summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-pcf8523.c
blob: 2e111cdb94f76cb74d7e96ef4fa4b336f91eaf56 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Avionic Design GmbH
 */

#include <linux/bcd.h>
#include <linux/bitfield.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/of.h>
#include <linux/pm_wakeirq.h>

#define PCF8523_REG_CONTROL1 0x00
#define PCF8523_CONTROL1_CAP_SEL BIT(7)
#define PCF8523_CONTROL1_STOP    BIT(5)
#define PCF8523_CONTROL1_AIE    BIT(1)

#define PCF8523_REG_CONTROL2 0x01
#define PCF8523_CONTROL2_AF BIT(3)

#define PCF8523_REG_CONTROL3 0x02
#define PCF8523_CONTROL3_PM  GENMASK(7,5)
#define PCF8523_PM_STANDBY   0x7
#define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
#define PCF8523_CONTROL3_BSF BIT(3)

#define PCF8523_REG_SECONDS  0x03
#define PCF8523_SECONDS_OS BIT(7)

#define PCF8523_REG_MINUTES  0x04
#define PCF8523_REG_HOURS    0x05
#define PCF8523_REG_DAYS     0x06
#define PCF8523_REG_WEEKDAYS 0x07
#define PCF8523_REG_MONTHS   0x08
#define PCF8523_REG_YEARS    0x09

#define PCF8523_REG_MINUTE_ALARM	0x0a
#define PCF8523_REG_HOUR_ALARM		0x0b
#define PCF8523_REG_DAY_ALARM		0x0c
#define PCF8523_REG_WEEKDAY_ALARM	0x0d
#define ALARM_DIS BIT(7)

#define PCF8523_REG_OFFSET   0x0e
#define PCF8523_OFFSET_MODE BIT(7)

#define PCF8523_TMR_CLKOUT_CTRL 0x0f

struct pcf8523 {
	struct rtc_device *rtc;
	struct regmap *regmap;
};

static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
{
	u32 load, value = 0;

	load = 12500;
	of_property_read_u32(node, "quartz-load-femtofarads", &load);

	switch (load) {
	default:
		dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
			 load);
		fallthrough;
	case 12500:
		value |= PCF8523_CONTROL1_CAP_SEL;
		break;
	case 7000:
		break;
	}

	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
				  PCF8523_CONTROL1_CAP_SEL, value);
}

static irqreturn_t pcf8523_irq(int irq, void *dev_id)
{
	struct pcf8523 *pcf8523 = dev_id;
	u32 value;
	int err;

	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
	if (err < 0)
		return IRQ_HANDLED;

	if (value & PCF8523_CONTROL2_AF) {
		value &= ~PCF8523_CONTROL2_AF;
		regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
		rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);

		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	u8 regs[10];
	int err;

	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
			       sizeof(regs));
	if (err < 0)
		return err;

	if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
		return -EINVAL;

	tm->tm_sec = bcd2bin(regs[3] & 0x7f);
	tm->tm_min = bcd2bin(regs[4] & 0x7f);
	tm->tm_hour = bcd2bin(regs[5] & 0x3f);
	tm->tm_mday = bcd2bin(regs[6] & 0x3f);
	tm->tm_wday = regs[7] & 0x7;
	tm->tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
	tm->tm_year = bcd2bin(regs[9]) + 100;

	return 0;
}

static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	u8 regs[7];
	int err;

	err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
				 PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
	if (err < 0)
		return err;

	/* This will purposely overwrite PCF8523_SECONDS_OS */
	regs[0] = bin2bcd(tm->tm_sec);
	regs[1] = bin2bcd(tm->tm_min);
	regs[2] = bin2bcd(tm->tm_hour);
	regs[3] = bin2bcd(tm->tm_mday);
	regs[4] = tm->tm_wday;
	regs[5] = bin2bcd(tm->tm_mon + 1);
	regs[6] = bin2bcd(tm->tm_year - 100);

	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
				sizeof(regs));
	if (err < 0) {
		/*
		 * If the time cannot be set, restart the RTC anyway. Note
		 * that errors are ignored if the RTC cannot be started so
		 * that we have a chance to propagate the original error.
		 */
		regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
				   PCF8523_CONTROL1_STOP, 0);
		return err;
	}

	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
				 PCF8523_CONTROL1_STOP, 0);
}

static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	u8 regs[4];
	u32 value;
	int err;

	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
			       sizeof(regs));
	if (err < 0)
		return err;

	tm->time.tm_sec = 0;
	tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
	tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
	tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
	tm->time.tm_wday = bcd2bin(regs[3] & 0x7);

	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
	if (err < 0)
		return err;
	tm->enabled = !!(value & PCF8523_CONTROL1_AIE);

	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
	if (err < 0)
		return err;
	tm->pending = !!(value & PCF8523_CONTROL2_AF);

	return 0;
}

static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);

	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
				  PCF8523_CONTROL1_AIE, enabled ?
				  PCF8523_CONTROL1_AIE : 0);
}

static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	u8 regs[5];
	int err;

	err = pcf8523_irq_enable(dev, 0);
	if (err)
		return err;

	err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
	if (err < 0)
		return err;

	regs[0] = bin2bcd(tm->time.tm_min);
	regs[1] = bin2bcd(tm->time.tm_hour);
	regs[2] = bin2bcd(tm->time.tm_mday);
	regs[3] = ALARM_DIS;

	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
				sizeof(regs));
	if (err < 0)
		return err;

	if (tm->enabled)
		return pcf8523_irq_enable(dev, tm->enabled);

	return 0;
}

static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	int ret;
	u32 value;

	switch(param->param) {

	case RTC_PARAM_BACKUP_SWITCH_MODE:
		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
		if (ret < 0)
			return ret;

		value = FIELD_GET(PCF8523_CONTROL3_PM, value);

		switch(value) {
		case 0x0:
		case 0x4:
			param->uvalue = RTC_BSM_LEVEL;
			break;
		case 0x1:
		case 0x5:
			param->uvalue = RTC_BSM_DIRECT;
			break;
		case PCF8523_PM_STANDBY:
			param->uvalue = RTC_BSM_STANDBY;
			break;
		default:
			param->uvalue = RTC_BSM_DISABLED;
		}

		break;

	default:
		return -EINVAL;
	}

	return 0;
}

static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	u8 mode;

	switch(param->param) {
	case RTC_PARAM_BACKUP_SWITCH_MODE:
		switch (param->uvalue) {
		case RTC_BSM_DISABLED:
			mode = 0x2;
			break;
		case RTC_BSM_DIRECT:
			mode = 0x1;
			break;
		case RTC_BSM_LEVEL:
			mode = 0x0;
			break;
		case RTC_BSM_STANDBY:
			mode = PCF8523_PM_STANDBY;
			break;
		default:
			return -EINVAL;
		}

		return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
					  PCF8523_CONTROL3_PM,
					  FIELD_PREP(PCF8523_CONTROL3_PM, mode));

		break;

	default:
		return -EINVAL;
	}

	return 0;
}

static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
			     unsigned long arg)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	unsigned int flags = 0;
	u32 value;
	int ret;

	switch (cmd) {
	case RTC_VL_READ:
		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
		if (ret < 0)
			return ret;

		if (value & PCF8523_CONTROL3_BLF)
			flags |= RTC_VL_BACKUP_LOW;

		ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
		if (ret < 0)
			return ret;

		if (value & PCF8523_SECONDS_OS)
			flags |= RTC_VL_DATA_INVALID;

		return put_user(flags, (unsigned int __user *)arg);

	default:
		return -ENOIOCTLCMD;
	}
}

static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	int err;
	u32 value;
	s8 val;

	err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
	if (err < 0)
		return err;

	/* sign extend the 7-bit offset value */
	val = value << 1;
	*offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);

	return 0;
}

static int pcf8523_rtc_set_offset(struct device *dev, long offset)
{
	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
	long reg_m0, reg_m1;
	u32 value;

	reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
	reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);

	if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
		value = reg_m0 & 0x7f;
	else
		value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;

	return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
}

static const struct rtc_class_ops pcf8523_rtc_ops = {
	.read_time = pcf8523_rtc_read_time,
	.set_time = pcf8523_rtc_set_time,
	.read_alarm = pcf8523_rtc_read_alarm,
	.set_alarm = pcf8523_rtc_set_alarm,
	.alarm_irq_enable = pcf8523_irq_enable,
	.ioctl = pcf8523_rtc_ioctl,
	.read_offset = pcf8523_rtc_read_offset,
	.set_offset = pcf8523_rtc_set_offset,
	.param_get = pcf8523_param_get,
	.param_set = pcf8523_param_set,
};

static const struct regmap_config regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = 0x13,
};

static int pcf8523_probe(struct i2c_client *client)
{
	struct pcf8523 *pcf8523;
	struct rtc_device *rtc;
	bool wakeup_source = false;
	u32 value;
	int err;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

	pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
	if (!pcf8523)
		return -ENOMEM;

	pcf8523->regmap = devm_regmap_init_i2c(client, &regmap_config);
	if (IS_ERR(pcf8523->regmap))
		return PTR_ERR(pcf8523->regmap);

	i2c_set_clientdata(client, pcf8523);

	rtc = devm_rtc_allocate_device(&client->dev);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);
	pcf8523->rtc = rtc;

	err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
	if (err < 0)
		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
			 err);

	err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
	if (err < 0)
		return err;

	if (value & PCF8523_SECONDS_OS) {
		err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
		if (err < 0)
			return err;

		if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
			err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
					   value & ~PCF8523_CONTROL3_PM);
			if (err < 0)
				return err;
		}
	}

	rtc->ops = &pcf8523_rtc_ops;
	rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
	rtc->range_max = RTC_TIMESTAMP_END_2099;
	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);

	if (client->irq > 0) {
		unsigned long irqflags = IRQF_TRIGGER_LOW;

		if (dev_fwnode(&client->dev))
			irqflags = 0;

		err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
		if (err < 0)
			return err;

		err = devm_request_threaded_irq(&client->dev, client->irq,
						NULL, pcf8523_irq,
						IRQF_SHARED | IRQF_ONESHOT | irqflags,
						dev_name(&rtc->dev), pcf8523);
		if (err)
			return err;

		dev_pm_set_wake_irq(&client->dev, client->irq);
	}

	wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
	if (client->irq > 0 || wakeup_source)
		device_init_wakeup(&client->dev, true);

	return devm_rtc_register_device(rtc);
}

static const struct i2c_device_id pcf8523_id[] = {
	{ "pcf8523", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8523_id);

static const struct of_device_id pcf8523_of_match[] = {
	{ .compatible = "nxp,pcf8523" },
	{ .compatible = "microcrystal,rv8523" },
	{ }
};
MODULE_DEVICE_TABLE(of, pcf8523_of_match);

static struct i2c_driver pcf8523_driver = {
	.driver = {
		.name = "rtc-pcf8523",
		.of_match_table = pcf8523_of_match,
	},
	.probe_new = pcf8523_probe,
	.id_table = pcf8523_id,
};
module_i2c_driver(pcf8523_driver);

MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
MODULE_LICENSE("GPL v2");