summaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-pl031.c
blob: cc0533994f6e0650bbd7c2bc2a4976cfb947593e (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
/*
 * drivers/rtc/rtc-pl031.c
 *
 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
 *
 * Author: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright 2006 (c) MontaVista Software, Inc.
 *
 * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
 * Copyright 2010 (c) ST-Ericsson AB
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/amba/bus.h>
#include <linux/io.h>
#include <linux/bcd.h>
#include <linux/delay.h>
#include <linux/slab.h>

/*
 * Register definitions
 */
#define	RTC_DR		0x00	/* Data read register */
#define	RTC_MR		0x04	/* Match register */
#define	RTC_LR		0x08	/* Data load register */
#define	RTC_CR		0x0c	/* Control register */
#define	RTC_IMSC	0x10	/* Interrupt mask and set register */
#define	RTC_RIS		0x14	/* Raw interrupt status register */
#define	RTC_MIS		0x18	/* Masked interrupt status register */
#define	RTC_ICR		0x1c	/* Interrupt clear register */
/* ST variants have additional timer functionality */
#define RTC_TDR		0x20	/* Timer data read register */
#define RTC_TLR		0x24	/* Timer data load register */
#define RTC_TCR		0x28	/* Timer control register */
#define RTC_YDR		0x30	/* Year data read register */
#define RTC_YMR		0x34	/* Year match register */
#define RTC_YLR		0x38	/* Year data load register */

#define RTC_CR_CWEN	(1 << 26)	/* Clockwatch enable bit */

#define RTC_TCR_EN	(1 << 1) /* Periodic timer enable bit */

/* Common bit definitions for Interrupt status and control registers */
#define RTC_BIT_AI	(1 << 0) /* Alarm interrupt bit */
#define RTC_BIT_PI	(1 << 1) /* Periodic interrupt bit. ST variants only. */

/* Common bit definations for ST v2 for reading/writing time */
#define RTC_SEC_SHIFT 0
#define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
#define RTC_MIN_SHIFT 6
#define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
#define RTC_HOUR_SHIFT 12
#define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
#define RTC_WDAY_SHIFT 17
#define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
#define RTC_MDAY_SHIFT 20
#define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
#define RTC_MON_SHIFT 25
#define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */

#define RTC_TIMER_FREQ 32768

struct pl031_local {
	struct rtc_device *rtc;
	void __iomem *base;
	u8 hw_designer;
	u8 hw_revision:4;
};

static int pl031_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
{
	struct pl031_local *ldata = dev_get_drvdata(dev);
	unsigned long imsc;

	/* Clear any pending alarm interrupts. */
	writel(RTC_BIT_AI, ldata->base + RTC_ICR);

	imsc = readl(ldata->base + RTC_IMSC);

	if (enabled == 1)
		writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
	else
		writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);

	return 0;
}

/*
 * Convert Gregorian date to ST v2 RTC format.
 */
static int pl031_stv2_tm_to_time(struct device *dev,
				 struct rtc_time *tm, unsigned long *st_time,
	unsigned long *bcd_year)
{
	int year = tm->tm_year + 1900;
	int wday = tm->tm_wday;

	/* wday masking is not working in hardware so wday must be valid */
	if (wday < -1 || wday > 6) {
		dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
		return -EINVAL;
	} else if (wday == -1) {
		/* wday is not provided, calculate it here */
		unsigned long time;
		struct rtc_time calc_tm;

		rtc_tm_to_time(tm, &time);
		rtc_time_to_tm(time, &calc_tm);
		wday = calc_tm.tm_wday;
	}

	*bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);

	*st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
			|	(tm->tm_mday << RTC_MDAY_SHIFT)
			|	((wday + 1) << RTC_WDAY_SHIFT)
			|	(tm->tm_hour << RTC_HOUR_SHIFT)
			|	(tm->tm_min << RTC_MIN_SHIFT)
			|	(tm->tm_sec << RTC_SEC_SHIFT);

	return 0;
}

/*
 * Convert ST v2 RTC format to Gregorian date.
 */
static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
	struct rtc_time *tm)
{
	tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
	tm->tm_mon  = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
	tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
	tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
	tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
	tm->tm_min  = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
	tm->tm_sec  = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);

	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
	tm->tm_year -= 1900;

	return 0;
}

static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
{
	struct pl031_local *ldata = dev_get_drvdata(dev);

	pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
			readl(ldata->base + RTC_YDR), tm);

	return 0;
}

static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
{
	unsigned long time;
	unsigned long bcd_year;
	struct pl031_local *ldata = dev_get_drvdata(dev);
	int ret;

	ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
	if (ret == 0) {
		writel(bcd_year, ldata->base + RTC_YLR);
		writel(time, ldata->base + RTC_LR);
	}

	return ret;
}

static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct pl031_local *ldata = dev_get_drvdata(dev);
	int ret;

	ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
			readl(ldata->base + RTC_YMR), &alarm->time);

	alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
	alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;

	return ret;
}

static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct pl031_local *ldata = dev_get_drvdata(dev);
	unsigned long time;
	unsigned long bcd_year;
	int ret;

	/* At the moment, we can only deal with non-wildcarded alarm times. */
	ret = rtc_valid_tm(&alarm->time);
	if (ret == 0) {
		ret = pl031_stv2_tm_to_time(dev, &alarm->time,
					    &time, &bcd_year);
		if (ret == 0) {
			writel(bcd_year, ldata->base + RTC_YMR);
			writel(time, ldata->base + RTC_MR);

			pl031_alarm_irq_enable(dev, alarm->enabled);
		}
	}

	return ret;
}

static irqreturn_t pl031_interrupt(int irq, void *dev_id)
{
	struct pl031_local *ldata = dev_id;
	unsigned long rtcmis;
	unsigned long events = 0;

	rtcmis = readl(ldata->base + RTC_MIS);
	if (rtcmis & RTC_BIT_AI) {
		writel(RTC_BIT_AI, ldata->base + RTC_ICR);
		events |= (RTC_AF | RTC_IRQF);
		rtc_update_irq(ldata->rtc, 1, events);

		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int pl031_read_time(struct device *dev, struct rtc_time *tm)
{
	struct pl031_local *ldata = dev_get_drvdata(dev);

	rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);

	return 0;
}

static int pl031_set_time(struct device *dev, struct rtc_time *tm)
{
	unsigned long time;
	struct pl031_local *ldata = dev_get_drvdata(dev);
	int ret;

	ret = rtc_tm_to_time(tm, &time);

	if (ret == 0)
		writel(time, ldata->base + RTC_LR);

	return ret;
}

static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct pl031_local *ldata = dev_get_drvdata(dev);

	rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);

	alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
	alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;

	return 0;
}

static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct pl031_local *ldata = dev_get_drvdata(dev);
	unsigned long time;
	int ret;

	/* At the moment, we can only deal with non-wildcarded alarm times. */
	ret = rtc_valid_tm(&alarm->time);
	if (ret == 0) {
		ret = rtc_tm_to_time(&alarm->time, &time);
		if (ret == 0) {
			writel(time, ldata->base + RTC_MR);
			pl031_alarm_irq_enable(dev, alarm->enabled);
		}
	}

	return ret;
}

static int pl031_remove(struct amba_device *adev)
{
	struct pl031_local *ldata = dev_get_drvdata(&adev->dev);

	amba_set_drvdata(adev, NULL);
	free_irq(adev->irq[0], ldata->rtc);
	rtc_device_unregister(ldata->rtc);
	iounmap(ldata->base);
	kfree(ldata);
	amba_release_regions(adev);

	return 0;
}

static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
{
	int ret;
	struct pl031_local *ldata;
	struct rtc_class_ops *ops = id->data;
	unsigned long time;

	ret = amba_request_regions(adev, NULL);
	if (ret)
		goto err_req;

	ldata = kzalloc(sizeof(struct pl031_local), GFP_KERNEL);
	if (!ldata) {
		ret = -ENOMEM;
		goto out;
	}

	ldata->base = ioremap(adev->res.start, resource_size(&adev->res));

	if (!ldata->base) {
		ret = -ENOMEM;
		goto out_no_remap;
	}

	amba_set_drvdata(adev, ldata);

	ldata->hw_designer = amba_manf(adev);
	ldata->hw_revision = amba_rev(adev);

	dev_dbg(&adev->dev, "designer ID = 0x%02x\n", ldata->hw_designer);
	dev_dbg(&adev->dev, "revision = 0x%01x\n", ldata->hw_revision);

	/* Enable the clockwatch on ST Variants */
	if (ldata->hw_designer == AMBA_VENDOR_ST)
		writel(readl(ldata->base + RTC_CR) | RTC_CR_CWEN,
		       ldata->base + RTC_CR);

	/*
	 * On ST PL031 variants, the RTC reset value does not provide correct
	 * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
	 */
	if (ldata->hw_designer == AMBA_VENDOR_ST) {
		if (readl(ldata->base + RTC_YDR) == 0x2000) {
			time = readl(ldata->base + RTC_DR);
			if ((time &
			     (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
			    == 0x02120000) {
				time = time | (0x7 << RTC_WDAY_SHIFT);
				writel(0x2000, ldata->base + RTC_YLR);
				writel(time, ldata->base + RTC_LR);
			}
		}
	}

	ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
					THIS_MODULE);
	if (IS_ERR(ldata->rtc)) {
		ret = PTR_ERR(ldata->rtc);
		goto out_no_rtc;
	}

	if (request_irq(adev->irq[0], pl031_interrupt,
			0, "rtc-pl031", ldata)) {
		ret = -EIO;
		goto out_no_irq;
	}

	return 0;

out_no_irq:
	rtc_device_unregister(ldata->rtc);
out_no_rtc:
	iounmap(ldata->base);
	amba_set_drvdata(adev, NULL);
out_no_remap:
	kfree(ldata);
out:
	amba_release_regions(adev);
err_req:

	return ret;
}

/* Operations for the original ARM version */
static struct rtc_class_ops arm_pl031_ops = {
	.read_time = pl031_read_time,
	.set_time = pl031_set_time,
	.read_alarm = pl031_read_alarm,
	.set_alarm = pl031_set_alarm,
	.alarm_irq_enable = pl031_alarm_irq_enable,
};

/* The First ST derivative */
static struct rtc_class_ops stv1_pl031_ops = {
	.read_time = pl031_read_time,
	.set_time = pl031_set_time,
	.read_alarm = pl031_read_alarm,
	.set_alarm = pl031_set_alarm,
	.alarm_irq_enable = pl031_alarm_irq_enable,
};

/* And the second ST derivative */
static struct rtc_class_ops stv2_pl031_ops = {
	.read_time = pl031_stv2_read_time,
	.set_time = pl031_stv2_set_time,
	.read_alarm = pl031_stv2_read_alarm,
	.set_alarm = pl031_stv2_set_alarm,
	.alarm_irq_enable = pl031_alarm_irq_enable,
};

static struct amba_id pl031_ids[] = {
	{
		.id = 0x00041031,
		.mask = 0x000fffff,
		.data = &arm_pl031_ops,
	},
	/* ST Micro variants */
	{
		.id = 0x00180031,
		.mask = 0x00ffffff,
		.data = &stv1_pl031_ops,
	},
	{
		.id = 0x00280031,
		.mask = 0x00ffffff,
		.data = &stv2_pl031_ops,
	},
	{0, 0},
};

MODULE_DEVICE_TABLE(amba, pl031_ids);

static struct amba_driver pl031_driver = {
	.drv = {
		.name = "rtc-pl031",
	},
	.id_table = pl031_ids,
	.probe = pl031_probe,
	.remove = pl031_remove,
};

module_amba_driver(pl031_driver);

MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
MODULE_LICENSE("GPL");