summaryrefslogtreecommitdiffstats
path: root/drivers/char/s3c2410-rtc.c
blob: d724c0de4f28334ad1de8d84ad54291f570f0a15 (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
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
/* drivers/char/s3c2410_rtc.c
 *
 * Copyright (c) 2004 Simtec Electronics <linux@simtec.co.uk>
 *		      http://www.simtec.co.uk/products/SWLINUX/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * S3C2410 Internal RTC Driver
 *
 *  Changelog:
 *	08-Nov-2004	BJD	Initial creation
 *	12-Nov-2004	BJD	Added periodic IRQ and PM code
 *	22-Nov-2004	BJD	Sign-test on alarm code to check for <0
 *	10-Mar-2005	LCVR	Changed S3C2410_VA_RTC to S3C24XX_VA_RTC
*/

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/bcd.h>

#include <asm/hardware.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/rtc.h>

#include <asm/mach/time.h>

#include <asm/hardware/clock.h>
#include <asm/arch/regs-rtc.h>

/* need this for the RTC_AF definitions */
#include <linux/mc146818rtc.h>

#undef S3C24XX_VA_RTC
#define S3C24XX_VA_RTC s3c2410_rtc_base

static struct resource *s3c2410_rtc_mem;

static void __iomem *s3c2410_rtc_base;
static int s3c2410_rtc_alarmno = NO_IRQ;
static int s3c2410_rtc_tickno  = NO_IRQ;
static int s3c2410_rtc_freq    = 1;

static DEFINE_SPINLOCK(s3c2410_rtc_pie_lock);

/* IRQ Handlers */

static irqreturn_t s3c2410_rtc_alarmirq(int irq, void *id, struct pt_regs *r)
{
	rtc_update(1, RTC_AF | RTC_IRQF);
	return IRQ_HANDLED;
}

static irqreturn_t s3c2410_rtc_tickirq(int irq, void *id, struct pt_regs *r)
{
	rtc_update(1, RTC_PF | RTC_IRQF);
	return IRQ_HANDLED;
}

/* Update control registers */
static void s3c2410_rtc_setaie(int to)
{
	unsigned int tmp;

	pr_debug("%s: aie=%d\n", __FUNCTION__, to);

	tmp = readb(S3C2410_RTCALM);

	if (to)
		tmp |= S3C2410_RTCALM_ALMEN;
	else
		tmp &= ~S3C2410_RTCALM_ALMEN;


	writeb(tmp, S3C2410_RTCALM);
}

static void s3c2410_rtc_setpie(int to)
{
	unsigned int tmp;

	pr_debug("%s: pie=%d\n", __FUNCTION__, to);

	spin_lock_irq(&s3c2410_rtc_pie_lock);
	tmp = readb(S3C2410_TICNT) & ~S3C2410_TICNT_ENABLE;

	if (to)
		tmp |= S3C2410_TICNT_ENABLE;

	writeb(tmp, S3C2410_TICNT);
	spin_unlock_irq(&s3c2410_rtc_pie_lock);
}

static void s3c2410_rtc_setfreq(int freq)
{
	unsigned int tmp;

	spin_lock_irq(&s3c2410_rtc_pie_lock);
	tmp = readb(S3C2410_TICNT) & S3C2410_TICNT_ENABLE;

	s3c2410_rtc_freq = freq;

	tmp |= (128 / freq)-1;

	writeb(tmp, S3C2410_TICNT);
	spin_unlock_irq(&s3c2410_rtc_pie_lock);
}

/* Time read/write */

static int s3c2410_rtc_gettime(struct rtc_time *rtc_tm)
{
	unsigned int have_retried = 0;

 retry_get_time:
	rtc_tm->tm_min  = readb(S3C2410_RTCMIN);
	rtc_tm->tm_hour = readb(S3C2410_RTCHOUR);
	rtc_tm->tm_mday = readb(S3C2410_RTCDATE);
	rtc_tm->tm_mon  = readb(S3C2410_RTCMON);
	rtc_tm->tm_year = readb(S3C2410_RTCYEAR);
	rtc_tm->tm_sec  = readb(S3C2410_RTCSEC);

	/* the only way to work out wether the system was mid-update
	 * when we read it is to check the second counter, and if it
	 * is zero, then we re-try the entire read
	 */

	if (rtc_tm->tm_sec == 0 && !have_retried) {
		have_retried = 1;
		goto retry_get_time;
	}

	pr_debug("read time %02x.%02x.%02x %02x/%02x/%02x\n",
		 rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,
		 rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);

	BCD_TO_BIN(rtc_tm->tm_sec);
	BCD_TO_BIN(rtc_tm->tm_min);
	BCD_TO_BIN(rtc_tm->tm_hour);
	BCD_TO_BIN(rtc_tm->tm_mday);
	BCD_TO_BIN(rtc_tm->tm_mon);
	BCD_TO_BIN(rtc_tm->tm_year);

	rtc_tm->tm_year += 100;
	rtc_tm->tm_mon -= 1;

	return 0;
}


static int s3c2410_rtc_settime(struct rtc_time *tm)
{
	/* the rtc gets round the y2k problem by just not supporting it */

	if (tm->tm_year < 100)
		return -EINVAL;

	writeb(BIN2BCD(tm->tm_sec),  S3C2410_RTCSEC);
	writeb(BIN2BCD(tm->tm_min),  S3C2410_RTCMIN);
	writeb(BIN2BCD(tm->tm_hour), S3C2410_RTCHOUR);
	writeb(BIN2BCD(tm->tm_mday), S3C2410_RTCDATE);
	writeb(BIN2BCD(tm->tm_mon + 1), S3C2410_RTCMON);
	writeb(BIN2BCD(tm->tm_year - 100), S3C2410_RTCYEAR);

	return 0;
}

static int s3c2410_rtc_getalarm(struct rtc_wkalrm *alrm)
{
	struct rtc_time *alm_tm = &alrm->time;
	unsigned int alm_en;

	alm_tm->tm_sec  = readb(S3C2410_ALMSEC);
	alm_tm->tm_min  = readb(S3C2410_ALMMIN);
	alm_tm->tm_hour = readb(S3C2410_ALMHOUR);
	alm_tm->tm_mon  = readb(S3C2410_ALMMON);
	alm_tm->tm_mday = readb(S3C2410_ALMDATE);
	alm_tm->tm_year = readb(S3C2410_ALMYEAR);

	alm_en = readb(S3C2410_RTCALM);

	pr_debug("read alarm %02x %02x.%02x.%02x %02x/%02x/%02x\n",
		 alm_en,
		 alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,
		 alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);


	/* decode the alarm enable field */

	if (alm_en & S3C2410_RTCALM_SECEN) {
		BCD_TO_BIN(alm_tm->tm_sec);
	} else {
		alm_tm->tm_sec = 0xff;
	}

	if (alm_en & S3C2410_RTCALM_MINEN) {
		BCD_TO_BIN(alm_tm->tm_min);
	} else {
		alm_tm->tm_min = 0xff;
	}

	if (alm_en & S3C2410_RTCALM_HOUREN) {
		BCD_TO_BIN(alm_tm->tm_hour);
	} else {
		alm_tm->tm_hour = 0xff;
	}

	if (alm_en & S3C2410_RTCALM_DAYEN) {
		BCD_TO_BIN(alm_tm->tm_mday);
	} else {
		alm_tm->tm_mday = 0xff;
	}

	if (alm_en & S3C2410_RTCALM_MONEN) {
		BCD_TO_BIN(alm_tm->tm_mon);
		alm_tm->tm_mon -= 1;
	} else {
		alm_tm->tm_mon = 0xff;
	}

	if (alm_en & S3C2410_RTCALM_YEAREN) {
		BCD_TO_BIN(alm_tm->tm_year);
	} else {
		alm_tm->tm_year = 0xffff;
	}

	/* todo - set alrm->enabled ? */

	return 0;
}

static int s3c2410_rtc_setalarm(struct rtc_wkalrm *alrm)
{
	struct rtc_time *tm = &alrm->time;
	unsigned int alrm_en;

	pr_debug("s3c2410_rtc_setalarm: %d, %02x/%02x/%02x %02x.%02x.%02x\n",
		 alrm->enabled,
		 tm->tm_mday & 0xff, tm->tm_mon & 0xff, tm->tm_year & 0xff,
		 tm->tm_hour & 0xff, tm->tm_min & 0xff, tm->tm_sec);

	if (alrm->enabled || 1) {
		alrm_en = readb(S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
		writeb(0x00, S3C2410_RTCALM);

		if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
			alrm_en |= S3C2410_RTCALM_SECEN;
			writeb(BIN2BCD(tm->tm_sec), S3C2410_ALMSEC);
		}

		if (tm->tm_min < 60 && tm->tm_min >= 0) {
			alrm_en |= S3C2410_RTCALM_MINEN;
			writeb(BIN2BCD(tm->tm_min), S3C2410_ALMMIN);
		}

		if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
			alrm_en |= S3C2410_RTCALM_HOUREN;
			writeb(BIN2BCD(tm->tm_hour), S3C2410_ALMHOUR);
		}

		pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);

		writeb(alrm_en, S3C2410_RTCALM);
		enable_irq_wake(s3c2410_rtc_alarmno);
	} else {
		alrm_en = readb(S3C2410_RTCALM);
		alrm_en &= ~S3C2410_RTCALM_ALMEN;
		writeb(alrm_en, S3C2410_RTCALM);
		disable_irq_wake(s3c2410_rtc_alarmno);
	}

	return 0;
}

static int s3c2410_rtc_ioctl(unsigned int cmd, unsigned long arg)
{
	switch (cmd) {
	case RTC_AIE_OFF:
	case RTC_AIE_ON:
		s3c2410_rtc_setaie((cmd == RTC_AIE_ON) ? 1 : 0);
		return 0;

	case RTC_PIE_OFF:
	case RTC_PIE_ON:
		s3c2410_rtc_setpie((cmd == RTC_PIE_ON) ? 1 : 0);
		return 0;

	case RTC_IRQP_READ:
		return put_user(s3c2410_rtc_freq, (unsigned long __user *)arg);

	case RTC_IRQP_SET:
		if (arg < 1 || arg > 64)
			return -EINVAL;

		if (!capable(CAP_SYS_RESOURCE))
			return -EACCES;

		/* check for power of 2 */

		if ((arg & (arg-1)) != 0)
			return -EINVAL;

		pr_debug("s3c2410_rtc: setting frequency %ld\n", arg);

		s3c2410_rtc_setfreq(arg);
		return 0;

	case RTC_UIE_ON:
	case RTC_UIE_OFF:
		return -EINVAL;
	}

	return -EINVAL;
}

static int s3c2410_rtc_proc(char *buf)
{
	unsigned int rtcalm = readb(S3C2410_RTCALM);
	unsigned int ticnt = readb (S3C2410_TICNT);
	char *p = buf;

	p += sprintf(p, "alarm_IRQ\t: %s\n",
		     (rtcalm & S3C2410_RTCALM_ALMEN) ? "yes" : "no" );
	p += sprintf(p, "periodic_IRQ\t: %s\n",
		     (ticnt & S3C2410_TICNT_ENABLE) ? "yes" : "no" );
	p += sprintf(p, "periodic_freq\t: %d\n", s3c2410_rtc_freq);

	return p - buf;
}

static int s3c2410_rtc_open(void)
{
	int ret;

	ret = request_irq(s3c2410_rtc_alarmno, s3c2410_rtc_alarmirq,
			  SA_INTERRUPT,  "s3c2410-rtc alarm", NULL);

	if (ret)
		printk(KERN_ERR "IRQ%d already in use\n", s3c2410_rtc_alarmno);

	ret = request_irq(s3c2410_rtc_tickno, s3c2410_rtc_tickirq,
			  SA_INTERRUPT,  "s3c2410-rtc tick", NULL);

	if (ret) {
		printk(KERN_ERR "IRQ%d already in use\n", s3c2410_rtc_tickno);
		goto tick_err;
	}

	return ret;

 tick_err:
	free_irq(s3c2410_rtc_alarmno, NULL);
	return ret;
}

static void s3c2410_rtc_release(void)
{
	/* do not clear AIE here, it may be needed for wake */

	s3c2410_rtc_setpie(0);
	free_irq(s3c2410_rtc_alarmno, NULL);
	free_irq(s3c2410_rtc_tickno, NULL);
}

static struct rtc_ops s3c2410_rtcops = {
	.owner		= THIS_MODULE,
	.open		= s3c2410_rtc_open,
	.release	= s3c2410_rtc_release,
	.ioctl		= s3c2410_rtc_ioctl,
	.read_time	= s3c2410_rtc_gettime,
	.set_time	= s3c2410_rtc_settime,
	.read_alarm	= s3c2410_rtc_getalarm,
	.set_alarm	= s3c2410_rtc_setalarm,
	.proc	        = s3c2410_rtc_proc,
};

static void s3c2410_rtc_enable(struct device *dev, int en)
{
	unsigned int tmp;

	if (s3c2410_rtc_base == NULL)
		return;

	if (!en) {
		tmp = readb(S3C2410_RTCCON);
		writeb(tmp & ~S3C2410_RTCCON_RTCEN, S3C2410_RTCCON);

		tmp = readb(S3C2410_TICNT);
		writeb(tmp & ~S3C2410_TICNT_ENABLE, S3C2410_TICNT);
	} else {
		/* re-enable the device, and check it is ok */

		if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0){
			dev_info(dev, "rtc disabled, re-enabling\n");

			tmp = readb(S3C2410_RTCCON);
			writeb(tmp | S3C2410_RTCCON_RTCEN , S3C2410_RTCCON);
		}

		if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)){
			dev_info(dev, "removing S3C2410_RTCCON_CNTSEL\n");

			tmp = readb(S3C2410_RTCCON);
			writeb(tmp& ~S3C2410_RTCCON_CNTSEL , S3C2410_RTCCON);
		}

		if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)){
			dev_info(dev, "removing S3C2410_RTCCON_CLKRST\n");

			tmp = readb(S3C2410_RTCCON);
			writeb(tmp & ~S3C2410_RTCCON_CLKRST, S3C2410_RTCCON);
		}
	}
}

static int s3c2410_rtc_remove(struct device *dev)
{
	unregister_rtc(&s3c2410_rtcops);

	s3c2410_rtc_setpie(0);
	s3c2410_rtc_setaie(0);

	if (s3c2410_rtc_mem != NULL) {
		pr_debug("s3c2410_rtc: releasing s3c2410_rtc_mem\n");
		iounmap(s3c2410_rtc_base);
		release_resource(s3c2410_rtc_mem);
		kfree(s3c2410_rtc_mem);
	}

	return 0;
}

static int s3c2410_rtc_probe(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct resource *res;
	int ret;

	pr_debug("%s: probe=%p, device=%p\n", __FUNCTION__, pdev, dev);

	/* find the IRQs */

	s3c2410_rtc_tickno = platform_get_irq(pdev, 1);
	if (s3c2410_rtc_tickno <= 0) {
		dev_err(dev, "no irq for rtc tick\n");
		return -ENOENT;
	}

	s3c2410_rtc_alarmno = platform_get_irq(pdev, 0);
	if (s3c2410_rtc_alarmno <= 0) {
		dev_err(dev, "no irq for alarm\n");
		return -ENOENT;
	}

	pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n",
		 s3c2410_rtc_tickno, s3c2410_rtc_alarmno);

	/* get the memory region */

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
		dev_err(dev, "failed to get memory region resource\n");
		return -ENOENT;
	}

	s3c2410_rtc_mem = request_mem_region(res->start, res->end-res->start+1,
				     pdev->name);

	if (s3c2410_rtc_mem == NULL) {
		dev_err(dev, "failed to reserve memory region\n");
		ret = -ENOENT;
		goto exit_err;
	}

	s3c2410_rtc_base = ioremap(res->start, res->end - res->start + 1);
	if (s3c2410_rtc_base == NULL) {
		dev_err(dev, "failed ioremap()\n");
		ret = -EINVAL;
		goto exit_err;
	}

	s3c2410_rtc_mem = res;
	pr_debug("s3c2410_rtc_base=%p\n", s3c2410_rtc_base);

 	pr_debug("s3c2410_rtc: RTCCON=%02x\n", readb(S3C2410_RTCCON));

	/* check to see if everything is setup correctly */

	s3c2410_rtc_enable(dev, 1);

 	pr_debug("s3c2410_rtc: RTCCON=%02x\n", readb(S3C2410_RTCCON));

	s3c2410_rtc_setfreq(s3c2410_rtc_freq);

	/* register RTC and exit */

	register_rtc(&s3c2410_rtcops);
	return 0;

 exit_err:
	dev_err(dev, "error %d during initialisation\n", ret);

	return ret;
}

#ifdef CONFIG_PM

/* S3C2410 RTC Power management control */

static struct timespec s3c2410_rtc_delta;

static int ticnt_save;

static int s3c2410_rtc_suspend(struct device *dev, pm_message_t state)
{
	struct rtc_time tm;
	struct timespec time;

	time.tv_nsec = 0;

	/* save TICNT for anyone using periodic interrupts */

	ticnt_save = readb(S3C2410_TICNT);

	/* calculate time delta for suspend */

	s3c2410_rtc_gettime(&tm);
	rtc_tm_to_time(&tm, &time.tv_sec);
	save_time_delta(&s3c2410_rtc_delta, &time);
	s3c2410_rtc_enable(dev, 0);

	return 0;
}

static int s3c2410_rtc_resume(struct device *dev)
{
	struct rtc_time tm;
	struct timespec time;

	time.tv_nsec = 0;

	s3c2410_rtc_enable(dev, 1);
	s3c2410_rtc_gettime(&tm);
	rtc_tm_to_time(&tm, &time.tv_sec);
	restore_time_delta(&s3c2410_rtc_delta, &time);

	writeb(ticnt_save, S3C2410_TICNT);
	return 0;
}
#else
#define s3c2410_rtc_suspend NULL
#define s3c2410_rtc_resume  NULL
#endif

static struct device_driver s3c2410_rtcdrv = {
	.name		= "s3c2410-rtc",
	.owner		= THIS_MODULE,
	.bus		= &platform_bus_type,
	.probe		= s3c2410_rtc_probe,
	.remove		= s3c2410_rtc_remove,
	.suspend	= s3c2410_rtc_suspend,
	.resume		= s3c2410_rtc_resume,
};

static char __initdata banner[] = "S3C2410 RTC, (c) 2004 Simtec Electronics\n";

static int __init s3c2410_rtc_init(void)
{
	printk(banner);
	return driver_register(&s3c2410_rtcdrv);
}

static void __exit s3c2410_rtc_exit(void)
{
	driver_unregister(&s3c2410_rtcdrv);
}

module_init(s3c2410_rtc_init);
module_exit(s3c2410_rtc_exit);

MODULE_DESCRIPTION("S3C24XX RTC Driver");
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud