xref: /linux/drivers/hwmon/max6639.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * max6639.c - Support for Maxim MAX6639
4  *
5  * 2-Channel Temperature Monitor with Dual PWM Fan-Speed Controller
6  *
7  * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
8  *
9  * based on the initial MAX6639 support from semptian.net
10  * by He Changqing <hechangqing@semptian.com>
11  */
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/jiffies.h>
17 #include <linux/i2c.h>
18 #include <linux/hwmon.h>
19 #include <linux/hwmon-sysfs.h>
20 #include <linux/err.h>
21 #include <linux/mutex.h>
22 #include <linux/platform_data/max6639.h>
23 #include <linux/regmap.h>
24 #include <linux/util_macros.h>
25 
26 /* Addresses to scan */
27 static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
28 
29 /* The MAX6639 registers, valid channel numbers: 0, 1 */
30 #define MAX6639_REG_TEMP(ch)			(0x00 + (ch))
31 #define MAX6639_REG_STATUS			0x02
32 #define MAX6639_REG_OUTPUT_MASK			0x03
33 #define MAX6639_REG_GCONFIG			0x04
34 #define MAX6639_REG_TEMP_EXT(ch)		(0x05 + (ch))
35 #define MAX6639_REG_ALERT_LIMIT(ch)		(0x08 + (ch))
36 #define MAX6639_REG_OT_LIMIT(ch)		(0x0A + (ch))
37 #define MAX6639_REG_THERM_LIMIT(ch)		(0x0C + (ch))
38 #define MAX6639_REG_FAN_CONFIG1(ch)		(0x10 + (ch) * 4)
39 #define MAX6639_REG_FAN_CONFIG2a(ch)		(0x11 + (ch) * 4)
40 #define MAX6639_REG_FAN_CONFIG2b(ch)		(0x12 + (ch) * 4)
41 #define MAX6639_REG_FAN_CONFIG3(ch)		(0x13 + (ch) * 4)
42 #define MAX6639_REG_FAN_CNT(ch)			(0x20 + (ch))
43 #define MAX6639_REG_TARGET_CNT(ch)		(0x22 + (ch))
44 #define MAX6639_REG_FAN_PPR(ch)			(0x24 + (ch))
45 #define MAX6639_REG_TARGTDUTY(ch)		(0x26 + (ch))
46 #define MAX6639_REG_FAN_START_TEMP(ch)		(0x28 + (ch))
47 #define MAX6639_REG_DEVID			0x3D
48 #define MAX6639_REG_MANUID			0x3E
49 #define MAX6639_REG_DEVREV			0x3F
50 
51 /* Register bits */
52 #define MAX6639_GCONFIG_STANDBY			0x80
53 #define MAX6639_GCONFIG_POR			0x40
54 #define MAX6639_GCONFIG_DISABLE_TIMEOUT		0x20
55 #define MAX6639_GCONFIG_CH2_LOCAL		0x10
56 #define MAX6639_GCONFIG_PWM_FREQ_HI		0x08
57 
58 #define MAX6639_FAN_CONFIG1_PWM			0x80
59 #define MAX6639_FAN_CONFIG3_FREQ_MASK		0x03
60 #define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED	0x40
61 
62 #define MAX6639_NUM_CHANNELS			2
63 
64 static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
65 
66 /* Supported PWM frequency */
67 static const unsigned int freq_table[] = { 20, 33, 50, 100, 5000, 8333, 12500,
68 					   25000 };
69 
70 #define FAN_FROM_REG(val, rpm_range)	((val) == 0 || (val) == 255 ? \
71 				0 : (rpm_ranges[rpm_range] * 30) / (val))
72 #define TEMP_LIMIT_TO_REG(val)	clamp_val((val) / 1000, 0, 255)
73 
74 /*
75  * Client data (each client gets its own)
76  */
77 struct max6639_data {
78 	struct regmap *regmap;
79 	struct mutex update_lock;
80 
81 	/* Register values initialized only once */
82 	u8 ppr[MAX6639_NUM_CHANNELS];	/* Pulses per rotation 0..3 for 1..4 ppr */
83 	u8 rpm_range[MAX6639_NUM_CHANNELS]; /* Index in above rpm_ranges table */
84 
85 	/* Optional regulator for FAN supply */
86 	struct regulator *reg;
87 };
88 
89 static int max6639_temp_read_input(struct device *dev, int channel, long *temp)
90 {
91 	u32 regs[2] = { MAX6639_REG_TEMP_EXT(channel), MAX6639_REG_TEMP(channel) };
92 	struct max6639_data *data = dev_get_drvdata(dev);
93 	u8 regvals[2];
94 	int res;
95 
96 	res = regmap_multi_reg_read(data->regmap, regs, regvals, 2);
97 	if (res < 0)
98 		return res;
99 
100 	*temp = ((regvals[0] >> 5) | (regvals[1] << 3)) * 125;
101 
102 	return 0;
103 }
104 
105 static int max6639_temp_read_fault(struct device *dev, int channel, long *fault)
106 {
107 	struct max6639_data *data = dev_get_drvdata(dev);
108 	unsigned int val;
109 	int res;
110 
111 	res = regmap_read(data->regmap, MAX6639_REG_TEMP_EXT(channel), &val);
112 	if (res < 0)
113 		return res;
114 
115 	*fault = val & 1;
116 
117 	return 0;
118 }
119 
120 static int max6639_temp_read_max(struct device *dev, int channel, long *max)
121 {
122 	struct max6639_data *data = dev_get_drvdata(dev);
123 	unsigned int val;
124 	int res;
125 
126 	res = regmap_read(data->regmap, MAX6639_REG_THERM_LIMIT(channel), &val);
127 	if (res < 0)
128 		return res;
129 
130 	*max = (long)val * 1000;
131 
132 	return 0;
133 }
134 
135 static int max6639_temp_read_crit(struct device *dev, int channel, long *crit)
136 {
137 	struct max6639_data *data = dev_get_drvdata(dev);
138 	unsigned int val;
139 	int res;
140 
141 	res = regmap_read(data->regmap, MAX6639_REG_ALERT_LIMIT(channel), &val);
142 	if (res < 0)
143 		return res;
144 
145 	*crit = (long)val * 1000;
146 
147 	return 0;
148 }
149 
150 static int max6639_temp_read_emergency(struct device *dev, int channel, long *emerg)
151 {
152 	struct max6639_data *data = dev_get_drvdata(dev);
153 	unsigned int val;
154 	int res;
155 
156 	res = regmap_read(data->regmap, MAX6639_REG_OT_LIMIT(channel), &val);
157 	if (res < 0)
158 		return res;
159 
160 	*emerg = (long)val * 1000;
161 
162 	return 0;
163 }
164 
165 static int max6639_get_status(struct device *dev, unsigned int *status)
166 {
167 	struct max6639_data *data = dev_get_drvdata(dev);
168 	unsigned int val;
169 	int res;
170 
171 	res = regmap_read(data->regmap, MAX6639_REG_STATUS, &val);
172 	if (res < 0)
173 		return res;
174 
175 	*status = val;
176 
177 	return 0;
178 }
179 
180 static int max6639_temp_set_max(struct max6639_data *data, int channel, long val)
181 {
182 	int res;
183 
184 	res = regmap_write(data->regmap, MAX6639_REG_THERM_LIMIT(channel),
185 			   TEMP_LIMIT_TO_REG(val));
186 	return res;
187 }
188 
189 static int max6639_temp_set_crit(struct max6639_data *data, int channel, long val)
190 {
191 	int res;
192 
193 	res = regmap_write(data->regmap, MAX6639_REG_ALERT_LIMIT(channel), TEMP_LIMIT_TO_REG(val));
194 
195 	return res;
196 }
197 
198 static int max6639_temp_set_emergency(struct max6639_data *data, int channel, long val)
199 {
200 	int res;
201 
202 	res = regmap_write(data->regmap, MAX6639_REG_OT_LIMIT(channel), TEMP_LIMIT_TO_REG(val));
203 
204 	return res;
205 }
206 
207 static int max6639_read_fan(struct device *dev, u32 attr, int channel,
208 			    long *fan_val)
209 {
210 	struct max6639_data *data = dev_get_drvdata(dev);
211 	unsigned int val;
212 	int res;
213 
214 	switch (attr) {
215 	case hwmon_fan_input:
216 		res = regmap_read(data->regmap, MAX6639_REG_FAN_CNT(channel), &val);
217 		if (res < 0)
218 			return res;
219 		*fan_val = FAN_FROM_REG(val, data->rpm_range[channel]);
220 		return 0;
221 	case hwmon_fan_fault:
222 		res = max6639_get_status(dev, &val);
223 		if (res < 0)
224 			return res;
225 		*fan_val = !!(val & BIT(1 - channel));
226 		return 0;
227 	case hwmon_fan_pulses:
228 		*fan_val = data->ppr[channel];
229 		return 0;
230 	default:
231 		return -EOPNOTSUPP;
232 	}
233 }
234 
235 static int max6639_set_ppr(struct max6639_data *data, int channel, u8 ppr)
236 {
237 	/* Decrement the PPR value and shift left by 6 to match the register format */
238 	return regmap_write(data->regmap, MAX6639_REG_FAN_PPR(channel), ppr-- << 6);
239 }
240 
241 static int max6639_write_fan(struct device *dev, u32 attr, int channel,
242 			     long val)
243 {
244 	struct max6639_data *data = dev_get_drvdata(dev);
245 	int err;
246 
247 	switch (attr) {
248 	case hwmon_fan_pulses:
249 		if (val <= 0 || val > 4)
250 			return -EINVAL;
251 
252 		mutex_lock(&data->update_lock);
253 		/* Set Fan pulse per revolution */
254 		err = max6639_set_ppr(data, channel, val);
255 		if (err < 0) {
256 			mutex_unlock(&data->update_lock);
257 			return err;
258 		}
259 		data->ppr[channel] = val;
260 
261 		mutex_unlock(&data->update_lock);
262 		return 0;
263 	default:
264 		return -EOPNOTSUPP;
265 	}
266 }
267 
268 static umode_t max6639_fan_is_visible(const void *_data, u32 attr, int channel)
269 {
270 	switch (attr) {
271 	case hwmon_fan_input:
272 	case hwmon_fan_fault:
273 		return 0444;
274 	case hwmon_fan_pulses:
275 		return 0644;
276 	default:
277 		return 0;
278 	}
279 }
280 
281 static int max6639_read_pwm(struct device *dev, u32 attr, int channel,
282 			    long *pwm_val)
283 {
284 	u32 regs[2] = { MAX6639_REG_FAN_CONFIG3(channel), MAX6639_REG_GCONFIG };
285 	struct max6639_data *data = dev_get_drvdata(dev);
286 	unsigned int val;
287 	u8 regvals[2];
288 	int res;
289 	u8 i;
290 
291 	switch (attr) {
292 	case hwmon_pwm_input:
293 		res = regmap_read(data->regmap, MAX6639_REG_TARGTDUTY(channel), &val);
294 		if (res < 0)
295 			return res;
296 		*pwm_val = val * 255 / 120;
297 		return 0;
298 	case hwmon_pwm_freq:
299 		res = regmap_multi_reg_read(data->regmap, regs, regvals, 2);
300 		if (res < 0)
301 			return res;
302 		i = regvals[0] & MAX6639_FAN_CONFIG3_FREQ_MASK;
303 		if (regvals[1] & MAX6639_GCONFIG_PWM_FREQ_HI)
304 			i |= 0x4;
305 		*pwm_val = freq_table[i];
306 		return 0;
307 	default:
308 		return -EOPNOTSUPP;
309 	}
310 }
311 
312 static int max6639_write_pwm(struct device *dev, u32 attr, int channel,
313 			     long val)
314 {
315 	struct max6639_data *data = dev_get_drvdata(dev);
316 	int err;
317 	u8 i;
318 
319 	switch (attr) {
320 	case hwmon_pwm_input:
321 		if (val < 0 || val > 255)
322 			return -EINVAL;
323 		err = regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(channel),
324 				   val * 120 / 255);
325 		return err;
326 	case hwmon_pwm_freq:
327 		val = clamp_val(val, 0, 25000);
328 
329 		i = find_closest(val, freq_table, ARRAY_SIZE(freq_table));
330 
331 		mutex_lock(&data->update_lock);
332 		err = regmap_update_bits(data->regmap, MAX6639_REG_FAN_CONFIG3(channel),
333 					 MAX6639_FAN_CONFIG3_FREQ_MASK, i);
334 		if (err < 0) {
335 			mutex_unlock(&data->update_lock);
336 			return err;
337 		}
338 
339 		if (i >> 2)
340 			err = regmap_set_bits(data->regmap, MAX6639_REG_GCONFIG,
341 					      MAX6639_GCONFIG_PWM_FREQ_HI);
342 		else
343 			err = regmap_clear_bits(data->regmap, MAX6639_REG_GCONFIG,
344 						MAX6639_GCONFIG_PWM_FREQ_HI);
345 
346 		mutex_unlock(&data->update_lock);
347 		return err;
348 	default:
349 		return -EOPNOTSUPP;
350 	}
351 }
352 
353 static umode_t max6639_pwm_is_visible(const void *_data, u32 attr, int channel)
354 {
355 	switch (attr) {
356 	case hwmon_pwm_input:
357 	case hwmon_pwm_freq:
358 		return 0644;
359 	default:
360 		return 0;
361 	}
362 }
363 
364 static int max6639_read_temp(struct device *dev, u32 attr, int channel,
365 			     long *val)
366 {
367 	unsigned int status;
368 	int res;
369 
370 	switch (attr) {
371 	case hwmon_temp_input:
372 		res = max6639_temp_read_input(dev, channel, val);
373 		return res;
374 	case hwmon_temp_fault:
375 		res = max6639_temp_read_fault(dev, channel, val);
376 		return res;
377 	case hwmon_temp_max:
378 		res = max6639_temp_read_max(dev, channel, val);
379 		return res;
380 	case hwmon_temp_crit:
381 		res = max6639_temp_read_crit(dev, channel, val);
382 		return res;
383 	case hwmon_temp_emergency:
384 		res = max6639_temp_read_emergency(dev, channel, val);
385 		return res;
386 	case hwmon_temp_max_alarm:
387 		res = max6639_get_status(dev, &status);
388 		if (res < 0)
389 			return res;
390 		*val = !!(status & BIT(3 - channel));
391 		return 0;
392 	case hwmon_temp_crit_alarm:
393 		res = max6639_get_status(dev, &status);
394 		if (res < 0)
395 			return res;
396 		*val = !!(status & BIT(7 - channel));
397 		return 0;
398 	case hwmon_temp_emergency_alarm:
399 		res = max6639_get_status(dev, &status);
400 		if (res < 0)
401 			return res;
402 		*val = !!(status & BIT(5 - channel));
403 		return 0;
404 	default:
405 		return -EOPNOTSUPP;
406 	}
407 }
408 
409 static int max6639_write_temp(struct device *dev, u32 attr, int channel,
410 			      long val)
411 {
412 	struct max6639_data *data = dev_get_drvdata(dev);
413 
414 	switch (attr) {
415 	case hwmon_temp_max:
416 		return max6639_temp_set_max(data, channel, val);
417 	case hwmon_temp_crit:
418 		return max6639_temp_set_crit(data, channel, val);
419 	case hwmon_temp_emergency:
420 		return max6639_temp_set_emergency(data, channel, val);
421 	default:
422 		return -EOPNOTSUPP;
423 	}
424 }
425 
426 static umode_t max6639_temp_is_visible(const void *_data, u32 attr, int channel)
427 {
428 	switch (attr) {
429 	case hwmon_temp_input:
430 	case hwmon_temp_fault:
431 	case hwmon_temp_max_alarm:
432 	case hwmon_temp_crit_alarm:
433 	case hwmon_temp_emergency_alarm:
434 		return 0444;
435 	case hwmon_temp_max:
436 	case hwmon_temp_crit:
437 	case hwmon_temp_emergency:
438 		return 0644;
439 	default:
440 		return 0;
441 	}
442 }
443 
444 static int max6639_read(struct device *dev, enum hwmon_sensor_types type,
445 			u32 attr, int channel, long *val)
446 {
447 	switch (type) {
448 	case hwmon_fan:
449 		return max6639_read_fan(dev, attr, channel, val);
450 	case hwmon_pwm:
451 		return max6639_read_pwm(dev, attr, channel, val);
452 	case hwmon_temp:
453 		return max6639_read_temp(dev, attr, channel, val);
454 	default:
455 		return -EOPNOTSUPP;
456 	}
457 }
458 
459 static int max6639_write(struct device *dev, enum hwmon_sensor_types type,
460 			 u32 attr, int channel, long val)
461 {
462 	switch (type) {
463 	case hwmon_fan:
464 		return max6639_write_fan(dev, attr, channel, val);
465 	case hwmon_pwm:
466 		return max6639_write_pwm(dev, attr, channel, val);
467 	case hwmon_temp:
468 		return max6639_write_temp(dev, attr, channel, val);
469 	default:
470 		return -EOPNOTSUPP;
471 	}
472 }
473 
474 static umode_t max6639_is_visible(const void *data,
475 				  enum hwmon_sensor_types type,
476 				  u32 attr, int channel)
477 {
478 	switch (type) {
479 	case hwmon_fan:
480 		return max6639_fan_is_visible(data, attr, channel);
481 	case hwmon_pwm:
482 		return max6639_pwm_is_visible(data, attr, channel);
483 	case hwmon_temp:
484 		return max6639_temp_is_visible(data, attr, channel);
485 	default:
486 		return 0;
487 	}
488 }
489 
490 static const struct hwmon_channel_info * const max6639_info[] = {
491 	HWMON_CHANNEL_INFO(fan,
492 			   HWMON_F_INPUT | HWMON_F_FAULT | HWMON_F_PULSES,
493 			   HWMON_F_INPUT | HWMON_F_FAULT | HWMON_F_PULSES),
494 	HWMON_CHANNEL_INFO(pwm,
495 			   HWMON_PWM_INPUT | HWMON_PWM_FREQ,
496 			   HWMON_PWM_INPUT | HWMON_PWM_FREQ),
497 	HWMON_CHANNEL_INFO(temp,
498 			   HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_MAX | HWMON_T_MAX_ALARM |
499 			   HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_EMERGENCY |
500 			   HWMON_T_EMERGENCY_ALARM,
501 			   HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_MAX | HWMON_T_MAX_ALARM |
502 			   HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_EMERGENCY |
503 			   HWMON_T_EMERGENCY_ALARM),
504 	NULL
505 };
506 
507 static const struct hwmon_ops max6639_hwmon_ops = {
508 	.is_visible = max6639_is_visible,
509 	.read = max6639_read,
510 	.write = max6639_write,
511 };
512 
513 static const struct hwmon_chip_info max6639_chip_info = {
514 	.ops = &max6639_hwmon_ops,
515 	.info = max6639_info,
516 };
517 
518 /*
519  *  returns respective index in rpm_ranges table
520  *  1 by default on invalid range
521  */
522 static int rpm_range_to_reg(int range)
523 {
524 	int i;
525 
526 	for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
527 		if (rpm_ranges[i] == range)
528 			return i;
529 	}
530 
531 	return 1; /* default: 4000 RPM */
532 }
533 
534 static int max6639_init_client(struct i2c_client *client,
535 			       struct max6639_data *data)
536 {
537 	struct max6639_platform_data *max6639_info =
538 		dev_get_platdata(&client->dev);
539 	int i;
540 	int rpm_range = 1; /* default: 4000 RPM */
541 	int err, ppr;
542 
543 	/* Reset chip to default values, see below for GCONFIG setup */
544 	err = regmap_write(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_POR);
545 	if (err)
546 		return err;
547 
548 	/* Fans pulse per revolution is 2 by default */
549 	if (max6639_info && max6639_info->ppr > 0 &&
550 			max6639_info->ppr < 5)
551 		ppr = max6639_info->ppr;
552 	else
553 		ppr = 2;
554 
555 	data->ppr[0] = ppr;
556 	data->ppr[1] = ppr;
557 
558 	if (max6639_info)
559 		rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
560 	data->rpm_range[0] = rpm_range;
561 	data->rpm_range[1] = rpm_range;
562 
563 	for (i = 0; i < MAX6639_NUM_CHANNELS; i++) {
564 		/* Set Fan pulse per revolution */
565 		err = max6639_set_ppr(data, i, data->ppr[i]);
566 		if (err)
567 			return err;
568 
569 		/* Fans config PWM, RPM */
570 		err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG1(i),
571 				   MAX6639_FAN_CONFIG1_PWM | data->rpm_range[i]);
572 		if (err)
573 			return err;
574 
575 		/* Fans PWM polarity high by default */
576 		if (max6639_info) {
577 			if (max6639_info->pwm_polarity == 0)
578 				err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG2a(i), 0x00);
579 			else
580 				err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG2a(i), 0x02);
581 		}
582 		if (err)
583 			return err;
584 
585 		/*
586 		 * /THERM full speed enable,
587 		 * PWM frequency 25kHz, see also GCONFIG below
588 		 */
589 		err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG3(i),
590 				   MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
591 		if (err)
592 			return err;
593 
594 		/* Max. temp. 80C/90C/100C */
595 		err = regmap_write(data->regmap, MAX6639_REG_THERM_LIMIT(i), 80);
596 		if (err)
597 			return err;
598 		err = regmap_write(data->regmap, MAX6639_REG_ALERT_LIMIT(i), 90);
599 		if (err)
600 			return err;
601 		err = regmap_write(data->regmap, MAX6639_REG_OT_LIMIT(i), 100);
602 		if (err)
603 			return err;
604 
605 		/* PWM 120/120 (i.e. 100%) */
606 		err = regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(i), 120);
607 		if (err)
608 			return err;
609 	}
610 	/* Start monitoring */
611 	return regmap_write(data->regmap, MAX6639_REG_GCONFIG,
612 			    MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
613 			    MAX6639_GCONFIG_PWM_FREQ_HI);
614 
615 }
616 
617 /* Return 0 if detection is successful, -ENODEV otherwise */
618 static int max6639_detect(struct i2c_client *client,
619 			  struct i2c_board_info *info)
620 {
621 	struct i2c_adapter *adapter = client->adapter;
622 	int dev_id, manu_id;
623 
624 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
625 		return -ENODEV;
626 
627 	/* Actual detection via device and manufacturer ID */
628 	dev_id = i2c_smbus_read_byte_data(client, MAX6639_REG_DEVID);
629 	manu_id = i2c_smbus_read_byte_data(client, MAX6639_REG_MANUID);
630 	if (dev_id != 0x58 || manu_id != 0x4D)
631 		return -ENODEV;
632 
633 	strscpy(info->type, "max6639", I2C_NAME_SIZE);
634 
635 	return 0;
636 }
637 
638 static void max6639_regulator_disable(void *data)
639 {
640 	regulator_disable(data);
641 }
642 
643 static bool max6639_regmap_is_volatile(struct device *dev, unsigned int reg)
644 {
645 	switch (reg) {
646 	case MAX6639_REG_TEMP(0):
647 	case MAX6639_REG_TEMP_EXT(0):
648 	case MAX6639_REG_TEMP(1):
649 	case MAX6639_REG_TEMP_EXT(1):
650 	case MAX6639_REG_STATUS:
651 	case MAX6639_REG_FAN_CNT(0):
652 	case MAX6639_REG_FAN_CNT(1):
653 	case MAX6639_REG_TARGTDUTY(0):
654 	case MAX6639_REG_TARGTDUTY(1):
655 		return true;
656 	default:
657 		return false;
658 	}
659 }
660 
661 static const struct regmap_config max6639_regmap_config = {
662 	.reg_bits = 8,
663 	.val_bits = 8,
664 	.max_register = MAX6639_REG_DEVREV,
665 	.cache_type = REGCACHE_MAPLE,
666 	.volatile_reg = max6639_regmap_is_volatile,
667 };
668 
669 static int max6639_probe(struct i2c_client *client)
670 {
671 	struct device *dev = &client->dev;
672 	struct max6639_data *data;
673 	struct device *hwmon_dev;
674 	int err;
675 
676 	data = devm_kzalloc(dev, sizeof(struct max6639_data), GFP_KERNEL);
677 	if (!data)
678 		return -ENOMEM;
679 
680 	data->regmap = devm_regmap_init_i2c(client, &max6639_regmap_config);
681 	if (IS_ERR(data->regmap))
682 		return dev_err_probe(dev,
683 				     PTR_ERR(data->regmap),
684 				     "regmap initialization failed\n");
685 
686 	data->reg = devm_regulator_get_optional(dev, "fan");
687 	if (IS_ERR(data->reg)) {
688 		if (PTR_ERR(data->reg) != -ENODEV)
689 			return PTR_ERR(data->reg);
690 
691 		data->reg = NULL;
692 	} else {
693 		/* Spin up fans */
694 		err = regulator_enable(data->reg);
695 		if (err) {
696 			dev_err(dev, "Failed to enable fan supply: %d\n", err);
697 			return err;
698 		}
699 		err = devm_add_action_or_reset(dev, max6639_regulator_disable,
700 					       data->reg);
701 		if (err) {
702 			dev_err(dev, "Failed to register action: %d\n", err);
703 			return err;
704 		}
705 	}
706 
707 	mutex_init(&data->update_lock);
708 
709 	/* Initialize the max6639 chip */
710 	err = max6639_init_client(client, data);
711 	if (err < 0)
712 		return err;
713 
714 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
715 							 data, &max6639_chip_info,
716 							 NULL);
717 
718 	return PTR_ERR_OR_ZERO(hwmon_dev);
719 }
720 
721 static int max6639_suspend(struct device *dev)
722 {
723 	struct max6639_data *data = dev_get_drvdata(dev);
724 
725 	if (data->reg)
726 		regulator_disable(data->reg);
727 
728 	return regmap_write_bits(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_STANDBY,
729 				 MAX6639_GCONFIG_STANDBY);
730 }
731 
732 static int max6639_resume(struct device *dev)
733 {
734 	struct max6639_data *data = dev_get_drvdata(dev);
735 	int ret;
736 
737 	if (data->reg) {
738 		ret = regulator_enable(data->reg);
739 		if (ret) {
740 			dev_err(dev, "Failed to enable fan supply: %d\n", ret);
741 			return ret;
742 		}
743 	}
744 
745 	return regmap_write_bits(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_STANDBY,
746 				 ~MAX6639_GCONFIG_STANDBY);
747 }
748 
749 static const struct i2c_device_id max6639_id[] = {
750 	{"max6639"},
751 	{ }
752 };
753 
754 MODULE_DEVICE_TABLE(i2c, max6639_id);
755 
756 static DEFINE_SIMPLE_DEV_PM_OPS(max6639_pm_ops, max6639_suspend, max6639_resume);
757 
758 static const struct of_device_id max6639_of_match[] = {
759 	{ .compatible = "maxim,max6639", },
760 	{ },
761 };
762 
763 static struct i2c_driver max6639_driver = {
764 	.class = I2C_CLASS_HWMON,
765 	.driver = {
766 		   .name = "max6639",
767 		   .pm = pm_sleep_ptr(&max6639_pm_ops),
768 		   .of_match_table = max6639_of_match,
769 		   },
770 	.probe = max6639_probe,
771 	.id_table = max6639_id,
772 	.detect = max6639_detect,
773 	.address_list = normal_i2c,
774 };
775 
776 module_i2c_driver(max6639_driver);
777 
778 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
779 MODULE_DESCRIPTION("max6639 driver");
780 MODULE_LICENSE("GPL");
781