Free Electrons

Embedded Linux Experts

  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
/*
 * An RTC driver for Allwinner A10/A20
 *
 * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/types.h>

#define SUNXI_LOSC_CTRL				0x0000
#define SUNXI_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
#define SUNXI_LOSC_CTRL_RTC_YMD_ACC		BIT(7)

#define SUNXI_RTC_YMD				0x0004

#define SUNXI_RTC_HMS				0x0008

#define SUNXI_ALRM_DHMS				0x000c

#define SUNXI_ALRM_EN				0x0014
#define SUNXI_ALRM_EN_CNT_EN			BIT(8)

#define SUNXI_ALRM_IRQ_EN			0x0018
#define SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)

#define SUNXI_ALRM_IRQ_STA			0x001c
#define SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)

#define SUNXI_MASK_DH				0x0000001f
#define SUNXI_MASK_SM				0x0000003f
#define SUNXI_MASK_M				0x0000000f
#define SUNXI_MASK_LY				0x00000001
#define SUNXI_MASK_D				0x00000ffe
#define SUNXI_MASK_M				0x0000000f

#define SUNXI_GET(x, mask, shift)		(((x) & ((mask) << (shift))) \
							>> (shift))

#define SUNXI_SET(x, mask, shift)		(((x) & (mask)) << (shift))

/*
 * Get date values
 */
#define SUNXI_DATE_GET_DAY_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 0)
#define SUNXI_DATE_GET_MON_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_M, 8)
#define SUNXI_DATE_GET_YEAR_VALUE(x, mask)	SUNXI_GET(x, mask, 16)

/*
 * Get time values
 */
#define SUNXI_TIME_GET_SEC_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 0)
#define SUNXI_TIME_GET_MIN_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 8)
#define SUNXI_TIME_GET_HOUR_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 16)

/*
 * Get alarm values
 */
#define SUNXI_ALRM_GET_SEC_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 0)
#define SUNXI_ALRM_GET_MIN_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 8)
#define SUNXI_ALRM_GET_HOUR_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 16)

/*
 * Set date values
 */
#define SUNXI_DATE_SET_DAY_VALUE(x)		SUNXI_DATE_GET_DAY_VALUE(x)
#define SUNXI_DATE_SET_MON_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_M, 8)
#define SUNXI_DATE_SET_YEAR_VALUE(x, mask)	SUNXI_SET(x, mask, 16)
#define SUNXI_LEAP_SET_VALUE(x, shift)		SUNXI_SET(x, SUNXI_MASK_LY, shift)

/*
 * Set time values
 */
#define SUNXI_TIME_SET_SEC_VALUE(x)		SUNXI_TIME_GET_SEC_VALUE(x)
#define SUNXI_TIME_SET_MIN_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_SM, 8)
#define SUNXI_TIME_SET_HOUR_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_DH, 16)

/*
 * Set alarm values
 */
#define SUNXI_ALRM_SET_SEC_VALUE(x)		SUNXI_ALRM_GET_SEC_VALUE(x)
#define SUNXI_ALRM_SET_MIN_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_SM, 8)
#define SUNXI_ALRM_SET_HOUR_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_DH, 16)
#define SUNXI_ALRM_SET_DAY_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_D, 21)

/*
 * Time unit conversions
 */
#define SEC_IN_MIN				60
#define SEC_IN_HOUR				(60 * SEC_IN_MIN)
#define SEC_IN_DAY				(24 * SEC_IN_HOUR)

/*
 * The year parameter passed to the driver is usually an offset relative to
 * the year 1900. This macro is used to convert this offset to another one
 * relative to the minimum year allowed by the hardware.
 */
#define SUNXI_YEAR_OFF(x)			((x)->min - 1900)

/*
 * min and max year are arbitrary set considering the limited range of the
 * hardware register field
 */
struct sunxi_rtc_data_year {
	unsigned int min;		/* min year allowed */
	unsigned int max;		/* max year allowed */
	unsigned int mask;		/* mask for the year field */
	unsigned char leap_shift;	/* bit shift to get the leap year */
};

static const struct sunxi_rtc_data_year data_year_param[] = {
	[0] = {
		.min		= 2010,
		.max		= 2073,
		.mask		= 0x3f,
		.leap_shift	= 22,
	},
	[1] = {
		.min		= 1970,
		.max		= 2225,
		.mask		= 0xff,
		.leap_shift	= 24,
	},
};

struct sunxi_rtc_dev {
	struct rtc_device *rtc;
	struct device *dev;
	const struct sunxi_rtc_data_year *data_year;
	void __iomem *base;
	int irq;
};

static irqreturn_t sunxi_rtc_alarmirq(int irq, void *id)
{
	struct sunxi_rtc_dev *chip = (struct sunxi_rtc_dev *) id;
	u32 val;

	val = readl(chip->base + SUNXI_ALRM_IRQ_STA);

	if (val & SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND) {
		val |= SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND;
		writel(val, chip->base + SUNXI_ALRM_IRQ_STA);

		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);

		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static void sunxi_rtc_setaie(unsigned int to, struct sunxi_rtc_dev *chip)
{
	u32 alrm_val = 0;
	u32 alrm_irq_val = 0;

	if (to) {
		alrm_val = readl(chip->base + SUNXI_ALRM_EN);
		alrm_val |= SUNXI_ALRM_EN_CNT_EN;

		alrm_irq_val = readl(chip->base + SUNXI_ALRM_IRQ_EN);
		alrm_irq_val |= SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN;
	} else {
		writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND,
				chip->base + SUNXI_ALRM_IRQ_STA);
	}

	writel(alrm_val, chip->base + SUNXI_ALRM_EN);
	writel(alrm_irq_val, chip->base + SUNXI_ALRM_IRQ_EN);
}

static int sunxi_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
	struct rtc_time *alrm_tm = &wkalrm->time;
	u32 alrm;
	u32 alrm_en;
	u32 date;

	alrm = readl(chip->base + SUNXI_ALRM_DHMS);
	date = readl(chip->base + SUNXI_RTC_YMD);

	alrm_tm->tm_sec = SUNXI_ALRM_GET_SEC_VALUE(alrm);
	alrm_tm->tm_min = SUNXI_ALRM_GET_MIN_VALUE(alrm);
	alrm_tm->tm_hour = SUNXI_ALRM_GET_HOUR_VALUE(alrm);

	alrm_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
	alrm_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);
	alrm_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
			chip->data_year->mask);

	alrm_tm->tm_mon -= 1;

	/*
	 * switch from (data_year->min)-relative offset to
	 * a (1900)-relative one
	 */
	alrm_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);

	alrm_en = readl(chip->base + SUNXI_ALRM_IRQ_EN);
	if (alrm_en & SUNXI_ALRM_EN_CNT_EN)
		wkalrm->enabled = 1;

	return 0;
}

static int sunxi_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
	u32 date, time;

	/*
	 * read again in case it changes
	 */
	do {
		date = readl(chip->base + SUNXI_RTC_YMD);
		time = readl(chip->base + SUNXI_RTC_HMS);
	} while ((date != readl(chip->base + SUNXI_RTC_YMD)) ||
		 (time != readl(chip->base + SUNXI_RTC_HMS)));

	rtc_tm->tm_sec  = SUNXI_TIME_GET_SEC_VALUE(time);
	rtc_tm->tm_min  = SUNXI_TIME_GET_MIN_VALUE(time);
	rtc_tm->tm_hour = SUNXI_TIME_GET_HOUR_VALUE(time);

	rtc_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
	rtc_tm->tm_mon  = SUNXI_DATE_GET_MON_VALUE(date);
	rtc_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
					chip->data_year->mask);

	rtc_tm->tm_mon  -= 1;

	/*
	 * switch from (data_year->min)-relative offset to
	 * a (1900)-relative one
	 */
	rtc_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);

	return rtc_valid_tm(rtc_tm);
}

static int sunxi_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
	struct rtc_time *alrm_tm = &wkalrm->time;
	struct rtc_time tm_now;
	u32 alrm;
	time64_t diff;
	unsigned long time_gap;
	unsigned long time_gap_day;
	unsigned long time_gap_hour;
	unsigned long time_gap_min;
	int ret;

	ret = sunxi_rtc_gettime(dev, &tm_now);
	if (ret < 0) {
		dev_err(dev, "Error in getting time\n");
		return -EINVAL;
	}

	diff = rtc_tm_sub(alrm_tm, &tm_now);
	if (diff <= 0) {
		dev_err(dev, "Date to set in the past\n");
		return -EINVAL;
	}

	if (diff > 255 * SEC_IN_DAY) {
		dev_err(dev, "Day must be in the range 0 - 255\n");
		return -EINVAL;
	}

	time_gap = diff;
	time_gap_day = time_gap / SEC_IN_DAY;
	time_gap -= time_gap_day * SEC_IN_DAY;
	time_gap_hour = time_gap / SEC_IN_HOUR;
	time_gap -= time_gap_hour * SEC_IN_HOUR;
	time_gap_min = time_gap / SEC_IN_MIN;
	time_gap -= time_gap_min * SEC_IN_MIN;

	sunxi_rtc_setaie(0, chip);
	writel(0, chip->base + SUNXI_ALRM_DHMS);
	usleep_range(100, 300);

	alrm = SUNXI_ALRM_SET_SEC_VALUE(time_gap) |
		SUNXI_ALRM_SET_MIN_VALUE(time_gap_min) |
		SUNXI_ALRM_SET_HOUR_VALUE(time_gap_hour) |
		SUNXI_ALRM_SET_DAY_VALUE(time_gap_day);
	writel(alrm, chip->base + SUNXI_ALRM_DHMS);

	writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
	writel(SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN, chip->base + SUNXI_ALRM_IRQ_EN);

	sunxi_rtc_setaie(wkalrm->enabled, chip);

	return 0;
}

static int sunxi_rtc_wait(struct sunxi_rtc_dev *chip, int offset,
			  unsigned int mask, unsigned int ms_timeout)
{
	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
	u32 reg;

	do {
		reg = readl(chip->base + offset);
		reg &= mask;

		if (reg == mask)
			return 0;

	} while (time_before(jiffies, timeout));

	return -ETIMEDOUT;
}

static int sunxi_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
{
	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
	u32 date = 0;
	u32 time = 0;
	unsigned int year;

	/*
	 * the input rtc_tm->tm_year is the offset relative to 1900. We use
	 * the SUNXI_YEAR_OFF macro to rebase it with respect to the min year
	 * allowed by the hardware
	 */

	year = rtc_tm->tm_year + 1900;
	if (year < chip->data_year->min || year > chip->data_year->max) {
		dev_err(dev, "rtc only supports year in range %u - %u\n",
			chip->data_year->min, chip->data_year->max);
		return -EINVAL;
	}

	rtc_tm->tm_year -= SUNXI_YEAR_OFF(chip->data_year);
	rtc_tm->tm_mon += 1;

	date = SUNXI_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
		SUNXI_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
		SUNXI_DATE_SET_YEAR_VALUE(rtc_tm->tm_year,
				chip->data_year->mask);

	if (is_leap_year(year))
		date |= SUNXI_LEAP_SET_VALUE(1, chip->data_year->leap_shift);

	time = SUNXI_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
		SUNXI_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
		SUNXI_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);

	writel(0, chip->base + SUNXI_RTC_HMS);
	writel(0, chip->base + SUNXI_RTC_YMD);

	writel(time, chip->base + SUNXI_RTC_HMS);

	/*
	 * After writing the RTC HH-MM-SS register, the
	 * SUNXI_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
	 * be cleared until the real writing operation is finished
	 */

	if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
				SUNXI_LOSC_CTRL_RTC_HMS_ACC, 50)) {
		dev_err(dev, "Failed to set rtc time.\n");
		return -1;
	}

	writel(date, chip->base + SUNXI_RTC_YMD);

	/*
	 * After writing the RTC YY-MM-DD register, the
	 * SUNXI_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
	 * be cleared until the real writing operation is finished
	 */

	if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
				SUNXI_LOSC_CTRL_RTC_YMD_ACC, 50)) {
		dev_err(dev, "Failed to set rtc time.\n");
		return -1;
	}

	return 0;
}

static int sunxi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);

	if (!enabled)
		sunxi_rtc_setaie(enabled, chip);

	return 0;
}

static const struct rtc_class_ops sunxi_rtc_ops = {
	.read_time		= sunxi_rtc_gettime,
	.set_time		= sunxi_rtc_settime,
	.read_alarm		= sunxi_rtc_getalarm,
	.set_alarm		= sunxi_rtc_setalarm,
	.alarm_irq_enable	= sunxi_rtc_alarm_irq_enable
};

static const struct of_device_id sunxi_rtc_dt_ids[] = {
	{ .compatible = "allwinner,sun4i-a10-rtc", .data = &data_year_param[0] },
	{ .compatible = "allwinner,sun7i-a20-rtc", .data = &data_year_param[1] },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, sunxi_rtc_dt_ids);

static int sunxi_rtc_probe(struct platform_device *pdev)
{
	struct sunxi_rtc_dev *chip;
	struct resource *res;
	int ret;

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

	platform_set_drvdata(pdev, chip);
	chip->dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	chip->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(chip->base))
		return PTR_ERR(chip->base);

	chip->irq = platform_get_irq(pdev, 0);
	if (chip->irq < 0) {
		dev_err(&pdev->dev, "No IRQ resource\n");
		return chip->irq;
	}
	ret = devm_request_irq(&pdev->dev, chip->irq, sunxi_rtc_alarmirq,
			0, dev_name(&pdev->dev), chip);
	if (ret) {
		dev_err(&pdev->dev, "Could not request IRQ\n");
		return ret;
	}

	chip->data_year = of_device_get_match_data(&pdev->dev);
	if (!chip->data_year) {
		dev_err(&pdev->dev, "Unable to setup RTC data\n");
		return -ENODEV;
	}

	/* clear the alarm count value */
	writel(0, chip->base + SUNXI_ALRM_DHMS);

	/* disable alarm, not generate irq pending */
	writel(0, chip->base + SUNXI_ALRM_EN);

	/* disable alarm week/cnt irq, unset to cpu */
	writel(0, chip->base + SUNXI_ALRM_IRQ_EN);

	/* clear alarm week/cnt irq pending */
	writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND, chip->base +
			SUNXI_ALRM_IRQ_STA);

	chip->rtc = rtc_device_register("rtc-sunxi", &pdev->dev,
			&sunxi_rtc_ops, THIS_MODULE);
	if (IS_ERR(chip->rtc)) {
		dev_err(&pdev->dev, "unable to register device\n");
		return PTR_ERR(chip->rtc);
	}

	dev_info(&pdev->dev, "RTC enabled\n");

	return 0;
}

static int sunxi_rtc_remove(struct platform_device *pdev)
{
	struct sunxi_rtc_dev *chip = platform_get_drvdata(pdev);

	rtc_device_unregister(chip->rtc);

	return 0;
}

static struct platform_driver sunxi_rtc_driver = {
	.probe		= sunxi_rtc_probe,
	.remove		= sunxi_rtc_remove,
	.driver		= {
		.name		= "sunxi-rtc",
		.of_match_table = sunxi_rtc_dt_ids,
	},
};

module_platform_driver(sunxi_rtc_driver);

MODULE_DESCRIPTION("sunxi RTC driver");
MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
MODULE_LICENSE("GPL");