xref: /openbmc/linux/drivers/rtc/rtc-abx80x.c (revision b830f94f)
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);
527 
528 		if (copy_to_user((void __user *)arg, &tmp, sizeof(int)))
529 			return -EFAULT;
530 
531 		return 0;
532 
533 	case RTC_VL_CLR:
534 		status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
535 		if (status < 0)
536 			return status;
537 
538 		status &= ~ABX8XX_STATUS_BLF;
539 
540 		tmp = i2c_smbus_write_byte_data(client, ABX8XX_REG_STATUS, 0);
541 		if (tmp < 0)
542 			return tmp;
543 
544 		return 0;
545 
546 	default:
547 		return -ENOIOCTLCMD;
548 	}
549 }
550 
551 static const struct rtc_class_ops abx80x_rtc_ops = {
552 	.read_time	= abx80x_rtc_read_time,
553 	.set_time	= abx80x_rtc_set_time,
554 	.read_alarm	= abx80x_read_alarm,
555 	.set_alarm	= abx80x_set_alarm,
556 	.alarm_irq_enable = abx80x_alarm_irq_enable,
557 	.ioctl		= abx80x_ioctl,
558 };
559 
560 static int abx80x_dt_trickle_cfg(struct device_node *np)
561 {
562 	const char *diode;
563 	int trickle_cfg = 0;
564 	int i, ret;
565 	u32 tmp;
566 
567 	ret = of_property_read_string(np, "abracon,tc-diode", &diode);
568 	if (ret)
569 		return ret;
570 
571 	if (!strcmp(diode, "standard"))
572 		trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE;
573 	else if (!strcmp(diode, "schottky"))
574 		trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE;
575 	else
576 		return -EINVAL;
577 
578 	ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp);
579 	if (ret)
580 		return ret;
581 
582 	for (i = 0; i < sizeof(trickle_resistors); i++)
583 		if (trickle_resistors[i] == tmp)
584 			break;
585 
586 	if (i == sizeof(trickle_resistors))
587 		return -EINVAL;
588 
589 	return (trickle_cfg | i);
590 }
591 
592 #ifdef CONFIG_WATCHDOG
593 
594 static inline u8 timeout_bits(unsigned int timeout)
595 {
596 	return ((timeout << ABX8XX_WDT_BMB_SHIFT) & ABX8XX_WDT_BMB_MASK) |
597 		 ABX8XX_WDT_WRB_1HZ;
598 }
599 
600 static int __abx80x_wdog_set_timeout(struct watchdog_device *wdog,
601 				     unsigned int timeout)
602 {
603 	struct abx80x_priv *priv = watchdog_get_drvdata(wdog);
604 	u8 val = ABX8XX_WDT_WDS | timeout_bits(timeout);
605 
606 	/*
607 	 * Writing any timeout to the WDT register resets the watchdog timer.
608 	 * Writing 0 disables it.
609 	 */
610 	return i2c_smbus_write_byte_data(priv->client, ABX8XX_REG_WDT, val);
611 }
612 
613 static int abx80x_wdog_set_timeout(struct watchdog_device *wdog,
614 				   unsigned int new_timeout)
615 {
616 	int err = 0;
617 
618 	if (watchdog_hw_running(wdog))
619 		err = __abx80x_wdog_set_timeout(wdog, new_timeout);
620 
621 	if (err == 0)
622 		wdog->timeout = new_timeout;
623 
624 	return err;
625 }
626 
627 static int abx80x_wdog_ping(struct watchdog_device *wdog)
628 {
629 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
630 }
631 
632 static int abx80x_wdog_start(struct watchdog_device *wdog)
633 {
634 	return __abx80x_wdog_set_timeout(wdog, wdog->timeout);
635 }
636 
637 static int abx80x_wdog_stop(struct watchdog_device *wdog)
638 {
639 	return __abx80x_wdog_set_timeout(wdog, 0);
640 }
641 
642 static const struct watchdog_info abx80x_wdog_info = {
643 	.identity = "abx80x watchdog",
644 	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
645 };
646 
647 static const struct watchdog_ops abx80x_wdog_ops = {
648 	.owner = THIS_MODULE,
649 	.start = abx80x_wdog_start,
650 	.stop = abx80x_wdog_stop,
651 	.ping = abx80x_wdog_ping,
652 	.set_timeout = abx80x_wdog_set_timeout,
653 };
654 
655 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
656 {
657 	priv->wdog.parent = &priv->client->dev;
658 	priv->wdog.ops = &abx80x_wdog_ops;
659 	priv->wdog.info = &abx80x_wdog_info;
660 	priv->wdog.min_timeout = 1;
661 	priv->wdog.max_timeout = ABX8XX_WDT_MAX_TIME;
662 	priv->wdog.timeout = ABX8XX_WDT_MAX_TIME;
663 
664 	watchdog_set_drvdata(&priv->wdog, priv);
665 
666 	return devm_watchdog_register_device(&priv->client->dev, &priv->wdog);
667 }
668 #else
669 static int abx80x_setup_watchdog(struct abx80x_priv *priv)
670 {
671 	return 0;
672 }
673 #endif
674 
675 static int abx80x_probe(struct i2c_client *client,
676 			const struct i2c_device_id *id)
677 {
678 	struct device_node *np = client->dev.of_node;
679 	struct abx80x_priv *priv;
680 	int i, data, err, trickle_cfg = -EINVAL;
681 	char buf[7];
682 	unsigned int part = id->driver_data;
683 	unsigned int partnumber;
684 	unsigned int majrev, minrev;
685 	unsigned int lot;
686 	unsigned int wafer;
687 	unsigned int uid;
688 
689 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
690 		return -ENODEV;
691 
692 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0,
693 					    sizeof(buf), buf);
694 	if (err < 0) {
695 		dev_err(&client->dev, "Unable to read partnumber\n");
696 		return -EIO;
697 	}
698 
699 	partnumber = (buf[0] << 8) | buf[1];
700 	majrev = buf[2] >> 3;
701 	minrev = buf[2] & 0x7;
702 	lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3];
703 	uid = ((buf[4] & 0x7f) << 8) | buf[5];
704 	wafer = (buf[6] & 0x7c) >> 2;
705 	dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n",
706 		 partnumber, majrev, minrev, lot, wafer, uid);
707 
708 	data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1);
709 	if (data < 0) {
710 		dev_err(&client->dev, "Unable to read control register\n");
711 		return -EIO;
712 	}
713 
714 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1,
715 					((data & ~(ABX8XX_CTRL_12_24 |
716 						   ABX8XX_CTRL_ARST)) |
717 					 ABX8XX_CTRL_WRITE));
718 	if (err < 0) {
719 		dev_err(&client->dev, "Unable to write control register\n");
720 		return -EIO;
721 	}
722 
723 	/* Configure RV1805 specifics */
724 	if (part == RV1805) {
725 		/*
726 		 * Avoid accidentally entering test mode. This can happen
727 		 * on the RV1805 in case the reserved bit 5 in control2
728 		 * register is set. RV-1805-C3 datasheet indicates that
729 		 * the bit should be cleared in section 11h - Control2.
730 		 */
731 		data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL2);
732 		if (data < 0) {
733 			dev_err(&client->dev,
734 				"Unable to read control2 register\n");
735 			return -EIO;
736 		}
737 
738 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL2,
739 						data & ~ABX8XX_CTRL2_RSVD);
740 		if (err < 0) {
741 			dev_err(&client->dev,
742 				"Unable to write control2 register\n");
743 			return -EIO;
744 		}
745 
746 		/*
747 		 * Avoid extra power leakage. The RV1805 uses smaller
748 		 * 10pin package and the EXTI input is not present.
749 		 * Disable it to avoid leakage.
750 		 */
751 		data = i2c_smbus_read_byte_data(client, ABX8XX_REG_OUT_CTRL);
752 		if (data < 0) {
753 			dev_err(&client->dev,
754 				"Unable to read output control register\n");
755 			return -EIO;
756 		}
757 
758 		/*
759 		 * Write the configuration key register to enable access to
760 		 * the config2 register
761 		 */
762 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
763 						ABX8XX_CFG_KEY_MISC);
764 		if (err < 0) {
765 			dev_err(&client->dev,
766 				"Unable to write configuration key\n");
767 			return -EIO;
768 		}
769 
770 		err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OUT_CTRL,
771 						data | ABX8XX_OUT_CTRL_EXDS);
772 		if (err < 0) {
773 			dev_err(&client->dev,
774 				"Unable to write output control register\n");
775 			return -EIO;
776 		}
777 	}
778 
779 	/* part autodetection */
780 	if (part == ABX80X) {
781 		for (i = 0; abx80x_caps[i].pn; i++)
782 			if (partnumber == abx80x_caps[i].pn)
783 				break;
784 		if (abx80x_caps[i].pn == 0) {
785 			dev_err(&client->dev, "Unknown part: %04x\n",
786 				partnumber);
787 			return -EINVAL;
788 		}
789 		part = i;
790 	}
791 
792 	if (partnumber != abx80x_caps[part].pn) {
793 		dev_err(&client->dev, "partnumber mismatch %04x != %04x\n",
794 			partnumber, abx80x_caps[part].pn);
795 		return -EINVAL;
796 	}
797 
798 	if (np && abx80x_caps[part].has_tc)
799 		trickle_cfg = abx80x_dt_trickle_cfg(np);
800 
801 	if (trickle_cfg > 0) {
802 		dev_info(&client->dev, "Enabling trickle charger: %02x\n",
803 			 trickle_cfg);
804 		abx80x_enable_trickle_charger(client, trickle_cfg);
805 	}
806 
807 	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CD_TIMER_CTL,
808 					BIT(2));
809 	if (err)
810 		return err;
811 
812 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
813 	if (priv == NULL)
814 		return -ENOMEM;
815 
816 	priv->rtc = devm_rtc_allocate_device(&client->dev);
817 	if (IS_ERR(priv->rtc))
818 		return PTR_ERR(priv->rtc);
819 
820 	priv->rtc->ops = &abx80x_rtc_ops;
821 	priv->client = client;
822 
823 	i2c_set_clientdata(client, priv);
824 
825 	if (abx80x_caps[part].has_wdog) {
826 		err = abx80x_setup_watchdog(priv);
827 		if (err)
828 			return err;
829 	}
830 
831 	if (client->irq > 0) {
832 		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
833 		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
834 						abx80x_handle_irq,
835 						IRQF_SHARED | IRQF_ONESHOT,
836 						"abx8xx",
837 						client);
838 		if (err) {
839 			dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
840 			client->irq = 0;
841 		}
842 	}
843 
844 	err = rtc_add_group(priv->rtc, &rtc_calib_attr_group);
845 	if (err) {
846 		dev_err(&client->dev, "Failed to create sysfs group: %d\n",
847 			err);
848 		return err;
849 	}
850 
851 	return rtc_register_device(priv->rtc);
852 }
853 
854 static const struct i2c_device_id abx80x_id[] = {
855 	{ "abx80x", ABX80X },
856 	{ "ab0801", AB0801 },
857 	{ "ab0803", AB0803 },
858 	{ "ab0804", AB0804 },
859 	{ "ab0805", AB0805 },
860 	{ "ab1801", AB1801 },
861 	{ "ab1803", AB1803 },
862 	{ "ab1804", AB1804 },
863 	{ "ab1805", AB1805 },
864 	{ "rv1805", RV1805 },
865 	{ }
866 };
867 MODULE_DEVICE_TABLE(i2c, abx80x_id);
868 
869 static struct i2c_driver abx80x_driver = {
870 	.driver		= {
871 		.name	= "rtc-abx80x",
872 	},
873 	.probe		= abx80x_probe,
874 	.id_table	= abx80x_id,
875 };
876 
877 module_i2c_driver(abx80x_driver);
878 
879 MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
880 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
881 MODULE_DESCRIPTION("Abracon ABX80X RTC driver");
882 MODULE_LICENSE("GPL v2");
883