if (ret) {
431 dev_err(&client->dev, "unable to request IRQ\n");
Roy Zangc03675f2010-08-10 18:02:20 -0700432 }
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700433 device_init_wakeup(&client->dev, 1);
Roy Zangc03675f2010-08-10 18:02:20 -0700434 }
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700435 ds3232->rtc = devm_rtc_device_register(&client->dev, client->name,
436 &ds3232_rtc_ops, THIS_MODULE);
437 return PTR_ERR_OR_ZERO(ds3232->rtc);
Roy Zangc03675f2010-08-10 18:02:20 -0700438}
439
Greg Kroah-Hartman5a167f42012-12-21 13:09:38 -0800440static int ds3232_remove(struct i2c_client *client)
Roy Zangc03675f2010-08-10 18:02:20 -0700441{
442 struct ds3232 *ds3232 = i2c_get_clientdata(client);
443
444 if (client->irq >= 0) {
445 mutex_lock(&ds3232->mutex);
446 ds3232->exiting = 1;
447 mutex_unlock(&ds3232->mutex);
448
Sachin Kamat66714612013-04-29 16:20:31 -0700449 devm_free_irq(&client->dev, client->irq, client);
Tejun Heo9db89952010-12-24 16:00:17 +0100450 cancel_work_sync(&ds3232->work);
Roy Zangc03675f2010-08-10 18:02:20 -0700451 }
452
Roy Zangc03675f2010-08-10 18:02:20 -0700453 return 0;
454}
455
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700456#ifdef CONFIG_PM_SLEEP
457static int ds3232_suspend(struct device *dev)
458{
459 struct ds3232 *ds3232 = dev_get_drvdata(dev);
460 struct i2c_client *client = to_i2c_client(dev);
461
462 if (device_can_wakeup(dev)) {
463 ds3232->suspended = true;
464 irq_set_irq_wake(client->irq, 1);
465 }
466
467 return 0;
468}
469
470static int ds3232_resume(struct device *dev)
471{
472 struct ds3232 *ds3232 = dev_get_drvdata(dev);
473 struct i2c_client *client = to_i2c_client(dev);
474
475 if (ds3232->suspended) {
476 ds3232->suspended = false;
477
478 /* Clear the hardware alarm pend flag */
479 schedule_work(&ds3232->work);
480
481 irq_set_irq_wake(client->irq, 0);
482 }
483
484 return 0;
485}
486#endif
487
488static const struct dev_pm_ops ds3232_pm_ops = {
489 SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume)
490};
491
Roy Zangc03675f2010-08-10 18:02:20 -0700492static const struct i2c_device_id ds3232_id[] = {
493 { "ds3232", 0 },
494 { }
495};
496MODULE_DEVICE_TABLE(i2c, ds3232_id);
497
498static struct i2c_driver ds3232_driver = {
499 .driver = {
500 .name = "rtc-ds3232",
501 .owner = THIS_MODULE,
Wang Dongshengc93a3ae2014-04-03 14:50:08 -0700502 .pm = &ds3232_pm_ops,
Roy Zangc03675f2010-08-10 18:02:20 -0700503 },
504 .probe = ds3232_probe,
Greg Kroah-Hartman5a167f42012-12-21 13:09:38 -0800505 .remove = ds3232_remove,
Roy Zangc03675f2010-08-10 18:02:20 -0700506 .id_table = ds3232_id,
507};
508
Axel Lin0abc9202012-03-23 15:02:31 -0700509module_i2c_driver(ds3232_driver);
Roy Zangc03675f2010-08-10 18:02:20 -0700510
511MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>");
512MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver");
513MODULE_LICENSE("GPL");