xref: /openbmc/linux/drivers/hwmon/emc6w201.c (revision 63dc02bd)
1 /*
2  * emc6w201.c - Hardware monitoring driver for the SMSC EMC6W201
3  * Copyright (C) 2011  Jean Delvare <khali@linux-fr.org>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18  */
19 
20 #include <linux/module.h>
21 #include <linux/delay.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/jiffies.h>
25 #include <linux/i2c.h>
26 #include <linux/hwmon.h>
27 #include <linux/hwmon-sysfs.h>
28 #include <linux/err.h>
29 #include <linux/mutex.h>
30 
31 /*
32  * Addresses to scan
33  */
34 
35 static const unsigned short normal_i2c[] = { 0x2c, 0x2d, 0x2e, I2C_CLIENT_END };
36 
37 /*
38  * The EMC6W201 registers
39  */
40 
41 #define EMC6W201_REG_IN(nr)		(0x20 + (nr))
42 #define EMC6W201_REG_TEMP(nr)		(0x26 + (nr))
43 #define EMC6W201_REG_FAN(nr)		(0x2C + (nr) * 2)
44 #define EMC6W201_REG_COMPANY		0x3E
45 #define EMC6W201_REG_VERSTEP		0x3F
46 #define EMC6W201_REG_CONFIG		0x40
47 #define EMC6W201_REG_IN_LOW(nr)		(0x4A + (nr) * 2)
48 #define EMC6W201_REG_IN_HIGH(nr)	(0x4B + (nr) * 2)
49 #define EMC6W201_REG_TEMP_LOW(nr)	(0x56 + (nr) * 2)
50 #define EMC6W201_REG_TEMP_HIGH(nr)	(0x57 + (nr) * 2)
51 #define EMC6W201_REG_FAN_MIN(nr)	(0x62 + (nr) * 2)
52 
53 enum { input, min, max } subfeature;
54 
55 /*
56  * Per-device data
57  */
58 
59 struct emc6w201_data {
60 	struct device *hwmon_dev;
61 	struct mutex update_lock;
62 	char valid; /* zero until following fields are valid */
63 	unsigned long last_updated; /* in jiffies */
64 
65 	/* registers values */
66 	u8 in[3][6];
67 	s8 temp[3][6];
68 	u16 fan[2][5];
69 };
70 
71 /*
72  * Combine LSB and MSB registers in a single value
73  * Locking: must be called with data->update_lock held
74  */
75 static u16 emc6w201_read16(struct i2c_client *client, u8 reg)
76 {
77 	int lsb, msb;
78 
79 	lsb = i2c_smbus_read_byte_data(client, reg);
80 	msb = i2c_smbus_read_byte_data(client, reg + 1);
81 	if (unlikely(lsb < 0 || msb < 0)) {
82 		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
83 			16, "read", reg);
84 		return 0xFFFF;	/* Arbitrary value */
85 	}
86 
87 	return (msb << 8) | lsb;
88 }
89 
90 /*
91  * Write 16-bit value to LSB and MSB registers
92  * Locking: must be called with data->update_lock held
93  */
94 static int emc6w201_write16(struct i2c_client *client, u8 reg, u16 val)
95 {
96 	int err;
97 
98 	err = i2c_smbus_write_byte_data(client, reg, val & 0xff);
99 	if (likely(!err))
100 		err = i2c_smbus_write_byte_data(client, reg + 1, val >> 8);
101 	if (unlikely(err < 0))
102 		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
103 			16, "write", reg);
104 
105 	return err;
106 }
107 
108 /* Read 8-bit value from register */
109 static u8 emc6w201_read8(struct i2c_client *client, u8 reg)
110 {
111 	int val;
112 
113 	val = i2c_smbus_read_byte_data(client, reg);
114 	if (unlikely(val < 0)) {
115 		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
116 			8, "read", reg);
117 		return 0x00;	/* Arbitrary value */
118 	}
119 
120 	return val;
121 }
122 
123 /* Write 8-bit value to register */
124 static int emc6w201_write8(struct i2c_client *client, u8 reg, u8 val)
125 {
126 	int err;
127 
128 	err = i2c_smbus_write_byte_data(client, reg, val);
129 	if (unlikely(err < 0))
130 		dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
131 			8, "write", reg);
132 
133 	return err;
134 }
135 
136 static struct emc6w201_data *emc6w201_update_device(struct device *dev)
137 {
138 	struct i2c_client *client = to_i2c_client(dev);
139 	struct emc6w201_data *data = i2c_get_clientdata(client);
140 	int nr;
141 
142 	mutex_lock(&data->update_lock);
143 
144 	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
145 		for (nr = 0; nr < 6; nr++) {
146 			data->in[input][nr] =
147 				emc6w201_read8(client,
148 						EMC6W201_REG_IN(nr));
149 			data->in[min][nr] =
150 				emc6w201_read8(client,
151 						EMC6W201_REG_IN_LOW(nr));
152 			data->in[max][nr] =
153 				emc6w201_read8(client,
154 						EMC6W201_REG_IN_HIGH(nr));
155 		}
156 
157 		for (nr = 0; nr < 6; nr++) {
158 			data->temp[input][nr] =
159 				emc6w201_read8(client,
160 						EMC6W201_REG_TEMP(nr));
161 			data->temp[min][nr] =
162 				emc6w201_read8(client,
163 						EMC6W201_REG_TEMP_LOW(nr));
164 			data->temp[max][nr] =
165 				emc6w201_read8(client,
166 						EMC6W201_REG_TEMP_HIGH(nr));
167 		}
168 
169 		for (nr = 0; nr < 5; nr++) {
170 			data->fan[input][nr] =
171 				emc6w201_read16(client,
172 						EMC6W201_REG_FAN(nr));
173 			data->fan[min][nr] =
174 				emc6w201_read16(client,
175 						EMC6W201_REG_FAN_MIN(nr));
176 		}
177 
178 		data->last_updated = jiffies;
179 		data->valid = 1;
180 	}
181 
182 	mutex_unlock(&data->update_lock);
183 
184 	return data;
185 }
186 
187 /*
188  * Sysfs callback functions
189  */
190 
191 static const u16 nominal_mv[6] = { 2500, 1500, 3300, 5000, 1500, 1500 };
192 
193 static ssize_t show_in(struct device *dev, struct device_attribute *devattr,
194 	char *buf)
195 {
196 	struct emc6w201_data *data = emc6w201_update_device(dev);
197 	int sf = to_sensor_dev_attr_2(devattr)->index;
198 	int nr = to_sensor_dev_attr_2(devattr)->nr;
199 
200 	return sprintf(buf, "%u\n",
201 		       (unsigned)data->in[sf][nr] * nominal_mv[nr] / 0xC0);
202 }
203 
204 static ssize_t set_in(struct device *dev, struct device_attribute *devattr,
205 		      const char *buf, size_t count)
206 {
207 	struct i2c_client *client = to_i2c_client(dev);
208 	struct emc6w201_data *data = i2c_get_clientdata(client);
209 	int sf = to_sensor_dev_attr_2(devattr)->index;
210 	int nr = to_sensor_dev_attr_2(devattr)->nr;
211 	int err;
212 	long val;
213 	u8 reg;
214 
215 	err = kstrtol(buf, 10, &val);
216 	if (err < 0)
217 		return err;
218 
219 	val = DIV_ROUND_CLOSEST(val * 0xC0, nominal_mv[nr]);
220 	reg = (sf == min) ? EMC6W201_REG_IN_LOW(nr)
221 			  : EMC6W201_REG_IN_HIGH(nr);
222 
223 	mutex_lock(&data->update_lock);
224 	data->in[sf][nr] = SENSORS_LIMIT(val, 0, 255);
225 	err = emc6w201_write8(client, reg, data->in[sf][nr]);
226 	mutex_unlock(&data->update_lock);
227 
228 	return err < 0 ? err : count;
229 }
230 
231 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
232 	char *buf)
233 {
234 	struct emc6w201_data *data = emc6w201_update_device(dev);
235 	int sf = to_sensor_dev_attr_2(devattr)->index;
236 	int nr = to_sensor_dev_attr_2(devattr)->nr;
237 
238 	return sprintf(buf, "%d\n", (int)data->temp[sf][nr] * 1000);
239 }
240 
241 static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
242 			const char *buf, size_t count)
243 {
244 	struct i2c_client *client = to_i2c_client(dev);
245 	struct emc6w201_data *data = i2c_get_clientdata(client);
246 	int sf = to_sensor_dev_attr_2(devattr)->index;
247 	int nr = to_sensor_dev_attr_2(devattr)->nr;
248 	int err;
249 	long val;
250 	u8 reg;
251 
252 	err = kstrtol(buf, 10, &val);
253 	if (err < 0)
254 		return err;
255 
256 	val /= 1000;
257 	reg = (sf == min) ? EMC6W201_REG_TEMP_LOW(nr)
258 			  : EMC6W201_REG_TEMP_HIGH(nr);
259 
260 	mutex_lock(&data->update_lock);
261 	data->temp[sf][nr] = SENSORS_LIMIT(val, -127, 128);
262 	err = emc6w201_write8(client, reg, data->temp[sf][nr]);
263 	mutex_unlock(&data->update_lock);
264 
265 	return err < 0 ? err : count;
266 }
267 
268 static ssize_t show_fan(struct device *dev, struct device_attribute *devattr,
269 	char *buf)
270 {
271 	struct emc6w201_data *data = emc6w201_update_device(dev);
272 	int sf = to_sensor_dev_attr_2(devattr)->index;
273 	int nr = to_sensor_dev_attr_2(devattr)->nr;
274 	unsigned rpm;
275 
276 	if (data->fan[sf][nr] == 0 || data->fan[sf][nr] == 0xFFFF)
277 		rpm = 0;
278 	else
279 		rpm = 5400000U / data->fan[sf][nr];
280 
281 	return sprintf(buf, "%u\n", rpm);
282 }
283 
284 static ssize_t set_fan(struct device *dev, struct device_attribute *devattr,
285 		       const char *buf, size_t count)
286 {
287 	struct i2c_client *client = to_i2c_client(dev);
288 	struct emc6w201_data *data = i2c_get_clientdata(client);
289 	int sf = to_sensor_dev_attr_2(devattr)->index;
290 	int nr = to_sensor_dev_attr_2(devattr)->nr;
291 	int err;
292 	unsigned long val;
293 
294 	err = kstrtoul(buf, 10, &val);
295 	if (err < 0)
296 		return err;
297 
298 	if (val == 0) {
299 		val = 0xFFFF;
300 	} else {
301 		val = DIV_ROUND_CLOSEST(5400000U, val);
302 		val = SENSORS_LIMIT(val, 0, 0xFFFE);
303 	}
304 
305 	mutex_lock(&data->update_lock);
306 	data->fan[sf][nr] = val;
307 	err = emc6w201_write16(client, EMC6W201_REG_FAN_MIN(nr),
308 			       data->fan[sf][nr]);
309 	mutex_unlock(&data->update_lock);
310 
311 	return err < 0 ? err : count;
312 }
313 
314 static SENSOR_DEVICE_ATTR_2(in0_input, S_IRUGO, show_in, NULL, 0, input);
315 static SENSOR_DEVICE_ATTR_2(in0_min, S_IRUGO | S_IWUSR, show_in, set_in,
316 			    0, min);
317 static SENSOR_DEVICE_ATTR_2(in0_max, S_IRUGO | S_IWUSR, show_in, set_in,
318 			    0, max);
319 static SENSOR_DEVICE_ATTR_2(in1_input, S_IRUGO, show_in, NULL, 1, input);
320 static SENSOR_DEVICE_ATTR_2(in1_min, S_IRUGO | S_IWUSR, show_in, set_in,
321 			    1, min);
322 static SENSOR_DEVICE_ATTR_2(in1_max, S_IRUGO | S_IWUSR, show_in, set_in,
323 			    1, max);
324 static SENSOR_DEVICE_ATTR_2(in2_input, S_IRUGO, show_in, NULL, 2, input);
325 static SENSOR_DEVICE_ATTR_2(in2_min, S_IRUGO | S_IWUSR, show_in, set_in,
326 			    2, min);
327 static SENSOR_DEVICE_ATTR_2(in2_max, S_IRUGO | S_IWUSR, show_in, set_in,
328 			    2, max);
329 static SENSOR_DEVICE_ATTR_2(in3_input, S_IRUGO, show_in, NULL, 3, input);
330 static SENSOR_DEVICE_ATTR_2(in3_min, S_IRUGO | S_IWUSR, show_in, set_in,
331 			    3, min);
332 static SENSOR_DEVICE_ATTR_2(in3_max, S_IRUGO | S_IWUSR, show_in, set_in,
333 			    3, max);
334 static SENSOR_DEVICE_ATTR_2(in4_input, S_IRUGO, show_in, NULL, 4, input);
335 static SENSOR_DEVICE_ATTR_2(in4_min, S_IRUGO | S_IWUSR, show_in, set_in,
336 			    4, min);
337 static SENSOR_DEVICE_ATTR_2(in4_max, S_IRUGO | S_IWUSR, show_in, set_in,
338 			    4, max);
339 static SENSOR_DEVICE_ATTR_2(in5_input, S_IRUGO, show_in, NULL, 5, input);
340 static SENSOR_DEVICE_ATTR_2(in5_min, S_IRUGO | S_IWUSR, show_in, set_in,
341 			    5, min);
342 static SENSOR_DEVICE_ATTR_2(in5_max, S_IRUGO | S_IWUSR, show_in, set_in,
343 			    5, max);
344 
345 static SENSOR_DEVICE_ATTR_2(temp1_input, S_IRUGO, show_temp, NULL, 0, input);
346 static SENSOR_DEVICE_ATTR_2(temp1_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
347 			    0, min);
348 static SENSOR_DEVICE_ATTR_2(temp1_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
349 			    0, max);
350 static SENSOR_DEVICE_ATTR_2(temp2_input, S_IRUGO, show_temp, NULL, 1, input);
351 static SENSOR_DEVICE_ATTR_2(temp2_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
352 			    1, min);
353 static SENSOR_DEVICE_ATTR_2(temp2_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
354 			    1, max);
355 static SENSOR_DEVICE_ATTR_2(temp3_input, S_IRUGO, show_temp, NULL, 2, input);
356 static SENSOR_DEVICE_ATTR_2(temp3_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
357 			    2, min);
358 static SENSOR_DEVICE_ATTR_2(temp3_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
359 			    2, max);
360 static SENSOR_DEVICE_ATTR_2(temp4_input, S_IRUGO, show_temp, NULL, 3, input);
361 static SENSOR_DEVICE_ATTR_2(temp4_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
362 			    3, min);
363 static SENSOR_DEVICE_ATTR_2(temp4_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
364 			    3, max);
365 static SENSOR_DEVICE_ATTR_2(temp5_input, S_IRUGO, show_temp, NULL, 4, input);
366 static SENSOR_DEVICE_ATTR_2(temp5_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
367 			    4, min);
368 static SENSOR_DEVICE_ATTR_2(temp5_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
369 			    4, max);
370 static SENSOR_DEVICE_ATTR_2(temp6_input, S_IRUGO, show_temp, NULL, 5, input);
371 static SENSOR_DEVICE_ATTR_2(temp6_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
372 			    5, min);
373 static SENSOR_DEVICE_ATTR_2(temp6_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
374 			    5, max);
375 
376 static SENSOR_DEVICE_ATTR_2(fan1_input, S_IRUGO, show_fan, NULL, 0, input);
377 static SENSOR_DEVICE_ATTR_2(fan1_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
378 			    0, min);
379 static SENSOR_DEVICE_ATTR_2(fan2_input, S_IRUGO, show_fan, NULL, 1, input);
380 static SENSOR_DEVICE_ATTR_2(fan2_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
381 			    1, min);
382 static SENSOR_DEVICE_ATTR_2(fan3_input, S_IRUGO, show_fan, NULL, 2, input);
383 static SENSOR_DEVICE_ATTR_2(fan3_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
384 			    2, min);
385 static SENSOR_DEVICE_ATTR_2(fan4_input, S_IRUGO, show_fan, NULL, 3, input);
386 static SENSOR_DEVICE_ATTR_2(fan4_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
387 			    3, min);
388 static SENSOR_DEVICE_ATTR_2(fan5_input, S_IRUGO, show_fan, NULL, 4, input);
389 static SENSOR_DEVICE_ATTR_2(fan5_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
390 			    4, min);
391 
392 static struct attribute *emc6w201_attributes[] = {
393 	&sensor_dev_attr_in0_input.dev_attr.attr,
394 	&sensor_dev_attr_in0_min.dev_attr.attr,
395 	&sensor_dev_attr_in0_max.dev_attr.attr,
396 	&sensor_dev_attr_in1_input.dev_attr.attr,
397 	&sensor_dev_attr_in1_min.dev_attr.attr,
398 	&sensor_dev_attr_in1_max.dev_attr.attr,
399 	&sensor_dev_attr_in2_input.dev_attr.attr,
400 	&sensor_dev_attr_in2_min.dev_attr.attr,
401 	&sensor_dev_attr_in2_max.dev_attr.attr,
402 	&sensor_dev_attr_in3_input.dev_attr.attr,
403 	&sensor_dev_attr_in3_min.dev_attr.attr,
404 	&sensor_dev_attr_in3_max.dev_attr.attr,
405 	&sensor_dev_attr_in4_input.dev_attr.attr,
406 	&sensor_dev_attr_in4_min.dev_attr.attr,
407 	&sensor_dev_attr_in4_max.dev_attr.attr,
408 	&sensor_dev_attr_in5_input.dev_attr.attr,
409 	&sensor_dev_attr_in5_min.dev_attr.attr,
410 	&sensor_dev_attr_in5_max.dev_attr.attr,
411 
412 	&sensor_dev_attr_temp1_input.dev_attr.attr,
413 	&sensor_dev_attr_temp1_min.dev_attr.attr,
414 	&sensor_dev_attr_temp1_max.dev_attr.attr,
415 	&sensor_dev_attr_temp2_input.dev_attr.attr,
416 	&sensor_dev_attr_temp2_min.dev_attr.attr,
417 	&sensor_dev_attr_temp2_max.dev_attr.attr,
418 	&sensor_dev_attr_temp3_input.dev_attr.attr,
419 	&sensor_dev_attr_temp3_min.dev_attr.attr,
420 	&sensor_dev_attr_temp3_max.dev_attr.attr,
421 	&sensor_dev_attr_temp4_input.dev_attr.attr,
422 	&sensor_dev_attr_temp4_min.dev_attr.attr,
423 	&sensor_dev_attr_temp4_max.dev_attr.attr,
424 	&sensor_dev_attr_temp5_input.dev_attr.attr,
425 	&sensor_dev_attr_temp5_min.dev_attr.attr,
426 	&sensor_dev_attr_temp5_max.dev_attr.attr,
427 	&sensor_dev_attr_temp6_input.dev_attr.attr,
428 	&sensor_dev_attr_temp6_min.dev_attr.attr,
429 	&sensor_dev_attr_temp6_max.dev_attr.attr,
430 
431 	&sensor_dev_attr_fan1_input.dev_attr.attr,
432 	&sensor_dev_attr_fan1_min.dev_attr.attr,
433 	&sensor_dev_attr_fan2_input.dev_attr.attr,
434 	&sensor_dev_attr_fan2_min.dev_attr.attr,
435 	&sensor_dev_attr_fan3_input.dev_attr.attr,
436 	&sensor_dev_attr_fan3_min.dev_attr.attr,
437 	&sensor_dev_attr_fan4_input.dev_attr.attr,
438 	&sensor_dev_attr_fan4_min.dev_attr.attr,
439 	&sensor_dev_attr_fan5_input.dev_attr.attr,
440 	&sensor_dev_attr_fan5_min.dev_attr.attr,
441 	NULL
442 };
443 
444 static const struct attribute_group emc6w201_group = {
445 	.attrs = emc6w201_attributes,
446 };
447 
448 /*
449  * Driver interface
450  */
451 
452 /* Return 0 if detection is successful, -ENODEV otherwise */
453 static int emc6w201_detect(struct i2c_client *client,
454 			   struct i2c_board_info *info)
455 {
456 	struct i2c_adapter *adapter = client->adapter;
457 	int company, verstep, config;
458 
459 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
460 		return -ENODEV;
461 
462 	/* Identification */
463 	company = i2c_smbus_read_byte_data(client, EMC6W201_REG_COMPANY);
464 	if (company != 0x5C)
465 		return -ENODEV;
466 	verstep = i2c_smbus_read_byte_data(client, EMC6W201_REG_VERSTEP);
467 	if (verstep < 0 || (verstep & 0xF0) != 0xB0)
468 		return -ENODEV;
469 	if ((verstep & 0x0F) > 2) {
470 		dev_dbg(&client->dev, "Unknwown EMC6W201 stepping %d\n",
471 			verstep & 0x0F);
472 		return -ENODEV;
473 	}
474 
475 	/* Check configuration */
476 	config = i2c_smbus_read_byte_data(client, EMC6W201_REG_CONFIG);
477 	if (config < 0 || (config & 0xF4) != 0x04)
478 		return -ENODEV;
479 	if (!(config & 0x01)) {
480 		dev_err(&client->dev, "Monitoring not enabled\n");
481 		return -ENODEV;
482 	}
483 
484 	strlcpy(info->type, "emc6w201", I2C_NAME_SIZE);
485 
486 	return 0;
487 }
488 
489 static int emc6w201_probe(struct i2c_client *client,
490 			  const struct i2c_device_id *id)
491 {
492 	struct emc6w201_data *data;
493 	int err;
494 
495 	data = kzalloc(sizeof(struct emc6w201_data), GFP_KERNEL);
496 	if (!data) {
497 		err = -ENOMEM;
498 		goto exit;
499 	}
500 
501 	i2c_set_clientdata(client, data);
502 	mutex_init(&data->update_lock);
503 
504 	/* Create sysfs attribute */
505 	err = sysfs_create_group(&client->dev.kobj, &emc6w201_group);
506 	if (err)
507 		goto exit_free;
508 
509 	/* Expose as a hwmon device */
510 	data->hwmon_dev = hwmon_device_register(&client->dev);
511 	if (IS_ERR(data->hwmon_dev)) {
512 		err = PTR_ERR(data->hwmon_dev);
513 		goto exit_remove;
514 	}
515 
516 	return 0;
517 
518  exit_remove:
519 	sysfs_remove_group(&client->dev.kobj, &emc6w201_group);
520  exit_free:
521 	kfree(data);
522  exit:
523 	return err;
524 }
525 
526 static int emc6w201_remove(struct i2c_client *client)
527 {
528 	struct emc6w201_data *data = i2c_get_clientdata(client);
529 
530 	hwmon_device_unregister(data->hwmon_dev);
531 	sysfs_remove_group(&client->dev.kobj, &emc6w201_group);
532 	kfree(data);
533 
534 	return 0;
535 }
536 
537 static const struct i2c_device_id emc6w201_id[] = {
538 	{ "emc6w201", 0 },
539 	{ }
540 };
541 MODULE_DEVICE_TABLE(i2c, emc6w201_id);
542 
543 static struct i2c_driver emc6w201_driver = {
544 	.class		= I2C_CLASS_HWMON,
545 	.driver = {
546 		.name	= "emc6w201",
547 	},
548 	.probe		= emc6w201_probe,
549 	.remove		= emc6w201_remove,
550 	.id_table	= emc6w201_id,
551 	.detect		= emc6w201_detect,
552 	.address_list	= normal_i2c,
553 };
554 
555 module_i2c_driver(emc6w201_driver);
556 
557 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
558 MODULE_DESCRIPTION("SMSC EMC6W201 hardware monitoring driver");
559 MODULE_LICENSE("GPL");
560