xref: /openbmc/linux/drivers/rtc/rtc-abx80x.c (revision dc6a81c3)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * A driver for the I2C members of the Abracon AB x8xx RTC family,
4  * and compatible: AB 1805 and AB 0805
5  *
6  * Copyright 2014-2015 Macq S.A.
7  *
8  * Author: Philippe De Muyter <phdm@macqel.be>
9  * Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
10  *
11  */
12 
13 #include <linux/bcd.h>
14 #include <linux/i2c.h>
15 #include <linux/module.h>
16 #include <linux/rtc.h>
17 #include <linux/watchdog.h>
18 
19 #define ABX8XX_REG_HTH		0x00
20 #define ABX8XX_REG_SC		0x01
21 #define ABX8XX_REG_MN		0x02
22 #define ABX8XX_REG_HR		0x03
23 #define ABX8XX_REG_DA		0x04
24 #define ABX8XX_REG_MO		0x05
25 #define ABX8XX_REG_YR		0x06
26 #define ABX8XX_REG_WD		0x07
27 
28 #define ABX8XX_REG_AHTH		0x08
29 #define ABX8XX_REG_ASC		0x09
30 #define ABX8XX_REG_AMN		0x0a
31 #define ABX8XX_REG_AHR		0x0b
32 #define ABX8XX_REG_ADA		0x0c
33 #define ABX8XX_REG_AMO		0x0d
34 #define ABX8XX_REG_AWD		0x0e
35 
36 #define ABX8XX_REG_STATUS	0x0f
37 #define ABX8XX_STATUS_AF	BIT(2)
38 #define ABX8XX_STATUS_BLF	BIT(4)
39 #define ABX8XX_STATUS_WDT	BIT(6)
40 
41 #define ABX8XX_REG_CTRL1	0x10
42 #define ABX8XX_CTRL_WRITE	BIT(0)
43 #define ABX8XX_CTRL_ARST	BIT(2)
44 #define ABX8XX_CTRL_12_24	BIT(6)
45 
46 #define ABX8XX_REG_CTRL2	0x11
47 #define ABX8XX_CTRL2_RSVD	BIT(5)
48 
49 #define ABX8XX_REG_IRQ		0x12
50 #define ABX8XX_IRQ_AIE		BIT(2)
51 #define ABX8XX_IRQ_IM_1_4	(0x3 << 5)
52 
53 #define ABX8XX_REG_CD_TIMER_CTL	0x18
54 
55 #define ABX8XX_REG_OSC		0x1c
56 #define ABX8XX_OSC_FOS		BIT(3)
57 #define ABX8XX_OSC_BOS		BIT(4)
58 #define ABX8XX_OSC_ACAL_512	BIT(5)
59 #define ABX8XX_OSC_ACAL_1024	BIT(6)
60 
61 #define ABX8XX_OSC_OSEL		BIT(7)
62 
63 #define ABX8XX_REG_OSS		0x1d
64 #define ABX8XX_OSS_OF		BIT(1)
65 #define ABX8XX_OSS_OMODE	BIT(4)
66 
67 #define ABX8XX_REG_WDT		0x1b
68 #define ABX8XX_WDT_WDS		BIT(7)
69 #define ABX8XX_WDT_BMB_MASK	0x7c
70 #define ABX8XX_WDT_BMB_SHIFT	2
71 #define ABX8XX_WDT_MAX_TIME	(ABX8XX_WDT_BMB_MASK >> ABX8XX_WDT_BMB_SHIFT)
72 #define ABX8XX_WDT_WRB_MASK	0x03
73 #define ABX8XX_WDT_WRB_1HZ	0x02
74 
75 #define ABX8XX_REG_CFG_KEY	0x1f
76 #define ABX8XX_CFG_KEY_OSC	0xa1
77 #define ABX8XX_CFG_KEY_MISC	0x9d
78 
79 #define ABX8XX_REG_ID0		0x28
80 
81 #define ABX8XX_REG_OUT_CTRL	0x30
82 #define ABX8XX_OUT_CTRL_EXDS	BIT(4)
83 
84 #define ABX8XX_REG_TRICKLE	0x20
85 #define ABX8XX_TRICKLE_CHARGE_ENABLE	0xa0
86 #define ABX8XX_TRICKLE_STANDARD_DIODE	0x8
87 #define ABX8XX_TRICKLE_SCHOTTKY_DIODE	0x4
88 
89 static u8 trickle_resistors[] = {0, 3, 6, 11};
90 
91 enum abx80x_chip {AB0801, AB0803, AB0804, AB0805,
92 	AB1801, AB1803, AB1804, AB1805, RV1805, ABX80X};
93 
94 struct abx80x_cap {
95 	u16 pn;
96 	bool has_tc;
97 	bool has_wdog;
98 };
99 
100 static struct abx80x_cap abx80x_caps[] = {
101 	[AB0801] = {.pn = 0x0801},
102 	[AB0803] = {.pn = 0x0803},
103 	[AB0804] = {.pn = 0x0804, .has_tc = true, .has_wdog = true},
104 	[AB0805] = {.pn = 0x0805, .has_tc = true, .has_wdog = true},
105 	[AB1801] = {.pn = 0x1801},
106 	[AB1803] = {.pn = 0x1803},
107 	[AB1804] = {.pn = 0x1804, .has_tc = true, .has_wdog = true},
108 	[AB1805] = {.pn = 0x1805, .has_tc = true, .has_wdog = true},
109 	[RV1805] = {.pn = 0x1805, .has_tc = true, .has_wdog = true},
110 	[ABX80X] = {.pn = 0}
111 };
112 
113 struct abx80x_priv {
114 	struct rtc_device *rtc;
115 	struct i2c_client *client;
116 	struct watchdog_device wdog;
117 };
118 
119 static int abx80x_is_rc_mode(struct i2c_client *client)
120 {
121 	int flags = 0;
122 
123 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
124 	if (flags < 0) {
125 		dev_err(&client->dev,
126 			"Failed to read autocalibration attribute\n");
127 		return flags;
128 	}
129 
130 	return (flags & ABX8XX_OSS_OMODE) ? 1 : 0;
131 }
132 
133 static int abx80x_enable_trickle_charger(struct i2c_client *client,
134 					 u8 trickle_cfg)
135 {
136 	int err;
137 
138 	/*
139 	 * Write the configuration key register to enable access to the Trickle
140 	 * register
141 	 */
142 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
143 					ABX8XX_CFG_KEY_MISC);
144 	if (err < 0) {
145 		dev_err(&client->dev, "Unable to write configuration key\n");
146 		return -EIO;
147 	}
148 
149 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_TRICKLE,
150 					ABX8XX_TRICKLE_CHARGE_ENABLE |
151 					trickle_cfg);
152 	if (err < 0) {
153 		dev_err(&client->dev, "Unable to write trickle register\n");
154 		return -EIO;
155 	}
156 
157 	return 0;
158 }
159 
160 static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
161 {
162 	struct i2c_client *client = to_i2c_client(dev);
163 	unsigned char buf[8];
164 	int err, flags, rc_mode = 0;
165 
166 	/* Read the Oscillator Failure only in XT mode */
167 	rc_mode = abx80x_is_rc_mode(client);
168 	if (rc_mode < 0)
169 		return rc_mode;
170 
171 	if (!rc_mode) {
172 		flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
173 		if (flags < 0)
174 			return flags;
175 
176 		if (flags & ABX8XX_OSS_OF) {
177 			dev_err(dev, "Oscillator failure, data is invalid.\n");
178 			return -EINVAL;
179 		}
180 	}
181 
182 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH,
183 					    sizeof(buf), buf);
184 	if (err < 0) {
185 		dev_err(&client->dev, "Unable to read date\n");
186 		return -EIO;
187 	}
188 
189 	tm->tm_sec = bcd2bin(buf[ABX8XX_REG_SC] & 0x7F);
190 	tm->tm_min = bcd2bin(buf[ABX8XX_REG_MN] & 0x7F);
191 	tm->tm_hour = bcd2bin(buf[ABX8XX_REG_HR] & 0x3F);
192 	tm->tm_wday = buf[ABX8XX_REG_WD] & 0x7;
193 	tm->tm_mday = bcd2bin(buf[ABX8XX_REG_DA] & 0x3F);
194 	tm->tm_mon = bcd2bin(buf[ABX8XX_REG_MO] & 0x1F) - 1;
195 	tm->tm_year = bcd2bin(buf[ABX8XX_REG_YR]) + 100;
196 
197 	return 0;
198 }
199 
200 static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
201 {
202 	struct i2c_client *client = to_i2c_client(dev);
203 	unsigned char buf[8];
204 	int err, flags;
205 
206 	if (tm->tm_year < 100)
207 		return -EINVAL;
208 
209 	buf[ABX8XX_REG_HTH] = 0;
210 	buf[ABX8XX_REG_SC] = bin2bcd(tm->tm_sec);
211 	buf[ABX8XX_REG_MN] = bin2bcd(tm->tm_min);
212 	buf[ABX8XX_REG_HR] = bin2bcd(tm->tm_hour);
213 	buf[ABX8XX_REG_DA] = bin2bcd(tm->tm_mday);
214 	buf[ABX8XX_REG_MO] = bin2bcd(tm->tm_mon + 1);
215 	buf[ABX8XX_REG_YR] = bin2bcd(tm->tm_year - 100);
216 	buf[ABX8XX_REG_WD] = tm->tm_wday;
217 
218 	err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_HTH,
219 					     sizeof(buf), buf);
220 	if (err < 0) {
221 		dev_err(&client->dev, "Unable to write to date registers\n");
222 		return -EIO;
223 	}
224 
225 	/* Clear the OF bit of Oscillator Status Register */
226 	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
227 	if (flags < 0)
228 		return flags;
229 
230 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSS,
231 					flags & ~ABX8XX_OSS_OF);
232 	if (err < 0) {
233 		dev_err(&client->dev, "Unable to write oscillator status register\n");
234 		return err;
235 	}
236 
237 	return 0;
238 }
239 
240 static irqreturn_t abx80x_handle_irq(int irq, void *dev_id)
241 {
242 	struct i2c_client *client = dev_id;
243 	struct abx80x_priv *priv = i2c_get_clientdata(client);
244 	struct rtc_device *rtc = priv->rtc;
245 	int status;
246 
247 	status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
248 	if (status < 0)
249 		return IRQ_NONE;
250 
251 	if (status & ABX8XX_STATUS_AF)
252 		rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF);
253 
254 	/*
255 	 * It is unclear if we'll get an interrupt before the external
256 	 * reset kicks in.
257 	 */
258 	if (status & ABX8XX_STATUS_WDT)
259 		dev_alert(&client->dev, "watchdog timeout interrupt.\n");
260 
261 	i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS, 0);
262 
263 	return IRQ_HANDLED;
264 }
265 
266 static int abx80x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
267 {
268 	struct i2c_client *client = to_i2c_client(dev);
269 	unsigned char buf[7];
270 
271 	int irq_mask, err;
272 
273 	if (client->irq <= 0)
274 		return -EINVAL;
275 
276 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ASC,
277 					    sizeof(buf), buf);
278 	if (err)
279 		return err;
280 
281 	irq_mask = i2c_smbus_read_byte_data(client, ABX8XX_REG_IRQ);
282 	if (irq_mask < 0)
283 		return irq_mask;
284 
285 	t->time.tm_sec = bcd2bin(buf[0] & 0x7F);
286 	t->time.tm_min = bcd2bin(buf[1] & 0x7F);
287 	t->time.tm_hour = bcd2bin(buf[2] & 0x3F);
288 	t->time.tm_mday = bcd2bin(buf[3] & 0x3F);
289 	t->time.tm_mon = bcd2bin(buf[4] & 0x1F) - 1;
290 	t->time.tm_wday = buf[5] & 0x7;
291 
292 	t->enabled = !!(irq_mask & ABX8XX_IRQ_AIE);
293 	t->pending = (buf[6] & ABX8XX_STATUS_AF) && t->enabled;
294 
295 	return err;
296 }
297 
298 static int abx80x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
299 {
300 	struct i2c_client *client = to_i2c_client(dev);
301 	u8 alarm[6];
302 	int err;
303 
304 	if (client->irq <= 0)
305 		return -EINVAL;
306 
307 	alarm[0] = 0x0;
308 	alarm[1] = bin2bcd(t->time.tm_sec);
309 	alarm[2] = bin2bcd(t->time.tm_min);
310 	alarm[3] = bin2bcd(t->time.tm_hour);
311 	alarm[4] = bin2bcd(t->time.tm_mday);
312 	alarm[5] = bin2bcd(t->time.tm_mon + 1);
313 
314 	err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_AHTH,
315 					     sizeof(alarm), alarm);
316 	if (err < 0) {
317 		dev_err(&client->dev, "Unable to write alarm registers\n");
318 		return -EIO;
319 	}
320 
321 	if (t->enabled) {
322 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
323 						(ABX8XX_IRQ_IM_1_4 |
324 						 ABX8XX_IRQ_AIE));
325 		if (err)
326 			return err;
327 	}
328 
329 	return 0;
330 }
331 
332 static int abx80x_rtc_set_autocalibration(struct device *dev,
333 					  int autocalibration)
334 {
335 	struct i2c_client *client = to_i2c_client(dev);
336 	int retval, flags = 0;
337 
338 	if ((autocalibration != 0) && (autocalibration != 1024) &&
339 	    (autocalibration != 512)) {
340 		dev_err(dev, "autocalibration value outside permitted range\n");
341 		return -EINVAL;
342 	}
343 
344 	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
345 	if (flags < 0)
346 		return flags;
347 
348 	if (autocalibration == 0) {
349 		flags &= ~(ABX8XX_OSC_ACAL_512 | ABX8XX_OSC_ACAL_1024);
350 	} else if (autocalibration == 1024) {
351 		/* 1024 autocalibration is 0x10 */
352 		flags |= ABX8XX_OSC_ACAL_1024;
353 		flags &= ~(ABX8XX_OSC_ACAL_512);
354 	} else {
355 		/* 512 autocalibration is 0x11 */
356 		flags |= (ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512);
357 	}
358 
359 	/* Unlock write access to Oscillator Control Register */
360 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
361 					   ABX8XX_CFG_KEY_OSC);
362 	if (retval < 0) {
363 		dev_err(dev, "Failed to write CONFIG_KEY register\n");
364 		return retval;
365 	}
366 
367 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
368 
369 	return retval;
370 }
371 
372 static int abx80x_rtc_get_autocalibration(struct device *dev)
373 {
374 	struct i2c_client *client = to_i2c_client(dev);
375 	int flags = 0, autocalibration;
376 
377 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
378 	if (flags < 0)
379 		return flags;
380 
381 	if (flags & ABX8XX_OSC_ACAL_512)
382 		autocalibration = 512;
383 	else if (flags & ABX8XX_OSC_ACAL_1024)
384 		autocalibration = 1024;
385 	else
386 		autocalibration = 0;
387 
388 	return autocalibration;
389 }
390 
391 static ssize_t autocalibration_store(struct device *dev,
392 				     struct device_attribute *attr,
393 				     const char *buf, size_t count)
394 {
395 	int retval;
396 	unsigned long autocalibration = 0;
397 
398 	retval = kstrtoul(buf, 10, &autocalibration);
399 	if (retval < 0) {
400 		dev_err(dev, "Failed to store RTC autocalibration attribute\n");
401 		return -EINVAL;
402 	}
403 
404 	retval = abx80x_rtc_set_autocalibration(dev->parent, autocalibration);
405 
406 	return retval ? retval : count;
407 }
408 
409 static ssize_t autocalibration_show(struct device *dev,
410 				    struct device_attribute *attr, char *buf)
411 {
412 	int autocalibration = 0;
413 
414 	autocalibration = abx80x_rtc_get_autocalibration(dev->parent);
415 	if (autocalibration < 0) {
416 		dev_err(dev, "Failed to read RTC autocalibration\n");
417 		sprintf(buf, "0\n");
418 		return autocalibration;
419 	}
420 
421 	return sprintf(buf, "%d\n", autocalibration);
422 }
423 
424 static DEVICE_ATTR_RW(autocalibration);
425 
426 static ssize_t oscillator_store(struct device *dev,
427 				struct device_attribute *attr,
428 				const char *buf, size_t count)
429 {
430 	struct i2c_client *client = to_i2c_client(dev->parent);
431 	int retval, flags, rc_mode = 0;
432 
433 	if (strncmp(buf, "rc", 2) == 0) {
434 		rc_mode = 1;
435 	} else if (strncmp(buf, "xtal", 4) == 0) {
436 		rc_mode = 0;
437 	} else {
438 		dev_err(dev, "Oscillator selection value outside permitted ones\n");
439 		return -EINVAL;
440 	}
441 
442 	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
443 	if (flags < 0)
444 		return flags;
445 
446 	if (rc_mode == 0)
447 		flags &= ~(ABX8XX_OSC_OSEL);
448 	else
449 		flags |= (ABX8XX_OSC_OSEL);
450 
451 	/* Unlock write access on Oscillator Control register */
452 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
453 					   ABX8XX_CFG_KEY_OSC);
454 	if (retval < 0) {
455 		dev_err(dev, "Failed to write CONFIG_KEY register\n");
456 		return retval;
457 	}
458 
459 	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
460 	if (retval < 0) {
461 		dev_err(dev, "Failed to write Oscillator Control register\n");
462 		return retval;
463 	}
464 
465 	return retval ? retval : count;
466 }
467 
468 static ssize_t oscillator_show(struct device *dev,
469 			       struct device_attribute *attr, char *buf)
470 {
471 	int rc_mode = 0;
472 	struct i2c_client *client = to_i2c_client(dev->parent);
473 
474 	rc_mode = abx80x_is_rc_mode(client);
475 
476 	if (rc_mode < 0) {
477 		dev_err(dev, "Failed to read RTC oscillator selection\n");
478 		sprintf(buf, "\n");
479 		return rc_mode;
480 	}
481 
482 	if (rc_mode)
483 		return sprintf(buf, "rc\n");
484 	else
485 		return sprintf(buf, "xtal\n");
486 }
487 
488 static DEVICE_ATTR_RW(oscillator);
489 
490 static struct attribute *rtc_calib_attrs[] = {
491 	&dev_attr_autocalibration.attr,
492 	&dev_attr_oscillator.attr,
493 	NULL,
494 };
495 
496 static const struct attribute_group rtc_calib_attr_group = {
497 	.attrs		= rtc_calib_attrs,
498 };
499 
500 static int abx80x_alarm_irq_enable(struct device *dev, unsigned int enabled)
501 {
502 	struct i2c_client *client = to_i2c_client(dev);
503 	int err;
504 
505 	if (enabled)
506 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
507 						(ABX8XX_IRQ_IM_1_4 |
508 						 ABX8XX_IRQ_AIE));
509 	else
510 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_IRQ,
511 						ABX8XX_IRQ_IM_1_4);
512 	return err;
513 }
514 
515 static int abx80x_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
516 {
517 	struct i2c_client *client = to_i2c_client(dev);
518 	int status, tmp;
519 
520 	switch (cmd) {
521 	case RTC_VL_READ:
522 		status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
523 		if (status < 0)
524 			return status;
525 
526 		tmp = status & ABX8XX_STATUS_BLF ? RTC_VL_BACKUP_LOW : 0;
527 
528 		return put_user(tmp, (unsigned int __user *)arg);
529 
530 	case RTC_VL_CLR:
531 		status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
532 		if (status < 0)
533 			return status;
534 
535 		status &= ~ABX8XX_STATUS_BLF;
536 
537 		tmp = i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS, 0);
538 		if (tmp < 0)
539 			return tmp;
540 
541 		return 0;
542 
543 	default:
544 		return -ENOIOCTLCMD;
545 	}
546 }
547 
548 static const struct rtc_class_ops abx80x_rtc_ops = {
549 	.read_time	= abx80x_rtc_read_time,
550 	.set_time	= abx80x_rtc_set_time,
551 	.read_alarm	= abx80x_read_alarm,
552 	.set_alarm	= abx80x_set_alarm,
553 	.alarm_irq_enable = abx80x_alarm_irq_enable,
554 	.ioctl		= abx80x_ioctl,
555 };
556 
557 static int abx80x_dt_trickle_cfg(struct device_node *np)
558 {
559 	const char *diode;
560 	int trickle_cfg = 0;
561 	int i, ret;
562 	u32 tmp;
563 
564 	ret = of_property_read_string(np, "abracon,tc-diode", &diode);
565 	if (ret)
566 		return ret;
567 
568 	if (!strcmp(diode, "standard"))
569 		trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE;
570 	else if (!strcmp(diode, "schottky"))
571 		trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE;
572 	else
573 		return -EINVAL;
574 
575 	ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp);
576 	if (ret)
577 		return ret;
578 
579 	for (i = 0; i < sizeof(trickle_resistors); i++)
580 		if (trickle_resistors[i] == tmp)
581 			break;
582 
583 	if (i == sizeof(trickle_resistors))
584 		return -EINVAL;
585 
586 	return (trickle_cfg | i);
587 }
588 
589 #ifdef CONFIG_WATCHDOG
590 
591 static inline u8 timeout_bits(unsigned int timeout)
592 {
593 	return ((timeout << ABX8XX_WDT_BMB_SHIFT) & ABX8XX_WDT_BMB_MASK) |
594 		 ABX8XX_WDT_WRB_1HZ;
595 }
596 
597 static int __abx80x_wdog_set_timeout(struct watchdog_device *wdog,
598 				     unsigned int timeout)
599 {
600 	struct abx80x_priv *priv = watchdog_get_drvdata(wdog);
601 	u8 val = ABX8XX_WDT_WDS | timeout_bits(timeout);
602 
603 	/*
604 	 * Writing any timeout to the WDT register resets the watchdog timer.
605 	 * Writing 0 disables it.
606 	 */
607 	return i2c_smbus_write_byte_data(priv->client, ABX8XX_REG_WDT, val);
608 }
609 
610 static int abx80x_wdog_set_timeout(struct watchdog_device *wdog,
611 				   unsigned int new_timeout)
612 {
613 	int err = 0;
614 
615 	if (watchdog_hw_running(wdog))
616 		err = __abx80x_wdog_set_timeout(wdog, new_timeout);
617 
618 	if (err == 0)
619 		wdog->timeout = new_timeout;
620 
621 	return err;
622 }
623 
624 static int abx80x_wdog_ping(struct watchdog_device *wdog)
625 {
626 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
627 }
628 
629 static int abx80x_wdog_start(struct watchdog_device *wdog)
630 {
631 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
632 }
633 
634 static int abx80x_wdog_stop(struct watchdog_device *wdog)
635 {
636 	return __abx80x_wdog_set_timeout(wdog, 0);
637 }
638 
639 static const struct watchdog_info abx80x_wdog_info = {
640 	.identity = "abx80x watchdog",
641 	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
642 };
643 
644 static const struct watchdog_ops abx80x_wdog_ops = {
645 	.owner = THIS_MODULE,
646 	.start = abx80x_wdog_start,
647 	.stop = abx80x_wdog_stop,
648 	.ping = abx80x_wdog_ping,
649 	.set_timeout = abx80x_wdog_set_timeout,
650 };
651 
652 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
653 {
654 	priv->wdog.parent = &priv->client->dev;
655 	priv->wdog.ops = &abx80x_wdog_ops;
656 	priv->wdog.info = &abx80x_wdog_info;
657 	priv->wdog.min_timeout = 1;
658 	priv->wdog.max_timeout = ABX8XX_WDT_MAX_TIME;
659 	priv->wdog.timeout = ABX8XX_WDT_MAX_TIME;
660 
661 	watchdog_set_drvdata(&priv->wdog, priv);
662 
663 	return devm_watchdog_register_device(&priv->client->dev, &priv->wdog);
664 }
665 #else
666 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
667 {
668 	return 0;
669 }
670 #endif
671 
672 static int abx80x_probe(struct i2c_client *client,
673 			const struct i2c_device_id *id)
674 {
675 	struct device_node *np = client->dev.of_node;
676 	struct abx80x_priv *priv;
677 	int i, data, err, trickle_cfg = -EINVAL;
678 	char buf[7];
679 	unsigned int part = id->driver_data;
680 	unsigned int partnumber;
681 	unsigned int majrev, minrev;
682 	unsigned int lot;
683 	unsigned int wafer;
684 	unsigned int uid;
685 
686 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
687 		return -ENODEV;
688 
689 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0,
690 					    sizeof(buf), buf);
691 	if (err < 0) {
692 		dev_err(&client->dev, "Unable to read partnumber\n");
693 		return -EIO;
694 	}
695 
696 	partnumber = (buf[0] << 8) | buf[1];
697 	majrev = buf[2] >> 3;
698 	minrev = buf[2] & 0x7;
699 	lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3];
700 	uid = ((buf[4] & 0x7f) << 8) | buf[5];
701 	wafer = (buf[6] & 0x7c) >> 2;
702 	dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n",
703 		 partnumber, majrev, minrev, lot, wafer, uid);
704 
705 	data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1);
706 	if (data < 0) {
707 		dev_err(&client->dev, "Unable to read control register\n");
708 		return -EIO;
709 	}
710 
711 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1,
712 					((data & ~(ABX8XX_CTRL_12_24 |
713 						   ABX8XX_CTRL_ARST)) |
714 					 ABX8XX_CTRL_WRITE));
715 	if (err < 0) {
716 		dev_err(&client->dev, "Unable to write control register\n");
717 		return -EIO;
718 	}
719 
720 	/* Configure RV1805 specifics */
721 	if (part == RV1805) {
722 		/*
723 		 * Avoid accidentally entering test mode. This can happen
724 		 * on the RV1805 in case the reserved bit 5 in control2
725 		 * register is set. RV-1805-C3 datasheet indicates that
726 		 * the bit should be cleared in section 11h - Control2.
727 		 */
728 		data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL2);
729 		if (data < 0) {
730 			dev_err(&client->dev,
731 				"Unable to read control2 register\n");
732 			return -EIO;
733 		}
734 
735 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL2,
736 						data & ~ABX8XX_CTRL2_RSVD);
737 		if (err < 0) {
738 			dev_err(&client->dev,
739 				"Unable to write control2 register\n");
740 			return -EIO;
741 		}
742 
743 		/*
744 		 * Avoid extra power leakage. The RV1805 uses smaller
745 		 * 10pin package and the EXTI input is not present.
746 		 * Disable it to avoid leakage.
747 		 */
748 		data = i2c_smbus_read_byte_data(client, ABX8XX_REG_OUT_CTRL);
749 		if (data < 0) {
750 			dev_err(&client->dev,
751 				"Unable to read output control register\n");
752 			return -EIO;
753 		}
754 
755 		/*
756 		 * Write the configuration key register to enable access to
757 		 * the config2 register
758 		 */
759 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
760 						ABX8XX_CFG_KEY_MISC);
761 		if (err < 0) {
762 			dev_err(&client->dev,
763 				"Unable to write configuration key\n");
764 			return -EIO;
765 		}
766 
767 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OUT_CTRL,
768 						data | ABX8XX_OUT_CTRL_EXDS);
769 		if (err < 0) {
770 			dev_err(&client->dev,
771 				"Unable to write output control register\n");
772 			return -EIO;
773 		}
774 	}
775 
776 	/* part autodetection */
777 	if (part == ABX80X) {
778 		for (i = 0; abx80x_caps[i].pn; i++)
779 			if (partnumber == abx80x_caps[i].pn)
780 				break;
781 		if (abx80x_caps[i].pn == 0) {
782 			dev_err(&client->dev, "Unknown part: %04x\n",
783 				partnumber);
784 			return -EINVAL;
785 		}
786 		part = i;
787 	}
788 
789 	if (partnumber != abx80x_caps[part].pn) {
790 		dev_err(&client->dev, "partnumber mismatch %04x != %04x\n",
791 			partnumber, abx80x_caps[part].pn);
792 		return -EINVAL;
793 	}
794 
795 	if (np && abx80x_caps[part].has_tc)
796 		trickle_cfg = abx80x_dt_trickle_cfg(np);
797 
798 	if (trickle_cfg > 0) {
799 		dev_info(&client->dev, "Enabling trickle charger: %02x\n",
800 			 trickle_cfg);
801 		abx80x_enable_trickle_charger(client, trickle_cfg);
802 	}
803 
804 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CD_TIMER_CTL,
805 					BIT(2));
806 	if (err)
807 		return err;
808 
809 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
810 	if (priv == NULL)
811 		return -ENOMEM;
812 
813 	priv->rtc = devm_rtc_allocate_device(&client->dev);
814 	if (IS_ERR(priv->rtc))
815 		return PTR_ERR(priv->rtc);
816 
817 	priv->rtc->ops = &abx80x_rtc_ops;
818 	priv->client = client;
819 
820 	i2c_set_clientdata(client, priv);
821 
822 	if (abx80x_caps[part].has_wdog) {
823 		err = abx80x_setup_watchdog(priv);
824 		if (err)
825 			return err;
826 	}
827 
828 	if (client->irq > 0) {
829 		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
830 		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
831 						abx80x_handle_irq,
832 						IRQF_SHARED | IRQF_ONESHOT,
833 						"abx8xx",
834 						client);
835 		if (err) {
836 			dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
837 			client->irq = 0;
838 		}
839 	}
840 
841 	err = rtc_add_group(priv->rtc, &rtc_calib_attr_group);
842 	if (err) {
843 		dev_err(&client->dev, "Failed to create sysfs group: %d\n",
844 			err);
845 		return err;
846 	}
847 
848 	return rtc_register_device(priv->rtc);
849 }
850 
851 static const struct i2c_device_id abx80x_id[] = {
852 	{ "abx80x", ABX80X },
853 	{ "ab0801", AB0801 },
854 	{ "ab0803", AB0803 },
855 	{ "ab0804", AB0804 },
856 	{ "ab0805", AB0805 },
857 	{ "ab1801", AB1801 },
858 	{ "ab1803", AB1803 },
859 	{ "ab1804", AB1804 },
860 	{ "ab1805", AB1805 },
861 	{ "rv1805", RV1805 },
862 	{ }
863 };
864 MODULE_DEVICE_TABLE(i2c, abx80x_id);
865 
866 static struct i2c_driver abx80x_driver = {
867 	.driver		= {
868 		.name	= "rtc-abx80x",
869 	},
870 	.probe		= abx80x_probe,
871 	.id_table	= abx80x_id,
872 };
873 
874 module_i2c_driver(abx80x_driver);
875 
876 MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
877 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
878 MODULE_DESCRIPTION("Abracon ABX80X RTC driver");
879 MODULE_LICENSE("GPL v2");
880