xref: /openbmc/linux/drivers/hwmon/max6639.c (revision 12eb4683)
1 /*
2  * max6639.c - Support for Maxim MAX6639
3  *
4  * 2-Channel Temperature Monitor with Dual PWM Fan-Speed Controller
5  *
6  * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
7  *
8  * based on the initial MAX6639 support from semptian.net
9  * by He Changqing <hechangqing@semptian.com>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  */
25 
26 #include <linux/module.h>
27 #include <linux/init.h>
28 #include <linux/slab.h>
29 #include <linux/jiffies.h>
30 #include <linux/i2c.h>
31 #include <linux/hwmon.h>
32 #include <linux/hwmon-sysfs.h>
33 #include <linux/err.h>
34 #include <linux/mutex.h>
35 #include <linux/i2c/max6639.h>
36 
37 /* Addresses to scan */
38 static unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
39 
40 /* The MAX6639 registers, valid channel numbers: 0, 1 */
41 #define MAX6639_REG_TEMP(ch)			(0x00 + (ch))
42 #define MAX6639_REG_STATUS			0x02
43 #define MAX6639_REG_OUTPUT_MASK			0x03
44 #define MAX6639_REG_GCONFIG			0x04
45 #define MAX6639_REG_TEMP_EXT(ch)		(0x05 + (ch))
46 #define MAX6639_REG_ALERT_LIMIT(ch)		(0x08 + (ch))
47 #define MAX6639_REG_OT_LIMIT(ch)		(0x0A + (ch))
48 #define MAX6639_REG_THERM_LIMIT(ch)		(0x0C + (ch))
49 #define MAX6639_REG_FAN_CONFIG1(ch)		(0x10 + (ch) * 4)
50 #define MAX6639_REG_FAN_CONFIG2a(ch)		(0x11 + (ch) * 4)
51 #define MAX6639_REG_FAN_CONFIG2b(ch)		(0x12 + (ch) * 4)
52 #define MAX6639_REG_FAN_CONFIG3(ch)		(0x13 + (ch) * 4)
53 #define MAX6639_REG_FAN_CNT(ch)			(0x20 + (ch))
54 #define MAX6639_REG_TARGET_CNT(ch)		(0x22 + (ch))
55 #define MAX6639_REG_FAN_PPR(ch)			(0x24 + (ch))
56 #define MAX6639_REG_TARGTDUTY(ch)		(0x26 + (ch))
57 #define MAX6639_REG_FAN_START_TEMP(ch)		(0x28 + (ch))
58 #define MAX6639_REG_DEVID			0x3D
59 #define MAX6639_REG_MANUID			0x3E
60 #define MAX6639_REG_DEVREV			0x3F
61 
62 /* Register bits */
63 #define MAX6639_GCONFIG_STANDBY			0x80
64 #define MAX6639_GCONFIG_POR			0x40
65 #define MAX6639_GCONFIG_DISABLE_TIMEOUT		0x20
66 #define MAX6639_GCONFIG_CH2_LOCAL		0x10
67 #define MAX6639_GCONFIG_PWM_FREQ_HI		0x08
68 
69 #define MAX6639_FAN_CONFIG1_PWM			0x80
70 
71 #define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED	0x40
72 
73 static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
74 
75 #define FAN_FROM_REG(val, rpm_range)	((val) == 0 || (val) == 255 ? \
76 				0 : (rpm_ranges[rpm_range] * 30) / (val))
77 #define TEMP_LIMIT_TO_REG(val)	clamp_val((val) / 1000, 0, 255)
78 
79 /*
80  * Client data (each client gets its own)
81  */
82 struct max6639_data {
83 	struct device *hwmon_dev;
84 	struct mutex update_lock;
85 	char valid;		/* !=0 if following fields are valid */
86 	unsigned long last_updated;	/* In jiffies */
87 
88 	/* Register values sampled regularly */
89 	u16 temp[2];		/* Temperature, in 1/8 C, 0..255 C */
90 	bool temp_fault[2];	/* Detected temperature diode failure */
91 	u8 fan[2];		/* Register value: TACH count for fans >=30 */
92 	u8 status;		/* Detected channel alarms and fan failures */
93 
94 	/* Register values only written to */
95 	u8 pwm[2];		/* Register value: Duty cycle 0..120 */
96 	u8 temp_therm[2];	/* THERM Temperature, 0..255 C (->_max) */
97 	u8 temp_alert[2];	/* ALERT Temperature, 0..255 C (->_crit) */
98 	u8 temp_ot[2];		/* OT Temperature, 0..255 C (->_emergency) */
99 
100 	/* Register values initialized only once */
101 	u8 ppr;			/* Pulses per rotation 0..3 for 1..4 ppr */
102 	u8 rpm_range;		/* Index in above rpm_ranges table */
103 };
104 
105 static struct max6639_data *max6639_update_device(struct device *dev)
106 {
107 	struct i2c_client *client = to_i2c_client(dev);
108 	struct max6639_data *data = i2c_get_clientdata(client);
109 	struct max6639_data *ret = data;
110 	int i;
111 	int status_reg;
112 
113 	mutex_lock(&data->update_lock);
114 
115 	if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
116 		int res;
117 
118 		dev_dbg(&client->dev, "Starting max6639 update\n");
119 
120 		status_reg = i2c_smbus_read_byte_data(client,
121 						      MAX6639_REG_STATUS);
122 		if (status_reg < 0) {
123 			ret = ERR_PTR(status_reg);
124 			goto abort;
125 		}
126 
127 		data->status = status_reg;
128 
129 		for (i = 0; i < 2; i++) {
130 			res = i2c_smbus_read_byte_data(client,
131 					MAX6639_REG_FAN_CNT(i));
132 			if (res < 0) {
133 				ret = ERR_PTR(res);
134 				goto abort;
135 			}
136 			data->fan[i] = res;
137 
138 			res = i2c_smbus_read_byte_data(client,
139 					MAX6639_REG_TEMP_EXT(i));
140 			if (res < 0) {
141 				ret = ERR_PTR(res);
142 				goto abort;
143 			}
144 			data->temp[i] = res >> 5;
145 			data->temp_fault[i] = res & 0x01;
146 
147 			res = i2c_smbus_read_byte_data(client,
148 					MAX6639_REG_TEMP(i));
149 			if (res < 0) {
150 				ret = ERR_PTR(res);
151 				goto abort;
152 			}
153 			data->temp[i] |= res << 3;
154 		}
155 
156 		data->last_updated = jiffies;
157 		data->valid = 1;
158 	}
159 abort:
160 	mutex_unlock(&data->update_lock);
161 
162 	return ret;
163 }
164 
165 static ssize_t show_temp_input(struct device *dev,
166 			       struct device_attribute *dev_attr, char *buf)
167 {
168 	long temp;
169 	struct max6639_data *data = max6639_update_device(dev);
170 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
171 
172 	if (IS_ERR(data))
173 		return PTR_ERR(data);
174 
175 	temp = data->temp[attr->index] * 125;
176 	return sprintf(buf, "%ld\n", temp);
177 }
178 
179 static ssize_t show_temp_fault(struct device *dev,
180 			       struct device_attribute *dev_attr, char *buf)
181 {
182 	struct max6639_data *data = max6639_update_device(dev);
183 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
184 
185 	if (IS_ERR(data))
186 		return PTR_ERR(data);
187 
188 	return sprintf(buf, "%d\n", data->temp_fault[attr->index]);
189 }
190 
191 static ssize_t show_temp_max(struct device *dev,
192 			     struct device_attribute *dev_attr, char *buf)
193 {
194 	struct i2c_client *client = to_i2c_client(dev);
195 	struct max6639_data *data = i2c_get_clientdata(client);
196 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
197 
198 	return sprintf(buf, "%d\n", (data->temp_therm[attr->index] * 1000));
199 }
200 
201 static ssize_t set_temp_max(struct device *dev,
202 			    struct device_attribute *dev_attr,
203 			    const char *buf, size_t count)
204 {
205 	struct i2c_client *client = to_i2c_client(dev);
206 	struct max6639_data *data = i2c_get_clientdata(client);
207 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
208 	unsigned long val;
209 	int res;
210 
211 	res = kstrtoul(buf, 10, &val);
212 	if (res)
213 		return res;
214 
215 	mutex_lock(&data->update_lock);
216 	data->temp_therm[attr->index] = TEMP_LIMIT_TO_REG(val);
217 	i2c_smbus_write_byte_data(client,
218 				  MAX6639_REG_THERM_LIMIT(attr->index),
219 				  data->temp_therm[attr->index]);
220 	mutex_unlock(&data->update_lock);
221 	return count;
222 }
223 
224 static ssize_t show_temp_crit(struct device *dev,
225 			      struct device_attribute *dev_attr, char *buf)
226 {
227 	struct i2c_client *client = to_i2c_client(dev);
228 	struct max6639_data *data = i2c_get_clientdata(client);
229 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
230 
231 	return sprintf(buf, "%d\n", (data->temp_alert[attr->index] * 1000));
232 }
233 
234 static ssize_t set_temp_crit(struct device *dev,
235 			     struct device_attribute *dev_attr,
236 			     const char *buf, size_t count)
237 {
238 	struct i2c_client *client = to_i2c_client(dev);
239 	struct max6639_data *data = i2c_get_clientdata(client);
240 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
241 	unsigned long val;
242 	int res;
243 
244 	res = kstrtoul(buf, 10, &val);
245 	if (res)
246 		return res;
247 
248 	mutex_lock(&data->update_lock);
249 	data->temp_alert[attr->index] = TEMP_LIMIT_TO_REG(val);
250 	i2c_smbus_write_byte_data(client,
251 				  MAX6639_REG_ALERT_LIMIT(attr->index),
252 				  data->temp_alert[attr->index]);
253 	mutex_unlock(&data->update_lock);
254 	return count;
255 }
256 
257 static ssize_t show_temp_emergency(struct device *dev,
258 				   struct device_attribute *dev_attr,
259 				   char *buf)
260 {
261 	struct i2c_client *client = to_i2c_client(dev);
262 	struct max6639_data *data = i2c_get_clientdata(client);
263 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
264 
265 	return sprintf(buf, "%d\n", (data->temp_ot[attr->index] * 1000));
266 }
267 
268 static ssize_t set_temp_emergency(struct device *dev,
269 				  struct device_attribute *dev_attr,
270 				  const char *buf, size_t count)
271 {
272 	struct i2c_client *client = to_i2c_client(dev);
273 	struct max6639_data *data = i2c_get_clientdata(client);
274 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
275 	unsigned long val;
276 	int res;
277 
278 	res = kstrtoul(buf, 10, &val);
279 	if (res)
280 		return res;
281 
282 	mutex_lock(&data->update_lock);
283 	data->temp_ot[attr->index] = TEMP_LIMIT_TO_REG(val);
284 	i2c_smbus_write_byte_data(client,
285 				  MAX6639_REG_OT_LIMIT(attr->index),
286 				  data->temp_ot[attr->index]);
287 	mutex_unlock(&data->update_lock);
288 	return count;
289 }
290 
291 static ssize_t show_pwm(struct device *dev,
292 			struct device_attribute *dev_attr, char *buf)
293 {
294 	struct i2c_client *client = to_i2c_client(dev);
295 	struct max6639_data *data = i2c_get_clientdata(client);
296 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
297 
298 	return sprintf(buf, "%d\n", data->pwm[attr->index] * 255 / 120);
299 }
300 
301 static ssize_t set_pwm(struct device *dev,
302 		       struct device_attribute *dev_attr,
303 		       const char *buf, size_t count)
304 {
305 	struct i2c_client *client = to_i2c_client(dev);
306 	struct max6639_data *data = i2c_get_clientdata(client);
307 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
308 	unsigned long val;
309 	int res;
310 
311 	res = kstrtoul(buf, 10, &val);
312 	if (res)
313 		return res;
314 
315 	val = clamp_val(val, 0, 255);
316 
317 	mutex_lock(&data->update_lock);
318 	data->pwm[attr->index] = (u8)(val * 120 / 255);
319 	i2c_smbus_write_byte_data(client,
320 				  MAX6639_REG_TARGTDUTY(attr->index),
321 				  data->pwm[attr->index]);
322 	mutex_unlock(&data->update_lock);
323 	return count;
324 }
325 
326 static ssize_t show_fan_input(struct device *dev,
327 			      struct device_attribute *dev_attr, char *buf)
328 {
329 	struct max6639_data *data = max6639_update_device(dev);
330 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
331 
332 	if (IS_ERR(data))
333 		return PTR_ERR(data);
334 
335 	return sprintf(buf, "%d\n", FAN_FROM_REG(data->fan[attr->index],
336 		       data->rpm_range));
337 }
338 
339 static ssize_t show_alarm(struct device *dev,
340 			  struct device_attribute *dev_attr, char *buf)
341 {
342 	struct max6639_data *data = max6639_update_device(dev);
343 	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
344 
345 	if (IS_ERR(data))
346 		return PTR_ERR(data);
347 
348 	return sprintf(buf, "%d\n", !!(data->status & (1 << attr->index)));
349 }
350 
351 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
352 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_input, NULL, 1);
353 static SENSOR_DEVICE_ATTR(temp1_fault, S_IRUGO, show_temp_fault, NULL, 0);
354 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_temp_fault, NULL, 1);
355 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
356 		set_temp_max, 0);
357 static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
358 		set_temp_max, 1);
359 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp_crit,
360 		set_temp_crit, 0);
361 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp_crit,
362 		set_temp_crit, 1);
363 static SENSOR_DEVICE_ATTR(temp1_emergency, S_IWUSR | S_IRUGO,
364 		show_temp_emergency, set_temp_emergency, 0);
365 static SENSOR_DEVICE_ATTR(temp2_emergency, S_IWUSR | S_IRUGO,
366 		show_temp_emergency, set_temp_emergency, 1);
367 static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 0);
368 static SENSOR_DEVICE_ATTR(pwm2, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 1);
369 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, show_fan_input, NULL, 0);
370 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, show_fan_input, NULL, 1);
371 static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, show_alarm, NULL, 1);
372 static SENSOR_DEVICE_ATTR(fan2_fault, S_IRUGO, show_alarm, NULL, 0);
373 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 3);
374 static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 2);
375 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 7);
376 static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 6);
377 static SENSOR_DEVICE_ATTR(temp1_emergency_alarm, S_IRUGO, show_alarm, NULL, 5);
378 static SENSOR_DEVICE_ATTR(temp2_emergency_alarm, S_IRUGO, show_alarm, NULL, 4);
379 
380 
381 static struct attribute *max6639_attributes[] = {
382 	&sensor_dev_attr_temp1_input.dev_attr.attr,
383 	&sensor_dev_attr_temp2_input.dev_attr.attr,
384 	&sensor_dev_attr_temp1_fault.dev_attr.attr,
385 	&sensor_dev_attr_temp2_fault.dev_attr.attr,
386 	&sensor_dev_attr_temp1_max.dev_attr.attr,
387 	&sensor_dev_attr_temp2_max.dev_attr.attr,
388 	&sensor_dev_attr_temp1_crit.dev_attr.attr,
389 	&sensor_dev_attr_temp2_crit.dev_attr.attr,
390 	&sensor_dev_attr_temp1_emergency.dev_attr.attr,
391 	&sensor_dev_attr_temp2_emergency.dev_attr.attr,
392 	&sensor_dev_attr_pwm1.dev_attr.attr,
393 	&sensor_dev_attr_pwm2.dev_attr.attr,
394 	&sensor_dev_attr_fan1_input.dev_attr.attr,
395 	&sensor_dev_attr_fan2_input.dev_attr.attr,
396 	&sensor_dev_attr_fan1_fault.dev_attr.attr,
397 	&sensor_dev_attr_fan2_fault.dev_attr.attr,
398 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
399 	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
400 	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
401 	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
402 	&sensor_dev_attr_temp1_emergency_alarm.dev_attr.attr,
403 	&sensor_dev_attr_temp2_emergency_alarm.dev_attr.attr,
404 	NULL
405 };
406 
407 static const struct attribute_group max6639_group = {
408 	.attrs = max6639_attributes,
409 };
410 
411 /*
412  *  returns respective index in rpm_ranges table
413  *  1 by default on invalid range
414  */
415 static int rpm_range_to_reg(int range)
416 {
417 	int i;
418 
419 	for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
420 		if (rpm_ranges[i] == range)
421 			return i;
422 	}
423 
424 	return 1; /* default: 4000 RPM */
425 }
426 
427 static int max6639_init_client(struct i2c_client *client)
428 {
429 	struct max6639_data *data = i2c_get_clientdata(client);
430 	struct max6639_platform_data *max6639_info =
431 		dev_get_platdata(&client->dev);
432 	int i;
433 	int rpm_range = 1; /* default: 4000 RPM */
434 	int err;
435 
436 	/* Reset chip to default values, see below for GCONFIG setup */
437 	err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
438 				  MAX6639_GCONFIG_POR);
439 	if (err)
440 		goto exit;
441 
442 	/* Fans pulse per revolution is 2 by default */
443 	if (max6639_info && max6639_info->ppr > 0 &&
444 			max6639_info->ppr < 5)
445 		data->ppr = max6639_info->ppr;
446 	else
447 		data->ppr = 2;
448 	data->ppr -= 1;
449 
450 	if (max6639_info)
451 		rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
452 	data->rpm_range = rpm_range;
453 
454 	for (i = 0; i < 2; i++) {
455 
456 		/* Set Fan pulse per revolution */
457 		err = i2c_smbus_write_byte_data(client,
458 				MAX6639_REG_FAN_PPR(i),
459 				data->ppr << 6);
460 		if (err)
461 			goto exit;
462 
463 		/* Fans config PWM, RPM */
464 		err = i2c_smbus_write_byte_data(client,
465 			MAX6639_REG_FAN_CONFIG1(i),
466 			MAX6639_FAN_CONFIG1_PWM | rpm_range);
467 		if (err)
468 			goto exit;
469 
470 		/* Fans PWM polarity high by default */
471 		if (max6639_info && max6639_info->pwm_polarity == 0)
472 			err = i2c_smbus_write_byte_data(client,
473 				MAX6639_REG_FAN_CONFIG2a(i), 0x00);
474 		else
475 			err = i2c_smbus_write_byte_data(client,
476 				MAX6639_REG_FAN_CONFIG2a(i), 0x02);
477 		if (err)
478 			goto exit;
479 
480 		/*
481 		 * /THERM full speed enable,
482 		 * PWM frequency 25kHz, see also GCONFIG below
483 		 */
484 		err = i2c_smbus_write_byte_data(client,
485 			MAX6639_REG_FAN_CONFIG3(i),
486 			MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
487 		if (err)
488 			goto exit;
489 
490 		/* Max. temp. 80C/90C/100C */
491 		data->temp_therm[i] = 80;
492 		data->temp_alert[i] = 90;
493 		data->temp_ot[i] = 100;
494 		err = i2c_smbus_write_byte_data(client,
495 				MAX6639_REG_THERM_LIMIT(i),
496 				data->temp_therm[i]);
497 		if (err)
498 			goto exit;
499 		err = i2c_smbus_write_byte_data(client,
500 				MAX6639_REG_ALERT_LIMIT(i),
501 				data->temp_alert[i]);
502 		if (err)
503 			goto exit;
504 		err = i2c_smbus_write_byte_data(client,
505 				MAX6639_REG_OT_LIMIT(i), data->temp_ot[i]);
506 		if (err)
507 			goto exit;
508 
509 		/* PWM 120/120 (i.e. 100%) */
510 		data->pwm[i] = 120;
511 		err = i2c_smbus_write_byte_data(client,
512 				MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
513 		if (err)
514 			goto exit;
515 	}
516 	/* Start monitoring */
517 	err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
518 		MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
519 		MAX6639_GCONFIG_PWM_FREQ_HI);
520 exit:
521 	return err;
522 }
523 
524 /* Return 0 if detection is successful, -ENODEV otherwise */
525 static int max6639_detect(struct i2c_client *client,
526 			  struct i2c_board_info *info)
527 {
528 	struct i2c_adapter *adapter = client->adapter;
529 	int dev_id, manu_id;
530 
531 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
532 		return -ENODEV;
533 
534 	/* Actual detection via device and manufacturer ID */
535 	dev_id = i2c_smbus_read_byte_data(client, MAX6639_REG_DEVID);
536 	manu_id = i2c_smbus_read_byte_data(client, MAX6639_REG_MANUID);
537 	if (dev_id != 0x58 || manu_id != 0x4D)
538 		return -ENODEV;
539 
540 	strlcpy(info->type, "max6639", I2C_NAME_SIZE);
541 
542 	return 0;
543 }
544 
545 static int max6639_probe(struct i2c_client *client,
546 			 const struct i2c_device_id *id)
547 {
548 	struct max6639_data *data;
549 	int err;
550 
551 	data = devm_kzalloc(&client->dev, sizeof(struct max6639_data),
552 			    GFP_KERNEL);
553 	if (!data)
554 		return -ENOMEM;
555 
556 	i2c_set_clientdata(client, data);
557 	mutex_init(&data->update_lock);
558 
559 	/* Initialize the max6639 chip */
560 	err = max6639_init_client(client);
561 	if (err < 0)
562 		return err;
563 
564 	/* Register sysfs hooks */
565 	err = sysfs_create_group(&client->dev.kobj, &max6639_group);
566 	if (err)
567 		return err;
568 
569 	data->hwmon_dev = hwmon_device_register(&client->dev);
570 	if (IS_ERR(data->hwmon_dev)) {
571 		err = PTR_ERR(data->hwmon_dev);
572 		goto error_remove;
573 	}
574 
575 	dev_info(&client->dev, "temperature sensor and fan control found\n");
576 
577 	return 0;
578 
579 error_remove:
580 	sysfs_remove_group(&client->dev.kobj, &max6639_group);
581 	return err;
582 }
583 
584 static int max6639_remove(struct i2c_client *client)
585 {
586 	struct max6639_data *data = i2c_get_clientdata(client);
587 
588 	hwmon_device_unregister(data->hwmon_dev);
589 	sysfs_remove_group(&client->dev.kobj, &max6639_group);
590 
591 	return 0;
592 }
593 
594 #ifdef CONFIG_PM_SLEEP
595 static int max6639_suspend(struct device *dev)
596 {
597 	struct i2c_client *client = to_i2c_client(dev);
598 	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
599 	if (data < 0)
600 		return data;
601 
602 	return i2c_smbus_write_byte_data(client,
603 			MAX6639_REG_GCONFIG, data | MAX6639_GCONFIG_STANDBY);
604 }
605 
606 static int max6639_resume(struct device *dev)
607 {
608 	struct i2c_client *client = to_i2c_client(dev);
609 	int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
610 	if (data < 0)
611 		return data;
612 
613 	return i2c_smbus_write_byte_data(client,
614 			MAX6639_REG_GCONFIG, data & ~MAX6639_GCONFIG_STANDBY);
615 }
616 #endif /* CONFIG_PM_SLEEP */
617 
618 static const struct i2c_device_id max6639_id[] = {
619 	{"max6639", 0},
620 	{ }
621 };
622 
623 MODULE_DEVICE_TABLE(i2c, max6639_id);
624 
625 static const struct dev_pm_ops max6639_pm_ops = {
626 	SET_SYSTEM_SLEEP_PM_OPS(max6639_suspend, max6639_resume)
627 };
628 
629 static struct i2c_driver max6639_driver = {
630 	.class = I2C_CLASS_HWMON,
631 	.driver = {
632 		   .name = "max6639",
633 		   .pm = &max6639_pm_ops,
634 		   },
635 	.probe = max6639_probe,
636 	.remove = max6639_remove,
637 	.id_table = max6639_id,
638 	.detect = max6639_detect,
639 	.address_list = normal_i2c,
640 };
641 
642 module_i2c_driver(max6639_driver);
643 
644 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
645 MODULE_DESCRIPTION("max6639 driver");
646 MODULE_LICENSE("GPL");
647