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
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
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
/*
 * Haoyu HYM8563 RTC driver
 *
 * Copyright (C) 2013 MundoReader S.L.
 * Author: Heiko Stuebner <heiko@sntech.de>
 *
 * based on rtc-HYM8563
 * Copyright (C) 2010 ROCKCHIP, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/clk-provider.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>

#define HYM8563_CTL1		0x00
#define HYM8563_CTL1_TEST	BIT(7)
#define HYM8563_CTL1_STOP	BIT(5)
#define HYM8563_CTL1_TESTC	BIT(3)

#define HYM8563_CTL2		0x01
#define HYM8563_CTL2_TI_TP	BIT(4)
#define HYM8563_CTL2_AF		BIT(3)
#define HYM8563_CTL2_TF		BIT(2)
#define HYM8563_CTL2_AIE	BIT(1)
#define HYM8563_CTL2_TIE	BIT(0)

#define HYM8563_SEC		0x02
#define HYM8563_SEC_VL		BIT(7)
#define HYM8563_SEC_MASK	0x7f

#define HYM8563_MIN		0x03
#define HYM8563_MIN_MASK	0x7f

#define HYM8563_HOUR		0x04
#define HYM8563_HOUR_MASK	0x3f

#define HYM8563_DAY		0x05
#define HYM8563_DAY_MASK	0x3f

#define HYM8563_WEEKDAY		0x06
#define HYM8563_WEEKDAY_MASK	0x07

#define HYM8563_MONTH		0x07
#define HYM8563_MONTH_CENTURY	BIT(7)
#define HYM8563_MONTH_MASK	0x1f

#define HYM8563_YEAR		0x08

#define HYM8563_ALM_MIN		0x09
#define HYM8563_ALM_HOUR	0x0a
#define HYM8563_ALM_DAY		0x0b
#define HYM8563_ALM_WEEK	0x0c

/* Each alarm check can be disabled by setting this bit in the register */
#define HYM8563_ALM_BIT_DISABLE	BIT(7)

#define HYM8563_CLKOUT		0x0d
#define HYM8563_CLKOUT_ENABLE	BIT(7)
#define HYM8563_CLKOUT_32768	0
#define HYM8563_CLKOUT_1024	1
#define HYM8563_CLKOUT_32	2
#define HYM8563_CLKOUT_1	3
#define HYM8563_CLKOUT_MASK	3

#define HYM8563_TMR_CTL		0x0e
#define HYM8563_TMR_CTL_ENABLE	BIT(7)
#define HYM8563_TMR_CTL_4096	0
#define HYM8563_TMR_CTL_64	1
#define HYM8563_TMR_CTL_1	2
#define HYM8563_TMR_CTL_1_60	3
#define HYM8563_TMR_CTL_MASK	3

#define HYM8563_TMR_CNT		0x0f

struct hym8563 {
	struct i2c_client	*client;
	struct rtc_device	*rtc;
	bool			valid;
#ifdef CONFIG_COMMON_CLK
	struct clk_hw		clkout_hw;
#endif
};

/*
 * RTC handling
 */

static int hym8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct hym8563 *hym8563 = i2c_get_clientdata(client);
	u8 buf[7];
	int ret;

	if (!hym8563->valid) {
		dev_warn(&client->dev, "no valid clock/calendar values available\n");
		return -EPERM;
	}

	ret = i2c_smbus_read_i2c_block_data(client, HYM8563_SEC, 7, buf);

	tm->tm_sec = bcd2bin(buf[0] & HYM8563_SEC_MASK);
	tm->tm_min = bcd2bin(buf[1] & HYM8563_MIN_MASK);
	tm->tm_hour = bcd2bin(buf[2] & HYM8563_HOUR_MASK);
	tm->tm_mday = bcd2bin(buf[3] & HYM8563_DAY_MASK);
	tm->tm_wday = bcd2bin(buf[4] & HYM8563_WEEKDAY_MASK); /* 0 = Sun */
	tm->tm_mon = bcd2bin(buf[5] & HYM8563_MONTH_MASK) - 1; /* 0 = Jan */
	tm->tm_year = bcd2bin(buf[6]) + 100;

	return 0;
}

static int hym8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct hym8563 *hym8563 = i2c_get_clientdata(client);
	u8 buf[7];
	int ret;

	/* Years >= 2100 are to far in the future, 19XX is to early */
	if (tm->tm_year < 100 || tm->tm_year >= 200)
		return -EINVAL;

	buf[0] = bin2bcd(tm->tm_sec);
	buf[1] = bin2bcd(tm->tm_min);
	buf[2] = bin2bcd(tm->tm_hour);
	buf[3] = bin2bcd(tm->tm_mday);
	buf[4] = bin2bcd(tm->tm_wday);
	buf[5] = bin2bcd(tm->tm_mon + 1);

	/*
	 * While the HYM8563 has a century flag in the month register,
	 * it does not seem to carry it over a subsequent write/read.
	 * So we'll limit ourself to 100 years, starting at 2000 for now.
	 */
	buf[6] = bin2bcd(tm->tm_year - 100);

	/*
	 * CTL1 only contains TEST-mode bits apart from stop,
	 * so no need to read the value first
	 */
	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1,
						HYM8563_CTL1_STOP);
	if (ret < 0)
		return ret;

	ret = i2c_smbus_write_i2c_block_data(client, HYM8563_SEC, 7, buf);
	if (ret < 0)
		return ret;

	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1, 0);
	if (ret < 0)
		return ret;

	hym8563->valid = true;

	return 0;
}

static int hym8563_rtc_alarm_irq_enable(struct device *dev,
					unsigned int enabled)
{
	struct i2c_client *client = to_i2c_client(dev);
	int data;

	data = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
	if (data < 0)
		return data;

	if (enabled)
		data |= HYM8563_CTL2_AIE;
	else
		data &= ~HYM8563_CTL2_AIE;

	return i2c_smbus_write_byte_data(client, HYM8563_CTL2, data);
};

static int hym8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rtc_time *alm_tm = &alm->time;
	u8 buf[4];
	int ret;

	ret = i2c_smbus_read_i2c_block_data(client, HYM8563_ALM_MIN, 4, buf);
	if (ret < 0)
		return ret;

	/* The alarm only has a minute accuracy */
	alm_tm->tm_sec = 0;

	alm_tm->tm_min = (buf[0] & HYM8563_ALM_BIT_DISABLE) ?
					-1 :
					bcd2bin(buf[0] & HYM8563_MIN_MASK);
	alm_tm->tm_hour = (buf[1] & HYM8563_ALM_BIT_DISABLE) ?
					-1 :
					bcd2bin(buf[1] & HYM8563_HOUR_MASK);
	alm_tm->tm_mday = (buf[2] & HYM8563_ALM_BIT_DISABLE) ?
					-1 :
					bcd2bin(buf[2] & HYM8563_DAY_MASK);
	alm_tm->tm_wday = (buf[3] & HYM8563_ALM_BIT_DISABLE) ?
					-1 :
					bcd2bin(buf[3] & HYM8563_WEEKDAY_MASK);

	ret = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
	if (ret < 0)
		return ret;

	if (ret & HYM8563_CTL2_AIE)
		alm->enabled = 1;

	return 0;
}

static int hym8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct rtc_time *alm_tm = &alm->time;
	u8 buf[4];
	int ret;

	/*
	 * The alarm has no seconds so deal with it
	 */
	if (alm_tm->tm_sec) {
		alm_tm->tm_sec = 0;
		alm_tm->tm_min++;
		if (alm_tm->tm_min >= 60) {
			alm_tm->tm_min = 0;
			alm_tm->tm_hour++;
			if (alm_tm->tm_hour >= 24) {
				alm_tm->tm_hour = 0;
				alm_tm->tm_mday++;
				if (alm_tm->tm_mday > 31)
					alm_tm->tm_mday = 0;
			}
		}
	}

	ret = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
	if (ret < 0)
		return ret;

	ret &= ~HYM8563_CTL2_AIE;

	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL2, ret);
	if (ret < 0)
		return ret;

	buf[0] = (alm_tm->tm_min < 60 && alm_tm->tm_min >= 0) ?
			bin2bcd(alm_tm->tm_min) : HYM8563_ALM_BIT_DISABLE;

	buf[1] = (alm_tm->tm_hour < 24 && alm_tm->tm_hour >= 0) ?
			bin2bcd(alm_tm->tm_hour) : HYM8563_ALM_BIT_DISABLE;

	buf[2] = (alm_tm->tm_mday <= 31 && alm_tm->tm_mday >= 1) ?
			bin2bcd(alm_tm->tm_mday) : HYM8563_ALM_BIT_DISABLE;

	buf[3] = (alm_tm->tm_wday < 7 && alm_tm->tm_wday >= 0) ?
			bin2bcd(alm_tm->tm_wday) : HYM8563_ALM_BIT_DISABLE;

	ret = i2c_smbus_write_i2c_block_data(client, HYM8563_ALM_MIN, 4, buf);
	if (ret < 0)
		return ret;

	return hym8563_rtc_alarm_irq_enable(dev, alm->enabled);
}

static const struct rtc_class_ops hym8563_rtc_ops = {
	.read_time		= hym8563_rtc_read_time,
	.set_time		= hym8563_rtc_set_time,
	.alarm_irq_enable	= hym8563_rtc_alarm_irq_enable,
	.read_alarm		= hym8563_rtc_read_alarm,
	.set_alarm		= hym8563_rtc_set_alarm,
};

/*
 * Handling of the clkout
 */

#ifdef CONFIG_COMMON_CLK
#define clkout_hw_to_hym8563(_hw) container_of(_hw, struct hym8563, clkout_hw)

static int clkout_rates[] = {
	32768,
	1024,
	32,
	1,
};

static unsigned long hym8563_clkout_recalc_rate(struct clk_hw *hw,
						unsigned long parent_rate)
{
	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
	struct i2c_client *client = hym8563->client;
	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);

	if (ret < 0)
		return 0;

	ret &= HYM8563_CLKOUT_MASK;
	return clkout_rates[ret];
}

static long hym8563_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
				      unsigned long *prate)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
		if (clkout_rates[i] <= rate)
			return clkout_rates[i];

	return 0;
}

static int hym8563_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
				   unsigned long parent_rate)
{
	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
	struct i2c_client *client = hym8563->client;
	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);
	int i;

	if (ret < 0)
		return ret;

	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
		if (clkout_rates[i] == rate) {
			ret &= ~HYM8563_CLKOUT_MASK;
			ret |= i;
			return i2c_smbus_write_byte_data(client,
							 HYM8563_CLKOUT, ret);
		}

	return -EINVAL;
}

static int hym8563_clkout_control(struct clk_hw *hw, bool enable)
{
	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
	struct i2c_client *client = hym8563->client;
	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);

	if (ret < 0)
		return ret;

	if (enable)
		ret |= HYM8563_CLKOUT_ENABLE;
	else
		ret &= ~HYM8563_CLKOUT_ENABLE;

	return i2c_smbus_write_byte_data(client, HYM8563_CLKOUT, ret);
}

static int hym8563_clkout_prepare(struct clk_hw *hw)
{
	return hym8563_clkout_control(hw, 1);
}

static void hym8563_clkout_unprepare(struct clk_hw *hw)
{
	hym8563_clkout_control(hw, 0);
}

static int hym8563_clkout_is_prepared(struct clk_hw *hw)
{
	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
	struct i2c_client *client = hym8563->client;
	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);

	if (ret < 0)
		return ret;

	return !!(ret & HYM8563_CLKOUT_ENABLE);
}

static const struct clk_ops hym8563_clkout_ops = {
	.prepare = hym8563_clkout_prepare,
	.unprepare = hym8563_clkout_unprepare,
	.is_prepared = hym8563_clkout_is_prepared,
	.recalc_rate = hym8563_clkout_recalc_rate,
	.round_rate = hym8563_clkout_round_rate,
	.set_rate = hym8563_clkout_set_rate,
};

static struct clk *hym8563_clkout_register_clk(struct hym8563 *hym8563)
{
	struct i2c_client *client = hym8563->client;
	struct device_node *node = client->dev.of_node;
	struct clk *clk;
	struct clk_init_data init;
	int ret;

	ret = i2c_smbus_write_byte_data(client, HYM8563_CLKOUT,
						0);
	if (ret < 0)
		return ERR_PTR(ret);

	init.name = "hym8563-clkout";
	init.ops = &hym8563_clkout_ops;
	init.flags = 0;
	init.parent_names = NULL;
	init.num_parents = 0;
	hym8563->clkout_hw.init = &init;

	/* optional override of the clockname */
	of_property_read_string(node, "clock-output-names", &init.name);

	/* register the clock */
	clk = clk_register(&client->dev, &hym8563->clkout_hw);

	if (!IS_ERR(clk))
		of_clk_add_provider(node, of_clk_src_simple_get, clk);

	return clk;
}
#endif

/*
 * The alarm interrupt is implemented as a level-low interrupt in the
 * hym8563, while the timer interrupt uses a falling edge.
 * We don't use the timer at all, so the interrupt is requested to
 * use the level-low trigger.
 */
static irqreturn_t hym8563_irq(int irq, void *dev_id)
{
	struct hym8563 *hym8563 = (struct hym8563 *)dev_id;
	struct i2c_client *client = hym8563->client;
	struct mutex *lock = &hym8563->rtc->ops_lock;
	int data, ret;

	mutex_lock(lock);

	/* Clear the alarm flag */

	data = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
	if (data < 0) {
		dev_err(&client->dev, "%s: error reading i2c data %d\n",
			__func__, data);
		goto out;
	}

	data &= ~HYM8563_CTL2_AF;

	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL2, data);
	if (ret < 0) {
		dev_err(&client->dev, "%s: error writing i2c data %d\n",
			__func__, ret);
	}

out:
	mutex_unlock(lock);
	return IRQ_HANDLED;
}

static int hym8563_init_device(struct i2c_client *client)
{
	int ret;

	/* Clear stop flag if present */
	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1, 0);
	if (ret < 0)
		return ret;

	ret = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
	if (ret < 0)
		return ret;

	/* Disable alarm and timer interrupts */
	ret &= ~HYM8563_CTL2_AIE;
	ret &= ~HYM8563_CTL2_TIE;

	/* Clear any pending alarm and timer flags */
	if (ret & HYM8563_CTL2_AF)
		ret &= ~HYM8563_CTL2_AF;

	if (ret & HYM8563_CTL2_TF)
		ret &= ~HYM8563_CTL2_TF;

	ret &= ~HYM8563_CTL2_TI_TP;

	return i2c_smbus_write_byte_data(client, HYM8563_CTL2, ret);
}

#ifdef CONFIG_PM_SLEEP
static int hym8563_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	int ret;

	if (device_may_wakeup(dev)) {
		ret = enable_irq_wake(client->irq);
		if (ret) {
			dev_err(dev, "enable_irq_wake failed, %d\n", ret);
			return ret;
		}
	}

	return 0;
}

static int hym8563_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

	if (device_may_wakeup(dev))
		disable_irq_wake(client->irq);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(hym8563_pm_ops, hym8563_suspend, hym8563_resume);

static int hym8563_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct hym8563 *hym8563;
	int ret;

	hym8563 = devm_kzalloc(&client->dev, sizeof(*hym8563), GFP_KERNEL);
	if (!hym8563)
		return -ENOMEM;

	hym8563->client = client;
	i2c_set_clientdata(client, hym8563);

	device_set_wakeup_capable(&client->dev, true);

	ret = hym8563_init_device(client);
	if (ret) {
		dev_err(&client->dev, "could not init device, %d\n", ret);
		return ret;
	}

	if (client->irq > 0) {
		ret = devm_request_threaded_irq(&client->dev, client->irq,
						NULL, hym8563_irq,
						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
						client->name, hym8563);
		if (ret < 0) {
			dev_err(&client->dev, "irq %d request failed, %d\n",
				client->irq, ret);
			return ret;
		}
	}

	/* check state of calendar information */
	ret = i2c_smbus_read_byte_data(client, HYM8563_SEC);
	if (ret < 0)
		return ret;

	hym8563->valid = !(ret & HYM8563_SEC_VL);
	dev_dbg(&client->dev, "rtc information is %s\n",
		hym8563->valid ? "valid" : "invalid");

	hym8563->rtc = devm_rtc_device_register(&client->dev, client->name,
						&hym8563_rtc_ops, THIS_MODULE);
	if (IS_ERR(hym8563->rtc))
		return PTR_ERR(hym8563->rtc);

	/* the hym8563 alarm only supports a minute accuracy */
	hym8563->rtc->uie_unsupported = 1;

#ifdef CONFIG_COMMON_CLK
	hym8563_clkout_register_clk(hym8563);
#endif

	return 0;
}

static const struct i2c_device_id hym8563_id[] = {
	{ "hym8563", 0 },
	{},
};
MODULE_DEVICE_TABLE(i2c, hym8563_id);

static const struct of_device_id hym8563_dt_idtable[] = {
	{ .compatible = "haoyu,hym8563" },
	{},
};
MODULE_DEVICE_TABLE(of, hym8563_dt_idtable);

static struct i2c_driver hym8563_driver = {
	.driver		= {
		.name	= "rtc-hym8563",
		.pm	= &hym8563_pm_ops,
		.of_match_table	= hym8563_dt_idtable,
	},
	.probe		= hym8563_probe,
	.id_table	= hym8563_id,
};

module_i2c_driver(hym8563_driver);

MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
MODULE_DESCRIPTION("HYM8563 RTC driver");
MODULE_LICENSE("GPL");