aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-rv3029c2.c
blob: 5032c24ec15938d2341927960de9e52a077b9773 (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
/*
 * Micro Crystal RV-3029C2 rtc class driver
 *
 * Author: Gregory Hermant <gregory.hermant@calao-systems.com>
 *
 * based on previously existing rtc class drivers
 *
 * 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.
 *
 * NOTE: Currently this driver only supports the bare minimum for read
 * and write the RTC and alarms. The extra features provided by this chip
 * (trickle charger, eeprom, T° compensation) are unavailable.
 */

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

/* Register map */
/* control section */
#define RV3029C2_ONOFF_CTRL		0x00
#define RV3029C2_IRQ_CTRL		0x01
#define RV3029C2_IRQ_CTRL_AIE		(1 << 0)
#define RV3029C2_IRQ_FLAGS		0x02
#define RV3029C2_IRQ_FLAGS_AF		(1 << 0)
#define RV3029C2_STATUS			0x03
#define RV3029C2_STATUS_VLOW1		(1 << 2)
#define RV3029C2_STATUS_VLOW2		(1 << 3)
#define RV3029C2_STATUS_SR		(1 << 4)
#define RV3029C2_STATUS_PON		(1 << 5)
#define RV3029C2_STATUS_EEBUSY		(1 << 7)
#define RV3029C2_RST_CTRL		0x04
#define RV3029C2_CONTROL_SECTION_LEN	0x05

/* watch section */
#define RV3029C2_W_SEC			0x08
#define RV3029C2_W_MINUTES		0x09
#define RV3029C2_W_HOURS		0x0A
#define RV3029C2_REG_HR_12_24		(1<<6)  /* 24h/12h mode */
#define RV3029C2_REG_HR_PM		(1<<5)  /* PM/AM bit in 12h mode */
#define RV3029C2_W_DATE			0x0B
#define RV3029C2_W_DAYS			0x0C
#define RV3029C2_W_MONTHS		0x0D
#define RV3029C2_W_YEARS		0x0E
#define RV3029C2_WATCH_SECTION_LEN	0x07

/* alarm section */
#define RV3029C2_A_SC			0x10
#define RV3029C2_A_MN			0x11
#define RV3029C2_A_HR			0x12
#define RV3029C2_A_DT			0x13
#define RV3029C2_A_DW			0x14
#define RV3029C2_A_MO			0x15
#define RV3029C2_A_YR			0x16
#define RV3029C2_ALARM_SECTION_LEN	0x07

/* timer section */
#define RV3029C2_TIMER_LOW		0x18
#define RV3029C2_TIMER_HIGH		0x19

/* temperature section */
#define RV3029C2_TEMP_PAGE		0x20

/* eeprom data section */
#define RV3029C2_E2P_EEDATA1		0x28
#define RV3029C2_E2P_EEDATA2		0x29

/* eeprom control section */
#define RV3029C2_CONTROL_E2P_EECTRL	0x30
#define RV3029C2_TRICKLE_1K		(1<<0)  /*  1K resistance */
#define RV3029C2_TRICKLE_5K		(1<<1)  /*  5K resistance */
#define RV3029C2_TRICKLE_20K		(1<<2)  /* 20K resistance */
#define RV3029C2_TRICKLE_80K		(1<<3)  /* 80K resistance */
#define RV3029C2_CONTROL_E2P_XTALOFFSET	0x31
#define RV3029C2_CONTROL_E2P_QCOEF	0x32
#define RV3029C2_CONTROL_E2P_TURNOVER	0x33

/* user ram section */
#define RV3029C2_USR1_RAM_PAGE		0x38
#define RV3029C2_USR1_SECTION_LEN	0x04
#define RV3029C2_USR2_RAM_PAGE		0x3C
#define RV3029C2_USR2_SECTION_LEN	0x04

static int
rv3029c2_i2c_read_regs(struct i2c_client *client, u8 reg, u8 *buf,
	unsigned len)
{
	int ret;

	if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
		(reg + len > RV3029C2_USR1_RAM_PAGE + 8))
		return -EINVAL;

	ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
	if (ret < 0)
		return ret;
	if (ret < len)
		return -EIO;
	return 0;
}

static int
rv3029c2_i2c_write_regs(struct i2c_client *client, u8 reg, u8 const buf[],
			unsigned len)
{
	if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
		(reg + len > RV3029C2_USR1_RAM_PAGE + 8))
		return -EINVAL;

	return i2c_smbus_write_i2c_block_data(client, reg, len, buf);
}

static int
rv3029c2_i2c_get_sr(struct i2c_client *client, u8 *buf)
{
	int ret = rv3029c2_i2c_read_regs(client, RV3029C2_STATUS, buf, 1);

	if (ret < 0)
		return -EIO;
	dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
	return 0;
}

static int
rv3029c2_i2c_set_sr(struct i2c_client *client, u8 val)
{
	u8 buf[1];
	int sr;

	buf[0] = val;
	sr = rv3029c2_i2c_write_regs(client, RV3029C2_STATUS, buf, 1);
	dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
	if (sr < 0)
		return -EIO;
	return 0;
}

static int
rv3029c2_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
{
	u8 buf[1];
	int ret;
	u8 regs[RV3029C2_WATCH_SECTION_LEN] = { 0, };

	ret = rv3029c2_i2c_get_sr(client, buf);
	if (ret < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return -EIO;
	}

	ret = rv3029c2_i2c_read_regs(client, RV3029C2_W_SEC , regs,
					RV3029C2_WATCH_SECTION_LEN);
	if (ret < 0) {
		dev_err(&client->dev, "%s: reading RTC section failed\n",
			__func__);
		return ret;
	}

	tm->tm_sec = bcd2bin(regs[RV3029C2_W_SEC-RV3029C2_W_SEC]);
	tm->tm_min = bcd2bin(regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC]);

	/* HR field has a more complex interpretation */
	{
		const u8 _hr = regs[RV3029C2_W_HOURS-RV3029C2_W_SEC];
		if (_hr & RV3029C2_REG_HR_12_24) {
			/* 12h format */
			tm->tm_hour = bcd2bin(_hr & 0x1f);
			if (_hr & RV3029C2_REG_HR_PM)	/* PM flag set */
				tm->tm_hour += 12;
		} else /* 24h format */
			tm->tm_hour = bcd2bin(_hr & 0x3f);
	}

	tm->tm_mday = bcd2bin(regs[RV3029C2_W_DATE-RV3029C2_W_SEC]);
	tm->tm_mon = bcd2bin(regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC]) - 1;
	tm->tm_year = bcd2bin(regs[RV3029C2_W_YEARS-RV3029C2_W_SEC]) + 100;
	tm->tm_wday = bcd2bin(regs[RV3029C2_W_DAYS-RV3029C2_W_SEC]) - 1;

	return 0;
}

static int rv3029c2_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	return rv3029c2_i2c_read_time(to_i2c_client(dev), tm);
}

static int
rv3029c2_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
{
	struct rtc_time *const tm = &alarm->time;
	int ret;
	u8 regs[8];

	ret = rv3029c2_i2c_get_sr(client, regs);
	if (ret < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return -EIO;
	}

	ret = rv3029c2_i2c_read_regs(client, RV3029C2_A_SC, regs,
					RV3029C2_ALARM_SECTION_LEN);

	if (ret < 0) {
		dev_err(&client->dev, "%s: reading alarm section failed\n",
			__func__);
		return ret;
	}

	tm->tm_sec = bcd2bin(regs[RV3029C2_A_SC-RV3029C2_A_SC] & 0x7f);
	tm->tm_min = bcd2bin(regs[RV3029C2_A_MN-RV3029C2_A_SC] & 0x7f);
	tm->tm_hour = bcd2bin(regs[RV3029C2_A_HR-RV3029C2_A_SC] & 0x3f);
	tm->tm_mday = bcd2bin(regs[RV3029C2_A_DT-RV3029C2_A_SC] & 0x3f);
	tm->tm_mon = bcd2bin(regs[RV3029C2_A_MO-RV3029C2_A_SC] & 0x1f) - 1;
	tm->tm_year = bcd2bin(regs[RV3029C2_A_YR-RV3029C2_A_SC] & 0x7f) + 100;
	tm->tm_wday = bcd2bin(regs[RV3029C2_A_DW-RV3029C2_A_SC] & 0x07) - 1;

	return 0;
}

static int
rv3029c2_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	return rv3029c2_i2c_read_alarm(to_i2c_client(dev), alarm);
}

static int rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client *client,
					int enable)
{
	int ret;
	u8 buf[1];

	/* enable AIE irq */
	ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_CTRL,	buf, 1);
	if (ret < 0) {
		dev_err(&client->dev, "can't read INT reg\n");
		return ret;
	}
	if (enable)
		buf[0] |= RV3029C2_IRQ_CTRL_AIE;
	else
		buf[0] &= ~RV3029C2_IRQ_CTRL_AIE;

	ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
	if (ret < 0) {
		dev_err(&client->dev, "can't set INT reg\n");
		return ret;
	}

	return 0;
}

static int rv3029c2_rtc_i2c_set_alarm(struct i2c_client *client,
					struct rtc_wkalrm *alarm)
{
	struct rtc_time *const tm = &alarm->time;
	int ret;
	u8 regs[8];

	/*
	 * The clock has an 8 bit wide bcd-coded register (they never learn)
	 * for the year. tm_year is an offset from 1900 and we are interested
	 * in the 2000-2099 range, so any value less than 100 is invalid.
	*/
	if (tm->tm_year < 100)
		return -EINVAL;

	ret = rv3029c2_i2c_get_sr(client, regs);
	if (ret < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return -EIO;
	}
	regs[RV3029C2_A_SC-RV3029C2_A_SC] = bin2bcd(tm->tm_sec & 0x7f);
	regs[RV3029C2_A_MN-RV3029C2_A_SC] = bin2bcd(tm->tm_min & 0x7f);
	regs[RV3029C2_A_HR-RV3029C2_A_SC] = bin2bcd(tm->tm_hour & 0x3f);
	regs[RV3029C2_A_DT-RV3029C2_A_SC] = bin2bcd(tm->tm_mday & 0x3f);
	regs[RV3029C2_A_MO-RV3029C2_A_SC] = bin2bcd((tm->tm_mon & 0x1f) - 1);
	regs[RV3029C2_A_DW-RV3029C2_A_SC] = bin2bcd((tm->tm_wday & 7) - 1);
	regs[RV3029C2_A_YR-RV3029C2_A_SC] = bin2bcd((tm->tm_year & 0x7f) - 100);

	ret = rv3029c2_i2c_write_regs(client, RV3029C2_A_SC, regs,
					RV3029C2_ALARM_SECTION_LEN);
	if (ret < 0)
		return ret;

	if (alarm->enabled) {
		u8 buf[1];

		/* clear AF flag */
		ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_FLAGS,
						buf, 1);
		if (ret < 0) {
			dev_err(&client->dev, "can't read alarm flag\n");
			return ret;
		}
		buf[0] &= ~RV3029C2_IRQ_FLAGS_AF;
		ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_FLAGS,
						buf, 1);
		if (ret < 0) {
			dev_err(&client->dev, "can't set alarm flag\n");
			return ret;
		}
		/* enable AIE irq */
		ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
		if (ret)
			return ret;

		dev_dbg(&client->dev, "alarm IRQ armed\n");
	} else {
		/* disable AIE irq */
		ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
		if (ret)
			return ret;

		dev_dbg(&client->dev, "alarm IRQ disabled\n");
	}

	return 0;
}

static int rv3029c2_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	return rv3029c2_rtc_i2c_set_alarm(to_i2c_client(dev), alarm);
}

static int
rv3029c2_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
{
	u8 regs[8];
	int ret;

	/*
	 * The clock has an 8 bit wide bcd-coded register (they never learn)
	 * for the year. tm_year is an offset from 1900 and we are interested
	 * in the 2000-2099 range, so any value less than 100 is invalid.
	*/
	if (tm->tm_year < 100)
		return -EINVAL;

	regs[RV3029C2_W_SEC-RV3029C2_W_SEC] = bin2bcd(tm->tm_sec);
	regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC] = bin2bcd(tm->tm_min);
	regs[RV3029C2_W_HOURS-RV3029C2_W_SEC] = bin2bcd(tm->tm_hour);
	regs[RV3029C2_W_DATE-RV3029C2_W_SEC] = bin2bcd(tm->tm_mday);
	regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC] = bin2bcd(tm->tm_mon+1);
	regs[RV3029C2_W_DAYS-RV3029C2_W_SEC] = bin2bcd((tm->tm_wday & 7)+1);
	regs[RV3029C2_W_YEARS-RV3029C2_W_SEC] = bin2bcd(tm->tm_year - 100);

	ret = rv3029c2_i2c_write_regs(client, RV3029C2_W_SEC, regs,
					RV3029C2_WATCH_SECTION_LEN);
	if (ret < 0)
		return ret;

	ret = rv3029c2_i2c_get_sr(client, regs);
	if (ret < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return ret;
	}
	/* clear PON bit */
	ret = rv3029c2_i2c_set_sr(client, (regs[0] & ~RV3029C2_STATUS_PON));
	if (ret < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return ret;
	}

	return 0;
}

static int rv3029c2_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	return rv3029c2_i2c_set_time(to_i2c_client(dev), tm);
}

static const struct rtc_class_ops rv3029c2_rtc_ops = {
	.read_time	= rv3029c2_rtc_read_time,
	.set_time	= rv3029c2_rtc_set_time,
	.read_alarm	= rv3029c2_rtc_read_alarm,
	.set_alarm	= rv3029c2_rtc_set_alarm,
};

static struct i2c_device_id rv3029c2_id[] = {
	{ "rv3029c2", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, rv3029c2_id);

static int rv3029c2_probe(struct i2c_client *client,
			  const struct i2c_device_id *id)
{
	struct rtc_device *rtc;
	int rc = 0;
	u8 buf[1];

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL))
		return -ENODEV;

	rtc = devm_rtc_device_register(&client->dev, client->name,
					&rv3029c2_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	i2c_set_clientdata(client, rtc);

	rc = rv3029c2_i2c_get_sr(client, buf);
	if (rc < 0) {
		dev_err(&client->dev, "reading status failed\n");
		return rc;
	}

	return 0;
}

static int rv3029c2_remove(struct i2c_client *client)
{
	return 0;
}

static struct i2c_driver rv3029c2_driver = {
	.driver = {
		.name = "rtc-rv3029c2",
	},
	.probe = rv3029c2_probe,
	.remove = rv3029c2_remove,
	.id_table = rv3029c2_id,
};

module_i2c_driver(rv3029c2_driver);

MODULE_AUTHOR("Gregory Hermant <gregory.hermant@calao-systems.com>");
MODULE_DESCRIPTION("Micro Crystal RV3029C2 RTC driver");
MODULE_LICENSE("GPL");