xref: /linux/drivers/rtc/rtc-abx80x.c (revision 18f90d372cf35b387663f1567de701e5393f6eb5)
1 /*
2  * A driver for the I2C members of the Abracon AB x8xx RTC family,
3  * and compatible: AB 1805 and AB 0805
4  *
5  * Copyright 2014-2015 Macq S.A.
6  *
7  * Author: Philippe De Muyter <phdm@macqel.be>
8  * Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  *
14  */
15 
16 #include <linux/bcd.h>
17 #include <linux/i2c.h>
18 #include <linux/module.h>
19 #include <linux/rtc.h>
20 #include <linux/watchdog.h>
21 
22 #define ABX8XX_REG_HTH		0x00
23 #define ABX8XX_REG_SC		0x01
24 #define ABX8XX_REG_MN		0x02
25 #define ABX8XX_REG_HR		0x03
26 #define ABX8XX_REG_DA		0x04
27 #define ABX8XX_REG_MO		0x05
28 #define ABX8XX_REG_YR		0x06
29 #define ABX8XX_REG_WD		0x07
30 
31 #define ABX8XX_REG_AHTH		0x08
32 #define ABX8XX_REG_ASC		0x09
33 #define ABX8XX_REG_AMN		0x0a
34 #define ABX8XX_REG_AHR		0x0b
35 #define ABX8XX_REG_ADA		0x0c
36 #define ABX8XX_REG_AMO		0x0d
37 #define ABX8XX_REG_AWD		0x0e
38 
39 #define ABX8XX_REG_STATUS	0x0f
40 #define ABX8XX_STATUS_AF	BIT(2)
41 #define ABX8XX_STATUS_BLF	BIT(4)
42 #define ABX8XX_STATUS_WDT	BIT(6)
43 
44 #define ABX8XX_REG_CTRL1	0x10
45 #define ABX8XX_CTRL_WRITE	BIT(0)
46 #define ABX8XX_CTRL_ARST	BIT(2)
47 #define ABX8XX_CTRL_12_24	BIT(6)
48 
49 #define ABX8XX_REG_CTRL2	0x11
50 #define ABX8XX_CTRL2_RSVD	BIT(5)
51 
52 #define ABX8XX_REG_IRQ		0x12
53 #define ABX8XX_IRQ_AIE		BIT(2)
54 #define ABX8XX_IRQ_IM_1_4	(0x3 << 5)
55 
56 #define ABX8XX_REG_CD_TIMER_CTL	0x18
57 
58 #define ABX8XX_REG_OSC		0x1c
59 #define ABX8XX_OSC_FOS		BIT(3)
60 #define ABX8XX_OSC_BOS		BIT(4)
61 #define ABX8XX_OSC_ACAL_512	BIT(5)
62 #define ABX8XX_OSC_ACAL_1024	BIT(6)
63 
64 #define ABX8XX_OSC_OSEL		BIT(7)
65 
66 #define ABX8XX_REG_OSS		0x1d
67 #define ABX8XX_OSS_OF		BIT(1)
68 #define ABX8XX_OSS_OMODE	BIT(4)
69 
70 #define ABX8XX_REG_WDT		0x1b
71 #define ABX8XX_WDT_WDS		BIT(7)
72 #define ABX8XX_WDT_BMB_MASK	0x7c
73 #define ABX8XX_WDT_BMB_SHIFT	2
74 #define ABX8XX_WDT_MAX_TIME	(ABX8XX_WDT_BMB_MASK >> ABX8XX_WDT_BMB_SHIFT)
75 #define ABX8XX_WDT_WRB_MASK	0x03
76 #define ABX8XX_WDT_WRB_1HZ	0x02
77 
78 #define ABX8XX_REG_CFG_KEY	0x1f
79 #define ABX8XX_CFG_KEY_OSC	0xa1
80 #define ABX8XX_CFG_KEY_MISC	0x9d
81 
82 #define ABX8XX_REG_ID0		0x28
83 
84 #define ABX8XX_REG_OUT_CTRL	0x30
85 #define ABX8XX_OUT_CTRL_EXDS	BIT(4)
86 
87 #define ABX8XX_REG_TRICKLE	0x20
88 #define ABX8XX_TRICKLE_CHARGE_ENABLE	0xa0
89 #define ABX8XX_TRICKLE_STANDARD_DIODE	0x8
90 #define ABX8XX_TRICKLE_SCHOTTKY_DIODE	0x4
91 
92 static u8 trickle_resistors[] = {0, 3, 6, 11};
93 
94 enum abx80x_chip {AB0801, AB0803, AB0804, AB0805,
95 	AB1801, AB1803, AB1804, AB1805, RV1805, ABX80X};
96 
97 struct abx80x_cap {
98 	u16 pn;
99 	bool has_tc;
100 	bool has_wdog;
101 };
102 
103 static struct abx80x_cap abx80x_caps[] = {
104 	[AB0801] = {.pn = 0x0801},
105 	[AB0803] = {.pn = 0x0803},
106 	[AB0804] = {.pn = 0x0804, .has_tc = true, .has_wdog = true},
107 	[AB0805] = {.pn = 0x0805, .has_tc = true, .has_wdog = true},
108 	[AB1801] = {.pn = 0x1801},
109 	[AB1803] = {.pn = 0x1803},
110 	[AB1804] = {.pn = 0x1804, .has_tc = true, .has_wdog = true},
111 	[AB1805] = {.pn = 0x1805, .has_tc = true, .has_wdog = true},
112 	[RV1805] = {.pn = 0x1805, .has_tc = true, .has_wdog = true},
113 	[ABX80X] = {.pn = 0}
114 };
115 
116 struct abx80x_priv {
117 	struct rtc_device *rtc;
118 	struct i2c_client *client;
119 	struct watchdog_device wdog;
120 };
121 
122 static int abx80x_is_rc_mode(struct i2c_client *client)
123 {
124 	int flags = 0;
125 
126 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
127 	if (flags < 0) {
128 		dev_err(&client->dev,
129 			"Failed to read autocalibration attribute\n");
130 		return flags;
131 	}
132 
133 	return (flags & ABX8XX_OSS_OMODE) ? 1 : 0;
134 }
135 
136 static int abx80x_enable_trickle_charger(struct i2c_client *client,
137 					 u8 trickle_cfg)
138 {
139 	int err;
140 
141 	/*
142 	 * Write the configuration key register to enable access to the Trickle
143 	 * register
144 	 */
145 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
146 					ABX8XX_CFG_KEY_MISC);
147 	if (err < 0) {
148 		dev_err(&client->dev, "Unable to write configuration key\n");
149 		return -EIO;
150 	}
151 
152 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_TRICKLE,
153 					ABX8XX_TRICKLE_CHARGE_ENABLE |
154 					trickle_cfg);
155 	if (err < 0) {
156 		dev_err(&client->dev, "Unable to write trickle register\n");
157 		return -EIO;
158 	}
159 
160 	return 0;
161 }
162 
163 static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
164 {
165 	struct i2c_client *client = to_i2c_client(dev);
166 	unsigned char buf[8];
167 	int err, flags, rc_mode = 0;
168 
169 	/* Read the Oscillator Failure only in XT mode */
170 	rc_mode = abx80x_is_rc_mode(client);
171 	if (rc_mode < 0)
172 		return rc_mode;
173 
174 	if (!rc_mode) {
175 		flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
176 		if (flags < 0)
177 			return flags;
178 
179 		if (flags & ABX8XX_OSS_OF) {
180 			dev_err(dev, "Oscillator failure, data is invalid.\n");
181 			return -EINVAL;
182 		}
183 	}
184 
185 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH,
186 					    sizeof(buf), buf);
187 	if (err < 0) {
188 		dev_err(&client->dev, "Unable to read date\n");
189 		return -EIO;
190 	}
191 
192 	tm->tm_sec = bcd2bin(buf[ABX8XX_REG_SC] & 0x7F);
193 	tm->tm_min = bcd2bin(buf[ABX8XX_REG_MN] & 0x7F);
194 	tm->tm_hour = bcd2bin(buf[ABX8XX_REG_HR] & 0x3F);
195 	tm->tm_wday = buf[ABX8XX_REG_WD] & 0x7;
196 	tm->tm_mday = bcd2bin(buf[ABX8XX_REG_DA] & 0x3F);
197 	tm->tm_mon = bcd2bin(buf[ABX8XX_REG_MO] & 0x1F) - 1;
198 	tm->tm_year = bcd2bin(buf[ABX8XX_REG_YR]) + 100;
199 
200 	return 0;
201 }
202 
203 static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
204 {
205 	struct i2c_client *client = to_i2c_client(dev);
206 	unsigned char buf[8];
207 	int err, flags;
208 
209 	if (tm->tm_year < 100)
210 		return -EINVAL;
211 
212 	buf[ABX8XX_REG_HTH] = 0;
213 	buf[ABX8XX_REG_SC] = bin2bcd(tm->tm_sec);
214 	buf[ABX8XX_REG_MN] = bin2bcd(tm->tm_min);
215 	buf[ABX8XX_REG_HR] = bin2bcd(tm->tm_hour);
216 	buf[ABX8XX_REG_DA] = bin2bcd(tm->tm_mday);
217 	buf[ABX8XX_REG_MO] = bin2bcd(tm->tm_mon + 1);
218 	buf[ABX8XX_REG_YR] = bin2bcd(tm->tm_year - 100);
219 	buf[ABX8XX_REG_WD] = tm->tm_wday;
220 
221 	err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_HTH,
222 					     sizeof(buf), buf);
223 	if (err < 0) {
224 		dev_err(&client->dev, "Unable to write to date registers\n");
225 		return -EIO;
226 	}
227 
228 	/* Clear the OF bit of Oscillator Status Register */
229 	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
230 	if (flags < 0)
231 		return flags;
232 
233 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSS,
234 					flags & ~ABX8XX_OSS_OF);
235 	if (err < 0) {
236 		dev_err(&client->dev, "Unable to write oscillator status register\n");
237 		return err;
238 	}
239 
240 	return 0;
241 }
242 
243 static irqreturn_t abx80x_handle_irq(int irq, void *dev_id)
244 {
245 	struct i2c_client *client = dev_id;
246 	struct abx80x_priv *priv = i2c_get_clientdata(client);
247 	struct rtc_device *rtc = priv->rtc;
248 	int status;
249 
250 	status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
251 	if (status < 0)
252 		return IRQ_NONE;
253 
254 	if (status & ABX8XX_STATUS_AF)
255 		rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF);
256 
257 	/*
258 	 * It is unclear if we'll get an interrupt before the external
259 	 * reset kicks in.
260 	 */
261 	if (status & ABX8XX_STATUS_WDT)
262 		dev_alert(&client->dev, "watchdog timeout interrupt.\n");
263 
264 	i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS, 0);
265 
266 	return IRQ_HANDLED;
267 }
268 
269 static int abx80x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
270 {
271 	struct i2c_client *client = to_i2c_client(dev);
272 	unsigned char buf[7];
273 
274 	int irq_mask, err;
275 
276 	if (client->irq <= 0)
277 		return -EINVAL;
278 
279 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ASC,
280 					    sizeof(buf), buf);
281 	if (err)
282 		return err;
283 
284 	irq_mask = i2c_smbus_read_byte_data(client, ABX8XX_REG_IRQ);
285 	if (irq_mask < 0)
286 		return irq_mask;
287 
288 	t->time.tm_sec = bcd2bin(buf[0] & 0x7F);
289 	t->time.tm_min = bcd2bin(buf[1] & 0x7F);
290 	t->time.tm_hour = bcd2bin(buf[2] & 0x3F);
291 	t->time.tm_mday = bcd2bin(buf[3] & 0x3F);
292 	t->time.tm_mon = bcd2bin(buf[4] & 0x1F) - 1;
293 	t->time.tm_wday = buf[5] & 0x7;
294 
295 	t->enabled = !!(irq_mask & ABX8XX_IRQ_AIE);
296 	t->pending = (buf[6] & ABX8XX_STATUS_AF) && t->enabled;
297 
298 	return err;
299 }
300 
301 static int abx80x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
302 {
303 	struct i2c_client *client = to_i2c_client(dev);
304 	u8 alarm[6];
305 	int err;
306 
307 	if (client->irq <= 0)
308 		return -EINVAL;
309 
310 	alarm[0] = 0x0;
311 	alarm[1] = bin2bcd(t->time.tm_sec);
312 	alarm[2] = bin2bcd(t->time.tm_min);
313 	alarm[3] = bin2bcd(t->time.tm_hour);
314 	alarm[4] = bin2bcd(t->time.tm_mday);
315 	alarm[5] = bin2bcd(t->time.tm_mon + 1);
316 
317 	err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_AHTH,
318 					     sizeof(alarm), alarm);
319 	if (err < 0) {
320 		dev_err(&client->dev, "Unable to write alarm registers\n");
321 		return -EIO;
322 	}
323 
324 	if (t->enabled) {
325 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
326 						(ABX8XX_IRQ_IM_1_4 |
327 						 ABX8XX_IRQ_AIE));
328 		if (err)
329 			return err;
330 	}
331 
332 	return 0;
333 }
334 
335 static int abx80x_rtc_set_autocalibration(struct device *dev,
336 					  int autocalibration)
337 {
338 	struct i2c_client *client = to_i2c_client(dev);
339 	int retval, flags = 0;
340 
341 	if ((autocalibration != 0) && (autocalibration != 1024) &&
342 	    (autocalibration != 512)) {
343 		dev_err(dev, "autocalibration value outside permitted range\n");
344 		return -EINVAL;
345 	}
346 
347 	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
348 	if (flags < 0)
349 		return flags;
350 
351 	if (autocalibration == 0) {
352 		flags &= ~(ABX8XX_OSC_ACAL_512 | ABX8XX_OSC_ACAL_1024);
353 	} else if (autocalibration == 1024) {
354 		/* 1024 autocalibration is 0x10 */
355 		flags |= ABX8XX_OSC_ACAL_1024;
356 		flags &= ~(ABX8XX_OSC_ACAL_512);
357 	} else {
358 		/* 512 autocalibration is 0x11 */
359 		flags |= (ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512);
360 	}
361 
362 	/* Unlock write access to Oscillator Control Register */
363 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
364 					   ABX8XX_CFG_KEY_OSC);
365 	if (retval < 0) {
366 		dev_err(dev, "Failed to write CONFIG_KEY register\n");
367 		return retval;
368 	}
369 
370 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
371 
372 	return retval;
373 }
374 
375 static int abx80x_rtc_get_autocalibration(struct device *dev)
376 {
377 	struct i2c_client *client = to_i2c_client(dev);
378 	int flags = 0, autocalibration;
379 
380 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
381 	if (flags < 0)
382 		return flags;
383 
384 	if (flags & ABX8XX_OSC_ACAL_512)
385 		autocalibration = 512;
386 	else if (flags & ABX8XX_OSC_ACAL_1024)
387 		autocalibration = 1024;
388 	else
389 		autocalibration = 0;
390 
391 	return autocalibration;
392 }
393 
394 static ssize_t autocalibration_store(struct device *dev,
395 				     struct device_attribute *attr,
396 				     const char *buf, size_t count)
397 {
398 	int retval;
399 	unsigned long autocalibration = 0;
400 
401 	retval = kstrtoul(buf, 10, &autocalibration);
402 	if (retval < 0) {
403 		dev_err(dev, "Failed to store RTC autocalibration attribute\n");
404 		return -EINVAL;
405 	}
406 
407 	retval = abx80x_rtc_set_autocalibration(dev, autocalibration);
408 
409 	return retval ? retval : count;
410 }
411 
412 static ssize_t autocalibration_show(struct device *dev,
413 				    struct device_attribute *attr, char *buf)
414 {
415 	int autocalibration = 0;
416 
417 	autocalibration = abx80x_rtc_get_autocalibration(dev);
418 	if (autocalibration < 0) {
419 		dev_err(dev, "Failed to read RTC autocalibration\n");
420 		sprintf(buf, "0\n");
421 		return autocalibration;
422 	}
423 
424 	return sprintf(buf, "%d\n", autocalibration);
425 }
426 
427 static DEVICE_ATTR_RW(autocalibration);
428 
429 static ssize_t oscillator_store(struct device *dev,
430 				struct device_attribute *attr,
431 				const char *buf, size_t count)
432 {
433 	struct i2c_client *client = to_i2c_client(dev);
434 	int retval, flags, rc_mode = 0;
435 
436 	if (strncmp(buf, "rc", 2) == 0) {
437 		rc_mode = 1;
438 	} else if (strncmp(buf, "xtal", 4) == 0) {
439 		rc_mode = 0;
440 	} else {
441 		dev_err(dev, "Oscillator selection value outside permitted ones\n");
442 		return -EINVAL;
443 	}
444 
445 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
446 	if (flags < 0)
447 		return flags;
448 
449 	if (rc_mode == 0)
450 		flags &= ~(ABX8XX_OSC_OSEL);
451 	else
452 		flags |= (ABX8XX_OSC_OSEL);
453 
454 	/* Unlock write access on Oscillator Control register */
455 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
456 					   ABX8XX_CFG_KEY_OSC);
457 	if (retval < 0) {
458 		dev_err(dev, "Failed to write CONFIG_KEY register\n");
459 		return retval;
460 	}
461 
462 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
463 	if (retval < 0) {
464 		dev_err(dev, "Failed to write Oscillator Control register\n");
465 		return retval;
466 	}
467 
468 	return retval ? retval : count;
469 }
470 
471 static ssize_t oscillator_show(struct device *dev,
472 			       struct device_attribute *attr, char *buf)
473 {
474 	int rc_mode = 0;
475 	struct i2c_client *client = to_i2c_client(dev);
476 
477 	rc_mode = abx80x_is_rc_mode(client);
478 
479 	if (rc_mode < 0) {
480 		dev_err(dev, "Failed to read RTC oscillator selection\n");
481 		sprintf(buf, "\n");
482 		return rc_mode;
483 	}
484 
485 	if (rc_mode)
486 		return sprintf(buf, "rc\n");
487 	else
488 		return sprintf(buf, "xtal\n");
489 }
490 
491 static DEVICE_ATTR_RW(oscillator);
492 
493 static struct attribute *rtc_calib_attrs[] = {
494 	&dev_attr_autocalibration.attr,
495 	&dev_attr_oscillator.attr,
496 	NULL,
497 };
498 
499 static const struct attribute_group rtc_calib_attr_group = {
500 	.attrs		= rtc_calib_attrs,
501 };
502 
503 static int abx80x_alarm_irq_enable(struct device *dev, unsigned int enabled)
504 {
505 	struct i2c_client *client = to_i2c_client(dev);
506 	int err;
507 
508 	if (enabled)
509 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
510 						(ABX8XX_IRQ_IM_1_4 |
511 						 ABX8XX_IRQ_AIE));
512 	else
513 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
514 						ABX8XX_IRQ_IM_1_4);
515 	return err;
516 }
517 
518 static int abx80x_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
519 {
520 	struct i2c_client *client = to_i2c_client(dev);
521 	int status, tmp;
522 
523 	switch (cmd) {
524 	case RTC_VL_READ:
525 		status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
526 		if (status < 0)
527 			return status;
528 
529 		tmp = !!(status & ABX8XX_STATUS_BLF);
530 
531 		if (copy_to_user((void __user *)arg, &tmp, sizeof(int)))
532 			return -EFAULT;
533 
534 		return 0;
535 
536 	case RTC_VL_CLR:
537 		status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
538 		if (status < 0)
539 			return status;
540 
541 		status &= ~ABX8XX_STATUS_BLF;
542 
543 		tmp = i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS, 0);
544 		if (tmp < 0)
545 			return tmp;
546 
547 		return 0;
548 
549 	default:
550 		return -ENOIOCTLCMD;
551 	}
552 }
553 
554 static const struct rtc_class_ops abx80x_rtc_ops = {
555 	.read_time	= abx80x_rtc_read_time,
556 	.set_time	= abx80x_rtc_set_time,
557 	.read_alarm	= abx80x_read_alarm,
558 	.set_alarm	= abx80x_set_alarm,
559 	.alarm_irq_enable = abx80x_alarm_irq_enable,
560 	.ioctl		= abx80x_ioctl,
561 };
562 
563 static int abx80x_dt_trickle_cfg(struct device_node *np)
564 {
565 	const char *diode;
566 	int trickle_cfg = 0;
567 	int i, ret;
568 	u32 tmp;
569 
570 	ret = of_property_read_string(np, "abracon,tc-diode", &diode);
571 	if (ret)
572 		return ret;
573 
574 	if (!strcmp(diode, "standard"))
575 		trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE;
576 	else if (!strcmp(diode, "schottky"))
577 		trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE;
578 	else
579 		return -EINVAL;
580 
581 	ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp);
582 	if (ret)
583 		return ret;
584 
585 	for (i = 0; i < sizeof(trickle_resistors); i++)
586 		if (trickle_resistors[i] == tmp)
587 			break;
588 
589 	if (i == sizeof(trickle_resistors))
590 		return -EINVAL;
591 
592 	return (trickle_cfg | i);
593 }
594 
595 static void rtc_calib_remove_sysfs_group(void *_dev)
596 {
597 	struct device *dev = _dev;
598 
599 	sysfs_remove_group(&dev->kobj, &rtc_calib_attr_group);
600 }
601 
602 #ifdef CONFIG_WATCHDOG
603 
604 static inline u8 timeout_bits(unsigned int timeout)
605 {
606 	return ((timeout << ABX8XX_WDT_BMB_SHIFT) & ABX8XX_WDT_BMB_MASK) |
607 		 ABX8XX_WDT_WRB_1HZ;
608 }
609 
610 static int __abx80x_wdog_set_timeout(struct watchdog_device *wdog,
611 				     unsigned int timeout)
612 {
613 	struct abx80x_priv *priv = watchdog_get_drvdata(wdog);
614 	u8 val = ABX8XX_WDT_WDS | timeout_bits(timeout);
615 
616 	/*
617 	 * Writing any timeout to the WDT register resets the watchdog timer.
618 	 * Writing 0 disables it.
619 	 */
620 	return i2c_smbus_write_byte_data(priv->client, ABX8XX_REG_WDT, val);
621 }
622 
623 static int abx80x_wdog_set_timeout(struct watchdog_device *wdog,
624 				   unsigned int new_timeout)
625 {
626 	int err = 0;
627 
628 	if (watchdog_hw_running(wdog))
629 		err = __abx80x_wdog_set_timeout(wdog, new_timeout);
630 
631 	if (err == 0)
632 		wdog->timeout = new_timeout;
633 
634 	return err;
635 }
636 
637 static int abx80x_wdog_ping(struct watchdog_device *wdog)
638 {
639 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
640 }
641 
642 static int abx80x_wdog_start(struct watchdog_device *wdog)
643 {
644 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
645 }
646 
647 static int abx80x_wdog_stop(struct watchdog_device *wdog)
648 {
649 	return __abx80x_wdog_set_timeout(wdog, 0);
650 }
651 
652 static const struct watchdog_info abx80x_wdog_info = {
653 	.identity = "abx80x watchdog",
654 	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
655 };
656 
657 static const struct watchdog_ops abx80x_wdog_ops = {
658 	.owner = THIS_MODULE,
659 	.start = abx80x_wdog_start,
660 	.stop = abx80x_wdog_stop,
661 	.ping = abx80x_wdog_ping,
662 	.set_timeout = abx80x_wdog_set_timeout,
663 };
664 
665 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
666 {
667 	priv->wdog.parent = &priv->client->dev;
668 	priv->wdog.ops = &abx80x_wdog_ops;
669 	priv->wdog.info = &abx80x_wdog_info;
670 	priv->wdog.min_timeout = 1;
671 	priv->wdog.max_timeout = ABX8XX_WDT_MAX_TIME;
672 	priv->wdog.timeout = ABX8XX_WDT_MAX_TIME;
673 
674 	watchdog_set_drvdata(&priv->wdog, priv);
675 
676 	return devm_watchdog_register_device(&priv->client->dev, &priv->wdog);
677 }
678 #else
679 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
680 {
681 	return 0;
682 }
683 #endif
684 
685 static int abx80x_probe(struct i2c_client *client,
686 			const struct i2c_device_id *id)
687 {
688 	struct device_node *np = client->dev.of_node;
689 	struct abx80x_priv *priv;
690 	int i, data, err, trickle_cfg = -EINVAL;
691 	char buf[7];
692 	unsigned int part = id->driver_data;
693 	unsigned int partnumber;
694 	unsigned int majrev, minrev;
695 	unsigned int lot;
696 	unsigned int wafer;
697 	unsigned int uid;
698 
699 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
700 		return -ENODEV;
701 
702 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0,
703 					    sizeof(buf), buf);
704 	if (err < 0) {
705 		dev_err(&client->dev, "Unable to read partnumber\n");
706 		return -EIO;
707 	}
708 
709 	partnumber = (buf[0] << 8) | buf[1];
710 	majrev = buf[2] >> 3;
711 	minrev = buf[2] & 0x7;
712 	lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3];
713 	uid = ((buf[4] & 0x7f) << 8) | buf[5];
714 	wafer = (buf[6] & 0x7c) >> 2;
715 	dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n",
716 		 partnumber, majrev, minrev, lot, wafer, uid);
717 
718 	data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1);
719 	if (data < 0) {
720 		dev_err(&client->dev, "Unable to read control register\n");
721 		return -EIO;
722 	}
723 
724 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1,
725 					((data & ~(ABX8XX_CTRL_12_24 |
726 						   ABX8XX_CTRL_ARST)) |
727 					 ABX8XX_CTRL_WRITE));
728 	if (err < 0) {
729 		dev_err(&client->dev, "Unable to write control register\n");
730 		return -EIO;
731 	}
732 
733 	/* Configure RV1805 specifics */
734 	if (part == RV1805) {
735 		/*
736 		 * Avoid accidentally entering test mode. This can happen
737 		 * on the RV1805 in case the reserved bit 5 in control2
738 		 * register is set. RV-1805-C3 datasheet indicates that
739 		 * the bit should be cleared in section 11h - Control2.
740 		 */
741 		data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL2);
742 		if (data < 0) {
743 			dev_err(&client->dev,
744 				"Unable to read control2 register\n");
745 			return -EIO;
746 		}
747 
748 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL2,
749 						data & ~ABX8XX_CTRL2_RSVD);
750 		if (err < 0) {
751 			dev_err(&client->dev,
752 				"Unable to write control2 register\n");
753 			return -EIO;
754 		}
755 
756 		/*
757 		 * Avoid extra power leakage. The RV1805 uses smaller
758 		 * 10pin package and the EXTI input is not present.
759 		 * Disable it to avoid leakage.
760 		 */
761 		data = i2c_smbus_read_byte_data(client, ABX8XX_REG_OUT_CTRL);
762 		if (data < 0) {
763 			dev_err(&client->dev,
764 				"Unable to read output control register\n");
765 			return -EIO;
766 		}
767 
768 		/*
769 		 * Write the configuration key register to enable access to
770 		 * the config2 register
771 		 */
772 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
773 						ABX8XX_CFG_KEY_MISC);
774 		if (err < 0) {
775 			dev_err(&client->dev,
776 				"Unable to write configuration key\n");
777 			return -EIO;
778 		}
779 
780 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OUT_CTRL,
781 						data | ABX8XX_OUT_CTRL_EXDS);
782 		if (err < 0) {
783 			dev_err(&client->dev,
784 				"Unable to write output control register\n");
785 			return -EIO;
786 		}
787 	}
788 
789 	/* part autodetection */
790 	if (part == ABX80X) {
791 		for (i = 0; abx80x_caps[i].pn; i++)
792 			if (partnumber == abx80x_caps[i].pn)
793 				break;
794 		if (abx80x_caps[i].pn == 0) {
795 			dev_err(&client->dev, "Unknown part: %04x\n",
796 				partnumber);
797 			return -EINVAL;
798 		}
799 		part = i;
800 	}
801 
802 	if (partnumber != abx80x_caps[part].pn) {
803 		dev_err(&client->dev, "partnumber mismatch %04x != %04x\n",
804 			partnumber, abx80x_caps[part].pn);
805 		return -EINVAL;
806 	}
807 
808 	if (np && abx80x_caps[part].has_tc)
809 		trickle_cfg = abx80x_dt_trickle_cfg(np);
810 
811 	if (trickle_cfg > 0) {
812 		dev_info(&client->dev, "Enabling trickle charger: %02x\n",
813 			 trickle_cfg);
814 		abx80x_enable_trickle_charger(client, trickle_cfg);
815 	}
816 
817 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CD_TIMER_CTL,
818 					BIT(2));
819 	if (err)
820 		return err;
821 
822 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
823 	if (priv == NULL)
824 		return -ENOMEM;
825 
826 	priv->rtc = devm_rtc_allocate_device(&client->dev);
827 	if (IS_ERR(priv->rtc))
828 		return PTR_ERR(priv->rtc);
829 
830 	priv->rtc->ops = &abx80x_rtc_ops;
831 	priv->client = client;
832 
833 	i2c_set_clientdata(client, priv);
834 
835 	if (abx80x_caps[part].has_wdog) {
836 		err = abx80x_setup_watchdog(priv);
837 		if (err)
838 			return err;
839 	}
840 
841 	if (client->irq > 0) {
842 		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
843 		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
844 						abx80x_handle_irq,
845 						IRQF_SHARED | IRQF_ONESHOT,
846 						"abx8xx",
847 						client);
848 		if (err) {
849 			dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
850 			client->irq = 0;
851 		}
852 	}
853 
854 	/* Export sysfs entries */
855 	err = sysfs_create_group(&(&client->dev)->kobj, &rtc_calib_attr_group);
856 	if (err) {
857 		dev_err(&client->dev, "Failed to create sysfs group: %d\n",
858 			err);
859 		return err;
860 	}
861 
862 	err = devm_add_action_or_reset(&client->dev,
863 				       rtc_calib_remove_sysfs_group,
864 				       &client->dev);
865 	if (err) {
866 		dev_err(&client->dev,
867 			"Failed to add sysfs cleanup action: %d\n",
868 			err);
869 		return err;
870 	}
871 
872 	err = rtc_register_device(priv->rtc);
873 
874 	return err;
875 }
876 
877 static int abx80x_remove(struct i2c_client *client)
878 {
879 	return 0;
880 }
881 
882 static const struct i2c_device_id abx80x_id[] = {
883 	{ "abx80x", ABX80X },
884 	{ "ab0801", AB0801 },
885 	{ "ab0803", AB0803 },
886 	{ "ab0804", AB0804 },
887 	{ "ab0805", AB0805 },
888 	{ "ab1801", AB1801 },
889 	{ "ab1803", AB1803 },
890 	{ "ab1804", AB1804 },
891 	{ "ab1805", AB1805 },
892 	{ "rv1805", RV1805 },
893 	{ }
894 };
895 MODULE_DEVICE_TABLE(i2c, abx80x_id);
896 
897 static struct i2c_driver abx80x_driver = {
898 	.driver		= {
899 		.name	= "rtc-abx80x",
900 	},
901 	.probe		= abx80x_probe,
902 	.remove		= abx80x_remove,
903 	.id_table	= abx80x_id,
904 };
905 
906 module_i2c_driver(abx80x_driver);
907 
908 MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
909 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
910 MODULE_DESCRIPTION("Abracon ABX80X RTC driver");
911 MODULE_LICENSE("GPL v2");
912