xref: /linux/drivers/rtc/rtc-at91rm9200.c (revision b77e0ce62d63a761ffb7f7245a215a49f5921c2f)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	Real Time Clock interface for Linux on Atmel AT91RM9200
4  *
5  *	Copyright (C) 2002 Rick Bronson
6  *
7  *	Converted to RTC class model by Andrew Victor
8  *
9  *	Ported to Linux 2.6 by Steven Scholz
10  *	Based on s3c2410-rtc.c Simtec Electronics
11  *
12  *	Based on sa1100-rtc.c by Nils Faerber
13  *	Based on rtc.c by Paul Gortmaker
14  */
15 
16 #include <linux/bcd.h>
17 #include <linux/bitfield.h>
18 #include <linux/clk.h>
19 #include <linux/completion.h>
20 #include <linux/interrupt.h>
21 #include <linux/ioctl.h>
22 #include <linux/io.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/of_device.h>
26 #include <linux/of.h>
27 #include <linux/platform_device.h>
28 #include <linux/rtc.h>
29 #include <linux/spinlock.h>
30 #include <linux/suspend.h>
31 #include <linux/time.h>
32 #include <linux/uaccess.h>
33 
34 #define	AT91_RTC_CR		0x00			/* Control Register */
35 #define		AT91_RTC_UPDTIM		BIT(0)		/* Update Request Time Register */
36 #define		AT91_RTC_UPDCAL		BIT(1)		/* Update Request Calendar Register */
37 
38 #define	AT91_RTC_MR		0x04			/* Mode Register */
39 #define		AT91_RTC_HRMOD		BIT(0)		/* 12/24 hour mode */
40 #define		AT91_RTC_NEGPPM		BIT(4)		/* Negative PPM correction */
41 #define		AT91_RTC_CORRECTION	GENMASK(14, 8)	/* Slow clock correction */
42 #define		AT91_RTC_HIGHPPM	BIT(15)		/* High PPM correction */
43 
44 #define	AT91_RTC_TIMR		0x08			/* Time Register */
45 #define		AT91_RTC_SEC		GENMASK(6, 0)	/* Current Second */
46 #define		AT91_RTC_MIN		GENMASK(14, 8)	/* Current Minute */
47 #define		AT91_RTC_HOUR		GENMASK(21, 16)	/* Current Hour */
48 #define		AT91_RTC_AMPM		BIT(22)		/* Ante Meridiem Post Meridiem Indicator */
49 
50 #define	AT91_RTC_CALR		0x0c			/* Calendar Register */
51 #define		AT91_RTC_CENT		GENMASK(6, 0)	/* Current Century */
52 #define		AT91_RTC_YEAR		GENMASK(15, 8)	/* Current Year */
53 #define		AT91_RTC_MONTH		GENMASK(20, 16)	/* Current Month */
54 #define		AT91_RTC_DAY		GENMASK(23, 21)	/* Current Day */
55 #define		AT91_RTC_DATE		GENMASK(29, 24)	/* Current Date */
56 
57 #define	AT91_RTC_TIMALR		0x10			/* Time Alarm Register */
58 #define		AT91_RTC_SECEN		BIT(7)		/* Second Alarm Enable */
59 #define		AT91_RTC_MINEN		BIT(15)		/* Minute Alarm Enable */
60 #define		AT91_RTC_HOUREN		BIT(23)		/* Hour Alarm Enable */
61 
62 #define	AT91_RTC_CALALR		0x14			/* Calendar Alarm Register */
63 #define		AT91_RTC_MTHEN		BIT(23)		/* Month Alarm Enable */
64 #define		AT91_RTC_DATEEN		BIT(31)		/* Date Alarm Enable */
65 
66 #define	AT91_RTC_SR		0x18			/* Status Register */
67 #define		AT91_RTC_ACKUPD		BIT(0)		/* Acknowledge for Update */
68 #define		AT91_RTC_ALARM		BIT(1)		/* Alarm Flag */
69 #define		AT91_RTC_SECEV		BIT(2)		/* Second Event */
70 #define		AT91_RTC_TIMEV		BIT(3)		/* Time Event */
71 #define		AT91_RTC_CALEV		BIT(4)		/* Calendar Event */
72 
73 #define	AT91_RTC_SCCR		0x1c			/* Status Clear Command Register */
74 #define	AT91_RTC_IER		0x20			/* Interrupt Enable Register */
75 #define	AT91_RTC_IDR		0x24			/* Interrupt Disable Register */
76 #define	AT91_RTC_IMR		0x28			/* Interrupt Mask Register */
77 
78 #define	AT91_RTC_VER		0x2c			/* Valid Entry Register */
79 #define		AT91_RTC_NVTIM		BIT(0)		/* Non valid Time */
80 #define		AT91_RTC_NVCAL		BIT(1)		/* Non valid Calendar */
81 #define		AT91_RTC_NVTIMALR	BIT(2)		/* Non valid Time Alarm */
82 #define		AT91_RTC_NVCALALR	BIT(3)		/* Non valid Calendar Alarm */
83 
84 #define AT91_RTC_CORR_DIVIDEND		3906000
85 #define AT91_RTC_CORR_LOW_RATIO		20
86 
87 #define at91_rtc_read(field) \
88 	readl_relaxed(at91_rtc_regs + field)
89 #define at91_rtc_write(field, val) \
90 	writel_relaxed((val), at91_rtc_regs + field)
91 
92 struct at91_rtc_config {
93 	bool use_shadow_imr;
94 	bool has_correction;
95 };
96 
97 static const struct at91_rtc_config *at91_rtc_config;
98 static DECLARE_COMPLETION(at91_rtc_updated);
99 static DECLARE_COMPLETION(at91_rtc_upd_rdy);
100 static void __iomem *at91_rtc_regs;
101 static int irq;
102 static DEFINE_SPINLOCK(at91_rtc_lock);
103 static u32 at91_rtc_shadow_imr;
104 static bool suspended;
105 static DEFINE_SPINLOCK(suspended_lock);
106 static unsigned long cached_events;
107 static u32 at91_rtc_imr;
108 static struct clk *sclk;
109 
110 static void at91_rtc_write_ier(u32 mask)
111 {
112 	unsigned long flags;
113 
114 	spin_lock_irqsave(&at91_rtc_lock, flags);
115 	at91_rtc_shadow_imr |= mask;
116 	at91_rtc_write(AT91_RTC_IER, mask);
117 	spin_unlock_irqrestore(&at91_rtc_lock, flags);
118 }
119 
120 static void at91_rtc_write_idr(u32 mask)
121 {
122 	unsigned long flags;
123 
124 	spin_lock_irqsave(&at91_rtc_lock, flags);
125 	at91_rtc_write(AT91_RTC_IDR, mask);
126 	/*
127 	 * Register read back (of any RTC-register) needed to make sure
128 	 * IDR-register write has reached the peripheral before updating
129 	 * shadow mask.
130 	 *
131 	 * Note that there is still a possibility that the mask is updated
132 	 * before interrupts have actually been disabled in hardware. The only
133 	 * way to be certain would be to poll the IMR-register, which is is
134 	 * the very register we are trying to emulate. The register read back
135 	 * is a reasonable heuristic.
136 	 */
137 	at91_rtc_read(AT91_RTC_SR);
138 	at91_rtc_shadow_imr &= ~mask;
139 	spin_unlock_irqrestore(&at91_rtc_lock, flags);
140 }
141 
142 static u32 at91_rtc_read_imr(void)
143 {
144 	unsigned long flags;
145 	u32 mask;
146 
147 	if (at91_rtc_config->use_shadow_imr) {
148 		spin_lock_irqsave(&at91_rtc_lock, flags);
149 		mask = at91_rtc_shadow_imr;
150 		spin_unlock_irqrestore(&at91_rtc_lock, flags);
151 	} else {
152 		mask = at91_rtc_read(AT91_RTC_IMR);
153 	}
154 
155 	return mask;
156 }
157 
158 /*
159  * Decode time/date into rtc_time structure
160  */
161 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
162 				struct rtc_time *tm)
163 {
164 	unsigned int time, date;
165 
166 	/* must read twice in case it changes */
167 	do {
168 		time = at91_rtc_read(timereg);
169 		date = at91_rtc_read(calreg);
170 	} while ((time != at91_rtc_read(timereg)) ||
171 			(date != at91_rtc_read(calreg)));
172 
173 	tm->tm_sec  = bcd2bin(FIELD_GET(AT91_RTC_SEC, time));
174 	tm->tm_min  = bcd2bin(FIELD_GET(AT91_RTC_MIN, time));
175 	tm->tm_hour = bcd2bin(FIELD_GET(AT91_RTC_HOUR, time));
176 
177 	/*
178 	 * The Calendar Alarm register does not have a field for
179 	 * the year - so these will return an invalid value.
180 	 */
181 	tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;	/* century */
182 	tm->tm_year += bcd2bin(FIELD_GET(AT91_RTC_YEAR, date));	/* year */
183 
184 	tm->tm_wday = bcd2bin(FIELD_GET(AT91_RTC_DAY, date)) - 1;	/* day of the week [0-6], Sunday=0 */
185 	tm->tm_mon  = bcd2bin(FIELD_GET(AT91_RTC_MONTH, date)) - 1;
186 	tm->tm_mday = bcd2bin(FIELD_GET(AT91_RTC_DATE, date));
187 }
188 
189 /*
190  * Read current time and date in RTC
191  */
192 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
193 {
194 	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
195 	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
196 	tm->tm_year = tm->tm_year - 1900;
197 
198 	dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
199 
200 	return 0;
201 }
202 
203 /*
204  * Set current time and date in RTC
205  */
206 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
207 {
208 	unsigned long cr;
209 
210 	dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
211 
212 	wait_for_completion(&at91_rtc_upd_rdy);
213 
214 	/* Stop Time/Calendar from counting */
215 	cr = at91_rtc_read(AT91_RTC_CR);
216 	at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
217 
218 	at91_rtc_write_ier(AT91_RTC_ACKUPD);
219 	wait_for_completion(&at91_rtc_updated);	/* wait for ACKUPD interrupt */
220 	at91_rtc_write_idr(AT91_RTC_ACKUPD);
221 
222 	at91_rtc_write(AT91_RTC_TIMR,
223 			  FIELD_PREP(AT91_RTC_SEC, bin2bcd(tm->tm_sec))
224 			| FIELD_PREP(AT91_RTC_MIN, bin2bcd(tm->tm_min))
225 			| FIELD_PREP(AT91_RTC_HOUR, bin2bcd(tm->tm_hour)));
226 
227 	at91_rtc_write(AT91_RTC_CALR,
228 			  FIELD_PREP(AT91_RTC_CENT,
229 				     bin2bcd((tm->tm_year + 1900) / 100))
230 			| FIELD_PREP(AT91_RTC_YEAR, bin2bcd(tm->tm_year % 100))
231 			| FIELD_PREP(AT91_RTC_MONTH, bin2bcd(tm->tm_mon + 1))
232 			| FIELD_PREP(AT91_RTC_DAY, bin2bcd(tm->tm_wday + 1))
233 			| FIELD_PREP(AT91_RTC_DATE, bin2bcd(tm->tm_mday)));
234 
235 	/* Restart Time/Calendar */
236 	cr = at91_rtc_read(AT91_RTC_CR);
237 	at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
238 	at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
239 	at91_rtc_write_ier(AT91_RTC_SECEV);
240 
241 	return 0;
242 }
243 
244 /*
245  * Read alarm time and date in RTC
246  */
247 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
248 {
249 	struct rtc_time *tm = &alrm->time;
250 
251 	at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
252 	tm->tm_year = -1;
253 
254 	alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
255 			? 1 : 0;
256 
257 	dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm,
258 		alrm->enabled ? "en" : "dis");
259 
260 	return 0;
261 }
262 
263 /*
264  * Set alarm time and date in RTC
265  */
266 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
267 {
268 	struct rtc_time tm = alrm->time;
269 
270 	at91_rtc_write_idr(AT91_RTC_ALARM);
271 	at91_rtc_write(AT91_RTC_TIMALR,
272 		  FIELD_PREP(AT91_RTC_SEC, bin2bcd(alrm->time.tm_sec))
273 		| FIELD_PREP(AT91_RTC_MIN, bin2bcd(alrm->time.tm_min))
274 		| FIELD_PREP(AT91_RTC_HOUR, bin2bcd(alrm->time.tm_hour))
275 		| AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
276 	at91_rtc_write(AT91_RTC_CALALR,
277 		  FIELD_PREP(AT91_RTC_MONTH, bin2bcd(alrm->time.tm_mon + 1))
278 		| FIELD_PREP(AT91_RTC_DATE, bin2bcd(alrm->time.tm_mday))
279 		| AT91_RTC_DATEEN | AT91_RTC_MTHEN);
280 
281 	if (alrm->enabled) {
282 		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
283 		at91_rtc_write_ier(AT91_RTC_ALARM);
284 	}
285 
286 	dev_dbg(dev, "%s(): %ptR\n", __func__, &tm);
287 
288 	return 0;
289 }
290 
291 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
292 {
293 	dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
294 
295 	if (enabled) {
296 		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
297 		at91_rtc_write_ier(AT91_RTC_ALARM);
298 	} else
299 		at91_rtc_write_idr(AT91_RTC_ALARM);
300 
301 	return 0;
302 }
303 
304 static int at91_rtc_readoffset(struct device *dev, long *offset)
305 {
306 	u32 mr = at91_rtc_read(AT91_RTC_MR);
307 	long val = FIELD_GET(AT91_RTC_CORRECTION, mr);
308 
309 	if (!val) {
310 		*offset = 0;
311 		return 0;
312 	}
313 
314 	val++;
315 
316 	if (!(mr & AT91_RTC_NEGPPM))
317 		val = -val;
318 
319 	if (!(mr & AT91_RTC_HIGHPPM))
320 		val *= AT91_RTC_CORR_LOW_RATIO;
321 
322 	*offset = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, val);
323 
324 	return 0;
325 }
326 
327 static int at91_rtc_setoffset(struct device *dev, long offset)
328 {
329 	long corr;
330 	u32 mr;
331 
332 	if (offset > AT91_RTC_CORR_DIVIDEND / 2)
333 		return -ERANGE;
334 	if (offset < -AT91_RTC_CORR_DIVIDEND / 2)
335 		return -ERANGE;
336 
337 	mr = at91_rtc_read(AT91_RTC_MR);
338 	mr &= ~(AT91_RTC_NEGPPM | AT91_RTC_CORRECTION | AT91_RTC_HIGHPPM);
339 
340 	if (offset > 0)
341 		mr |= AT91_RTC_NEGPPM;
342 	else
343 		offset = -offset;
344 
345 	/* offset less than 764 ppb, disable correction*/
346 	if (offset < 764) {
347 		at91_rtc_write(AT91_RTC_MR, mr & ~AT91_RTC_NEGPPM);
348 
349 		return 0;
350 	}
351 
352 	/*
353 	 * 29208 ppb is the perfect cutoff between low range and high range
354 	 * low range values are never better than high range value after that.
355 	 */
356 	if (offset < 29208) {
357 		corr = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, offset * AT91_RTC_CORR_LOW_RATIO);
358 	} else {
359 		corr = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, offset);
360 		mr |= AT91_RTC_HIGHPPM;
361 	}
362 
363 	if (corr > 128)
364 		corr = 128;
365 
366 	mr |= FIELD_PREP(AT91_RTC_CORRECTION, corr - 1);
367 
368 	at91_rtc_write(AT91_RTC_MR, mr);
369 
370 	return 0;
371 }
372 
373 /*
374  * IRQ handler for the RTC
375  */
376 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
377 {
378 	struct platform_device *pdev = dev_id;
379 	struct rtc_device *rtc = platform_get_drvdata(pdev);
380 	unsigned int rtsr;
381 	unsigned long events = 0;
382 	int ret = IRQ_NONE;
383 
384 	spin_lock(&suspended_lock);
385 	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
386 	if (rtsr) {		/* this interrupt is shared!  Is it ours? */
387 		if (rtsr & AT91_RTC_ALARM)
388 			events |= (RTC_AF | RTC_IRQF);
389 		if (rtsr & AT91_RTC_SECEV) {
390 			complete(&at91_rtc_upd_rdy);
391 			at91_rtc_write_idr(AT91_RTC_SECEV);
392 		}
393 		if (rtsr & AT91_RTC_ACKUPD)
394 			complete(&at91_rtc_updated);
395 
396 		at91_rtc_write(AT91_RTC_SCCR, rtsr);	/* clear status reg */
397 
398 		if (!suspended) {
399 			rtc_update_irq(rtc, 1, events);
400 
401 			dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
402 				__func__, events >> 8, events & 0x000000FF);
403 		} else {
404 			cached_events |= events;
405 			at91_rtc_write_idr(at91_rtc_imr);
406 			pm_system_wakeup();
407 		}
408 
409 		ret = IRQ_HANDLED;
410 	}
411 	spin_unlock(&suspended_lock);
412 
413 	return ret;
414 }
415 
416 static const struct at91_rtc_config at91rm9200_config = {
417 };
418 
419 static const struct at91_rtc_config at91sam9x5_config = {
420 	.use_shadow_imr	= true,
421 };
422 
423 static const struct at91_rtc_config sama5d4_config = {
424 	.has_correction = true,
425 };
426 
427 static const struct of_device_id at91_rtc_dt_ids[] = {
428 	{
429 		.compatible = "atmel,at91rm9200-rtc",
430 		.data = &at91rm9200_config,
431 	}, {
432 		.compatible = "atmel,at91sam9x5-rtc",
433 		.data = &at91sam9x5_config,
434 	}, {
435 		.compatible = "atmel,sama5d4-rtc",
436 		.data = &sama5d4_config,
437 	}, {
438 		.compatible = "atmel,sama5d2-rtc",
439 		.data = &sama5d4_config,
440 	}, {
441 		.compatible = "microchip,sam9x60-rtc",
442 		.data = &sama5d4_config,
443 	}, {
444 		/* sentinel */
445 	}
446 };
447 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
448 
449 static const struct rtc_class_ops at91_rtc_ops = {
450 	.read_time	= at91_rtc_readtime,
451 	.set_time	= at91_rtc_settime,
452 	.read_alarm	= at91_rtc_readalarm,
453 	.set_alarm	= at91_rtc_setalarm,
454 	.alarm_irq_enable = at91_rtc_alarm_irq_enable,
455 };
456 
457 static const struct rtc_class_ops sama5d4_rtc_ops = {
458 	.read_time	= at91_rtc_readtime,
459 	.set_time	= at91_rtc_settime,
460 	.read_alarm	= at91_rtc_readalarm,
461 	.set_alarm	= at91_rtc_setalarm,
462 	.alarm_irq_enable = at91_rtc_alarm_irq_enable,
463 	.set_offset	= at91_rtc_setoffset,
464 	.read_offset	= at91_rtc_readoffset,
465 };
466 
467 /*
468  * Initialize and install RTC driver
469  */
470 static int __init at91_rtc_probe(struct platform_device *pdev)
471 {
472 	struct rtc_device *rtc;
473 	struct resource *regs;
474 	int ret = 0;
475 
476 	at91_rtc_config = of_device_get_match_data(&pdev->dev);
477 	if (!at91_rtc_config)
478 		return -ENODEV;
479 
480 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
481 	if (!regs) {
482 		dev_err(&pdev->dev, "no mmio resource defined\n");
483 		return -ENXIO;
484 	}
485 
486 	irq = platform_get_irq(pdev, 0);
487 	if (irq < 0)
488 		return -ENXIO;
489 
490 	at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
491 				     resource_size(regs));
492 	if (!at91_rtc_regs) {
493 		dev_err(&pdev->dev, "failed to map registers, aborting.\n");
494 		return -ENOMEM;
495 	}
496 
497 	rtc = devm_rtc_allocate_device(&pdev->dev);
498 	if (IS_ERR(rtc))
499 		return PTR_ERR(rtc);
500 	platform_set_drvdata(pdev, rtc);
501 
502 	sclk = devm_clk_get(&pdev->dev, NULL);
503 	if (IS_ERR(sclk))
504 		return PTR_ERR(sclk);
505 
506 	ret = clk_prepare_enable(sclk);
507 	if (ret) {
508 		dev_err(&pdev->dev, "Could not enable slow clock\n");
509 		return ret;
510 	}
511 
512 	at91_rtc_write(AT91_RTC_CR, 0);
513 	at91_rtc_write(AT91_RTC_MR, at91_rtc_read(AT91_RTC_MR) & ~AT91_RTC_HRMOD);
514 
515 	/* Disable all interrupts */
516 	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
517 					AT91_RTC_SECEV | AT91_RTC_TIMEV |
518 					AT91_RTC_CALEV);
519 
520 	ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
521 			       IRQF_SHARED | IRQF_COND_SUSPEND,
522 			       "at91_rtc", pdev);
523 	if (ret) {
524 		dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
525 		goto err_clk;
526 	}
527 
528 	/* cpu init code should really have flagged this device as
529 	 * being wake-capable; if it didn't, do that here.
530 	 */
531 	if (!device_can_wakeup(&pdev->dev))
532 		device_init_wakeup(&pdev->dev, 1);
533 
534 	if (at91_rtc_config->has_correction)
535 		rtc->ops = &sama5d4_rtc_ops;
536 	else
537 		rtc->ops = &at91_rtc_ops;
538 
539 	rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
540 	rtc->range_max = RTC_TIMESTAMP_END_2099;
541 	ret = devm_rtc_register_device(rtc);
542 	if (ret)
543 		goto err_clk;
544 
545 	/* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
546 	 * completion.
547 	 */
548 	at91_rtc_write_ier(AT91_RTC_SECEV);
549 
550 	dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
551 	return 0;
552 
553 err_clk:
554 	clk_disable_unprepare(sclk);
555 
556 	return ret;
557 }
558 
559 /*
560  * Disable and remove the RTC driver
561  */
562 static int __exit at91_rtc_remove(struct platform_device *pdev)
563 {
564 	/* Disable all interrupts */
565 	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
566 					AT91_RTC_SECEV | AT91_RTC_TIMEV |
567 					AT91_RTC_CALEV);
568 
569 	clk_disable_unprepare(sclk);
570 
571 	return 0;
572 }
573 
574 static void at91_rtc_shutdown(struct platform_device *pdev)
575 {
576 	/* Disable all interrupts */
577 	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
578 					AT91_RTC_SECEV | AT91_RTC_TIMEV |
579 					AT91_RTC_CALEV);
580 }
581 
582 #ifdef CONFIG_PM_SLEEP
583 
584 /* AT91RM9200 RTC Power management control */
585 
586 static int at91_rtc_suspend(struct device *dev)
587 {
588 	/* this IRQ is shared with DBGU and other hardware which isn't
589 	 * necessarily doing PM like we are...
590 	 */
591 	at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
592 
593 	at91_rtc_imr = at91_rtc_read_imr()
594 			& (AT91_RTC_ALARM|AT91_RTC_SECEV);
595 	if (at91_rtc_imr) {
596 		if (device_may_wakeup(dev)) {
597 			unsigned long flags;
598 
599 			enable_irq_wake(irq);
600 
601 			spin_lock_irqsave(&suspended_lock, flags);
602 			suspended = true;
603 			spin_unlock_irqrestore(&suspended_lock, flags);
604 		} else {
605 			at91_rtc_write_idr(at91_rtc_imr);
606 		}
607 	}
608 	return 0;
609 }
610 
611 static int at91_rtc_resume(struct device *dev)
612 {
613 	struct rtc_device *rtc = dev_get_drvdata(dev);
614 
615 	if (at91_rtc_imr) {
616 		if (device_may_wakeup(dev)) {
617 			unsigned long flags;
618 
619 			spin_lock_irqsave(&suspended_lock, flags);
620 
621 			if (cached_events) {
622 				rtc_update_irq(rtc, 1, cached_events);
623 				cached_events = 0;
624 			}
625 
626 			suspended = false;
627 			spin_unlock_irqrestore(&suspended_lock, flags);
628 
629 			disable_irq_wake(irq);
630 		}
631 		at91_rtc_write_ier(at91_rtc_imr);
632 	}
633 	return 0;
634 }
635 #endif
636 
637 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
638 
639 static struct platform_driver at91_rtc_driver = {
640 	.remove		= __exit_p(at91_rtc_remove),
641 	.shutdown	= at91_rtc_shutdown,
642 	.driver		= {
643 		.name	= "at91_rtc",
644 		.pm	= &at91_rtc_pm_ops,
645 		.of_match_table = of_match_ptr(at91_rtc_dt_ids),
646 	},
647 };
648 
649 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
650 
651 MODULE_AUTHOR("Rick Bronson");
652 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
653 MODULE_LICENSE("GPL");
654 MODULE_ALIAS("platform:at91_rtc");
655