xref: /openbmc/linux/drivers/rtc/rtc-abx80x.c (revision 5d331b7f)
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@free-electrons.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_WDT	BIT(6)
42 
43 #define ABX8XX_REG_CTRL1	0x10
44 #define ABX8XX_CTRL_WRITE	BIT(0)
45 #define ABX8XX_CTRL_ARST	BIT(2)
46 #define ABX8XX_CTRL_12_24	BIT(6)
47 
48 #define ABX8XX_REG_IRQ		0x12
49 #define ABX8XX_IRQ_AIE		BIT(2)
50 #define ABX8XX_IRQ_IM_1_4	(0x3 << 5)
51 
52 #define ABX8XX_REG_CD_TIMER_CTL	0x18
53 
54 #define ABX8XX_REG_OSC		0x1c
55 #define ABX8XX_OSC_FOS		BIT(3)
56 #define ABX8XX_OSC_BOS		BIT(4)
57 #define ABX8XX_OSC_ACAL_512	BIT(5)
58 #define ABX8XX_OSC_ACAL_1024	BIT(6)
59 
60 #define ABX8XX_OSC_OSEL		BIT(7)
61 
62 #define ABX8XX_REG_OSS		0x1d
63 #define ABX8XX_OSS_OF		BIT(1)
64 #define ABX8XX_OSS_OMODE	BIT(4)
65 
66 #define ABX8XX_REG_WDT		0x1b
67 #define ABX8XX_WDT_WDS		BIT(7)
68 #define ABX8XX_WDT_BMB_MASK	0x7c
69 #define ABX8XX_WDT_BMB_SHIFT	2
70 #define ABX8XX_WDT_MAX_TIME	(ABX8XX_WDT_BMB_MASK >> ABX8XX_WDT_BMB_SHIFT)
71 #define ABX8XX_WDT_WRB_MASK	0x03
72 #define ABX8XX_WDT_WRB_1HZ	0x02
73 
74 #define ABX8XX_REG_CFG_KEY	0x1f
75 #define ABX8XX_CFG_KEY_OSC	0xa1
76 #define ABX8XX_CFG_KEY_MISC	0x9d
77 
78 #define ABX8XX_REG_ID0		0x28
79 
80 #define ABX8XX_REG_TRICKLE	0x20
81 #define ABX8XX_TRICKLE_CHARGE_ENABLE	0xa0
82 #define ABX8XX_TRICKLE_STANDARD_DIODE	0x8
83 #define ABX8XX_TRICKLE_SCHOTTKY_DIODE	0x4
84 
85 static u8 trickle_resistors[] = {0, 3, 6, 11};
86 
87 enum abx80x_chip {AB0801, AB0803, AB0804, AB0805,
88 	AB1801, AB1803, AB1804, AB1805, ABX80X};
89 
90 struct abx80x_cap {
91 	u16 pn;
92 	bool has_tc;
93 	bool has_wdog;
94 };
95 
96 static struct abx80x_cap abx80x_caps[] = {
97 	[AB0801] = {.pn = 0x0801},
98 	[AB0803] = {.pn = 0x0803},
99 	[AB0804] = {.pn = 0x0804, .has_tc = true, .has_wdog = true},
100 	[AB0805] = {.pn = 0x0805, .has_tc = true, .has_wdog = true},
101 	[AB1801] = {.pn = 0x1801},
102 	[AB1803] = {.pn = 0x1803},
103 	[AB1804] = {.pn = 0x1804, .has_tc = true, .has_wdog = true},
104 	[AB1805] = {.pn = 0x1805, .has_tc = true, .has_wdog = true},
105 	[ABX80X] = {.pn = 0}
106 };
107 
108 struct abx80x_priv {
109 	struct rtc_device *rtc;
110 	struct i2c_client *client;
111 	struct watchdog_device wdog;
112 };
113 
114 static int abx80x_is_rc_mode(struct i2c_client *client)
115 {
116 	int flags = 0;
117 
118 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
119 	if (flags < 0) {
120 		dev_err(&client->dev,
121 			"Failed to read autocalibration attribute\n");
122 		return flags;
123 	}
124 
125 	return (flags & ABX8XX_OSS_OMODE) ? 1 : 0;
126 }
127 
128 static int abx80x_enable_trickle_charger(struct i2c_client *client,
129 					 u8 trickle_cfg)
130 {
131 	int err;
132 
133 	/*
134 	 * Write the configuration key register to enable access to the Trickle
135 	 * register
136 	 */
137 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
138 					ABX8XX_CFG_KEY_MISC);
139 	if (err < 0) {
140 		dev_err(&client->dev, "Unable to write configuration key\n");
141 		return -EIO;
142 	}
143 
144 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_TRICKLE,
145 					ABX8XX_TRICKLE_CHARGE_ENABLE |
146 					trickle_cfg);
147 	if (err < 0) {
148 		dev_err(&client->dev, "Unable to write trickle register\n");
149 		return -EIO;
150 	}
151 
152 	return 0;
153 }
154 
155 static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
156 {
157 	struct i2c_client *client = to_i2c_client(dev);
158 	unsigned char buf[8];
159 	int err, flags, rc_mode = 0;
160 
161 	/* Read the Oscillator Failure only in XT mode */
162 	rc_mode = abx80x_is_rc_mode(client);
163 	if (rc_mode < 0)
164 		return rc_mode;
165 
166 	if (!rc_mode) {
167 		flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
168 		if (flags < 0)
169 			return flags;
170 
171 		if (flags & ABX8XX_OSS_OF) {
172 			dev_err(dev, "Oscillator failure, data is invalid.\n");
173 			return -EINVAL;
174 		}
175 	}
176 
177 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH,
178 					    sizeof(buf), buf);
179 	if (err < 0) {
180 		dev_err(&client->dev, "Unable to read date\n");
181 		return -EIO;
182 	}
183 
184 	tm->tm_sec = bcd2bin(buf[ABX8XX_REG_SC] & 0x7F);
185 	tm->tm_min = bcd2bin(buf[ABX8XX_REG_MN] & 0x7F);
186 	tm->tm_hour = bcd2bin(buf[ABX8XX_REG_HR] & 0x3F);
187 	tm->tm_wday = buf[ABX8XX_REG_WD] & 0x7;
188 	tm->tm_mday = bcd2bin(buf[ABX8XX_REG_DA] & 0x3F);
189 	tm->tm_mon = bcd2bin(buf[ABX8XX_REG_MO] & 0x1F) - 1;
190 	tm->tm_year = bcd2bin(buf[ABX8XX_REG_YR]) + 100;
191 
192 	return 0;
193 }
194 
195 static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
196 {
197 	struct i2c_client *client = to_i2c_client(dev);
198 	unsigned char buf[8];
199 	int err, flags;
200 
201 	if (tm->tm_year < 100)
202 		return -EINVAL;
203 
204 	buf[ABX8XX_REG_HTH] = 0;
205 	buf[ABX8XX_REG_SC] = bin2bcd(tm->tm_sec);
206 	buf[ABX8XX_REG_MN] = bin2bcd(tm->tm_min);
207 	buf[ABX8XX_REG_HR] = bin2bcd(tm->tm_hour);
208 	buf[ABX8XX_REG_DA] = bin2bcd(tm->tm_mday);
209 	buf[ABX8XX_REG_MO] = bin2bcd(tm->tm_mon + 1);
210 	buf[ABX8XX_REG_YR] = bin2bcd(tm->tm_year - 100);
211 	buf[ABX8XX_REG_WD] = tm->tm_wday;
212 
213 	err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_HTH,
214 					     sizeof(buf), buf);
215 	if (err < 0) {
216 		dev_err(&client->dev, "Unable to write to date registers\n");
217 		return -EIO;
218 	}
219 
220 	/* Clear the OF bit of Oscillator Status Register */
221 	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
222 	if (flags < 0)
223 		return flags;
224 
225 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSS,
226 					flags & ~ABX8XX_OSS_OF);
227 	if (err < 0) {
228 		dev_err(&client->dev, "Unable to write oscillator status register\n");
229 		return err;
230 	}
231 
232 	return 0;
233 }
234 
235 static irqreturn_t abx80x_handle_irq(int irq, void *dev_id)
236 {
237 	struct i2c_client *client = dev_id;
238 	struct abx80x_priv *priv = i2c_get_clientdata(client);
239 	struct rtc_device *rtc = priv->rtc;
240 	int status;
241 
242 	status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
243 	if (status < 0)
244 		return IRQ_NONE;
245 
246 	if (status & ABX8XX_STATUS_AF)
247 		rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF);
248 
249 	/*
250 	 * It is unclear if we'll get an interrupt before the external
251 	 * reset kicks in.
252 	 */
253 	if (status & ABX8XX_STATUS_WDT)
254 		dev_alert(&client->dev, "watchdog timeout interrupt.\n");
255 
256 	i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS, 0);
257 
258 	return IRQ_HANDLED;
259 }
260 
261 static int abx80x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
262 {
263 	struct i2c_client *client = to_i2c_client(dev);
264 	unsigned char buf[7];
265 
266 	int irq_mask, err;
267 
268 	if (client->irq <= 0)
269 		return -EINVAL;
270 
271 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ASC,
272 					    sizeof(buf), buf);
273 	if (err)
274 		return err;
275 
276 	irq_mask = i2c_smbus_read_byte_data(client, ABX8XX_REG_IRQ);
277 	if (irq_mask < 0)
278 		return irq_mask;
279 
280 	t->time.tm_sec = bcd2bin(buf[0] & 0x7F);
281 	t->time.tm_min = bcd2bin(buf[1] & 0x7F);
282 	t->time.tm_hour = bcd2bin(buf[2] & 0x3F);
283 	t->time.tm_mday = bcd2bin(buf[3] & 0x3F);
284 	t->time.tm_mon = bcd2bin(buf[4] & 0x1F) - 1;
285 	t->time.tm_wday = buf[5] & 0x7;
286 
287 	t->enabled = !!(irq_mask & ABX8XX_IRQ_AIE);
288 	t->pending = (buf[6] & ABX8XX_STATUS_AF) && t->enabled;
289 
290 	return err;
291 }
292 
293 static int abx80x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
294 {
295 	struct i2c_client *client = to_i2c_client(dev);
296 	u8 alarm[6];
297 	int err;
298 
299 	if (client->irq <= 0)
300 		return -EINVAL;
301 
302 	alarm[0] = 0x0;
303 	alarm[1] = bin2bcd(t->time.tm_sec);
304 	alarm[2] = bin2bcd(t->time.tm_min);
305 	alarm[3] = bin2bcd(t->time.tm_hour);
306 	alarm[4] = bin2bcd(t->time.tm_mday);
307 	alarm[5] = bin2bcd(t->time.tm_mon + 1);
308 
309 	err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_AHTH,
310 					     sizeof(alarm), alarm);
311 	if (err < 0) {
312 		dev_err(&client->dev, "Unable to write alarm registers\n");
313 		return -EIO;
314 	}
315 
316 	if (t->enabled) {
317 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
318 						(ABX8XX_IRQ_IM_1_4 |
319 						 ABX8XX_IRQ_AIE));
320 		if (err)
321 			return err;
322 	}
323 
324 	return 0;
325 }
326 
327 static int abx80x_rtc_set_autocalibration(struct device *dev,
328 					  int autocalibration)
329 {
330 	struct i2c_client *client = to_i2c_client(dev);
331 	int retval, flags = 0;
332 
333 	if ((autocalibration != 0) && (autocalibration != 1024) &&
334 	    (autocalibration != 512)) {
335 		dev_err(dev, "autocalibration value outside permitted range\n");
336 		return -EINVAL;
337 	}
338 
339 	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
340 	if (flags < 0)
341 		return flags;
342 
343 	if (autocalibration == 0) {
344 		flags &= ~(ABX8XX_OSC_ACAL_512 | ABX8XX_OSC_ACAL_1024);
345 	} else if (autocalibration == 1024) {
346 		/* 1024 autocalibration is 0x10 */
347 		flags |= ABX8XX_OSC_ACAL_1024;
348 		flags &= ~(ABX8XX_OSC_ACAL_512);
349 	} else {
350 		/* 512 autocalibration is 0x11 */
351 		flags |= (ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512);
352 	}
353 
354 	/* Unlock write access to Oscillator Control Register */
355 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
356 					   ABX8XX_CFG_KEY_OSC);
357 	if (retval < 0) {
358 		dev_err(dev, "Failed to write CONFIG_KEY register\n");
359 		return retval;
360 	}
361 
362 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
363 
364 	return retval;
365 }
366 
367 static int abx80x_rtc_get_autocalibration(struct device *dev)
368 {
369 	struct i2c_client *client = to_i2c_client(dev);
370 	int flags = 0, autocalibration;
371 
372 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
373 	if (flags < 0)
374 		return flags;
375 
376 	if (flags & ABX8XX_OSC_ACAL_512)
377 		autocalibration = 512;
378 	else if (flags & ABX8XX_OSC_ACAL_1024)
379 		autocalibration = 1024;
380 	else
381 		autocalibration = 0;
382 
383 	return autocalibration;
384 }
385 
386 static ssize_t autocalibration_store(struct device *dev,
387 				     struct device_attribute *attr,
388 				     const char *buf, size_t count)
389 {
390 	int retval;
391 	unsigned long autocalibration = 0;
392 
393 	retval = kstrtoul(buf, 10, &autocalibration);
394 	if (retval < 0) {
395 		dev_err(dev, "Failed to store RTC autocalibration attribute\n");
396 		return -EINVAL;
397 	}
398 
399 	retval = abx80x_rtc_set_autocalibration(dev, autocalibration);
400 
401 	return retval ? retval : count;
402 }
403 
404 static ssize_t autocalibration_show(struct device *dev,
405 				    struct device_attribute *attr, char *buf)
406 {
407 	int autocalibration = 0;
408 
409 	autocalibration = abx80x_rtc_get_autocalibration(dev);
410 	if (autocalibration < 0) {
411 		dev_err(dev, "Failed to read RTC autocalibration\n");
412 		sprintf(buf, "0\n");
413 		return autocalibration;
414 	}
415 
416 	return sprintf(buf, "%d\n", autocalibration);
417 }
418 
419 static DEVICE_ATTR_RW(autocalibration);
420 
421 static ssize_t oscillator_store(struct device *dev,
422 				struct device_attribute *attr,
423 				const char *buf, size_t count)
424 {
425 	struct i2c_client *client = to_i2c_client(dev);
426 	int retval, flags, rc_mode = 0;
427 
428 	if (strncmp(buf, "rc", 2) == 0) {
429 		rc_mode = 1;
430 	} else if (strncmp(buf, "xtal", 4) == 0) {
431 		rc_mode = 0;
432 	} else {
433 		dev_err(dev, "Oscillator selection value outside permitted ones\n");
434 		return -EINVAL;
435 	}
436 
437 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
438 	if (flags < 0)
439 		return flags;
440 
441 	if (rc_mode == 0)
442 		flags &= ~(ABX8XX_OSC_OSEL);
443 	else
444 		flags |= (ABX8XX_OSC_OSEL);
445 
446 	/* Unlock write access on Oscillator Control register */
447 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
448 					   ABX8XX_CFG_KEY_OSC);
449 	if (retval < 0) {
450 		dev_err(dev, "Failed to write CONFIG_KEY register\n");
451 		return retval;
452 	}
453 
454 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
455 	if (retval < 0) {
456 		dev_err(dev, "Failed to write Oscillator Control register\n");
457 		return retval;
458 	}
459 
460 	return retval ? retval : count;
461 }
462 
463 static ssize_t oscillator_show(struct device *dev,
464 			       struct device_attribute *attr, char *buf)
465 {
466 	int rc_mode = 0;
467 	struct i2c_client *client = to_i2c_client(dev);
468 
469 	rc_mode = abx80x_is_rc_mode(client);
470 
471 	if (rc_mode < 0) {
472 		dev_err(dev, "Failed to read RTC oscillator selection\n");
473 		sprintf(buf, "\n");
474 		return rc_mode;
475 	}
476 
477 	if (rc_mode)
478 		return sprintf(buf, "rc\n");
479 	else
480 		return sprintf(buf, "xtal\n");
481 }
482 
483 static DEVICE_ATTR_RW(oscillator);
484 
485 static struct attribute *rtc_calib_attrs[] = {
486 	&dev_attr_autocalibration.attr,
487 	&dev_attr_oscillator.attr,
488 	NULL,
489 };
490 
491 static const struct attribute_group rtc_calib_attr_group = {
492 	.attrs		= rtc_calib_attrs,
493 };
494 
495 static int abx80x_alarm_irq_enable(struct device *dev, unsigned int enabled)
496 {
497 	struct i2c_client *client = to_i2c_client(dev);
498 	int err;
499 
500 	if (enabled)
501 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
502 						(ABX8XX_IRQ_IM_1_4 |
503 						 ABX8XX_IRQ_AIE));
504 	else
505 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
506 						ABX8XX_IRQ_IM_1_4);
507 	return err;
508 }
509 
510 static const struct rtc_class_ops abx80x_rtc_ops = {
511 	.read_time	= abx80x_rtc_read_time,
512 	.set_time	= abx80x_rtc_set_time,
513 	.read_alarm	= abx80x_read_alarm,
514 	.set_alarm	= abx80x_set_alarm,
515 	.alarm_irq_enable = abx80x_alarm_irq_enable,
516 };
517 
518 static int abx80x_dt_trickle_cfg(struct device_node *np)
519 {
520 	const char *diode;
521 	int trickle_cfg = 0;
522 	int i, ret;
523 	u32 tmp;
524 
525 	ret = of_property_read_string(np, "abracon,tc-diode", &diode);
526 	if (ret)
527 		return ret;
528 
529 	if (!strcmp(diode, "standard"))
530 		trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE;
531 	else if (!strcmp(diode, "schottky"))
532 		trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE;
533 	else
534 		return -EINVAL;
535 
536 	ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp);
537 	if (ret)
538 		return ret;
539 
540 	for (i = 0; i < sizeof(trickle_resistors); i++)
541 		if (trickle_resistors[i] == tmp)
542 			break;
543 
544 	if (i == sizeof(trickle_resistors))
545 		return -EINVAL;
546 
547 	return (trickle_cfg | i);
548 }
549 
550 static void rtc_calib_remove_sysfs_group(void *_dev)
551 {
552 	struct device *dev = _dev;
553 
554 	sysfs_remove_group(&dev->kobj, &rtc_calib_attr_group);
555 }
556 
557 #ifdef CONFIG_WATCHDOG
558 
559 static inline u8 timeout_bits(unsigned int timeout)
560 {
561 	return ((timeout << ABX8XX_WDT_BMB_SHIFT) & ABX8XX_WDT_BMB_MASK) |
562 		 ABX8XX_WDT_WRB_1HZ;
563 }
564 
565 static int __abx80x_wdog_set_timeout(struct watchdog_device *wdog,
566 				     unsigned int timeout)
567 {
568 	struct abx80x_priv *priv = watchdog_get_drvdata(wdog);
569 	u8 val = ABX8XX_WDT_WDS | timeout_bits(timeout);
570 
571 	/*
572 	 * Writing any timeout to the WDT register resets the watchdog timer.
573 	 * Writing 0 disables it.
574 	 */
575 	return i2c_smbus_write_byte_data(priv->client, ABX8XX_REG_WDT, val);
576 }
577 
578 static int abx80x_wdog_set_timeout(struct watchdog_device *wdog,
579 				   unsigned int new_timeout)
580 {
581 	int err = 0;
582 
583 	if (watchdog_hw_running(wdog))
584 		err = __abx80x_wdog_set_timeout(wdog, new_timeout);
585 
586 	if (err == 0)
587 		wdog->timeout = new_timeout;
588 
589 	return err;
590 }
591 
592 static int abx80x_wdog_ping(struct watchdog_device *wdog)
593 {
594 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
595 }
596 
597 static int abx80x_wdog_start(struct watchdog_device *wdog)
598 {
599 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
600 }
601 
602 static int abx80x_wdog_stop(struct watchdog_device *wdog)
603 {
604 	return __abx80x_wdog_set_timeout(wdog, 0);
605 }
606 
607 static const struct watchdog_info abx80x_wdog_info = {
608 	.identity = "abx80x watchdog",
609 	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
610 };
611 
612 static const struct watchdog_ops abx80x_wdog_ops = {
613 	.owner = THIS_MODULE,
614 	.start = abx80x_wdog_start,
615 	.stop = abx80x_wdog_stop,
616 	.ping = abx80x_wdog_ping,
617 	.set_timeout = abx80x_wdog_set_timeout,
618 };
619 
620 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
621 {
622 	priv->wdog.parent = &priv->client->dev;
623 	priv->wdog.ops = &abx80x_wdog_ops;
624 	priv->wdog.info = &abx80x_wdog_info;
625 	priv->wdog.min_timeout = 1;
626 	priv->wdog.max_timeout = ABX8XX_WDT_MAX_TIME;
627 	priv->wdog.timeout = ABX8XX_WDT_MAX_TIME;
628 
629 	watchdog_set_drvdata(&priv->wdog, priv);
630 
631 	return devm_watchdog_register_device(&priv->client->dev, &priv->wdog);
632 }
633 #else
634 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
635 {
636 	return 0;
637 }
638 #endif
639 
640 static int abx80x_probe(struct i2c_client *client,
641 			const struct i2c_device_id *id)
642 {
643 	struct device_node *np = client->dev.of_node;
644 	struct abx80x_priv *priv;
645 	int i, data, err, trickle_cfg = -EINVAL;
646 	char buf[7];
647 	unsigned int part = id->driver_data;
648 	unsigned int partnumber;
649 	unsigned int majrev, minrev;
650 	unsigned int lot;
651 	unsigned int wafer;
652 	unsigned int uid;
653 
654 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
655 		return -ENODEV;
656 
657 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0,
658 					    sizeof(buf), buf);
659 	if (err < 0) {
660 		dev_err(&client->dev, "Unable to read partnumber\n");
661 		return -EIO;
662 	}
663 
664 	partnumber = (buf[0] << 8) | buf[1];
665 	majrev = buf[2] >> 3;
666 	minrev = buf[2] & 0x7;
667 	lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3];
668 	uid = ((buf[4] & 0x7f) << 8) | buf[5];
669 	wafer = (buf[6] & 0x7c) >> 2;
670 	dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n",
671 		 partnumber, majrev, minrev, lot, wafer, uid);
672 
673 	data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1);
674 	if (data < 0) {
675 		dev_err(&client->dev, "Unable to read control register\n");
676 		return -EIO;
677 	}
678 
679 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1,
680 					((data & ~(ABX8XX_CTRL_12_24 |
681 						   ABX8XX_CTRL_ARST)) |
682 					 ABX8XX_CTRL_WRITE));
683 	if (err < 0) {
684 		dev_err(&client->dev, "Unable to write control register\n");
685 		return -EIO;
686 	}
687 
688 	/* part autodetection */
689 	if (part == ABX80X) {
690 		for (i = 0; abx80x_caps[i].pn; i++)
691 			if (partnumber == abx80x_caps[i].pn)
692 				break;
693 		if (abx80x_caps[i].pn == 0) {
694 			dev_err(&client->dev, "Unknown part: %04x\n",
695 				partnumber);
696 			return -EINVAL;
697 		}
698 		part = i;
699 	}
700 
701 	if (partnumber != abx80x_caps[part].pn) {
702 		dev_err(&client->dev, "partnumber mismatch %04x != %04x\n",
703 			partnumber, abx80x_caps[part].pn);
704 		return -EINVAL;
705 	}
706 
707 	if (np && abx80x_caps[part].has_tc)
708 		trickle_cfg = abx80x_dt_trickle_cfg(np);
709 
710 	if (trickle_cfg > 0) {
711 		dev_info(&client->dev, "Enabling trickle charger: %02x\n",
712 			 trickle_cfg);
713 		abx80x_enable_trickle_charger(client, trickle_cfg);
714 	}
715 
716 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CD_TIMER_CTL,
717 					BIT(2));
718 	if (err)
719 		return err;
720 
721 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
722 	if (priv == NULL)
723 		return -ENOMEM;
724 
725 	priv->rtc = devm_rtc_allocate_device(&client->dev);
726 	if (IS_ERR(priv->rtc))
727 		return PTR_ERR(priv->rtc);
728 
729 	priv->rtc->ops = &abx80x_rtc_ops;
730 	priv->client = client;
731 
732 	i2c_set_clientdata(client, priv);
733 
734 	if (abx80x_caps[part].has_wdog) {
735 		err = abx80x_setup_watchdog(priv);
736 		if (err)
737 			return err;
738 	}
739 
740 	if (client->irq > 0) {
741 		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
742 		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
743 						abx80x_handle_irq,
744 						IRQF_SHARED | IRQF_ONESHOT,
745 						"abx8xx",
746 						client);
747 		if (err) {
748 			dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
749 			client->irq = 0;
750 		}
751 	}
752 
753 	/* Export sysfs entries */
754 	err = sysfs_create_group(&(&client->dev)->kobj, &rtc_calib_attr_group);
755 	if (err) {
756 		dev_err(&client->dev, "Failed to create sysfs group: %d\n",
757 			err);
758 		return err;
759 	}
760 
761 	err = devm_add_action_or_reset(&client->dev,
762 				       rtc_calib_remove_sysfs_group,
763 				       &client->dev);
764 	if (err) {
765 		dev_err(&client->dev,
766 			"Failed to add sysfs cleanup action: %d\n",
767 			err);
768 		return err;
769 	}
770 
771 	err = rtc_register_device(priv->rtc);
772 
773 	return err;
774 }
775 
776 static int abx80x_remove(struct i2c_client *client)
777 {
778 	return 0;
779 }
780 
781 static const struct i2c_device_id abx80x_id[] = {
782 	{ "abx80x", ABX80X },
783 	{ "ab0801", AB0801 },
784 	{ "ab0803", AB0803 },
785 	{ "ab0804", AB0804 },
786 	{ "ab0805", AB0805 },
787 	{ "ab1801", AB1801 },
788 	{ "ab1803", AB1803 },
789 	{ "ab1804", AB1804 },
790 	{ "ab1805", AB1805 },
791 	{ "rv1805", AB1805 },
792 	{ }
793 };
794 MODULE_DEVICE_TABLE(i2c, abx80x_id);
795 
796 static struct i2c_driver abx80x_driver = {
797 	.driver		= {
798 		.name	= "rtc-abx80x",
799 	},
800 	.probe		= abx80x_probe,
801 	.remove		= abx80x_remove,
802 	.id_table	= abx80x_id,
803 };
804 
805 module_i2c_driver(abx80x_driver);
806 
807 MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
808 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
809 MODULE_DESCRIPTION("Abracon ABX80X RTC driver");
810 MODULE_LICENSE("GPL v2");
811