1/*
2 *	Real Time Clock interface for Linux on Atmel AT91RM9200
3 *
4 *	Copyright (C) 2002 Rick Bronson
5 *
6 *	Converted to RTC class model by Andrew Victor
7 *
8 *	Ported to Linux 2.6 by Steven Scholz
9 *	Based on s3c2410-rtc.c Simtec Electronics
10 *
11 *	Based on sa1100-rtc.c by Nils Faerber
12 *	Based on rtc.c by Paul Gortmaker
13 *
14 *	This program is free software; you can redistribute it and/or
15 *	modify it under the terms of the GNU General Public License
16 *	as published by the Free Software Foundation; either version
17 *	2 of the License, or (at your option) any later version.
18 *
19 */
20
21#include <linux/bcd.h>
22#include <linux/clk.h>
23#include <linux/completion.h>
24#include <linux/interrupt.h>
25#include <linux/ioctl.h>
26#include <linux/io.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/of_device.h>
30#include <linux/of.h>
31#include <linux/platform_device.h>
32#include <linux/rtc.h>
33#include <linux/spinlock.h>
34#include <linux/suspend.h>
35#include <linux/time.h>
36#include <linux/uaccess.h>
37
38#include "rtc-at91rm9200.h"
39
40#define at91_rtc_read(field) \
41	readl_relaxed(at91_rtc_regs + field)
42#define at91_rtc_write(field, val) \
43	writel_relaxed((val), at91_rtc_regs + field)
44
45#define AT91_RTC_EPOCH		1900UL	/* just like arch/arm/common/rtctime.c */
46
47struct at91_rtc_config {
48	bool use_shadow_imr;
49};
50
51static const struct at91_rtc_config *at91_rtc_config;
52static DECLARE_COMPLETION(at91_rtc_updated);
53static DECLARE_COMPLETION(at91_rtc_upd_rdy);
54static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
55static void __iomem *at91_rtc_regs;
56static int irq;
57static DEFINE_SPINLOCK(at91_rtc_lock);
58static u32 at91_rtc_shadow_imr;
59static bool suspended;
60static DEFINE_SPINLOCK(suspended_lock);
61static unsigned long cached_events;
62static u32 at91_rtc_imr;
63static struct clk *sclk;
64
65static void at91_rtc_write_ier(u32 mask)
66{
67	unsigned long flags;
68
69	spin_lock_irqsave(&at91_rtc_lock, flags);
70	at91_rtc_shadow_imr |= mask;
71	at91_rtc_write(AT91_RTC_IER, mask);
72	spin_unlock_irqrestore(&at91_rtc_lock, flags);
73}
74
75static void at91_rtc_write_idr(u32 mask)
76{
77	unsigned long flags;
78
79	spin_lock_irqsave(&at91_rtc_lock, flags);
80	at91_rtc_write(AT91_RTC_IDR, mask);
81	/*
82	 * Register read back (of any RTC-register) needed to make sure
83	 * IDR-register write has reached the peripheral before updating
84	 * shadow mask.
85	 *
86	 * Note that there is still a possibility that the mask is updated
87	 * before interrupts have actually been disabled in hardware. The only
88	 * way to be certain would be to poll the IMR-register, which is is
89	 * the very register we are trying to emulate. The register read back
90	 * is a reasonable heuristic.
91	 */
92	at91_rtc_read(AT91_RTC_SR);
93	at91_rtc_shadow_imr &= ~mask;
94	spin_unlock_irqrestore(&at91_rtc_lock, flags);
95}
96
97static u32 at91_rtc_read_imr(void)
98{
99	unsigned long flags;
100	u32 mask;
101
102	if (at91_rtc_config->use_shadow_imr) {
103		spin_lock_irqsave(&at91_rtc_lock, flags);
104		mask = at91_rtc_shadow_imr;
105		spin_unlock_irqrestore(&at91_rtc_lock, flags);
106	} else {
107		mask = at91_rtc_read(AT91_RTC_IMR);
108	}
109
110	return mask;
111}
112
113/*
114 * Decode time/date into rtc_time structure
115 */
116static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
117				struct rtc_time *tm)
118{
119	unsigned int time, date;
120
121	/* must read twice in case it changes */
122	do {
123		time = at91_rtc_read(timereg);
124		date = at91_rtc_read(calreg);
125	} while ((time != at91_rtc_read(timereg)) ||
126			(date != at91_rtc_read(calreg)));
127
128	tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
129	tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
130	tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
131
132	/*
133	 * The Calendar Alarm register does not have a field for
134	 * the year - so these will return an invalid value.  When an
135	 * alarm is set, at91_alarm_year will store the current year.
136	 */
137	tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;	/* century */
138	tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);	/* year */
139
140	tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1;	/* day of the week [0-6], Sunday=0 */
141	tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
142	tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
143}
144
145/*
146 * Read current time and date in RTC
147 */
148static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
149{
150	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
151	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
152	tm->tm_year = tm->tm_year - 1900;
153
154	dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
155		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
156		tm->tm_hour, tm->tm_min, tm->tm_sec);
157
158	return 0;
159}
160
161/*
162 * Set current time and date in RTC
163 */
164static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
165{
166	unsigned long cr;
167
168	dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
169		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
170		tm->tm_hour, tm->tm_min, tm->tm_sec);
171
172	wait_for_completion(&at91_rtc_upd_rdy);
173
174	/* Stop Time/Calendar from counting */
175	cr = at91_rtc_read(AT91_RTC_CR);
176	at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
177
178	at91_rtc_write_ier(AT91_RTC_ACKUPD);
179	wait_for_completion(&at91_rtc_updated);	/* wait for ACKUPD interrupt */
180	at91_rtc_write_idr(AT91_RTC_ACKUPD);
181
182	at91_rtc_write(AT91_RTC_TIMR,
183			  bin2bcd(tm->tm_sec) << 0
184			| bin2bcd(tm->tm_min) << 8
185			| bin2bcd(tm->tm_hour) << 16);
186
187	at91_rtc_write(AT91_RTC_CALR,
188			  bin2bcd((tm->tm_year + 1900) / 100)	/* century */
189			| bin2bcd(tm->tm_year % 100) << 8	/* year */
190			| bin2bcd(tm->tm_mon + 1) << 16		/* tm_mon starts at zero */
191			| bin2bcd(tm->tm_wday + 1) << 21	/* day of the week [0-6], Sunday=0 */
192			| bin2bcd(tm->tm_mday) << 24);
193
194	/* Restart Time/Calendar */
195	cr = at91_rtc_read(AT91_RTC_CR);
196	at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
197	at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
198	at91_rtc_write_ier(AT91_RTC_SECEV);
199
200	return 0;
201}
202
203/*
204 * Read alarm time and date in RTC
205 */
206static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
207{
208	struct rtc_time *tm = &alrm->time;
209
210	at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
211	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
212	tm->tm_year = at91_alarm_year - 1900;
213
214	alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
215			? 1 : 0;
216
217	dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
218		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
219		tm->tm_hour, tm->tm_min, tm->tm_sec);
220
221	return 0;
222}
223
224/*
225 * Set alarm time and date in RTC
226 */
227static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
228{
229	struct rtc_time tm;
230
231	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
232
233	at91_alarm_year = tm.tm_year;
234
235	tm.tm_mon = alrm->time.tm_mon;
236	tm.tm_mday = alrm->time.tm_mday;
237	tm.tm_hour = alrm->time.tm_hour;
238	tm.tm_min = alrm->time.tm_min;
239	tm.tm_sec = alrm->time.tm_sec;
240
241	at91_rtc_write_idr(AT91_RTC_ALARM);
242	at91_rtc_write(AT91_RTC_TIMALR,
243		  bin2bcd(tm.tm_sec) << 0
244		| bin2bcd(tm.tm_min) << 8
245		| bin2bcd(tm.tm_hour) << 16
246		| AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
247	at91_rtc_write(AT91_RTC_CALALR,
248		  bin2bcd(tm.tm_mon + 1) << 16		/* tm_mon starts at zero */
249		| bin2bcd(tm.tm_mday) << 24
250		| AT91_RTC_DATEEN | AT91_RTC_MTHEN);
251
252	if (alrm->enabled) {
253		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
254		at91_rtc_write_ier(AT91_RTC_ALARM);
255	}
256
257	dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
258		at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
259		tm.tm_min, tm.tm_sec);
260
261	return 0;
262}
263
264static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
265{
266	dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
267
268	if (enabled) {
269		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
270		at91_rtc_write_ier(AT91_RTC_ALARM);
271	} else
272		at91_rtc_write_idr(AT91_RTC_ALARM);
273
274	return 0;
275}
276/*
277 * Provide additional RTC information in /proc/driver/rtc
278 */
279static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
280{
281	unsigned long imr = at91_rtc_read_imr();
282
283	seq_printf(seq, "update_IRQ\t: %s\n",
284			(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
285	seq_printf(seq, "periodic_IRQ\t: %s\n",
286			(imr & AT91_RTC_SECEV) ? "yes" : "no");
287
288	return 0;
289}
290
291/*
292 * IRQ handler for the RTC
293 */
294static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
295{
296	struct platform_device *pdev = dev_id;
297	struct rtc_device *rtc = platform_get_drvdata(pdev);
298	unsigned int rtsr;
299	unsigned long events = 0;
300	int ret = IRQ_NONE;
301
302	spin_lock(&suspended_lock);
303	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
304	if (rtsr) {		/* this interrupt is shared!  Is it ours? */
305		if (rtsr & AT91_RTC_ALARM)
306			events |= (RTC_AF | RTC_IRQF);
307		if (rtsr & AT91_RTC_SECEV) {
308			complete(&at91_rtc_upd_rdy);
309			at91_rtc_write_idr(AT91_RTC_SECEV);
310		}
311		if (rtsr & AT91_RTC_ACKUPD)
312			complete(&at91_rtc_updated);
313
314		at91_rtc_write(AT91_RTC_SCCR, rtsr);	/* clear status reg */
315
316		if (!suspended) {
317			rtc_update_irq(rtc, 1, events);
318
319			dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
320				__func__, events >> 8, events & 0x000000FF);
321		} else {
322			cached_events |= events;
323			at91_rtc_write_idr(at91_rtc_imr);
324			pm_system_wakeup();
325		}
326
327		ret = IRQ_HANDLED;
328	}
329	spin_unlock(&suspended_lock);
330
331	return ret;
332}
333
334static const struct at91_rtc_config at91rm9200_config = {
335};
336
337static const struct at91_rtc_config at91sam9x5_config = {
338	.use_shadow_imr	= true,
339};
340
341#ifdef CONFIG_OF
342static const struct of_device_id at91_rtc_dt_ids[] = {
343	{
344		.compatible = "atmel,at91rm9200-rtc",
345		.data = &at91rm9200_config,
346	}, {
347		.compatible = "atmel,at91sam9x5-rtc",
348		.data = &at91sam9x5_config,
349	}, {
350		/* sentinel */
351	}
352};
353MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
354#endif
355
356static const struct at91_rtc_config *
357at91_rtc_get_config(struct platform_device *pdev)
358{
359	const struct of_device_id *match;
360
361	if (pdev->dev.of_node) {
362		match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
363		if (!match)
364			return NULL;
365		return (const struct at91_rtc_config *)match->data;
366	}
367
368	return &at91rm9200_config;
369}
370
371static const struct rtc_class_ops at91_rtc_ops = {
372	.read_time	= at91_rtc_readtime,
373	.set_time	= at91_rtc_settime,
374	.read_alarm	= at91_rtc_readalarm,
375	.set_alarm	= at91_rtc_setalarm,
376	.proc		= at91_rtc_proc,
377	.alarm_irq_enable = at91_rtc_alarm_irq_enable,
378};
379
380/*
381 * Initialize and install RTC driver
382 */
383static int __init at91_rtc_probe(struct platform_device *pdev)
384{
385	struct rtc_device *rtc;
386	struct resource *regs;
387	int ret = 0;
388
389	at91_rtc_config = at91_rtc_get_config(pdev);
390	if (!at91_rtc_config)
391		return -ENODEV;
392
393	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
394	if (!regs) {
395		dev_err(&pdev->dev, "no mmio resource defined\n");
396		return -ENXIO;
397	}
398
399	irq = platform_get_irq(pdev, 0);
400	if (irq < 0) {
401		dev_err(&pdev->dev, "no irq resource defined\n");
402		return -ENXIO;
403	}
404
405	at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
406				     resource_size(regs));
407	if (!at91_rtc_regs) {
408		dev_err(&pdev->dev, "failed to map registers, aborting.\n");
409		return -ENOMEM;
410	}
411
412	sclk = devm_clk_get(&pdev->dev, NULL);
413	if (IS_ERR(sclk))
414		return PTR_ERR(sclk);
415
416	ret = clk_prepare_enable(sclk);
417	if (ret) {
418		dev_err(&pdev->dev, "Could not enable slow clock\n");
419		return ret;
420	}
421
422	at91_rtc_write(AT91_RTC_CR, 0);
423	at91_rtc_write(AT91_RTC_MR, 0);		/* 24 hour mode */
424
425	/* Disable all interrupts */
426	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
427					AT91_RTC_SECEV | AT91_RTC_TIMEV |
428					AT91_RTC_CALEV);
429
430	ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
431			       IRQF_SHARED | IRQF_COND_SUSPEND,
432			       "at91_rtc", pdev);
433	if (ret) {
434		dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
435		goto err_clk;
436	}
437
438	/* cpu init code should really have flagged this device as
439	 * being wake-capable; if it didn't, do that here.
440	 */
441	if (!device_can_wakeup(&pdev->dev))
442		device_init_wakeup(&pdev->dev, 1);
443
444	rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
445				&at91_rtc_ops, THIS_MODULE);
446	if (IS_ERR(rtc)) {
447		ret = PTR_ERR(rtc);
448		goto err_clk;
449	}
450	platform_set_drvdata(pdev, rtc);
451
452	/* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
453	 * completion.
454	 */
455	at91_rtc_write_ier(AT91_RTC_SECEV);
456
457	dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
458	return 0;
459
460err_clk:
461	clk_disable_unprepare(sclk);
462
463	return ret;
464}
465
466/*
467 * Disable and remove the RTC driver
468 */
469static int __exit at91_rtc_remove(struct platform_device *pdev)
470{
471	/* Disable all interrupts */
472	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
473					AT91_RTC_SECEV | AT91_RTC_TIMEV |
474					AT91_RTC_CALEV);
475
476	clk_disable_unprepare(sclk);
477
478	return 0;
479}
480
481static void at91_rtc_shutdown(struct platform_device *pdev)
482{
483	/* Disable all interrupts */
484	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
485					AT91_RTC_SECEV | AT91_RTC_TIMEV |
486					AT91_RTC_CALEV);
487}
488
489#ifdef CONFIG_PM_SLEEP
490
491/* AT91RM9200 RTC Power management control */
492
493static int at91_rtc_suspend(struct device *dev)
494{
495	/* this IRQ is shared with DBGU and other hardware which isn't
496	 * necessarily doing PM like we are...
497	 */
498	at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
499
500	at91_rtc_imr = at91_rtc_read_imr()
501			& (AT91_RTC_ALARM|AT91_RTC_SECEV);
502	if (at91_rtc_imr) {
503		if (device_may_wakeup(dev)) {
504			unsigned long flags;
505
506			enable_irq_wake(irq);
507
508			spin_lock_irqsave(&suspended_lock, flags);
509			suspended = true;
510			spin_unlock_irqrestore(&suspended_lock, flags);
511		} else {
512			at91_rtc_write_idr(at91_rtc_imr);
513		}
514	}
515	return 0;
516}
517
518static int at91_rtc_resume(struct device *dev)
519{
520	struct rtc_device *rtc = dev_get_drvdata(dev);
521
522	if (at91_rtc_imr) {
523		if (device_may_wakeup(dev)) {
524			unsigned long flags;
525
526			spin_lock_irqsave(&suspended_lock, flags);
527
528			if (cached_events) {
529				rtc_update_irq(rtc, 1, cached_events);
530				cached_events = 0;
531			}
532
533			suspended = false;
534			spin_unlock_irqrestore(&suspended_lock, flags);
535
536			disable_irq_wake(irq);
537		}
538		at91_rtc_write_ier(at91_rtc_imr);
539	}
540	return 0;
541}
542#endif
543
544static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
545
546static struct platform_driver at91_rtc_driver = {
547	.remove		= __exit_p(at91_rtc_remove),
548	.shutdown	= at91_rtc_shutdown,
549	.driver		= {
550		.name	= "at91_rtc",
551		.pm	= &at91_rtc_pm_ops,
552		.of_match_table = of_match_ptr(at91_rtc_dt_ids),
553	},
554};
555
556module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
557
558MODULE_AUTHOR("Rick Bronson");
559MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
560MODULE_LICENSE("GPL");
561MODULE_ALIAS("platform:at91_rtc");
562