1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * RTC client/driver for the Maxim/Dallas DS3232/DS3234 Real-Time Clock
4 *
5 * Copyright (C) 2009-2011 Freescale Semiconductor.
6 * Author: Jack Lan <jack.lan@freescale.com>
7 * Copyright (C) 2008 MIMOMax Wireless Ltd.
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/interrupt.h>
15#include <linux/i2c.h>
16#include <linux/spi/spi.h>
17#include <linux/rtc.h>
18#include <linux/bcd.h>
19#include <linux/slab.h>
20#include <linux/regmap.h>
21#include <linux/hwmon.h>
22
23#define DS3232_REG_SECONDS 0x00
24#define DS3232_REG_MINUTES 0x01
25#define DS3232_REG_HOURS 0x02
26#define DS3232_REG_AMPM 0x02
27#define DS3232_REG_DAY 0x03
28#define DS3232_REG_DATE 0x04
29#define DS3232_REG_MONTH 0x05
30#define DS3232_REG_CENTURY 0x05
31#define DS3232_REG_YEAR 0x06
32#define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */
33#define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */
34#define DS3232_REG_CR 0x0E /* Control register */
35# define DS3232_REG_CR_nEOSC 0x80
36# define DS3232_REG_CR_INTCN 0x04
37# define DS3232_REG_CR_A2IE 0x02
38# define DS3232_REG_CR_A1IE 0x01
39
40#define DS3232_REG_SR 0x0F /* control/status register */
41# define DS3232_REG_SR_OSF 0x80
42# define DS3232_REG_SR_BSY 0x04
43# define DS3232_REG_SR_A2F 0x02
44# define DS3232_REG_SR_A1F 0x01
45
46#define DS3232_REG_TEMPERATURE 0x11
47#define DS3232_REG_SRAM_START 0x14
48#define DS3232_REG_SRAM_END 0xFF
49
50#define DS3232_REG_SRAM_SIZE 236
51
52struct ds3232 {
53 struct device *dev;
54 struct regmap *regmap;
55 int irq;
56 struct rtc_device *rtc;
57
58 bool suspended;
59};
60
61static int ds3232_check_rtc_status(struct device *dev)
62{
63 struct ds3232 *ds3232 = dev_get_drvdata(dev);
64 int ret = 0;
65 int control, stat;
66
67 ret = regmap_read(map: ds3232->regmap, DS3232_REG_SR, val: &stat);
68 if (ret)
69 return ret;
70
71 if (stat & DS3232_REG_SR_OSF)
72 dev_warn(dev,
73 "oscillator discontinuity flagged, "
74 "time unreliable\n");
75
76 stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
77
78 ret = regmap_write(map: ds3232->regmap, DS3232_REG_SR, val: stat);
79 if (ret)
80 return ret;
81
82 /* If the alarm is pending, clear it before requesting
83 * the interrupt, so an interrupt event isn't reported
84 * before everything is initialized.
85 */
86
87 ret = regmap_read(map: ds3232->regmap, DS3232_REG_CR, val: &control);
88 if (ret)
89 return ret;
90
91 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
92 control |= DS3232_REG_CR_INTCN;
93
94 return regmap_write(map: ds3232->regmap, DS3232_REG_CR, val: control);
95}
96
97static int ds3232_read_time(struct device *dev, struct rtc_time *time)
98{
99 struct ds3232 *ds3232 = dev_get_drvdata(dev);
100 int ret;
101 u8 buf[7];
102 unsigned int year, month, day, hour, minute, second;
103 unsigned int week, twelve_hr, am_pm;
104 unsigned int century, add_century = 0;
105
106 ret = regmap_bulk_read(map: ds3232->regmap, DS3232_REG_SECONDS, val: buf, val_count: 7);
107 if (ret)
108 return ret;
109
110 second = buf[0];
111 minute = buf[1];
112 hour = buf[2];
113 week = buf[3];
114 day = buf[4];
115 month = buf[5];
116 year = buf[6];
117
118 /* Extract additional information for AM/PM and century */
119
120 twelve_hr = hour & 0x40;
121 am_pm = hour & 0x20;
122 century = month & 0x80;
123
124 /* Write to rtc_time structure */
125
126 time->tm_sec = bcd2bin(second);
127 time->tm_min = bcd2bin(minute);
128 if (twelve_hr) {
129 /* Convert to 24 hr */
130 if (am_pm)
131 time->tm_hour = bcd2bin(hour & 0x1F) + 12;
132 else
133 time->tm_hour = bcd2bin(hour & 0x1F);
134 } else {
135 time->tm_hour = bcd2bin(hour);
136 }
137
138 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
139 time->tm_wday = bcd2bin(week) - 1;
140 time->tm_mday = bcd2bin(day);
141 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
142 time->tm_mon = bcd2bin(month & 0x7F) - 1;
143 if (century)
144 add_century = 100;
145
146 time->tm_year = bcd2bin(year) + add_century;
147
148 return 0;
149}
150
151static int ds3232_set_time(struct device *dev, struct rtc_time *time)
152{
153 struct ds3232 *ds3232 = dev_get_drvdata(dev);
154 u8 buf[7];
155
156 /* Extract time from rtc_time and load into ds3232*/
157
158 buf[0] = bin2bcd(time->tm_sec);
159 buf[1] = bin2bcd(time->tm_min);
160 buf[2] = bin2bcd(time->tm_hour);
161 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
162 buf[3] = bin2bcd(time->tm_wday + 1);
163 buf[4] = bin2bcd(time->tm_mday); /* Date */
164 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
165 buf[5] = bin2bcd(time->tm_mon + 1);
166 if (time->tm_year >= 100) {
167 buf[5] |= 0x80;
168 buf[6] = bin2bcd(time->tm_year - 100);
169 } else {
170 buf[6] = bin2bcd(time->tm_year);
171 }
172
173 return regmap_bulk_write(map: ds3232->regmap, DS3232_REG_SECONDS, val: buf, val_count: 7);
174}
175
176/*
177 * DS3232 has two alarm, we only use alarm1
178 * According to linux specification, only support one-shot alarm
179 * no periodic alarm mode
180 */
181static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
182{
183 struct ds3232 *ds3232 = dev_get_drvdata(dev);
184 int control, stat;
185 int ret;
186 u8 buf[4];
187
188 ret = regmap_read(map: ds3232->regmap, DS3232_REG_SR, val: &stat);
189 if (ret)
190 goto out;
191 ret = regmap_read(map: ds3232->regmap, DS3232_REG_CR, val: &control);
192 if (ret)
193 goto out;
194 ret = regmap_bulk_read(map: ds3232->regmap, DS3232_REG_ALARM1, val: buf, val_count: 4);
195 if (ret)
196 goto out;
197
198 alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
199 alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
200 alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
201 alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
202
203 alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
204 alarm->pending = !!(stat & DS3232_REG_SR_A1F);
205
206 ret = 0;
207out:
208 return ret;
209}
210
211/*
212 * linux rtc-module does not support wday alarm
213 * and only 24h time mode supported indeed
214 */
215static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
216{
217 struct ds3232 *ds3232 = dev_get_drvdata(dev);
218 int control, stat;
219 int ret;
220 u8 buf[4];
221
222 if (ds3232->irq <= 0)
223 return -EINVAL;
224
225 buf[0] = bin2bcd(alarm->time.tm_sec);
226 buf[1] = bin2bcd(alarm->time.tm_min);
227 buf[2] = bin2bcd(alarm->time.tm_hour);
228 buf[3] = bin2bcd(alarm->time.tm_mday);
229
230 /* clear alarm interrupt enable bit */
231 ret = regmap_read(map: ds3232->regmap, DS3232_REG_CR, val: &control);
232 if (ret)
233 goto out;
234 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
235 ret = regmap_write(map: ds3232->regmap, DS3232_REG_CR, val: control);
236 if (ret)
237 goto out;
238
239 /* clear any pending alarm flag */
240 ret = regmap_read(map: ds3232->regmap, DS3232_REG_SR, val: &stat);
241 if (ret)
242 goto out;
243 stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
244 ret = regmap_write(map: ds3232->regmap, DS3232_REG_SR, val: stat);
245 if (ret)
246 goto out;
247
248 ret = regmap_bulk_write(map: ds3232->regmap, DS3232_REG_ALARM1, val: buf, val_count: 4);
249 if (ret)
250 goto out;
251
252 if (alarm->enabled) {
253 control |= DS3232_REG_CR_A1IE;
254 ret = regmap_write(map: ds3232->regmap, DS3232_REG_CR, val: control);
255 }
256out:
257 return ret;
258}
259
260static int ds3232_update_alarm(struct device *dev, unsigned int enabled)
261{
262 struct ds3232 *ds3232 = dev_get_drvdata(dev);
263 int control;
264 int ret;
265
266 ret = regmap_read(map: ds3232->regmap, DS3232_REG_CR, val: &control);
267 if (ret)
268 return ret;
269
270 if (enabled)
271 /* enable alarm1 interrupt */
272 control |= DS3232_REG_CR_A1IE;
273 else
274 /* disable alarm1 interrupt */
275 control &= ~(DS3232_REG_CR_A1IE);
276 ret = regmap_write(map: ds3232->regmap, DS3232_REG_CR, val: control);
277
278 return ret;
279}
280
281/*
282 * Temperature sensor support for ds3232/ds3234 devices.
283 * A user-initiated temperature conversion is not started by this function,
284 * so the temperature is updated once every 64 seconds.
285 */
286static int ds3232_hwmon_read_temp(struct device *dev, long int *mC)
287{
288 struct ds3232 *ds3232 = dev_get_drvdata(dev);
289 u8 temp_buf[2];
290 s16 temp;
291 int ret;
292
293 ret = regmap_bulk_read(map: ds3232->regmap, DS3232_REG_TEMPERATURE, val: temp_buf,
294 val_count: sizeof(temp_buf));
295 if (ret < 0)
296 return ret;
297
298 /*
299 * Temperature is represented as a 10-bit code with a resolution of
300 * 0.25 degree celsius and encoded in two's complement format.
301 */
302 temp = (temp_buf[0] << 8) | temp_buf[1];
303 temp >>= 6;
304 *mC = temp * 250;
305
306 return 0;
307}
308
309static umode_t ds3232_hwmon_is_visible(const void *data,
310 enum hwmon_sensor_types type,
311 u32 attr, int channel)
312{
313 if (type != hwmon_temp)
314 return 0;
315
316 switch (attr) {
317 case hwmon_temp_input:
318 return 0444;
319 default:
320 return 0;
321 }
322}
323
324static int ds3232_hwmon_read(struct device *dev,
325 enum hwmon_sensor_types type,
326 u32 attr, int channel, long *temp)
327{
328 int err;
329
330 switch (attr) {
331 case hwmon_temp_input:
332 err = ds3232_hwmon_read_temp(dev, mC: temp);
333 break;
334 default:
335 err = -EOPNOTSUPP;
336 break;
337 }
338
339 return err;
340}
341
342static u32 ds3232_hwmon_chip_config[] = {
343 HWMON_C_REGISTER_TZ,
344 0
345};
346
347static const struct hwmon_channel_info ds3232_hwmon_chip = {
348 .type = hwmon_chip,
349 .config = ds3232_hwmon_chip_config,
350};
351
352static u32 ds3232_hwmon_temp_config[] = {
353 HWMON_T_INPUT,
354 0
355};
356
357static const struct hwmon_channel_info ds3232_hwmon_temp = {
358 .type = hwmon_temp,
359 .config = ds3232_hwmon_temp_config,
360};
361
362static const struct hwmon_channel_info * const ds3232_hwmon_info[] = {
363 &ds3232_hwmon_chip,
364 &ds3232_hwmon_temp,
365 NULL
366};
367
368static const struct hwmon_ops ds3232_hwmon_hwmon_ops = {
369 .is_visible = ds3232_hwmon_is_visible,
370 .read = ds3232_hwmon_read,
371};
372
373static const struct hwmon_chip_info ds3232_hwmon_chip_info = {
374 .ops = &ds3232_hwmon_hwmon_ops,
375 .info = ds3232_hwmon_info,
376};
377
378static void ds3232_hwmon_register(struct device *dev, const char *name)
379{
380 struct ds3232 *ds3232 = dev_get_drvdata(dev);
381 struct device *hwmon_dev;
382
383 if (!IS_ENABLED(CONFIG_RTC_DRV_DS3232_HWMON))
384 return;
385
386 hwmon_dev = devm_hwmon_device_register_with_info(dev, name, drvdata: ds3232,
387 info: &ds3232_hwmon_chip_info,
388 NULL);
389 if (IS_ERR(ptr: hwmon_dev)) {
390 dev_err(dev, "unable to register hwmon device %ld\n",
391 PTR_ERR(hwmon_dev));
392 }
393}
394
395static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
396{
397 struct ds3232 *ds3232 = dev_get_drvdata(dev);
398
399 if (ds3232->irq <= 0)
400 return -EINVAL;
401
402 return ds3232_update_alarm(dev, enabled);
403}
404
405static irqreturn_t ds3232_irq(int irq, void *dev_id)
406{
407 struct device *dev = dev_id;
408 struct ds3232 *ds3232 = dev_get_drvdata(dev);
409 int ret;
410 int stat, control;
411
412 rtc_lock(ds3232->rtc);
413
414 ret = regmap_read(map: ds3232->regmap, DS3232_REG_SR, val: &stat);
415 if (ret)
416 goto unlock;
417
418 if (stat & DS3232_REG_SR_A1F) {
419 ret = regmap_read(map: ds3232->regmap, DS3232_REG_CR, val: &control);
420 if (ret) {
421 dev_warn(ds3232->dev,
422 "Read Control Register error %d\n", ret);
423 } else {
424 /* disable alarm1 interrupt */
425 control &= ~(DS3232_REG_CR_A1IE);
426 ret = regmap_write(map: ds3232->regmap, DS3232_REG_CR,
427 val: control);
428 if (ret) {
429 dev_warn(ds3232->dev,
430 "Write Control Register error %d\n",
431 ret);
432 goto unlock;
433 }
434
435 /* clear the alarm pend flag */
436 stat &= ~DS3232_REG_SR_A1F;
437 ret = regmap_write(map: ds3232->regmap, DS3232_REG_SR, val: stat);
438 if (ret) {
439 dev_warn(ds3232->dev,
440 "Write Status Register error %d\n",
441 ret);
442 goto unlock;
443 }
444
445 rtc_update_irq(rtc: ds3232->rtc, num: 1, RTC_AF | RTC_IRQF);
446 }
447 }
448
449unlock:
450 rtc_unlock(ds3232->rtc);
451
452 return IRQ_HANDLED;
453}
454
455static const struct rtc_class_ops ds3232_rtc_ops = {
456 .read_time = ds3232_read_time,
457 .set_time = ds3232_set_time,
458 .read_alarm = ds3232_read_alarm,
459 .set_alarm = ds3232_set_alarm,
460 .alarm_irq_enable = ds3232_alarm_irq_enable,
461};
462
463static int ds3232_nvmem_read(void *priv, unsigned int offset, void *val,
464 size_t bytes)
465{
466 struct regmap *ds3232_regmap = (struct regmap *)priv;
467
468 return regmap_bulk_read(map: ds3232_regmap, DS3232_REG_SRAM_START + offset,
469 val, val_count: bytes);
470}
471
472static int ds3232_nvmem_write(void *priv, unsigned int offset, void *val,
473 size_t bytes)
474{
475 struct regmap *ds3232_regmap = (struct regmap *)priv;
476
477 return regmap_bulk_write(map: ds3232_regmap, DS3232_REG_SRAM_START + offset,
478 val, val_count: bytes);
479}
480
481static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq,
482 const char *name)
483{
484 struct ds3232 *ds3232;
485 int ret;
486 struct nvmem_config nvmem_cfg = {
487 .name = "ds3232_sram",
488 .stride = 1,
489 .size = DS3232_REG_SRAM_SIZE,
490 .word_size = 1,
491 .reg_read = ds3232_nvmem_read,
492 .reg_write = ds3232_nvmem_write,
493 .priv = regmap,
494 .type = NVMEM_TYPE_BATTERY_BACKED
495 };
496
497 ds3232 = devm_kzalloc(dev, size: sizeof(*ds3232), GFP_KERNEL);
498 if (!ds3232)
499 return -ENOMEM;
500
501 ds3232->regmap = regmap;
502 ds3232->irq = irq;
503 ds3232->dev = dev;
504 dev_set_drvdata(dev, data: ds3232);
505
506 ret = ds3232_check_rtc_status(dev);
507 if (ret)
508 return ret;
509
510 if (ds3232->irq > 0)
511 device_init_wakeup(dev, enable: 1);
512
513 ds3232_hwmon_register(dev, name);
514
515 ds3232->rtc = devm_rtc_device_register(dev, name, ops: &ds3232_rtc_ops,
516 THIS_MODULE);
517 if (IS_ERR(ptr: ds3232->rtc))
518 return PTR_ERR(ptr: ds3232->rtc);
519
520 ret = devm_rtc_nvmem_register(rtc: ds3232->rtc, nvmem_config: &nvmem_cfg);
521 if(ret)
522 return ret;
523
524 if (ds3232->irq > 0) {
525 ret = devm_request_threaded_irq(dev, irq: ds3232->irq, NULL,
526 thread_fn: ds3232_irq,
527 IRQF_SHARED | IRQF_ONESHOT,
528 devname: name, dev_id: dev);
529 if (ret) {
530 device_set_wakeup_capable(dev, capable: 0);
531 ds3232->irq = 0;
532 dev_err(dev, "unable to request IRQ\n");
533 }
534 }
535
536 return 0;
537}
538
539#ifdef CONFIG_PM_SLEEP
540static int ds3232_suspend(struct device *dev)
541{
542 struct ds3232 *ds3232 = dev_get_drvdata(dev);
543
544 if (device_may_wakeup(dev)) {
545 if (enable_irq_wake(irq: ds3232->irq))
546 dev_warn_once(dev, "Cannot set wakeup source\n");
547 }
548
549 return 0;
550}
551
552static int ds3232_resume(struct device *dev)
553{
554 struct ds3232 *ds3232 = dev_get_drvdata(dev);
555
556 if (device_may_wakeup(dev))
557 disable_irq_wake(irq: ds3232->irq);
558
559 return 0;
560}
561#endif
562
563static const struct dev_pm_ops ds3232_pm_ops = {
564 SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume)
565};
566
567#if IS_ENABLED(CONFIG_I2C)
568
569static int ds3232_i2c_probe(struct i2c_client *client)
570{
571 struct regmap *regmap;
572 static const struct regmap_config config = {
573 .reg_bits = 8,
574 .val_bits = 8,
575 .max_register = DS3232_REG_SRAM_END,
576 };
577
578 regmap = devm_regmap_init_i2c(client, &config);
579 if (IS_ERR(ptr: regmap)) {
580 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
581 __func__, PTR_ERR(regmap));
582 return PTR_ERR(ptr: regmap);
583 }
584
585 return ds3232_probe(dev: &client->dev, regmap, irq: client->irq, name: client->name);
586}
587
588static const struct i2c_device_id ds3232_id[] = {
589 { "ds3232", 0 },
590 { }
591};
592MODULE_DEVICE_TABLE(i2c, ds3232_id);
593
594static const __maybe_unused struct of_device_id ds3232_of_match[] = {
595 { .compatible = "dallas,ds3232" },
596 { }
597};
598MODULE_DEVICE_TABLE(of, ds3232_of_match);
599
600static struct i2c_driver ds3232_driver = {
601 .driver = {
602 .name = "rtc-ds3232",
603 .of_match_table = of_match_ptr(ds3232_of_match),
604 .pm = &ds3232_pm_ops,
605 },
606 .probe = ds3232_i2c_probe,
607 .id_table = ds3232_id,
608};
609
610static int ds3232_register_driver(void)
611{
612 return i2c_add_driver(&ds3232_driver);
613}
614
615static void ds3232_unregister_driver(void)
616{
617 i2c_del_driver(driver: &ds3232_driver);
618}
619
620#else
621
622static int ds3232_register_driver(void)
623{
624 return 0;
625}
626
627static void ds3232_unregister_driver(void)
628{
629}
630
631#endif
632
633#if IS_ENABLED(CONFIG_SPI_MASTER)
634
635static int ds3234_probe(struct spi_device *spi)
636{
637 int res;
638 unsigned int tmp;
639 static const struct regmap_config config = {
640 .reg_bits = 8,
641 .val_bits = 8,
642 .max_register = DS3232_REG_SRAM_END,
643 .write_flag_mask = 0x80,
644 };
645 struct regmap *regmap;
646
647 regmap = devm_regmap_init_spi(spi, &config);
648 if (IS_ERR(ptr: regmap)) {
649 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
650 __func__, PTR_ERR(regmap));
651 return PTR_ERR(ptr: regmap);
652 }
653
654 spi->mode = SPI_MODE_3;
655 spi->bits_per_word = 8;
656 spi_setup(spi);
657
658 res = regmap_read(map: regmap, DS3232_REG_SECONDS, val: &tmp);
659 if (res)
660 return res;
661
662 /* Control settings
663 *
664 * CONTROL_REG
665 * BIT 7 6 5 4 3 2 1 0
666 * EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE
667 *
668 * 0 0 0 1 1 1 0 0
669 *
670 * CONTROL_STAT_REG
671 * BIT 7 6 5 4 3 2 1 0
672 * OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F
673 *
674 * 1 0 0 0 1 0 0 0
675 */
676 res = regmap_read(map: regmap, DS3232_REG_CR, val: &tmp);
677 if (res)
678 return res;
679 res = regmap_write(map: regmap, DS3232_REG_CR, val: tmp & 0x1c);
680 if (res)
681 return res;
682
683 res = regmap_read(map: regmap, DS3232_REG_SR, val: &tmp);
684 if (res)
685 return res;
686 res = regmap_write(map: regmap, DS3232_REG_SR, val: tmp & 0x88);
687 if (res)
688 return res;
689
690 /* Print our settings */
691 res = regmap_read(map: regmap, DS3232_REG_CR, val: &tmp);
692 if (res)
693 return res;
694 dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
695
696 res = regmap_read(map: regmap, DS3232_REG_SR, val: &tmp);
697 if (res)
698 return res;
699 dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
700
701 return ds3232_probe(dev: &spi->dev, regmap, irq: spi->irq, name: "ds3234");
702}
703
704static struct spi_driver ds3234_driver = {
705 .driver = {
706 .name = "ds3234",
707 },
708 .probe = ds3234_probe,
709};
710
711static int ds3234_register_driver(void)
712{
713 return spi_register_driver(&ds3234_driver);
714}
715
716static void ds3234_unregister_driver(void)
717{
718 spi_unregister_driver(sdrv: &ds3234_driver);
719}
720
721#else
722
723static int ds3234_register_driver(void)
724{
725 return 0;
726}
727
728static void ds3234_unregister_driver(void)
729{
730}
731
732#endif
733
734static int __init ds323x_init(void)
735{
736 int ret;
737
738 ret = ds3232_register_driver();
739 if (ret) {
740 pr_err("Failed to register ds3232 driver: %d\n", ret);
741 return ret;
742 }
743
744 ret = ds3234_register_driver();
745 if (ret) {
746 pr_err("Failed to register ds3234 driver: %d\n", ret);
747 ds3232_unregister_driver();
748 }
749
750 return ret;
751}
752module_init(ds323x_init)
753
754static void __exit ds323x_exit(void)
755{
756 ds3234_unregister_driver();
757 ds3232_unregister_driver();
758}
759module_exit(ds323x_exit)
760
761MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>");
762MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
763MODULE_DESCRIPTION("Maxim/Dallas DS3232/DS3234 RTC Driver");
764MODULE_LICENSE("GPL");
765MODULE_ALIAS("spi:ds3234");
766

source code of linux/drivers/rtc/rtc-ds3232.c