aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-ds1511.c
blob: b13d1399b81a356a63bb11c613420dbf2fcccdad (plain) (blame)
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
/*
 * An rtc driver for the Dallas DS1511
 *
 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
 * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
 *
 * 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.
 *
 * Real time clock driver for the Dallas 1511 chip, which also
 * contains a watchdog timer.  There is a tiny amount of code that
 * platform code could use to mess with the watchdog device a little
 * bit, but not a full watchdog driver.
 */

#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/module.h>

#define DRV_VERSION "0.6"

enum ds1511reg {
	DS1511_SEC = 0x0,
	DS1511_MIN = 0x1,
	DS1511_HOUR = 0x2,
	DS1511_DOW = 0x3,
	DS1511_DOM = 0x4,
	DS1511_MONTH = 0x5,
	DS1511_YEAR = 0x6,
	DS1511_CENTURY = 0x7,
	DS1511_AM1_SEC = 0x8,
	DS1511_AM2_MIN = 0x9,
	DS1511_AM3_HOUR = 0xa,
	DS1511_AM4_DATE = 0xb,
	DS1511_WD_MSEC = 0xc,
	DS1511_WD_SEC = 0xd,
	DS1511_CONTROL_A = 0xe,
	DS1511_CONTROL_B = 0xf,
	DS1511_RAMADDR_LSB = 0x10,
	DS1511_RAMDATA = 0x13
};

#define DS1511_BLF1	0x80
#define DS1511_BLF2	0x40
#define DS1511_PRS	0x20
#define DS1511_PAB	0x10
#define DS1511_TDF	0x08
#define DS1511_KSF	0x04
#define DS1511_WDF	0x02
#define DS1511_IRQF	0x01
#define DS1511_TE	0x80
#define DS1511_CS	0x40
#define DS1511_BME	0x20
#define DS1511_TPE	0x10
#define DS1511_TIE	0x08
#define DS1511_KIE	0x04
#define DS1511_WDE	0x02
#define DS1511_WDS	0x01
#define DS1511_RAM_MAX	0xff

#define RTC_CMD		DS1511_CONTROL_B
#define RTC_CMD1	DS1511_CONTROL_A

#define RTC_ALARM_SEC	DS1511_AM1_SEC
#define RTC_ALARM_MIN	DS1511_AM2_MIN
#define RTC_ALARM_HOUR	DS1511_AM3_HOUR
#define RTC_ALARM_DATE	DS1511_AM4_DATE

#define RTC_SEC		DS1511_SEC
#define RTC_MIN		DS1511_MIN
#define RTC_HOUR	DS1511_HOUR
#define RTC_DOW		DS1511_DOW
#define RTC_DOM		DS1511_DOM
#define RTC_MON		DS1511_MONTH
#define RTC_YEAR	DS1511_YEAR
#define RTC_CENTURY	DS1511_CENTURY

#define RTC_TIE	DS1511_TIE
#define RTC_TE	DS1511_TE

struct rtc_plat_data {
	struct rtc_device *rtc;
	void __iomem *ioaddr;		/* virtual base address */
	int irq;
	unsigned int irqen;
	int alrm_sec;
	int alrm_min;
	int alrm_hour;
	int alrm_mday;
	spinlock_t lock;
};

static DEFINE_SPINLOCK(ds1511_lock);

static __iomem char *ds1511_base;
static u32 reg_spacing = 1;

static noinline void
rtc_write(uint8_t val, uint32_t reg)
{
	writeb(val, ds1511_base + (reg * reg_spacing));
}

static inline void
rtc_write_alarm(uint8_t val, enum ds1511reg reg)
{
	rtc_write((val | 0x80), reg);
}

static noinline uint8_t
rtc_read(enum ds1511reg reg)
{
	return readb(ds1511_base + (reg * reg_spacing));
}

static inline void
rtc_disable_update(void)
{
	rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
}

static void
rtc_enable_update(void)
{
	rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
}

/*
 * #define DS1511_WDOG_RESET_SUPPORT
 *
 * Uncomment this if you want to use these routines in
 * some platform code.
 */
#ifdef DS1511_WDOG_RESET_SUPPORT
/*
 * just enough code to set the watchdog timer so that it
 * will reboot the system
 */
void
ds1511_wdog_set(unsigned long deciseconds)
{
	/*
	 * the wdog timer can take 99.99 seconds
	 */
	deciseconds %= 10000;
	/*
	 * set the wdog values in the wdog registers
	 */
	rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
	rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
	/*
	 * set wdog enable and wdog 'steering' bit to issue a reset
	 */
	rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
}

void
ds1511_wdog_disable(void)
{
	/*
	 * clear wdog enable and wdog 'steering' bits
	 */
	rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
	/*
	 * clear the wdog counter
	 */
	rtc_write(0, DS1511_WD_MSEC);
	rtc_write(0, DS1511_WD_SEC);
}
#endif

/*
 * set the rtc chip's idea of the time.
 * stupidly, some callers call with year unmolested;
 * and some call with  year = year - 1900.  thanks.
 */
static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
{
	u8 mon, day, dow, hrs, min, sec, yrs, cen;
	unsigned long flags;

	/*
	 * won't have to change this for a while
	 */
	if (rtc_tm->tm_year < 1900)
		rtc_tm->tm_year += 1900;

	if (rtc_tm->tm_year < 1970)
		return -EINVAL;

	yrs = rtc_tm->tm_year % 100;
	cen = rtc_tm->tm_year / 100;
	mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
	day = rtc_tm->tm_mday;
	dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
	hrs = rtc_tm->tm_hour;
	min = rtc_tm->tm_min;
	sec = rtc_tm->tm_sec;

	if ((mon > 12) || (day == 0))
		return -EINVAL;

	if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year))
		return -EINVAL;

	if ((hrs >= 24) || (min >= 60) || (sec >= 60))
		return -EINVAL;

	/*
	 * each register is a different number of valid bits
	 */
	sec = bin2bcd(sec) & 0x7f;
	min = bin2bcd(min) & 0x7f;
	hrs = bin2bcd(hrs) & 0x3f;
	day = bin2bcd(day) & 0x3f;
	mon = bin2bcd(mon) & 0x1f;
	yrs = bin2bcd(yrs) & 0xff;
	cen = bin2bcd(cen) & 0xff;

	spin_lock_irqsave(&ds1511_lock, flags);
	rtc_disable_update();
	rtc_write(cen, RTC_CENTURY);
	rtc_write(yrs, RTC_YEAR);
	rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
	rtc_write(day, RTC_DOM);
	rtc_write(hrs, RTC_HOUR);
	rtc_write(min, RTC_MIN);
	rtc_write(sec, RTC_SEC);
	rtc_write(dow, RTC_DOW);
	rtc_enable_update();
	spin_unlock_irqrestore(&ds1511_lock, flags);

	return 0;
}

static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
{
	unsigned int century;
	unsigned long flags;

	spin_lock_irqsave(&ds1511_lock, flags);
	rtc_disable_update();

	rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
	rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
	rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
	rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
	rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
	rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
	rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
	century = rtc_read(RTC_CENTURY);

	rtc_enable_update();
	spin_unlock_irqrestore(&ds1511_lock, flags);

	rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
	rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
	rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
	rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
	rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
	rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
	rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
	century = bcd2bin(century) * 100;

	/*
	 * Account for differences between how the RTC uses the values
	 * and how they are defined in a struct rtc_time;
	 */
	century += rtc_tm->tm_year;
	rtc_tm->tm_year = century - 1900;

	rtc_tm->tm_mon--;

	if (rtc_valid_tm(rtc_tm) < 0) {
		dev_err(dev, "retrieved date/time is not valid.\n");
		rtc_time_to_tm(0, rtc_tm);
	}
	return 0;
}

/*
 * write the alarm register settings
 *
 * we only have the use to interrupt every second, otherwise
 * known as the update interrupt, or the interrupt if the whole
 * date/hours/mins/secs matches.  the ds1511 has many more
 * permutations, but the kernel doesn't.
 */
static void
ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
{
	unsigned long flags;

	spin_lock_irqsave(&pdata->lock, flags);
	rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
	       0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
	       RTC_ALARM_DATE);
	rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
	       0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
	       RTC_ALARM_HOUR);
	rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
	       0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
	       RTC_ALARM_MIN);
	rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
	       0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
	       RTC_ALARM_SEC);
	rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
	rtc_read(RTC_CMD1);	/* clear interrupts */
	spin_unlock_irqrestore(&pdata->lock, flags);
}

static int
ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	if (pdata->irq <= 0)
		return -EINVAL;

	pdata->alrm_mday = alrm->time.tm_mday;
	pdata->alrm_hour = alrm->time.tm_hour;
	pdata->alrm_min = alrm->time.tm_min;
	pdata->alrm_sec = alrm->time.tm_sec;
	if (alrm->enabled)
		pdata->irqen |= RTC_AF;

	ds1511_rtc_update_alarm(pdata);
	return 0;
}

static int
ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	if (pdata->irq <= 0)
		return -EINVAL;

	alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
	alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
	alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
	alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
	alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
	return 0;
}

static irqreturn_t
ds1511_interrupt(int irq, void *dev_id)
{
	struct platform_device *pdev = dev_id;
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	unsigned long events = 0;

	spin_lock(&pdata->lock);
	/*
	 * read and clear interrupt
	 */
	if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
		events = RTC_IRQF;
		if (rtc_read(RTC_ALARM_SEC) & 0x80)
			events |= RTC_UF;
		else
			events |= RTC_AF;
		rtc_update_irq(pdata->rtc, 1, events);
	}
	spin_unlock(&pdata->lock);
	return events ? IRQ_HANDLED : IRQ_NONE;
}

static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	if (pdata->irq <= 0)
		return -EINVAL;
	if (enabled)
		pdata->irqen |= RTC_AF;
	else
		pdata->irqen &= ~RTC_AF;
	ds1511_rtc_update_alarm(pdata);
	return 0;
}

static const struct rtc_class_ops ds1511_rtc_ops = {
	.read_time		= ds1511_rtc_read_time,
	.set_time		= ds1511_rtc_set_time,
	.read_alarm		= ds1511_rtc_read_alarm,
	.set_alarm		= ds1511_rtc_set_alarm,
	.alarm_irq_enable	= ds1511_rtc_alarm_irq_enable,
};

static ssize_t
ds1511_nvram_read(struct file *filp, struct kobject *kobj,
		  struct bin_attribute *ba,
		  char *buf, loff_t pos, size_t size)
{
	ssize_t count;

	/*
	 * if count is more than one, turn on "burst" mode
	 * turn it off when you're done
	 */
	if (size > 1)
		rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);

	if (pos > DS1511_RAM_MAX)
		pos = DS1511_RAM_MAX;

	if (size + pos > DS1511_RAM_MAX + 1)
		size = DS1511_RAM_MAX - pos + 1;

	rtc_write(pos, DS1511_RAMADDR_LSB);
	for (count = 0; size > 0; count++, size--)
		*buf++ = rtc_read(DS1511_RAMDATA);

	if (count > 1)
		rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);

	return count;
}

static ssize_t
ds1511_nvram_write(struct file *filp, struct kobject *kobj,
		   struct bin_attribute *bin_attr,
		   char *buf, loff_t pos, size_t size)
{
	ssize_t count;

	/*
	 * if count is more than one, turn on "burst" mode
	 * turn it off when you're done
	 */
	if (size > 1)
		rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);

	if (pos > DS1511_RAM_MAX)
		pos = DS1511_RAM_MAX;

	if (size + pos > DS1511_RAM_MAX + 1)
		size = DS1511_RAM_MAX - pos + 1;

	rtc_write(pos, DS1511_RAMADDR_LSB);
	for (count = 0; size > 0; count++, size--)
		rtc_write(*buf++, DS1511_RAMDATA);

	if (count > 1)
		rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);

	return count;
}

static struct bin_attribute ds1511_nvram_attr = {
	.attr = {
		.name = "nvram",
		.mode = S_IRUGO | S_IWUSR,
	},
	.size = DS1511_RAM_MAX,
	.read = ds1511_nvram_read,
	.write = ds1511_nvram_write,
};

static int ds1511_rtc_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct rtc_plat_data *pdata;
	int ret = 0;

	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	ds1511_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(ds1511_base))
		return PTR_ERR(ds1511_base);
	pdata->ioaddr = ds1511_base;
	pdata->irq = platform_get_irq(pdev, 0);

	/*
	 * turn on the clock and the crystal, etc.
	 */
	rtc_write(0, RTC_CMD);
	rtc_write(0, RTC_CMD1);
	/*
	 * clear the wdog counter
	 */
	rtc_write(0, DS1511_WD_MSEC);
	rtc_write(0, DS1511_WD_SEC);
	/*
	 * start the clock
	 */
	rtc_enable_update();

	/*
	 * check for a dying bat-tree
	 */
	if (rtc_read(RTC_CMD1) & DS1511_BLF1)
		dev_warn(&pdev->dev, "voltage-low detected.\n");

	spin_lock_init(&pdata->lock);
	platform_set_drvdata(pdev, pdata);

	pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
					      &ds1511_rtc_ops, THIS_MODULE);
	if (IS_ERR(pdata->rtc))
		return PTR_ERR(pdata->rtc);

	/*
	 * if the platform has an interrupt in mind for this device,
	 * then by all means, set it
	 */
	if (pdata->irq > 0) {
		rtc_read(RTC_CMD1);
		if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
			IRQF_SHARED, pdev->name, pdev) < 0) {

			dev_warn(&pdev->dev, "interrupt not available.\n");
			pdata->irq = 0;
		}
	}

	ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
	if (ret)
		dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
			ds1511_nvram_attr.attr.name);

	return 0;
}

static int ds1511_rtc_remove(struct platform_device *pdev)
{
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
	if (pdata->irq > 0) {
		/*
		 * disable the alarm interrupt
		 */
		rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
		rtc_read(RTC_CMD1);
	}
	return 0;
}

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:ds1511");

static struct platform_driver ds1511_rtc_driver = {
	.probe		= ds1511_rtc_probe,
	.remove		= ds1511_rtc_remove,
	.driver		= {
		.name	= "ds1511",
		.owner	= THIS_MODULE,
	},
};

module_platform_driver(ds1511_rtc_driver);

MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);