rtc-ds3232.c

  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(ds3232->regmap, DS3232_REG_SR, &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(ds3232->regmap, DS3232_REG_SR, 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(ds3232->regmap, DS3232_REG_CR, &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(ds3232->regmap, DS3232_REG_CR, 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(ds3232->regmap, DS3232_REG_SECONDS, buf, 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(ds3232->regmap, DS3232_REG_SECONDS, buf, 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(ds3232->regmap, DS3232_REG_SR, &stat);
189	if (ret)
190		goto out;
191	ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
192	if (ret)
193		goto out;
194	ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_ALARM1, buf, 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(ds3232->regmap, DS3232_REG_CR, &control);
232	if (ret)
233		goto out;
234	control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
235	ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control);
236	if (ret)
237		goto out;
238
239	/* clear any pending alarm flag */
240	ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
241	if (ret)
242		goto out;
243	stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
244	ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
245	if (ret)
246		goto out;
247
248	ret = regmap_bulk_write(ds3232->regmap, DS3232_REG_ALARM1, buf, 4);
249	if (ret)
250		goto out;
251
252	if (alarm->enabled) {
253		control |= DS3232_REG_CR_A1IE;
254		ret = regmap_write(ds3232->regmap, DS3232_REG_CR, 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(ds3232->regmap, DS3232_REG_CR, &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(ds3232->regmap, DS3232_REG_CR, 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(ds3232->regmap, DS3232_REG_TEMPERATURE, temp_buf,
294			       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, temp);
333		break;
334	default:
335		err = -EOPNOTSUPP;
336		break;
337	}
338
339	return err;
340}
341
342static const struct hwmon_channel_info * const ds3232_hwmon_info[] = {
343	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
344	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
345	NULL
346};
347
348static const struct hwmon_ops ds3232_hwmon_hwmon_ops = {
349	.is_visible = ds3232_hwmon_is_visible,
350	.read = ds3232_hwmon_read,
351};
352
353static const struct hwmon_chip_info ds3232_hwmon_chip_info = {
354	.ops = &ds3232_hwmon_hwmon_ops,
355	.info = ds3232_hwmon_info,
356};
357
358static void ds3232_hwmon_register(struct device *dev, const char *name)
359{
360	struct ds3232 *ds3232 = dev_get_drvdata(dev);
361	struct device *hwmon_dev;
362
363	if (!IS_ENABLED(CONFIG_RTC_DRV_DS3232_HWMON))
364		return;
365
366	hwmon_dev = devm_hwmon_device_register_with_info(dev, name, ds3232,
367							&ds3232_hwmon_chip_info,
368							NULL);
369	if (IS_ERR(hwmon_dev)) {
370		dev_err(dev, "unable to register hwmon device %ld\n",
371			PTR_ERR(hwmon_dev));
372	}
373}
374
375static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
376{
377	struct ds3232 *ds3232 = dev_get_drvdata(dev);
378
379	if (ds3232->irq <= 0)
380		return -EINVAL;
381
382	return ds3232_update_alarm(dev, enabled);
383}
384
385static irqreturn_t ds3232_irq(int irq, void *dev_id)
386{
387	struct device *dev = dev_id;
388	struct ds3232 *ds3232 = dev_get_drvdata(dev);
389	int ret;
390	int stat, control;
391
392	rtc_lock(ds3232->rtc);
393
394	ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);
395	if (ret)
396		goto unlock;
397
398	if (stat & DS3232_REG_SR_A1F) {
399		ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);
400		if (ret) {
401			dev_warn(ds3232->dev,
402				 "Read Control Register error %d\n", ret);
403		} else {
404			/* disable alarm1 interrupt */
405			control &= ~(DS3232_REG_CR_A1IE);
406			ret = regmap_write(ds3232->regmap, DS3232_REG_CR,
407					   control);
408			if (ret) {
409				dev_warn(ds3232->dev,
410					 "Write Control Register error %d\n",
411					 ret);
412				goto unlock;
413			}
414
415			/* clear the alarm pend flag */
416			stat &= ~DS3232_REG_SR_A1F;
417			ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);
418			if (ret) {
419				dev_warn(ds3232->dev,
420					 "Write Status Register error %d\n",
421					 ret);
422				goto unlock;
423			}
424
425			rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
426		}
427	}
428
429unlock:
430	rtc_unlock(ds3232->rtc);
431
432	return IRQ_HANDLED;
433}
434
435static const struct rtc_class_ops ds3232_rtc_ops = {
436	.read_time = ds3232_read_time,
437	.set_time = ds3232_set_time,
438	.read_alarm = ds3232_read_alarm,
439	.set_alarm = ds3232_set_alarm,
440	.alarm_irq_enable = ds3232_alarm_irq_enable,
441};
442
443static int ds3232_nvmem_read(void *priv, unsigned int offset, void *val,
444			     size_t bytes)
445{
446	struct regmap *ds3232_regmap = (struct regmap *)priv;
447
448	return regmap_bulk_read(ds3232_regmap, DS3232_REG_SRAM_START + offset,
449				val, bytes);
450}
451
452static int ds3232_nvmem_write(void *priv, unsigned int offset, void *val,
453			      size_t bytes)
454{
455	struct regmap *ds3232_regmap = (struct regmap *)priv;
456
457	return regmap_bulk_write(ds3232_regmap, DS3232_REG_SRAM_START + offset,
458				 val, bytes);
459}
460
461static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq,
462			const char *name)
463{
464	struct ds3232 *ds3232;
465	int ret;
466	struct nvmem_config nvmem_cfg = {
467		.name = "ds3232_sram",
468		.stride = 1,
469		.size = DS3232_REG_SRAM_SIZE,
470		.word_size = 1,
471		.reg_read = ds3232_nvmem_read,
472		.reg_write = ds3232_nvmem_write,
473		.priv = regmap,
474		.type = NVMEM_TYPE_BATTERY_BACKED
475	};
476
477	ds3232 = devm_kzalloc(dev, sizeof(*ds3232), GFP_KERNEL);
478	if (!ds3232)
479		return -ENOMEM;
480
481	ds3232->regmap = regmap;
482	ds3232->irq = irq;
483	ds3232->dev = dev;
484	dev_set_drvdata(dev, ds3232);
485
486	ret = ds3232_check_rtc_status(dev);
487	if (ret)
488		return ret;
489
490	if (ds3232->irq > 0)
491		device_init_wakeup(dev, true);
492
493	ds3232_hwmon_register(dev, name);
494
495	ds3232->rtc = devm_rtc_device_register(dev, name, &ds3232_rtc_ops,
496						THIS_MODULE);
497	if (IS_ERR(ds3232->rtc))
498		return PTR_ERR(ds3232->rtc);
499
500	ret = devm_rtc_nvmem_register(ds3232->rtc, &nvmem_cfg);
501	if(ret)
502		return ret;
503
504	if (ds3232->irq > 0) {
505		ret = devm_request_threaded_irq(dev, ds3232->irq, NULL,
506						ds3232_irq,
507						IRQF_SHARED | IRQF_ONESHOT,
508						name, dev);
509		if (ret) {
510			device_set_wakeup_capable(dev, 0);
511			ds3232->irq = 0;
512			dev_err(dev, "unable to request IRQ\n");
513		}
514	}
515
516	return 0;
517}
518
519#if IS_ENABLED(CONFIG_I2C)
520
521#ifdef CONFIG_PM_SLEEP
522static int ds3232_suspend(struct device *dev)
523{
524	struct ds3232 *ds3232 = dev_get_drvdata(dev);
525
526	if (device_may_wakeup(dev)) {
527		if (enable_irq_wake(ds3232->irq))
528			dev_warn_once(dev, "Cannot set wakeup source\n");
529	}
530
531	return 0;
532}
533
534static int ds3232_resume(struct device *dev)
535{
536	struct ds3232 *ds3232 = dev_get_drvdata(dev);
537
538	if (device_may_wakeup(dev))
539		disable_irq_wake(ds3232->irq);
540
541	return 0;
542}
543#endif
544
545static const struct dev_pm_ops ds3232_pm_ops = {
546	SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume)
547};
548
549static int ds3232_i2c_probe(struct i2c_client *client)
550{
551	struct regmap *regmap;
552	static const struct regmap_config config = {
553		.reg_bits = 8,
554		.val_bits = 8,
555		.max_register = DS3232_REG_SRAM_END,
556	};
557
558	regmap = devm_regmap_init_i2c(client, &config);
559	if (IS_ERR(regmap)) {
560		dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
561			__func__, PTR_ERR(regmap));
562		return PTR_ERR(regmap);
563	}
564
565	return ds3232_probe(&client->dev, regmap, client->irq, client->name);
566}
567
568static const struct i2c_device_id ds3232_id[] = {
569	{ "ds3232" },
570	{ }
571};
572MODULE_DEVICE_TABLE(i2c, ds3232_id);
573
574static const  __maybe_unused struct of_device_id ds3232_of_match[] = {
575	{ .compatible = "dallas,ds3232" },
576	{ }
577};
578MODULE_DEVICE_TABLE(of, ds3232_of_match);
579
580static struct i2c_driver ds3232_driver = {
581	.driver = {
582		.name = "rtc-ds3232",
583		.of_match_table = of_match_ptr(ds3232_of_match),
584		.pm	= &ds3232_pm_ops,
585	},
586	.probe = ds3232_i2c_probe,
587	.id_table = ds3232_id,
588};
589
590static int ds3232_register_driver(void)
591{
592	return i2c_add_driver(&ds3232_driver);
593}
594
595static void ds3232_unregister_driver(void)
596{
597	i2c_del_driver(&ds3232_driver);
598}
599
600#else
601
602static int ds3232_register_driver(void)
603{
604	return 0;
605}
606
607static void ds3232_unregister_driver(void)
608{
609}
610
611#endif
612
613#if IS_ENABLED(CONFIG_SPI_MASTER)
614
615static int ds3234_probe(struct spi_device *spi)
616{
617	int res;
618	unsigned int tmp;
619	static const struct regmap_config config = {
620		.reg_bits = 8,
621		.val_bits = 8,
622		.max_register = DS3232_REG_SRAM_END,
623		.write_flag_mask = 0x80,
624	};
625	struct regmap *regmap;
626
627	regmap = devm_regmap_init_spi(spi, &config);
628	if (IS_ERR(regmap)) {
629		dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
630			__func__, PTR_ERR(regmap));
631		return PTR_ERR(regmap);
632	}
633
634	spi->mode = SPI_MODE_3;
635	spi->bits_per_word = 8;
636	spi_setup(spi);
637
638	res = regmap_read(regmap, DS3232_REG_SECONDS, &tmp);
639	if (res)
640		return res;
641
642	/* Control settings
643	 *
644	 * CONTROL_REG
645	 * BIT 7	6	5	4	3	2	1	0
646	 *     EOSC	BBSQW	CONV	RS2	RS1	INTCN	A2IE	A1IE
647	 *
648	 *     0	0	0	1	1	1	0	0
649	 *
650	 * CONTROL_STAT_REG
651	 * BIT 7	6	5	4	3	2	1	0
652	 *     OSF	BB32kHz	CRATE1	CRATE0	EN32kHz	BSY	A2F	A1F
653	 *
654	 *     1	0	0	0	1	0	0	0
655	 */
656	res = regmap_read(regmap, DS3232_REG_CR, &tmp);
657	if (res)
658		return res;
659	res = regmap_write(regmap, DS3232_REG_CR, tmp & 0x1c);
660	if (res)
661		return res;
662
663	res = regmap_read(regmap, DS3232_REG_SR, &tmp);
664	if (res)
665		return res;
666	res = regmap_write(regmap, DS3232_REG_SR, tmp & 0x88);
667	if (res)
668		return res;
669
670	/* Print our settings */
671	res = regmap_read(regmap, DS3232_REG_CR, &tmp);
672	if (res)
673		return res;
674	dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
675
676	res = regmap_read(regmap, DS3232_REG_SR, &tmp);
677	if (res)
678		return res;
679	dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
680
681	return ds3232_probe(&spi->dev, regmap, spi->irq, "ds3234");
682}
683
684static struct spi_driver ds3234_driver = {
685	.driver = {
686		.name	 = "ds3234",
687	},
688	.probe	 = ds3234_probe,
689};
690
691static int ds3234_register_driver(void)
692{
693	return spi_register_driver(&ds3234_driver);
694}
695
696static void ds3234_unregister_driver(void)
697{
698	spi_unregister_driver(&ds3234_driver);
699}
700
701#else
702
703static int ds3234_register_driver(void)
704{
705	return 0;
706}
707
708static void ds3234_unregister_driver(void)
709{
710}
711
712#endif
713
714static int __init ds323x_init(void)
715{
716	int ret;
717
718	ret = ds3232_register_driver();
719	if (ret) {
720		pr_err("Failed to register ds3232 driver: %d\n", ret);
721		return ret;
722	}
723
724	ret = ds3234_register_driver();
725	if (ret) {
726		pr_err("Failed to register ds3234 driver: %d\n", ret);
727		ds3232_unregister_driver();
728	}
729
730	return ret;
731}
732module_init(ds323x_init)
733
734static void __exit ds323x_exit(void)
735{
736	ds3234_unregister_driver();
737	ds3232_unregister_driver();
738}
739module_exit(ds323x_exit)
740
741MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>");
742MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
743MODULE_DESCRIPTION("Maxim/Dallas DS3232/DS3234 RTC Driver");
744MODULE_LICENSE("GPL");
745MODULE_ALIAS("spi:ds3234");