aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-at91rm9200.c
blob: 82a54e93ff04af0ed75237fa476da828d762e6ba (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	Real Time Clock interface for Linux on Atmel AT91RM9200
 *
 *	Copyright (C) 2002 Rick Bronson
 *
 *	Converted to RTC class model by Andrew Victor
 *
 *	Ported to Linux 2.6 by Steven Scholz
 *	Based on s3c2410-rtc.c Simtec Electronics
 *
 *	Based on sa1100-rtc.c by Nils Faerber
 *	Based on rtc.c by Paul Gortmaker
 */

#include <linux/bcd.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <linux/suspend.h>
#include <linux/time.h>
#include <linux/uaccess.h>

#include "rtc-at91rm9200.h"

#define at91_rtc_read(field) \
	readl_relaxed(at91_rtc_regs + field)
#define at91_rtc_write(field, val) \
	writel_relaxed((val), at91_rtc_regs + field)

struct at91_rtc_config {
	bool use_shadow_imr;
};

static const struct at91_rtc_config *at91_rtc_config;
static DECLARE_COMPLETION(at91_rtc_updated);
static DECLARE_COMPLETION(at91_rtc_upd_rdy);
static void __iomem *at91_rtc_regs;
static int irq;
static DEFINE_SPINLOCK(at91_rtc_lock);
static u32 at91_rtc_shadow_imr;
static bool suspended;
static DEFINE_SPINLOCK(suspended_lock);
static unsigned long cached_events;
static u32 at91_rtc_imr;
static struct clk *sclk;

static void at91_rtc_write_ier(u32 mask)
{
	unsigned long flags;

	spin_lock_irqsave(&at91_rtc_lock, flags);
	at91_rtc_shadow_imr |= mask;
	at91_rtc_write(AT91_RTC_IER, mask);
	spin_unlock_irqrestore(&at91_rtc_lock, flags);
}

static void at91_rtc_write_idr(u32 mask)
{
	unsigned long flags;

	spin_lock_irqsave(&at91_rtc_lock, flags);
	at91_rtc_write(AT91_RTC_IDR, mask);
	/*
	 * Register read back (of any RTC-register) needed to make sure
	 * IDR-register write has reached the peripheral before updating
	 * shadow mask.
	 *
	 * Note that there is still a possibility that the mask is updated
	 * before interrupts have actually been disabled in hardware. The only
	 * way to be certain would be to poll the IMR-register, which is is
	 * the very register we are trying to emulate. The register read back
	 * is a reasonable heuristic.
	 */
	at91_rtc_read(AT91_RTC_SR);
	at91_rtc_shadow_imr &= ~mask;
	spin_unlock_irqrestore(&at91_rtc_lock, flags);
}

static u32 at91_rtc_read_imr(void)
{
	unsigned long flags;
	u32 mask;

	if (at91_rtc_config->use_shadow_imr) {
		spin_lock_irqsave(&at91_rtc_lock, flags);
		mask = at91_rtc_shadow_imr;
		spin_unlock_irqrestore(&at91_rtc_lock, flags);
	} else {
		mask = at91_rtc_read(AT91_RTC_IMR);
	}

	return mask;
}

/*
 * Decode time/date into rtc_time structure
 */
static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
				struct rtc_time *tm)
{
	unsigned int time, date;

	/* must read twice in case it changes */
	do {
		time = at91_rtc_read(timereg);
		date = at91_rtc_read(calreg);
	} while ((time != at91_rtc_read(timereg)) ||
			(date != at91_rtc_read(calreg)));

	tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
	tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
	tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);

	/*
	 * The Calendar Alarm register does not have a field for
	 * the year - so these will return an invalid value.
	 */
	tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;	/* century */
	tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);	/* year */

	tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1;	/* day of the week [0-6], Sunday=0 */
	tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
	tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
}

/*
 * Read current time and date in RTC
 */
static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
{
	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
	tm->tm_year = tm->tm_year - 1900;

	dev_dbg(dev, "%s(): %ptR\n", __func__, tm);

	return 0;
}

/*
 * Set current time and date in RTC
 */
static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
{
	unsigned long cr;

	dev_dbg(dev, "%s(): %ptR\n", __func__, tm);

	wait_for_completion(&at91_rtc_upd_rdy);

	/* Stop Time/Calendar from counting */
	cr = at91_rtc_read(AT91_RTC_CR);
	at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);

	at91_rtc_write_ier(AT91_RTC_ACKUPD);
	wait_for_completion(&at91_rtc_updated);	/* wait for ACKUPD interrupt */
	at91_rtc_write_idr(AT91_RTC_ACKUPD);

	at91_rtc_write(AT91_RTC_TIMR,
			  bin2bcd(tm->tm_sec) << 0
			| bin2bcd(tm->tm_min) << 8
			| bin2bcd(tm->tm_hour) << 16);

	at91_rtc_write(AT91_RTC_CALR,
			  bin2bcd((tm->tm_year + 1900) / 100)	/* century */
			| bin2bcd(tm->tm_year % 100) << 8	/* year */
			| bin2bcd(tm->tm_mon + 1) << 16		/* tm_mon starts at zero */
			| bin2bcd(tm->tm_wday + 1) << 21	/* day of the week [0-6], Sunday=0 */
			| bin2bcd(tm->tm_mday) << 24);

	/* Restart Time/Calendar */
	cr = at91_rtc_read(AT91_RTC_CR);
	at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
	at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
	at91_rtc_write_ier(AT91_RTC_SECEV);

	return 0;
}

/*
 * Read alarm time and date in RTC
 */
static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct rtc_time *tm = &alrm->time;

	at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
	tm->tm_year = -1;

	alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
			? 1 : 0;

	dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm,
		alrm->enabled ? "en" : "dis");

	return 0;
}

/*
 * Set alarm time and date in RTC
 */
static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct rtc_time tm;

	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);

	tm.tm_mon = alrm->time.tm_mon;
	tm.tm_mday = alrm->time.tm_mday;
	tm.tm_hour = alrm->time.tm_hour;
	tm.tm_min = alrm->time.tm_min;
	tm.tm_sec = alrm->time.tm_sec;

	at91_rtc_write_idr(AT91_RTC_ALARM);
	at91_rtc_write(AT91_RTC_TIMALR,
		  bin2bcd(tm.tm_sec) << 0
		| bin2bcd(tm.tm_min) << 8
		| bin2bcd(tm.tm_hour) << 16
		| AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
	at91_rtc_write(AT91_RTC_CALALR,
		  bin2bcd(tm.tm_mon + 1) << 16		/* tm_mon starts at zero */
		| bin2bcd(tm.tm_mday) << 24
		| AT91_RTC_DATEEN | AT91_RTC_MTHEN);

	if (alrm->enabled) {
		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
		at91_rtc_write_ier(AT91_RTC_ALARM);
	}

	dev_dbg(dev, "%s(): %ptR\n", __func__, &tm);

	return 0;
}

static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);

	if (enabled) {
		at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
		at91_rtc_write_ier(AT91_RTC_ALARM);
	} else
		at91_rtc_write_idr(AT91_RTC_ALARM);

	return 0;
}
/*
 * Provide additional RTC information in /proc/driver/rtc
 */
static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
{
	unsigned long imr = at91_rtc_read_imr();

	seq_printf(seq, "update_IRQ\t: %s\n",
			(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
	seq_printf(seq, "periodic_IRQ\t: %s\n",
			(imr & AT91_RTC_SECEV) ? "yes" : "no");

	return 0;
}

/*
 * IRQ handler for the RTC
 */
static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
{
	struct platform_device *pdev = dev_id;
	struct rtc_device *rtc = platform_get_drvdata(pdev);
	unsigned int rtsr;
	unsigned long events = 0;
	int ret = IRQ_NONE;

	spin_lock(&suspended_lock);
	rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
	if (rtsr) {		/* this interrupt is shared!  Is it ours? */
		if (rtsr & AT91_RTC_ALARM)
			events |= (RTC_AF | RTC_IRQF);
		if (rtsr & AT91_RTC_SECEV) {
			complete(&at91_rtc_upd_rdy);
			at91_rtc_write_idr(AT91_RTC_SECEV);
		}
		if (rtsr & AT91_RTC_ACKUPD)
			complete(&at91_rtc_updated);

		at91_rtc_write(AT91_RTC_SCCR, rtsr);	/* clear status reg */

		if (!suspended) {
			rtc_update_irq(rtc, 1, events);

			dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
				__func__, events >> 8, events & 0x000000FF);
		} else {
			cached_events |= events;
			at91_rtc_write_idr(at91_rtc_imr);
			pm_system_wakeup();
		}

		ret = IRQ_HANDLED;
	}
	spin_unlock(&suspended_lock);

	return ret;
}

static const struct at91_rtc_config at91rm9200_config = {
};

static const struct at91_rtc_config at91sam9x5_config = {
	.use_shadow_imr	= true,
};

#ifdef CONFIG_OF
static const struct of_device_id at91_rtc_dt_ids[] = {
	{
		.compatible = "atmel,at91rm9200-rtc",
		.data = &at91rm9200_config,
	}, {
		.compatible = "atmel,at91sam9x5-rtc",
		.data = &at91sam9x5_config,
	}, {
		/* sentinel */
	}
};
MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
#endif

static const struct at91_rtc_config *
at91_rtc_get_config(struct platform_device *pdev)
{
	const struct of_device_id *match;

	if (pdev->dev.of_node) {
		match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
		if (!match)
			return NULL;
		return (const struct at91_rtc_config *)match->data;
	}

	return &at91rm9200_config;
}

static const struct rtc_class_ops at91_rtc_ops = {
	.read_time	= at91_rtc_readtime,
	.set_time	= at91_rtc_settime,
	.read_alarm	= at91_rtc_readalarm,
	.set_alarm	= at91_rtc_setalarm,
	.proc		= at91_rtc_proc,
	.alarm_irq_enable = at91_rtc_alarm_irq_enable,
};

/*
 * Initialize and install RTC driver
 */
static int __init at91_rtc_probe(struct platform_device *pdev)
{
	struct rtc_device *rtc;
	struct resource *regs;
	int ret = 0;

	at91_rtc_config = at91_rtc_get_config(pdev);
	if (!at91_rtc_config)
		return -ENODEV;

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!regs) {
		dev_err(&pdev->dev, "no mmio resource defined\n");
		return -ENXIO;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "no irq resource defined\n");
		return -ENXIO;
	}

	at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
				     resource_size(regs));
	if (!at91_rtc_regs) {
		dev_err(&pdev->dev, "failed to map registers, aborting.\n");
		return -ENOMEM;
	}

	rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);
	platform_set_drvdata(pdev, rtc);

	sclk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(sclk))
		return PTR_ERR(sclk);

	ret = clk_prepare_enable(sclk);
	if (ret) {
		dev_err(&pdev->dev, "Could not enable slow clock\n");
		return ret;
	}

	at91_rtc_write(AT91_RTC_CR, 0);
	at91_rtc_write(AT91_RTC_MR, 0);		/* 24 hour mode */

	/* Disable all interrupts */
	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
					AT91_RTC_SECEV | AT91_RTC_TIMEV |
					AT91_RTC_CALEV);

	ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
			       IRQF_SHARED | IRQF_COND_SUSPEND,
			       "at91_rtc", pdev);
	if (ret) {
		dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
		goto err_clk;
	}

	/* cpu init code should really have flagged this device as
	 * being wake-capable; if it didn't, do that here.
	 */
	if (!device_can_wakeup(&pdev->dev))
		device_init_wakeup(&pdev->dev, 1);

	rtc->ops = &at91_rtc_ops;
	rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
	rtc->range_max = RTC_TIMESTAMP_END_2099;
	ret = rtc_register_device(rtc);
	if (ret)
		goto err_clk;

	/* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
	 * completion.
	 */
	at91_rtc_write_ier(AT91_RTC_SECEV);

	dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
	return 0;

err_clk:
	clk_disable_unprepare(sclk);

	return ret;
}

/*
 * Disable and remove the RTC driver
 */
static int __exit at91_rtc_remove(struct platform_device *pdev)
{
	/* Disable all interrupts */
	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
					AT91_RTC_SECEV | AT91_RTC_TIMEV |
					AT91_RTC_CALEV);

	clk_disable_unprepare(sclk);

	return 0;
}

static void at91_rtc_shutdown(struct platform_device *pdev)
{
	/* Disable all interrupts */
	at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
					AT91_RTC_SECEV | AT91_RTC_TIMEV |
					AT91_RTC_CALEV);
}

#ifdef CONFIG_PM_SLEEP

/* AT91RM9200 RTC Power management control */

static int at91_rtc_suspend(struct device *dev)
{
	/* this IRQ is shared with DBGU and other hardware which isn't
	 * necessarily doing PM like we are...
	 */
	at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);

	at91_rtc_imr = at91_rtc_read_imr()
			& (AT91_RTC_ALARM|AT91_RTC_SECEV);
	if (at91_rtc_imr) {
		if (device_may_wakeup(dev)) {
			unsigned long flags;

			enable_irq_wake(irq);

			spin_lock_irqsave(&suspended_lock, flags);
			suspended = true;
			spin_unlock_irqrestore(&suspended_lock, flags);
		} else {
			at91_rtc_write_idr(at91_rtc_imr);
		}
	}
	return 0;
}

static int at91_rtc_resume(struct device *dev)
{
	struct rtc_device *rtc = dev_get_drvdata(dev);

	if (at91_rtc_imr) {
		if (device_may_wakeup(dev)) {
			unsigned long flags;

			spin_lock_irqsave(&suspended_lock, flags);

			if (cached_events) {
				rtc_update_irq(rtc, 1, cached_events);
				cached_events = 0;
			}

			suspended = false;
			spin_unlock_irqrestore(&suspended_lock, flags);

			disable_irq_wake(irq);
		}
		at91_rtc_write_ier(at91_rtc_imr);
	}
	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);

static struct platform_driver at91_rtc_driver = {
	.remove		= __exit_p(at91_rtc_remove),
	.shutdown	= at91_rtc_shutdown,
	.driver		= {
		.name	= "at91_rtc",
		.pm	= &at91_rtc_pm_ops,
		.of_match_table = of_match_ptr(at91_rtc_dt_ids),
	},
};

module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);

MODULE_AUTHOR("Rick Bronson");
MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:at91_rtc");