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  1/*
  2 * Copyright (C) 2017 Spreadtrum Communications Inc.
  3 *
  4 * SPDX-License-Identifier: GPL-2.0
  5 */
  6
  7#include <linux/bitops.h>
  8#include <linux/delay.h>
  9#include <linux/err.h>
 10#include <linux/module.h>
 11#include <linux/of.h>
 12#include <linux/platform_device.h>
 13#include <linux/regmap.h>
 14#include <linux/rtc.h>
 15
 16#define SPRD_RTC_SEC_CNT_VALUE		0x0
 17#define SPRD_RTC_MIN_CNT_VALUE		0x4
 18#define SPRD_RTC_HOUR_CNT_VALUE		0x8
 19#define SPRD_RTC_DAY_CNT_VALUE		0xc
 20#define SPRD_RTC_SEC_CNT_UPD		0x10
 21#define SPRD_RTC_MIN_CNT_UPD		0x14
 22#define SPRD_RTC_HOUR_CNT_UPD		0x18
 23#define SPRD_RTC_DAY_CNT_UPD		0x1c
 24#define SPRD_RTC_SEC_ALM_UPD		0x20
 25#define SPRD_RTC_MIN_ALM_UPD		0x24
 26#define SPRD_RTC_HOUR_ALM_UPD		0x28
 27#define SPRD_RTC_DAY_ALM_UPD		0x2c
 28#define SPRD_RTC_INT_EN			0x30
 29#define SPRD_RTC_INT_RAW_STS		0x34
 30#define SPRD_RTC_INT_CLR		0x38
 31#define SPRD_RTC_INT_MASK_STS		0x3C
 32#define SPRD_RTC_SEC_ALM_VALUE		0x40
 33#define SPRD_RTC_MIN_ALM_VALUE		0x44
 34#define SPRD_RTC_HOUR_ALM_VALUE		0x48
 35#define SPRD_RTC_DAY_ALM_VALUE		0x4c
 36#define SPRD_RTC_SPG_VALUE		0x50
 37#define SPRD_RTC_SPG_UPD		0x54
 38#define SPRD_RTC_SEC_AUXALM_UPD		0x60
 39#define SPRD_RTC_MIN_AUXALM_UPD		0x64
 40#define SPRD_RTC_HOUR_AUXALM_UPD	0x68
 41#define SPRD_RTC_DAY_AUXALM_UPD		0x6c
 42
 43/* BIT & MASK definition for SPRD_RTC_INT_* registers */
 44#define SPRD_RTC_SEC_EN			BIT(0)
 45#define SPRD_RTC_MIN_EN			BIT(1)
 46#define SPRD_RTC_HOUR_EN		BIT(2)
 47#define SPRD_RTC_DAY_EN			BIT(3)
 48#define SPRD_RTC_ALARM_EN		BIT(4)
 49#define SPRD_RTC_HRS_FORMAT_EN		BIT(5)
 50#define SPRD_RTC_AUXALM_EN		BIT(6)
 51#define SPRD_RTC_SPG_UPD_EN		BIT(7)
 52#define SPRD_RTC_SEC_UPD_EN		BIT(8)
 53#define SPRD_RTC_MIN_UPD_EN		BIT(9)
 54#define SPRD_RTC_HOUR_UPD_EN		BIT(10)
 55#define SPRD_RTC_DAY_UPD_EN		BIT(11)
 56#define SPRD_RTC_ALMSEC_UPD_EN		BIT(12)
 57#define SPRD_RTC_ALMMIN_UPD_EN		BIT(13)
 58#define SPRD_RTC_ALMHOUR_UPD_EN		BIT(14)
 59#define SPRD_RTC_ALMDAY_UPD_EN		BIT(15)
 60#define SPRD_RTC_INT_MASK		GENMASK(15, 0)
 61
 62#define SPRD_RTC_TIME_INT_MASK				\
 63	(SPRD_RTC_SEC_UPD_EN | SPRD_RTC_MIN_UPD_EN |	\
 64	 SPRD_RTC_HOUR_UPD_EN | SPRD_RTC_DAY_UPD_EN)
 65
 66#define SPRD_RTC_ALMTIME_INT_MASK				\
 67	(SPRD_RTC_ALMSEC_UPD_EN | SPRD_RTC_ALMMIN_UPD_EN |	\
 68	 SPRD_RTC_ALMHOUR_UPD_EN | SPRD_RTC_ALMDAY_UPD_EN)
 69
 70#define SPRD_RTC_ALM_INT_MASK			\
 71	(SPRD_RTC_SEC_EN | SPRD_RTC_MIN_EN |	\
 72	 SPRD_RTC_HOUR_EN | SPRD_RTC_DAY_EN |	\
 73	 SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN)
 74
 75/* second/minute/hour/day values mask definition */
 76#define SPRD_RTC_SEC_MASK		GENMASK(5, 0)
 77#define SPRD_RTC_MIN_MASK		GENMASK(5, 0)
 78#define SPRD_RTC_HOUR_MASK		GENMASK(4, 0)
 79#define SPRD_RTC_DAY_MASK		GENMASK(15, 0)
 80
 81/* alarm lock definition for SPRD_RTC_SPG_UPD register */
 82#define SPRD_RTC_ALMLOCK_MASK		GENMASK(7, 0)
 83#define SPRD_RTC_ALM_UNLOCK		0xa5
 84#define SPRD_RTC_ALM_LOCK		(~SPRD_RTC_ALM_UNLOCK &	\
 85					 SPRD_RTC_ALMLOCK_MASK)
 86
 87/* SPG values definition for SPRD_RTC_SPG_UPD register */
 88#define SPRD_RTC_POWEROFF_ALM_FLAG	BIT(8)
 89#define SPRD_RTC_POWER_RESET_FLAG	BIT(9)
 90
 91/* timeout of synchronizing time and alarm registers (us) */
 92#define SPRD_RTC_POLL_TIMEOUT		200000
 93#define SPRD_RTC_POLL_DELAY_US		20000
 94
 95struct sprd_rtc {
 96	struct rtc_device	*rtc;
 97	struct regmap		*regmap;
 98	struct device		*dev;
 99	u32			base;
100	int			irq;
101	bool			valid;
102};
103
104/*
105 * The Spreadtrum RTC controller has 3 groups registers, including time, normal
106 * alarm and auxiliary alarm. The time group registers are used to set RTC time,
107 * the normal alarm registers are used to set normal alarm, and the auxiliary
108 * alarm registers are used to set auxiliary alarm. Both alarm event and
109 * auxiliary alarm event can wake up system from deep sleep, but only alarm
110 * event can power up system from power down status.
111 */
112enum sprd_rtc_reg_types {
113	SPRD_RTC_TIME,
114	SPRD_RTC_ALARM,
115	SPRD_RTC_AUX_ALARM,
116};
117
118static int sprd_rtc_clear_alarm_ints(struct sprd_rtc *rtc)
119{
120	return regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
121			    SPRD_RTC_ALM_INT_MASK);
122}
123
124static int sprd_rtc_disable_ints(struct sprd_rtc *rtc)
125{
126	int ret;
127
128	ret = regmap_update_bits(rtc->regmap, rtc->base + SPRD_RTC_INT_EN,
129				 SPRD_RTC_INT_MASK, 0);
130	if (ret)
131		return ret;
132
133	return regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
134			    SPRD_RTC_INT_MASK);
135}
136
137static int sprd_rtc_lock_alarm(struct sprd_rtc *rtc, bool lock)
138{
139	int ret;
140	u32 val;
141
142	ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_SPG_VALUE, &val);
143	if (ret)
144		return ret;
145
146	val &= ~(SPRD_RTC_ALMLOCK_MASK | SPRD_RTC_POWEROFF_ALM_FLAG);
147	if (lock)
148		val |= SPRD_RTC_ALM_LOCK;
149	else
150		val |= SPRD_RTC_ALM_UNLOCK | SPRD_RTC_POWEROFF_ALM_FLAG;
151
152	ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_SPG_UPD, val);
153	if (ret)
154		return ret;
155
156	/* wait until the SPG value is updated successfully */
157	ret = regmap_read_poll_timeout(rtc->regmap,
158				       rtc->base + SPRD_RTC_INT_RAW_STS, val,
159				       (val & SPRD_RTC_SPG_UPD_EN),
160				       SPRD_RTC_POLL_DELAY_US,
161				       SPRD_RTC_POLL_TIMEOUT);
162	if (ret) {
163		dev_err(rtc->dev, "failed to update SPG value:%d\n", ret);
164		return ret;
165	}
166
167	return 0;
168}
169
170static int sprd_rtc_get_secs(struct sprd_rtc *rtc, enum sprd_rtc_reg_types type,
171			     time64_t *secs)
172{
173	u32 sec_reg, min_reg, hour_reg, day_reg;
174	u32 val, sec, min, hour, day;
175	int ret;
176
177	switch (type) {
178	case SPRD_RTC_TIME:
179		sec_reg = SPRD_RTC_SEC_CNT_VALUE;
180		min_reg = SPRD_RTC_MIN_CNT_VALUE;
181		hour_reg = SPRD_RTC_HOUR_CNT_VALUE;
182		day_reg = SPRD_RTC_DAY_CNT_VALUE;
183		break;
184	case SPRD_RTC_ALARM:
185		sec_reg = SPRD_RTC_SEC_ALM_VALUE;
186		min_reg = SPRD_RTC_MIN_ALM_VALUE;
187		hour_reg = SPRD_RTC_HOUR_ALM_VALUE;
188		day_reg = SPRD_RTC_DAY_ALM_VALUE;
189		break;
190	case SPRD_RTC_AUX_ALARM:
191		sec_reg = SPRD_RTC_SEC_AUXALM_UPD;
192		min_reg = SPRD_RTC_MIN_AUXALM_UPD;
193		hour_reg = SPRD_RTC_HOUR_AUXALM_UPD;
194		day_reg = SPRD_RTC_DAY_AUXALM_UPD;
195		break;
196	default:
197		return -EINVAL;
198	}
199
200	ret = regmap_read(rtc->regmap, rtc->base + sec_reg, &val);
201	if (ret)
202		return ret;
203
204	sec = val & SPRD_RTC_SEC_MASK;
205
206	ret = regmap_read(rtc->regmap, rtc->base + min_reg, &val);
207	if (ret)
208		return ret;
209
210	min = val & SPRD_RTC_MIN_MASK;
211
212	ret = regmap_read(rtc->regmap, rtc->base + hour_reg, &val);
213	if (ret)
214		return ret;
215
216	hour = val & SPRD_RTC_HOUR_MASK;
217
218	ret = regmap_read(rtc->regmap, rtc->base + day_reg, &val);
219	if (ret)
220		return ret;
221
222	day = val & SPRD_RTC_DAY_MASK;
223	*secs = (((time64_t)(day * 24) + hour) * 60 + min) * 60 + sec;
224	return 0;
225}
226
227static int sprd_rtc_set_secs(struct sprd_rtc *rtc, enum sprd_rtc_reg_types type,
228			     time64_t secs)
229{
230	u32 sec_reg, min_reg, hour_reg, day_reg, sts_mask;
231	u32 sec, min, hour, day, val;
232	int ret, rem;
233
234	/* convert seconds to RTC time format */
235	day = div_s64_rem(secs, 86400, &rem);
236	hour = rem / 3600;
237	rem -= hour * 3600;
238	min = rem / 60;
239	sec = rem - min * 60;
240
241	switch (type) {
242	case SPRD_RTC_TIME:
243		sec_reg = SPRD_RTC_SEC_CNT_UPD;
244		min_reg = SPRD_RTC_MIN_CNT_UPD;
245		hour_reg = SPRD_RTC_HOUR_CNT_UPD;
246		day_reg = SPRD_RTC_DAY_CNT_UPD;
247		sts_mask = SPRD_RTC_TIME_INT_MASK;
248		break;
249	case SPRD_RTC_ALARM:
250		sec_reg = SPRD_RTC_SEC_ALM_UPD;
251		min_reg = SPRD_RTC_MIN_ALM_UPD;
252		hour_reg = SPRD_RTC_HOUR_ALM_UPD;
253		day_reg = SPRD_RTC_DAY_ALM_UPD;
254		sts_mask = SPRD_RTC_ALMTIME_INT_MASK;
255		break;
256	case SPRD_RTC_AUX_ALARM:
257		sec_reg = SPRD_RTC_SEC_AUXALM_UPD;
258		min_reg = SPRD_RTC_MIN_AUXALM_UPD;
259		hour_reg = SPRD_RTC_HOUR_AUXALM_UPD;
260		day_reg = SPRD_RTC_DAY_AUXALM_UPD;
261		sts_mask = 0;
262		break;
263	default:
264		return -EINVAL;
265	}
266
267	ret = regmap_write(rtc->regmap, rtc->base + sec_reg, sec);
268	if (ret)
269		return ret;
270
271	ret = regmap_write(rtc->regmap, rtc->base + min_reg, min);
272	if (ret)
273		return ret;
274
275	ret = regmap_write(rtc->regmap, rtc->base + hour_reg, hour);
276	if (ret)
277		return ret;
278
279	ret = regmap_write(rtc->regmap, rtc->base + day_reg, day);
280	if (ret)
281		return ret;
282
283	if (type == SPRD_RTC_AUX_ALARM)
284		return 0;
285
286	/*
287	 * Since the time and normal alarm registers are put in always-power-on
288	 * region supplied by VDDRTC, then these registers changing time will
289	 * be very long, about 125ms. Thus here we should wait until all
290	 * values are updated successfully.
291	 */
292	ret = regmap_read_poll_timeout(rtc->regmap,
293				       rtc->base + SPRD_RTC_INT_RAW_STS, val,
294				       ((val & sts_mask) == sts_mask),
295				       SPRD_RTC_POLL_DELAY_US,
296				       SPRD_RTC_POLL_TIMEOUT);
297	if (ret < 0) {
298		dev_err(rtc->dev, "set time/alarm values timeout\n");
299		return ret;
300	}
301
302	return regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
303			    sts_mask);
304}
305
306static int sprd_rtc_read_aux_alarm(struct device *dev, struct rtc_wkalrm *alrm)
307{
308	struct sprd_rtc *rtc = dev_get_drvdata(dev);
309	time64_t secs;
310	u32 val;
311	int ret;
312
313	ret = sprd_rtc_get_secs(rtc, SPRD_RTC_AUX_ALARM, &secs);
314	if (ret)
315		return ret;
316
317	rtc_time64_to_tm(secs, &alrm->time);
318
319	ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_INT_EN, &val);
320	if (ret)
321		return ret;
322
323	alrm->enabled = !!(val & SPRD_RTC_AUXALM_EN);
324
325	ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_INT_RAW_STS, &val);
326	if (ret)
327		return ret;
328
329	alrm->pending = !!(val & SPRD_RTC_AUXALM_EN);
330	return 0;
331}
332
333static int sprd_rtc_set_aux_alarm(struct device *dev, struct rtc_wkalrm *alrm)
334{
335	struct sprd_rtc *rtc = dev_get_drvdata(dev);
336	time64_t secs = rtc_tm_to_time64(&alrm->time);
337	int ret;
338
339	/* clear the auxiliary alarm interrupt status */
340	ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
341			   SPRD_RTC_AUXALM_EN);
342	if (ret)
343		return ret;
344
345	ret = sprd_rtc_set_secs(rtc, SPRD_RTC_AUX_ALARM, secs);
346	if (ret)
347		return ret;
348
349	if (alrm->enabled) {
350		ret = regmap_update_bits(rtc->regmap,
351					 rtc->base + SPRD_RTC_INT_EN,
352					 SPRD_RTC_AUXALM_EN,
353					 SPRD_RTC_AUXALM_EN);
354	} else {
355		ret = regmap_update_bits(rtc->regmap,
356					 rtc->base + SPRD_RTC_INT_EN,
357					 SPRD_RTC_AUXALM_EN, 0);
358	}
359
360	return ret;
361}
362
363static int sprd_rtc_read_time(struct device *dev, struct rtc_time *tm)
364{
365	struct sprd_rtc *rtc = dev_get_drvdata(dev);
366	time64_t secs;
367	int ret;
368
369	if (!rtc->valid) {
370		dev_warn(dev, "RTC values are invalid\n");
371		return -EINVAL;
372	}
373
374	ret = sprd_rtc_get_secs(rtc, SPRD_RTC_TIME, &secs);
375	if (ret)
376		return ret;
377
378	rtc_time64_to_tm(secs, tm);
379	return 0;
380}
381
382static int sprd_rtc_set_time(struct device *dev, struct rtc_time *tm)
383{
384	struct sprd_rtc *rtc = dev_get_drvdata(dev);
385	time64_t secs = rtc_tm_to_time64(tm);
386	u32 val;
387	int ret;
388
389	ret = sprd_rtc_set_secs(rtc, SPRD_RTC_TIME, secs);
390	if (ret)
391		return ret;
392
393	if (!rtc->valid) {
394		/*
395		 * Set SPRD_RTC_POWER_RESET_FLAG to indicate now RTC has valid
396		 * time values.
397		 */
398		ret = regmap_update_bits(rtc->regmap,
399					 rtc->base + SPRD_RTC_SPG_UPD,
400					 SPRD_RTC_POWER_RESET_FLAG,
401					 SPRD_RTC_POWER_RESET_FLAG);
402		if (ret)
403			return ret;
404
405		ret = regmap_read_poll_timeout(rtc->regmap,
406					       rtc->base + SPRD_RTC_INT_RAW_STS,
407					       val, (val & SPRD_RTC_SPG_UPD_EN),
408					       SPRD_RTC_POLL_DELAY_US,
409					       SPRD_RTC_POLL_TIMEOUT);
410		if (ret) {
411			dev_err(rtc->dev, "failed to update SPG value:%d\n",
412				ret);
413			return ret;
414		}
415
416		rtc->valid = true;
417	}
418
419	return 0;
420}
421
422static int sprd_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
423{
424	struct sprd_rtc *rtc = dev_get_drvdata(dev);
425	time64_t secs;
426	int ret;
427	u32 val;
428
429	/*
430	 * If aie_timer is enabled, we should get the normal alarm time.
431	 * Otherwise we should get auxiliary alarm time.
432	 */
433	if (rtc->rtc && rtc->rtc->aie_timer.enabled == 0)
434		return sprd_rtc_read_aux_alarm(dev, alrm);
435
436	ret = sprd_rtc_get_secs(rtc, SPRD_RTC_ALARM, &secs);
437	if (ret)
438		return ret;
439
440	rtc_time64_to_tm(secs, &alrm->time);
441
442	ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_INT_EN, &val);
443	if (ret)
444		return ret;
445
446	alrm->enabled = !!(val & SPRD_RTC_ALARM_EN);
447
448	ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_INT_RAW_STS, &val);
449	if (ret)
450		return ret;
451
452	alrm->pending = !!(val & SPRD_RTC_ALARM_EN);
453	return 0;
454}
455
456static int sprd_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
457{
458	struct sprd_rtc *rtc = dev_get_drvdata(dev);
459	time64_t secs = rtc_tm_to_time64(&alrm->time);
460	struct rtc_time aie_time =
461		rtc_ktime_to_tm(rtc->rtc->aie_timer.node.expires);
462	int ret;
463
464	/*
465	 * We have 2 groups alarms: normal alarm and auxiliary alarm. Since
466	 * both normal alarm event and auxiliary alarm event can wake up system
467	 * from deep sleep, but only alarm event can power up system from power
468	 * down status. Moreover we do not need to poll about 125ms when
469	 * updating auxiliary alarm registers. Thus we usually set auxiliary
470	 * alarm when wake up system from deep sleep, and for other scenarios,
471	 * we should set normal alarm with polling status.
472	 *
473	 * So here we check if the alarm time is set by aie_timer, if yes, we
474	 * should set normal alarm, if not, we should set auxiliary alarm which
475	 * means it is just a wake event.
476	 */
477	if (!rtc->rtc->aie_timer.enabled || rtc_tm_sub(&aie_time, &alrm->time))
478		return sprd_rtc_set_aux_alarm(dev, alrm);
479
480	/* clear the alarm interrupt status firstly */
481	ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
482			   SPRD_RTC_ALARM_EN);
483	if (ret)
484		return ret;
485
486	ret = sprd_rtc_set_secs(rtc, SPRD_RTC_ALARM, secs);
487	if (ret)
488		return ret;
489
490	if (alrm->enabled) {
491		ret = regmap_update_bits(rtc->regmap,
492					 rtc->base + SPRD_RTC_INT_EN,
493					 SPRD_RTC_ALARM_EN,
494					 SPRD_RTC_ALARM_EN);
495		if (ret)
496			return ret;
497
498		/* unlock the alarm to enable the alarm function. */
499		ret = sprd_rtc_lock_alarm(rtc, false);
500	} else {
501		regmap_update_bits(rtc->regmap,
502				   rtc->base + SPRD_RTC_INT_EN,
503				   SPRD_RTC_ALARM_EN, 0);
504
505		/*
506		 * Lock the alarm function in case fake alarm event will power
507		 * up systems.
508		 */
509		ret = sprd_rtc_lock_alarm(rtc, true);
510	}
511
512	return ret;
513}
514
515static int sprd_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
516{
517	struct sprd_rtc *rtc = dev_get_drvdata(dev);
518	int ret;
519
520	if (enabled) {
521		ret = regmap_update_bits(rtc->regmap,
522					 rtc->base + SPRD_RTC_INT_EN,
523					 SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN,
524					 SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN);
525		if (ret)
526			return ret;
527
528		ret = sprd_rtc_lock_alarm(rtc, false);
529	} else {
530		regmap_update_bits(rtc->regmap, rtc->base + SPRD_RTC_INT_EN,
531				   SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN, 0);
532
533		ret = sprd_rtc_lock_alarm(rtc, true);
534	}
535
536	return ret;
537}
538
539static const struct rtc_class_ops sprd_rtc_ops = {
540	.read_time = sprd_rtc_read_time,
541	.set_time = sprd_rtc_set_time,
542	.read_alarm = sprd_rtc_read_alarm,
543	.set_alarm = sprd_rtc_set_alarm,
544	.alarm_irq_enable = sprd_rtc_alarm_irq_enable,
545};
546
547static irqreturn_t sprd_rtc_handler(int irq, void *dev_id)
548{
549	struct sprd_rtc *rtc = dev_id;
550	int ret;
551
552	ret = sprd_rtc_clear_alarm_ints(rtc);
553	if (ret)
554		return IRQ_RETVAL(ret);
555
556	rtc_update_irq(rtc->rtc, 1, RTC_AF | RTC_IRQF);
557	return IRQ_HANDLED;
558}
559
560static int sprd_rtc_check_power_down(struct sprd_rtc *rtc)
561{
562	u32 val;
563	int ret;
564
565	ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_SPG_VALUE, &val);
566	if (ret)
567		return ret;
568
569	/*
570	 * If the SPRD_RTC_POWER_RESET_FLAG was not set, which means the RTC has
571	 * been powered down, so the RTC time values are invalid.
572	 */
573	rtc->valid = (val & SPRD_RTC_POWER_RESET_FLAG) ? true : false;
574	return 0;
575}
576
577static int sprd_rtc_probe(struct platform_device *pdev)
578{
579	struct device_node *node = pdev->dev.of_node;
580	struct sprd_rtc *rtc;
581	int ret;
582
583	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
584	if (!rtc)
585		return -ENOMEM;
586
587	rtc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
588	if (!rtc->regmap)
589		return -ENODEV;
590
591	ret = of_property_read_u32(node, "reg", &rtc->base);
592	if (ret) {
593		dev_err(&pdev->dev, "failed to get RTC base address\n");
594		return ret;
595	}
596
597	rtc->irq = platform_get_irq(pdev, 0);
598	if (rtc->irq < 0) {
599		dev_err(&pdev->dev, "failed to get RTC irq number\n");
600		return rtc->irq;
601	}
602
603	rtc->dev = &pdev->dev;
604	platform_set_drvdata(pdev, rtc);
605
606	/* clear all RTC interrupts and disable all RTC interrupts */
607	ret = sprd_rtc_disable_ints(rtc);
608	if (ret) {
609		dev_err(&pdev->dev, "failed to disable RTC interrupts\n");
610		return ret;
611	}
612
613	/* check if RTC time values are valid */
614	ret = sprd_rtc_check_power_down(rtc);
615	if (ret) {
616		dev_err(&pdev->dev, "failed to check RTC time values\n");
617		return ret;
618	}
619
620	ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
621					sprd_rtc_handler,
622					IRQF_ONESHOT | IRQF_EARLY_RESUME,
623					pdev->name, rtc);
624	if (ret < 0) {
625		dev_err(&pdev->dev, "failed to request RTC irq\n");
626		return ret;
627	}
628
629	rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
630					    &sprd_rtc_ops, THIS_MODULE);
631	if (IS_ERR(rtc->rtc))
632		return PTR_ERR(rtc->rtc);
633
634	device_init_wakeup(&pdev->dev, 1);
635	return 0;
636}
637
638static int sprd_rtc_remove(struct platform_device *pdev)
639{
640	device_init_wakeup(&pdev->dev, 0);
641	return 0;
642}
643
644static const struct of_device_id sprd_rtc_of_match[] = {
645	{ .compatible = "sprd,sc2731-rtc", },
646	{ },
647};
648MODULE_DEVICE_TABLE(of, sprd_rtc_of_match);
649
650static struct platform_driver sprd_rtc_driver = {
651	.driver = {
652		.name = "sprd-rtc",
653		.of_match_table = sprd_rtc_of_match,
654	},
655	.probe	= sprd_rtc_probe,
656	.remove = sprd_rtc_remove,
657};
658module_platform_driver(sprd_rtc_driver);
659
660MODULE_LICENSE("GPL v2");
661MODULE_DESCRIPTION("Spreadtrum RTC Device Driver");
662MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");