xref: /openbmc/linux/drivers/hwmon/jc42.c (revision 81d67439)
1 /*
2  * jc42.c - driver for Jedec JC42.4 compliant temperature sensors
3  *
4  * Copyright (c) 2010  Ericsson AB.
5  *
6  * Derived from lm77.c by Andras BALI <drewie@freemail.hu>.
7  *
8  * JC42.4 compliant temperature sensors are typically used on memory modules.
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23  */
24 
25 #include <linux/module.h>
26 #include <linux/init.h>
27 #include <linux/slab.h>
28 #include <linux/jiffies.h>
29 #include <linux/i2c.h>
30 #include <linux/hwmon.h>
31 #include <linux/hwmon-sysfs.h>
32 #include <linux/err.h>
33 #include <linux/mutex.h>
34 
35 /* Addresses to scan */
36 static const unsigned short normal_i2c[] = {
37 	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, I2C_CLIENT_END };
38 
39 /* JC42 registers. All registers are 16 bit. */
40 #define JC42_REG_CAP		0x00
41 #define JC42_REG_CONFIG		0x01
42 #define JC42_REG_TEMP_UPPER	0x02
43 #define JC42_REG_TEMP_LOWER	0x03
44 #define JC42_REG_TEMP_CRITICAL	0x04
45 #define JC42_REG_TEMP		0x05
46 #define JC42_REG_MANID		0x06
47 #define JC42_REG_DEVICEID	0x07
48 
49 /* Status bits in temperature register */
50 #define JC42_ALARM_CRIT_BIT	15
51 #define JC42_ALARM_MAX_BIT	14
52 #define JC42_ALARM_MIN_BIT	13
53 
54 /* Configuration register defines */
55 #define JC42_CFG_CRIT_ONLY	(1 << 2)
56 #define JC42_CFG_TCRIT_LOCK	(1 << 6)
57 #define JC42_CFG_EVENT_LOCK	(1 << 7)
58 #define JC42_CFG_SHUTDOWN	(1 << 8)
59 #define JC42_CFG_HYST_SHIFT	9
60 #define JC42_CFG_HYST_MASK	0x03
61 
62 /* Capabilities */
63 #define JC42_CAP_RANGE		(1 << 2)
64 
65 /* Manufacturer IDs */
66 #define ADT_MANID		0x11d4  /* Analog Devices */
67 #define MAX_MANID		0x004d  /* Maxim */
68 #define IDT_MANID		0x00b3  /* IDT */
69 #define MCP_MANID		0x0054  /* Microchip */
70 #define NXP_MANID		0x1131  /* NXP Semiconductors */
71 #define ONS_MANID		0x1b09  /* ON Semiconductor */
72 #define STM_MANID		0x104a  /* ST Microelectronics */
73 
74 /* Supported chips */
75 
76 /* Analog Devices */
77 #define ADT7408_DEVID		0x0801
78 #define ADT7408_DEVID_MASK	0xffff
79 
80 /* IDT */
81 #define TS3000B3_DEVID		0x2903  /* Also matches TSE2002B3 */
82 #define TS3000B3_DEVID_MASK	0xffff
83 
84 /* Maxim */
85 #define MAX6604_DEVID		0x3e00
86 #define MAX6604_DEVID_MASK	0xffff
87 
88 /* Microchip */
89 #define MCP98242_DEVID		0x2000
90 #define MCP98242_DEVID_MASK	0xfffc
91 
92 #define MCP98243_DEVID		0x2100
93 #define MCP98243_DEVID_MASK	0xfffc
94 
95 #define MCP9843_DEVID		0x0000	/* Also matches mcp9805 */
96 #define MCP9843_DEVID_MASK	0xfffe
97 
98 /* NXP */
99 #define SE97_DEVID		0xa200
100 #define SE97_DEVID_MASK		0xfffc
101 
102 #define SE98_DEVID		0xa100
103 #define SE98_DEVID_MASK		0xfffc
104 
105 /* ON Semiconductor */
106 #define CAT6095_DEVID		0x0800	/* Also matches CAT34TS02 */
107 #define CAT6095_DEVID_MASK	0xffe0
108 
109 /* ST Microelectronics */
110 #define STTS424_DEVID		0x0101
111 #define STTS424_DEVID_MASK	0xffff
112 
113 #define STTS424E_DEVID		0x0000
114 #define STTS424E_DEVID_MASK	0xfffe
115 
116 static u16 jc42_hysteresis[] = { 0, 1500, 3000, 6000 };
117 
118 struct jc42_chips {
119 	u16 manid;
120 	u16 devid;
121 	u16 devid_mask;
122 };
123 
124 static struct jc42_chips jc42_chips[] = {
125 	{ ADT_MANID, ADT7408_DEVID, ADT7408_DEVID_MASK },
126 	{ IDT_MANID, TS3000B3_DEVID, TS3000B3_DEVID_MASK },
127 	{ MAX_MANID, MAX6604_DEVID, MAX6604_DEVID_MASK },
128 	{ MCP_MANID, MCP98242_DEVID, MCP98242_DEVID_MASK },
129 	{ MCP_MANID, MCP98243_DEVID, MCP98243_DEVID_MASK },
130 	{ MCP_MANID, MCP9843_DEVID, MCP9843_DEVID_MASK },
131 	{ NXP_MANID, SE97_DEVID, SE97_DEVID_MASK },
132 	{ ONS_MANID, CAT6095_DEVID, CAT6095_DEVID_MASK },
133 	{ NXP_MANID, SE98_DEVID, SE98_DEVID_MASK },
134 	{ STM_MANID, STTS424_DEVID, STTS424_DEVID_MASK },
135 	{ STM_MANID, STTS424E_DEVID, STTS424E_DEVID_MASK },
136 };
137 
138 /* Each client has this additional data */
139 struct jc42_data {
140 	struct device	*hwmon_dev;
141 	struct mutex	update_lock;	/* protect register access */
142 	bool		extended;	/* true if extended range supported */
143 	bool		valid;
144 	unsigned long	last_updated;	/* In jiffies */
145 	u16		orig_config;	/* original configuration */
146 	u16		config;		/* current configuration */
147 	u16		temp_input;	/* Temperatures */
148 	u16		temp_crit;
149 	u16		temp_min;
150 	u16		temp_max;
151 };
152 
153 static int jc42_probe(struct i2c_client *client,
154 		      const struct i2c_device_id *id);
155 static int jc42_detect(struct i2c_client *client, struct i2c_board_info *info);
156 static int jc42_remove(struct i2c_client *client);
157 static int jc42_read_value(struct i2c_client *client, u8 reg);
158 static int jc42_write_value(struct i2c_client *client, u8 reg, u16 value);
159 
160 static struct jc42_data *jc42_update_device(struct device *dev);
161 
162 static const struct i2c_device_id jc42_id[] = {
163 	{ "adt7408", 0 },
164 	{ "cat94ts02", 0 },
165 	{ "cat6095", 0 },
166 	{ "jc42", 0 },
167 	{ "max6604", 0 },
168 	{ "mcp9805", 0 },
169 	{ "mcp98242", 0 },
170 	{ "mcp98243", 0 },
171 	{ "mcp9843", 0 },
172 	{ "se97", 0 },
173 	{ "se97b", 0 },
174 	{ "se98", 0 },
175 	{ "stts424", 0 },
176 	{ "tse2002b3", 0 },
177 	{ "ts3000b3", 0 },
178 	{ }
179 };
180 MODULE_DEVICE_TABLE(i2c, jc42_id);
181 
182 #ifdef CONFIG_PM
183 
184 static int jc42_suspend(struct device *dev)
185 {
186 	struct i2c_client *client = to_i2c_client(dev);
187 	struct jc42_data *data = i2c_get_clientdata(client);
188 
189 	data->config |= JC42_CFG_SHUTDOWN;
190 	jc42_write_value(client, JC42_REG_CONFIG, data->config);
191 	return 0;
192 }
193 
194 static int jc42_resume(struct device *dev)
195 {
196 	struct i2c_client *client = to_i2c_client(dev);
197 	struct jc42_data *data = i2c_get_clientdata(client);
198 
199 	data->config &= ~JC42_CFG_SHUTDOWN;
200 	jc42_write_value(client, JC42_REG_CONFIG, data->config);
201 	return 0;
202 }
203 
204 static const struct dev_pm_ops jc42_dev_pm_ops = {
205 	.suspend = jc42_suspend,
206 	.resume = jc42_resume,
207 };
208 
209 #define JC42_DEV_PM_OPS (&jc42_dev_pm_ops)
210 #else
211 #define JC42_DEV_PM_OPS NULL
212 #endif /* CONFIG_PM */
213 
214 /* This is the driver that will be inserted */
215 static struct i2c_driver jc42_driver = {
216 	.class		= I2C_CLASS_SPD,
217 	.driver = {
218 		.name	= "jc42",
219 		.pm = JC42_DEV_PM_OPS,
220 	},
221 	.probe		= jc42_probe,
222 	.remove		= jc42_remove,
223 	.id_table	= jc42_id,
224 	.detect		= jc42_detect,
225 	.address_list	= normal_i2c,
226 };
227 
228 #define JC42_TEMP_MIN_EXTENDED	(-40000)
229 #define JC42_TEMP_MIN		0
230 #define JC42_TEMP_MAX		125000
231 
232 static u16 jc42_temp_to_reg(int temp, bool extended)
233 {
234 	int ntemp = SENSORS_LIMIT(temp,
235 				  extended ? JC42_TEMP_MIN_EXTENDED :
236 				  JC42_TEMP_MIN, JC42_TEMP_MAX);
237 
238 	/* convert from 0.001 to 0.0625 resolution */
239 	return (ntemp * 2 / 125) & 0x1fff;
240 }
241 
242 static int jc42_temp_from_reg(s16 reg)
243 {
244 	reg &= 0x1fff;
245 
246 	/* sign extend register */
247 	if (reg & 0x1000)
248 		reg |= 0xf000;
249 
250 	/* convert from 0.0625 to 0.001 resolution */
251 	return reg * 125 / 2;
252 }
253 
254 /* sysfs stuff */
255 
256 /* read routines for temperature limits */
257 #define show(value)	\
258 static ssize_t show_##value(struct device *dev,				\
259 			    struct device_attribute *attr,		\
260 			    char *buf)					\
261 {									\
262 	struct jc42_data *data = jc42_update_device(dev);		\
263 	if (IS_ERR(data))						\
264 		return PTR_ERR(data);					\
265 	return sprintf(buf, "%d\n", jc42_temp_from_reg(data->value));	\
266 }
267 
268 show(temp_input);
269 show(temp_crit);
270 show(temp_min);
271 show(temp_max);
272 
273 /* read routines for hysteresis values */
274 static ssize_t show_temp_crit_hyst(struct device *dev,
275 				   struct device_attribute *attr, char *buf)
276 {
277 	struct jc42_data *data = jc42_update_device(dev);
278 	int temp, hyst;
279 
280 	if (IS_ERR(data))
281 		return PTR_ERR(data);
282 
283 	temp = jc42_temp_from_reg(data->temp_crit);
284 	hyst = jc42_hysteresis[(data->config >> JC42_CFG_HYST_SHIFT)
285 			       & JC42_CFG_HYST_MASK];
286 	return sprintf(buf, "%d\n", temp - hyst);
287 }
288 
289 static ssize_t show_temp_max_hyst(struct device *dev,
290 				  struct device_attribute *attr, char *buf)
291 {
292 	struct jc42_data *data = jc42_update_device(dev);
293 	int temp, hyst;
294 
295 	if (IS_ERR(data))
296 		return PTR_ERR(data);
297 
298 	temp = jc42_temp_from_reg(data->temp_max);
299 	hyst = jc42_hysteresis[(data->config >> JC42_CFG_HYST_SHIFT)
300 			       & JC42_CFG_HYST_MASK];
301 	return sprintf(buf, "%d\n", temp - hyst);
302 }
303 
304 /* write routines */
305 #define set(value, reg)	\
306 static ssize_t set_##value(struct device *dev,				\
307 			   struct device_attribute *attr,		\
308 			   const char *buf, size_t count)		\
309 {									\
310 	struct i2c_client *client = to_i2c_client(dev);			\
311 	struct jc42_data *data = i2c_get_clientdata(client);		\
312 	int err, ret = count;						\
313 	long val;							\
314 	if (strict_strtol(buf, 10, &val) < 0)				\
315 		return -EINVAL;						\
316 	mutex_lock(&data->update_lock);					\
317 	data->value = jc42_temp_to_reg(val, data->extended);		\
318 	err = jc42_write_value(client, reg, data->value);		\
319 	if (err < 0)							\
320 		ret = err;						\
321 	mutex_unlock(&data->update_lock);				\
322 	return ret;							\
323 }
324 
325 set(temp_min, JC42_REG_TEMP_LOWER);
326 set(temp_max, JC42_REG_TEMP_UPPER);
327 set(temp_crit, JC42_REG_TEMP_CRITICAL);
328 
329 /* JC42.4 compliant chips only support four hysteresis values.
330  * Pick best choice and go from there. */
331 static ssize_t set_temp_crit_hyst(struct device *dev,
332 				  struct device_attribute *attr,
333 				  const char *buf, size_t count)
334 {
335 	struct i2c_client *client = to_i2c_client(dev);
336 	struct jc42_data *data = i2c_get_clientdata(client);
337 	unsigned long val;
338 	int diff, hyst;
339 	int err;
340 	int ret = count;
341 
342 	if (strict_strtoul(buf, 10, &val) < 0)
343 		return -EINVAL;
344 
345 	diff = jc42_temp_from_reg(data->temp_crit) - val;
346 	hyst = 0;
347 	if (diff > 0) {
348 		if (diff < 2250)
349 			hyst = 1;	/* 1.5 degrees C */
350 		else if (diff < 4500)
351 			hyst = 2;	/* 3.0 degrees C */
352 		else
353 			hyst = 3;	/* 6.0 degrees C */
354 	}
355 
356 	mutex_lock(&data->update_lock);
357 	data->config = (data->config
358 			& ~(JC42_CFG_HYST_MASK << JC42_CFG_HYST_SHIFT))
359 	  | (hyst << JC42_CFG_HYST_SHIFT);
360 	err = jc42_write_value(client, JC42_REG_CONFIG, data->config);
361 	if (err < 0)
362 		ret = err;
363 	mutex_unlock(&data->update_lock);
364 	return ret;
365 }
366 
367 static ssize_t show_alarm(struct device *dev,
368 			  struct device_attribute *attr, char *buf)
369 {
370 	u16 bit = to_sensor_dev_attr(attr)->index;
371 	struct jc42_data *data = jc42_update_device(dev);
372 	u16 val;
373 
374 	if (IS_ERR(data))
375 		return PTR_ERR(data);
376 
377 	val = data->temp_input;
378 	if (bit != JC42_ALARM_CRIT_BIT && (data->config & JC42_CFG_CRIT_ONLY))
379 		val = 0;
380 	return sprintf(buf, "%u\n", (val >> bit) & 1);
381 }
382 
383 static DEVICE_ATTR(temp1_input, S_IRUGO,
384 		   show_temp_input, NULL);
385 static DEVICE_ATTR(temp1_crit, S_IRUGO,
386 		   show_temp_crit, set_temp_crit);
387 static DEVICE_ATTR(temp1_min, S_IRUGO,
388 		   show_temp_min, set_temp_min);
389 static DEVICE_ATTR(temp1_max, S_IRUGO,
390 		   show_temp_max, set_temp_max);
391 
392 static DEVICE_ATTR(temp1_crit_hyst, S_IRUGO,
393 		   show_temp_crit_hyst, set_temp_crit_hyst);
394 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
395 		   show_temp_max_hyst, NULL);
396 
397 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
398 			  JC42_ALARM_CRIT_BIT);
399 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
400 			  JC42_ALARM_MIN_BIT);
401 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
402 			  JC42_ALARM_MAX_BIT);
403 
404 static struct attribute *jc42_attributes[] = {
405 	&dev_attr_temp1_input.attr,
406 	&dev_attr_temp1_crit.attr,
407 	&dev_attr_temp1_min.attr,
408 	&dev_attr_temp1_max.attr,
409 	&dev_attr_temp1_crit_hyst.attr,
410 	&dev_attr_temp1_max_hyst.attr,
411 	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
412 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
413 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
414 	NULL
415 };
416 
417 static mode_t jc42_attribute_mode(struct kobject *kobj,
418 				  struct attribute *attr, int index)
419 {
420 	struct device *dev = container_of(kobj, struct device, kobj);
421 	struct i2c_client *client = to_i2c_client(dev);
422 	struct jc42_data *data = i2c_get_clientdata(client);
423 	unsigned int config = data->config;
424 	bool readonly;
425 
426 	if (attr == &dev_attr_temp1_crit.attr)
427 		readonly = config & JC42_CFG_TCRIT_LOCK;
428 	else if (attr == &dev_attr_temp1_min.attr ||
429 		 attr == &dev_attr_temp1_max.attr)
430 		readonly = config & JC42_CFG_EVENT_LOCK;
431 	else if (attr == &dev_attr_temp1_crit_hyst.attr)
432 		readonly = config & (JC42_CFG_EVENT_LOCK | JC42_CFG_TCRIT_LOCK);
433 	else
434 		readonly = true;
435 
436 	return S_IRUGO | (readonly ? 0 : S_IWUSR);
437 }
438 
439 static const struct attribute_group jc42_group = {
440 	.attrs = jc42_attributes,
441 	.is_visible = jc42_attribute_mode,
442 };
443 
444 /* Return 0 if detection is successful, -ENODEV otherwise */
445 static int jc42_detect(struct i2c_client *new_client,
446 		       struct i2c_board_info *info)
447 {
448 	struct i2c_adapter *adapter = new_client->adapter;
449 	int i, config, cap, manid, devid;
450 
451 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
452 				     I2C_FUNC_SMBUS_WORD_DATA))
453 		return -ENODEV;
454 
455 	cap = jc42_read_value(new_client, JC42_REG_CAP);
456 	config = jc42_read_value(new_client, JC42_REG_CONFIG);
457 	manid = jc42_read_value(new_client, JC42_REG_MANID);
458 	devid = jc42_read_value(new_client, JC42_REG_DEVICEID);
459 
460 	if (cap < 0 || config < 0 || manid < 0 || devid < 0)
461 		return -ENODEV;
462 
463 	if ((cap & 0xff00) || (config & 0xf800))
464 		return -ENODEV;
465 
466 	for (i = 0; i < ARRAY_SIZE(jc42_chips); i++) {
467 		struct jc42_chips *chip = &jc42_chips[i];
468 		if (manid == chip->manid &&
469 		    (devid & chip->devid_mask) == chip->devid) {
470 			strlcpy(info->type, "jc42", I2C_NAME_SIZE);
471 			return 0;
472 		}
473 	}
474 	return -ENODEV;
475 }
476 
477 static int jc42_probe(struct i2c_client *new_client,
478 		      const struct i2c_device_id *id)
479 {
480 	struct jc42_data *data;
481 	int config, cap, err;
482 
483 	data = kzalloc(sizeof(struct jc42_data), GFP_KERNEL);
484 	if (!data) {
485 		err = -ENOMEM;
486 		goto exit;
487 	}
488 
489 	i2c_set_clientdata(new_client, data);
490 	mutex_init(&data->update_lock);
491 
492 	cap = jc42_read_value(new_client, JC42_REG_CAP);
493 	if (cap < 0) {
494 		err = -EINVAL;
495 		goto exit_free;
496 	}
497 	data->extended = !!(cap & JC42_CAP_RANGE);
498 
499 	config = jc42_read_value(new_client, JC42_REG_CONFIG);
500 	if (config < 0) {
501 		err = -EINVAL;
502 		goto exit_free;
503 	}
504 	data->orig_config = config;
505 	if (config & JC42_CFG_SHUTDOWN) {
506 		config &= ~JC42_CFG_SHUTDOWN;
507 		jc42_write_value(new_client, JC42_REG_CONFIG, config);
508 	}
509 	data->config = config;
510 
511 	/* Register sysfs hooks */
512 	err = sysfs_create_group(&new_client->dev.kobj, &jc42_group);
513 	if (err)
514 		goto exit_free;
515 
516 	data->hwmon_dev = hwmon_device_register(&new_client->dev);
517 	if (IS_ERR(data->hwmon_dev)) {
518 		err = PTR_ERR(data->hwmon_dev);
519 		goto exit_remove;
520 	}
521 
522 	return 0;
523 
524 exit_remove:
525 	sysfs_remove_group(&new_client->dev.kobj, &jc42_group);
526 exit_free:
527 	kfree(data);
528 exit:
529 	return err;
530 }
531 
532 static int jc42_remove(struct i2c_client *client)
533 {
534 	struct jc42_data *data = i2c_get_clientdata(client);
535 	hwmon_device_unregister(data->hwmon_dev);
536 	sysfs_remove_group(&client->dev.kobj, &jc42_group);
537 	if (data->config != data->orig_config)
538 		jc42_write_value(client, JC42_REG_CONFIG, data->orig_config);
539 	kfree(data);
540 	return 0;
541 }
542 
543 /* All registers are word-sized. */
544 static int jc42_read_value(struct i2c_client *client, u8 reg)
545 {
546 	int ret = i2c_smbus_read_word_data(client, reg);
547 	if (ret < 0)
548 		return ret;
549 	return swab16(ret);
550 }
551 
552 static int jc42_write_value(struct i2c_client *client, u8 reg, u16 value)
553 {
554 	return i2c_smbus_write_word_data(client, reg, swab16(value));
555 }
556 
557 static struct jc42_data *jc42_update_device(struct device *dev)
558 {
559 	struct i2c_client *client = to_i2c_client(dev);
560 	struct jc42_data *data = i2c_get_clientdata(client);
561 	struct jc42_data *ret = data;
562 	int val;
563 
564 	mutex_lock(&data->update_lock);
565 
566 	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
567 		val = jc42_read_value(client, JC42_REG_TEMP);
568 		if (val < 0) {
569 			ret = ERR_PTR(val);
570 			goto abort;
571 		}
572 		data->temp_input = val;
573 
574 		val = jc42_read_value(client, JC42_REG_TEMP_CRITICAL);
575 		if (val < 0) {
576 			ret = ERR_PTR(val);
577 			goto abort;
578 		}
579 		data->temp_crit = val;
580 
581 		val = jc42_read_value(client, JC42_REG_TEMP_LOWER);
582 		if (val < 0) {
583 			ret = ERR_PTR(val);
584 			goto abort;
585 		}
586 		data->temp_min = val;
587 
588 		val = jc42_read_value(client, JC42_REG_TEMP_UPPER);
589 		if (val < 0) {
590 			ret = ERR_PTR(val);
591 			goto abort;
592 		}
593 		data->temp_max = val;
594 
595 		data->last_updated = jiffies;
596 		data->valid = true;
597 	}
598 abort:
599 	mutex_unlock(&data->update_lock);
600 	return ret;
601 }
602 
603 static int __init sensors_jc42_init(void)
604 {
605 	return i2c_add_driver(&jc42_driver);
606 }
607 
608 static void __exit sensors_jc42_exit(void)
609 {
610 	i2c_del_driver(&jc42_driver);
611 }
612 
613 MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
614 MODULE_DESCRIPTION("JC42 driver");
615 MODULE_LICENSE("GPL");
616 
617 module_init(sensors_jc42_init);
618 module_exit(sensors_jc42_exit);
619