xref: /openbmc/linux/drivers/hwmon/lm90.c (revision f15cbe6f1a4b4d9df59142fc8e4abb973302cf44)
1 /*
2  * lm90.c - Part of lm_sensors, Linux kernel modules for hardware
3  *          monitoring
4  * Copyright (C) 2003-2006  Jean Delvare <khali@linux-fr.org>
5  *
6  * Based on the lm83 driver. The LM90 is a sensor chip made by National
7  * Semiconductor. It reports up to two temperatures (its own plus up to
8  * one external one) with a 0.125 deg resolution (1 deg for local
9  * temperature) and a 3-4 deg accuracy. Complete datasheet can be
10  * obtained from National's website at:
11  *   http://www.national.com/pf/LM/LM90.html
12  *
13  * This driver also supports the LM89 and LM99, two other sensor chips
14  * made by National Semiconductor. Both have an increased remote
15  * temperature measurement accuracy (1 degree), and the LM99
16  * additionally shifts remote temperatures (measured and limits) by 16
17  * degrees, which allows for higher temperatures measurement. The
18  * driver doesn't handle it since it can be done easily in user-space.
19  * Complete datasheets can be obtained from National's website at:
20  *   http://www.national.com/pf/LM/LM89.html
21  *   http://www.national.com/pf/LM/LM99.html
22  * Note that there is no way to differentiate between both chips.
23  *
24  * This driver also supports the LM86, another sensor chip made by
25  * National Semiconductor. It is exactly similar to the LM90 except it
26  * has a higher accuracy.
27  * Complete datasheet can be obtained from National's website at:
28  *   http://www.national.com/pf/LM/LM86.html
29  *
30  * This driver also supports the ADM1032, a sensor chip made by Analog
31  * Devices. That chip is similar to the LM90, with a few differences
32  * that are not handled by this driver. Complete datasheet can be
33  * obtained from Analog's website at:
34  *   http://www.analog.com/en/prod/0,2877,ADM1032,00.html
35  * Among others, it has a higher accuracy than the LM90, much like the
36  * LM86 does.
37  *
38  * This driver also supports the MAX6657, MAX6658 and MAX6659 sensor
39  * chips made by Maxim. These chips are similar to the LM86. Complete
40  * datasheet can be obtained at Maxim's website at:
41  *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578
42  * Note that there is no easy way to differentiate between the three
43  * variants. The extra address and features of the MAX6659 are not
44  * supported by this driver. These chips lack the remote temperature
45  * offset feature.
46  *
47  * This driver also supports the MAX6680 and MAX6681, two other sensor
48  * chips made by Maxim. These are quite similar to the other Maxim
49  * chips. Complete datasheet can be obtained at:
50  *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3370
51  * The MAX6680 and MAX6681 only differ in the pinout so they can be
52  * treated identically.
53  *
54  * This driver also supports the ADT7461 chip from Analog Devices but
55  * only in its "compatability mode". If an ADT7461 chip is found but
56  * is configured in non-compatible mode (where its temperature
57  * register values are decoded differently) it is ignored by this
58  * driver. Complete datasheet can be obtained from Analog's website
59  * at:
60  *   http://www.analog.com/en/prod/0,2877,ADT7461,00.html
61  *
62  * Since the LM90 was the first chipset supported by this driver, most
63  * comments will refer to this chipset, but are actually general and
64  * concern all supported chipsets, unless mentioned otherwise.
65  *
66  * This program is free software; you can redistribute it and/or modify
67  * it under the terms of the GNU General Public License as published by
68  * the Free Software Foundation; either version 2 of the License, or
69  * (at your option) any later version.
70  *
71  * This program is distributed in the hope that it will be useful,
72  * but WITHOUT ANY WARRANTY; without even the implied warranty of
73  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
74  * GNU General Public License for more details.
75  *
76  * You should have received a copy of the GNU General Public License
77  * along with this program; if not, write to the Free Software
78  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
79  */
80 
81 #include <linux/module.h>
82 #include <linux/init.h>
83 #include <linux/slab.h>
84 #include <linux/jiffies.h>
85 #include <linux/i2c.h>
86 #include <linux/hwmon-sysfs.h>
87 #include <linux/hwmon.h>
88 #include <linux/err.h>
89 #include <linux/mutex.h>
90 #include <linux/sysfs.h>
91 
92 /*
93  * Addresses to scan
94  * Address is fully defined internally and cannot be changed except for
95  * MAX6659, MAX6680 and MAX6681.
96  * LM86, LM89, LM90, LM99, ADM1032, ADM1032-1, ADT7461, MAX6657 and MAX6658
97  * have address 0x4c.
98  * ADM1032-2, ADT7461-2, LM89-1, and LM99-1 have address 0x4d.
99  * MAX6659 can have address 0x4c, 0x4d or 0x4e (unsupported).
100  * MAX6680 and MAX6681 can have address 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
101  * 0x4c, 0x4d or 0x4e.
102  */
103 
104 static const unsigned short normal_i2c[] = {
105 	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };
106 
107 /*
108  * Insmod parameters
109  */
110 
111 I2C_CLIENT_INSMOD_7(lm90, adm1032, lm99, lm86, max6657, adt7461, max6680);
112 
113 /*
114  * The LM90 registers
115  */
116 
117 #define LM90_REG_R_MAN_ID		0xFE
118 #define LM90_REG_R_CHIP_ID		0xFF
119 #define LM90_REG_R_CONFIG1		0x03
120 #define LM90_REG_W_CONFIG1		0x09
121 #define LM90_REG_R_CONFIG2		0xBF
122 #define LM90_REG_W_CONFIG2		0xBF
123 #define LM90_REG_R_CONVRATE		0x04
124 #define LM90_REG_W_CONVRATE		0x0A
125 #define LM90_REG_R_STATUS		0x02
126 #define LM90_REG_R_LOCAL_TEMP		0x00
127 #define LM90_REG_R_LOCAL_HIGH		0x05
128 #define LM90_REG_W_LOCAL_HIGH		0x0B
129 #define LM90_REG_R_LOCAL_LOW		0x06
130 #define LM90_REG_W_LOCAL_LOW		0x0C
131 #define LM90_REG_R_LOCAL_CRIT		0x20
132 #define LM90_REG_W_LOCAL_CRIT		0x20
133 #define LM90_REG_R_REMOTE_TEMPH		0x01
134 #define LM90_REG_R_REMOTE_TEMPL		0x10
135 #define LM90_REG_R_REMOTE_OFFSH		0x11
136 #define LM90_REG_W_REMOTE_OFFSH		0x11
137 #define LM90_REG_R_REMOTE_OFFSL		0x12
138 #define LM90_REG_W_REMOTE_OFFSL		0x12
139 #define LM90_REG_R_REMOTE_HIGHH		0x07
140 #define LM90_REG_W_REMOTE_HIGHH		0x0D
141 #define LM90_REG_R_REMOTE_HIGHL		0x13
142 #define LM90_REG_W_REMOTE_HIGHL		0x13
143 #define LM90_REG_R_REMOTE_LOWH		0x08
144 #define LM90_REG_W_REMOTE_LOWH		0x0E
145 #define LM90_REG_R_REMOTE_LOWL		0x14
146 #define LM90_REG_W_REMOTE_LOWL		0x14
147 #define LM90_REG_R_REMOTE_CRIT		0x19
148 #define LM90_REG_W_REMOTE_CRIT		0x19
149 #define LM90_REG_R_TCRIT_HYST		0x21
150 #define LM90_REG_W_TCRIT_HYST		0x21
151 
152 /*
153  * Conversions and various macros
154  * For local temperatures and limits, critical limits and the hysteresis
155  * value, the LM90 uses signed 8-bit values with LSB = 1 degree Celsius.
156  * For remote temperatures and limits, it uses signed 11-bit values with
157  * LSB = 0.125 degree Celsius, left-justified in 16-bit registers.
158  */
159 
160 #define TEMP1_FROM_REG(val)	((val) * 1000)
161 #define TEMP1_TO_REG(val)	((val) <= -128000 ? -128 : \
162 				 (val) >= 127000 ? 127 : \
163 				 (val) < 0 ? ((val) - 500) / 1000 : \
164 				 ((val) + 500) / 1000)
165 #define TEMP2_FROM_REG(val)	((val) / 32 * 125)
166 #define TEMP2_TO_REG(val)	((val) <= -128000 ? 0x8000 : \
167 				 (val) >= 127875 ? 0x7FE0 : \
168 				 (val) < 0 ? ((val) - 62) / 125 * 32 : \
169 				 ((val) + 62) / 125 * 32)
170 #define HYST_TO_REG(val)	((val) <= 0 ? 0 : (val) >= 30500 ? 31 : \
171 				 ((val) + 500) / 1000)
172 
173 /*
174  * ADT7461 is almost identical to LM90 except that attempts to write
175  * values that are outside the range 0 < temp < 127 are treated as
176  * the boundary value.
177  */
178 
179 #define TEMP1_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \
180 				 (val) >= 127000 ? 127 : \
181 				 ((val) + 500) / 1000)
182 #define TEMP2_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \
183 				 (val) >= 127750 ? 0x7FC0 : \
184 				 ((val) + 125) / 250 * 64)
185 
186 /*
187  * Functions declaration
188  */
189 
190 static int lm90_detect(struct i2c_client *client, int kind,
191 		       struct i2c_board_info *info);
192 static int lm90_probe(struct i2c_client *client,
193 		      const struct i2c_device_id *id);
194 static void lm90_init_client(struct i2c_client *client);
195 static int lm90_remove(struct i2c_client *client);
196 static struct lm90_data *lm90_update_device(struct device *dev);
197 
198 /*
199  * Driver data (common to all clients)
200  */
201 
202 static const struct i2c_device_id lm90_id[] = {
203 	{ "adm1032", adm1032 },
204 	{ "adt7461", adt7461 },
205 	{ "lm90", lm90 },
206 	{ "lm86", lm86 },
207 	{ "lm89", lm99 },
208 	{ "lm99", lm99 },	/* Missing temperature offset */
209 	{ "max6657", max6657 },
210 	{ "max6658", max6657 },
211 	{ "max6659", max6657 },
212 	{ "max6680", max6680 },
213 	{ "max6681", max6680 },
214 	{ }
215 };
216 MODULE_DEVICE_TABLE(i2c, lm90_id);
217 
218 static struct i2c_driver lm90_driver = {
219 	.class		= I2C_CLASS_HWMON,
220 	.driver = {
221 		.name	= "lm90",
222 	},
223 	.probe		= lm90_probe,
224 	.remove		= lm90_remove,
225 	.id_table	= lm90_id,
226 	.detect		= lm90_detect,
227 	.address_data	= &addr_data,
228 };
229 
230 /*
231  * Client data (each client gets its own)
232  */
233 
234 struct lm90_data {
235 	struct device *hwmon_dev;
236 	struct mutex update_lock;
237 	char valid; /* zero until following fields are valid */
238 	unsigned long last_updated; /* in jiffies */
239 	int kind;
240 
241 	/* registers values */
242 	s8 temp8[5];	/* 0: local input
243 			   1: local low limit
244 			   2: local high limit
245 			   3: local critical limit
246 			   4: remote critical limit */
247 	s16 temp11[4];	/* 0: remote input
248 			   1: remote low limit
249 			   2: remote high limit
250 			   3: remote offset (except max6657) */
251 	u8 temp_hyst;
252 	u8 alarms; /* bitvector */
253 };
254 
255 /*
256  * Sysfs stuff
257  */
258 
259 static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
260 			  char *buf)
261 {
262 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
263 	struct lm90_data *data = lm90_update_device(dev);
264 	return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index]));
265 }
266 
267 static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
268 			 const char *buf, size_t count)
269 {
270 	static const u8 reg[4] = {
271 		LM90_REG_W_LOCAL_LOW,
272 		LM90_REG_W_LOCAL_HIGH,
273 		LM90_REG_W_LOCAL_CRIT,
274 		LM90_REG_W_REMOTE_CRIT,
275 	};
276 
277 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
278 	struct i2c_client *client = to_i2c_client(dev);
279 	struct lm90_data *data = i2c_get_clientdata(client);
280 	long val = simple_strtol(buf, NULL, 10);
281 	int nr = attr->index;
282 
283 	mutex_lock(&data->update_lock);
284 	if (data->kind == adt7461)
285 		data->temp8[nr] = TEMP1_TO_REG_ADT7461(val);
286 	else
287 		data->temp8[nr] = TEMP1_TO_REG(val);
288 	i2c_smbus_write_byte_data(client, reg[nr - 1], data->temp8[nr]);
289 	mutex_unlock(&data->update_lock);
290 	return count;
291 }
292 
293 static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
294 			   char *buf)
295 {
296 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
297 	struct lm90_data *data = lm90_update_device(dev);
298 	return sprintf(buf, "%d\n", TEMP2_FROM_REG(data->temp11[attr->index]));
299 }
300 
301 static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
302 			  const char *buf, size_t count)
303 {
304 	static const u8 reg[6] = {
305 		LM90_REG_W_REMOTE_LOWH,
306 		LM90_REG_W_REMOTE_LOWL,
307 		LM90_REG_W_REMOTE_HIGHH,
308 		LM90_REG_W_REMOTE_HIGHL,
309 		LM90_REG_W_REMOTE_OFFSH,
310 		LM90_REG_W_REMOTE_OFFSL,
311 	};
312 
313 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
314 	struct i2c_client *client = to_i2c_client(dev);
315 	struct lm90_data *data = i2c_get_clientdata(client);
316 	long val = simple_strtol(buf, NULL, 10);
317 	int nr = attr->index;
318 
319 	mutex_lock(&data->update_lock);
320 	if (data->kind == adt7461)
321 		data->temp11[nr] = TEMP2_TO_REG_ADT7461(val);
322 	else
323 		data->temp11[nr] = TEMP2_TO_REG(val);
324 	i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2],
325 				  data->temp11[nr] >> 8);
326 	i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2 + 1],
327 				  data->temp11[nr] & 0xff);
328 	mutex_unlock(&data->update_lock);
329 	return count;
330 }
331 
332 static ssize_t show_temphyst(struct device *dev, struct device_attribute *devattr,
333 			     char *buf)
334 {
335 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
336 	struct lm90_data *data = lm90_update_device(dev);
337 	return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index])
338 		       - TEMP1_FROM_REG(data->temp_hyst));
339 }
340 
341 static ssize_t set_temphyst(struct device *dev, struct device_attribute *dummy,
342 			    const char *buf, size_t count)
343 {
344 	struct i2c_client *client = to_i2c_client(dev);
345 	struct lm90_data *data = i2c_get_clientdata(client);
346 	long val = simple_strtol(buf, NULL, 10);
347 	long hyst;
348 
349 	mutex_lock(&data->update_lock);
350 	hyst = TEMP1_FROM_REG(data->temp8[3]) - val;
351 	i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,
352 				  HYST_TO_REG(hyst));
353 	mutex_unlock(&data->update_lock);
354 	return count;
355 }
356 
357 static ssize_t show_alarms(struct device *dev, struct device_attribute *dummy,
358 			   char *buf)
359 {
360 	struct lm90_data *data = lm90_update_device(dev);
361 	return sprintf(buf, "%d\n", data->alarms);
362 }
363 
364 static ssize_t show_alarm(struct device *dev, struct device_attribute
365 			  *devattr, char *buf)
366 {
367 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
368 	struct lm90_data *data = lm90_update_device(dev);
369 	int bitnr = attr->index;
370 
371 	return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
372 }
373 
374 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp8, NULL, 0);
375 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp11, NULL, 0);
376 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp8,
377 	set_temp8, 1);
378 static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_temp11,
379 	set_temp11, 1);
380 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp8,
381 	set_temp8, 2);
382 static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp11,
383 	set_temp11, 2);
384 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp8,
385 	set_temp8, 3);
386 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp8,
387 	set_temp8, 4);
388 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temphyst,
389 	set_temphyst, 3);
390 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_temphyst, NULL, 4);
391 static SENSOR_DEVICE_ATTR(temp2_offset, S_IWUSR | S_IRUGO, show_temp11,
392 	set_temp11, 3);
393 
394 /* Individual alarm files */
395 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 0);
396 static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 1);
397 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
398 static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 3);
399 static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
400 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 5);
401 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
402 /* Raw alarm file for compatibility */
403 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
404 
405 static struct attribute *lm90_attributes[] = {
406 	&sensor_dev_attr_temp1_input.dev_attr.attr,
407 	&sensor_dev_attr_temp2_input.dev_attr.attr,
408 	&sensor_dev_attr_temp1_min.dev_attr.attr,
409 	&sensor_dev_attr_temp2_min.dev_attr.attr,
410 	&sensor_dev_attr_temp1_max.dev_attr.attr,
411 	&sensor_dev_attr_temp2_max.dev_attr.attr,
412 	&sensor_dev_attr_temp1_crit.dev_attr.attr,
413 	&sensor_dev_attr_temp2_crit.dev_attr.attr,
414 	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
415 	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
416 
417 	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
418 	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
419 	&sensor_dev_attr_temp2_fault.dev_attr.attr,
420 	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
421 	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
422 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
423 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
424 	&dev_attr_alarms.attr,
425 	NULL
426 };
427 
428 static const struct attribute_group lm90_group = {
429 	.attrs = lm90_attributes,
430 };
431 
432 /* pec used for ADM1032 only */
433 static ssize_t show_pec(struct device *dev, struct device_attribute *dummy,
434 			char *buf)
435 {
436 	struct i2c_client *client = to_i2c_client(dev);
437 	return sprintf(buf, "%d\n", !!(client->flags & I2C_CLIENT_PEC));
438 }
439 
440 static ssize_t set_pec(struct device *dev, struct device_attribute *dummy,
441 		       const char *buf, size_t count)
442 {
443 	struct i2c_client *client = to_i2c_client(dev);
444 	long val = simple_strtol(buf, NULL, 10);
445 
446 	switch (val) {
447 	case 0:
448 		client->flags &= ~I2C_CLIENT_PEC;
449 		break;
450 	case 1:
451 		client->flags |= I2C_CLIENT_PEC;
452 		break;
453 	default:
454 		return -EINVAL;
455 	}
456 
457 	return count;
458 }
459 
460 static DEVICE_ATTR(pec, S_IWUSR | S_IRUGO, show_pec, set_pec);
461 
462 /*
463  * Real code
464  */
465 
466 /* The ADM1032 supports PEC but not on write byte transactions, so we need
467    to explicitly ask for a transaction without PEC. */
468 static inline s32 adm1032_write_byte(struct i2c_client *client, u8 value)
469 {
470 	return i2c_smbus_xfer(client->adapter, client->addr,
471 			      client->flags & ~I2C_CLIENT_PEC,
472 			      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
473 }
474 
475 /* It is assumed that client->update_lock is held (unless we are in
476    detection or initialization steps). This matters when PEC is enabled,
477    because we don't want the address pointer to change between the write
478    byte and the read byte transactions. */
479 static int lm90_read_reg(struct i2c_client* client, u8 reg, u8 *value)
480 {
481 	int err;
482 
483  	if (client->flags & I2C_CLIENT_PEC) {
484  		err = adm1032_write_byte(client, reg);
485  		if (err >= 0)
486  			err = i2c_smbus_read_byte(client);
487  	} else
488  		err = i2c_smbus_read_byte_data(client, reg);
489 
490 	if (err < 0) {
491 		dev_warn(&client->dev, "Register %#02x read failed (%d)\n",
492 			 reg, err);
493 		return err;
494 	}
495 	*value = err;
496 
497 	return 0;
498 }
499 
500 /* Return 0 if detection is successful, -ENODEV otherwise */
501 static int lm90_detect(struct i2c_client *new_client, int kind,
502 		       struct i2c_board_info *info)
503 {
504 	struct i2c_adapter *adapter = new_client->adapter;
505 	int address = new_client->addr;
506 	const char *name = "";
507 
508 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
509 		return -ENODEV;
510 
511 	/*
512 	 * Now we do the remaining detection. A negative kind means that
513 	 * the driver was loaded with no force parameter (default), so we
514 	 * must both detect and identify the chip. A zero kind means that
515 	 * the driver was loaded with the force parameter, the detection
516 	 * step shall be skipped. A positive kind means that the driver
517 	 * was loaded with the force parameter and a given kind of chip is
518 	 * requested, so both the detection and the identification steps
519 	 * are skipped.
520 	 */
521 
522 	/* Default to an LM90 if forced */
523 	if (kind == 0)
524 		kind = lm90;
525 
526 	if (kind < 0) { /* detection and identification */
527 		int man_id, chip_id, reg_config1, reg_convrate;
528 
529 		if ((man_id = i2c_smbus_read_byte_data(new_client,
530 						LM90_REG_R_MAN_ID)) < 0
531 		 || (chip_id = i2c_smbus_read_byte_data(new_client,
532 						LM90_REG_R_CHIP_ID)) < 0
533 		 || (reg_config1 = i2c_smbus_read_byte_data(new_client,
534 						LM90_REG_R_CONFIG1)) < 0
535 		 || (reg_convrate = i2c_smbus_read_byte_data(new_client,
536 						LM90_REG_R_CONVRATE)) < 0)
537 			return -ENODEV;
538 
539 		if ((address == 0x4C || address == 0x4D)
540 		 && man_id == 0x01) { /* National Semiconductor */
541 			int reg_config2;
542 
543 			if ((reg_config2 = i2c_smbus_read_byte_data(new_client,
544 						LM90_REG_R_CONFIG2)) < 0)
545 				return -ENODEV;
546 
547 			if ((reg_config1 & 0x2A) == 0x00
548 			 && (reg_config2 & 0xF8) == 0x00
549 			 && reg_convrate <= 0x09) {
550 				if (address == 0x4C
551 				 && (chip_id & 0xF0) == 0x20) { /* LM90 */
552 					kind = lm90;
553 				} else
554 				if ((chip_id & 0xF0) == 0x30) { /* LM89/LM99 */
555 					kind = lm99;
556 				} else
557 				if (address == 0x4C
558 				 && (chip_id & 0xF0) == 0x10) { /* LM86 */
559 					kind = lm86;
560 				}
561 			}
562 		} else
563 		if ((address == 0x4C || address == 0x4D)
564 		 && man_id == 0x41) { /* Analog Devices */
565 			if ((chip_id & 0xF0) == 0x40 /* ADM1032 */
566 			 && (reg_config1 & 0x3F) == 0x00
567 			 && reg_convrate <= 0x0A) {
568 				kind = adm1032;
569 			} else
570 			if (chip_id == 0x51 /* ADT7461 */
571 			 && (reg_config1 & 0x1F) == 0x00 /* check compat mode */
572 			 && reg_convrate <= 0x0A) {
573 				kind = adt7461;
574 			}
575 		} else
576 		if (man_id == 0x4D) { /* Maxim */
577 			/*
578 			 * The MAX6657, MAX6658 and MAX6659 do NOT have a
579 			 * chip_id register. Reading from that address will
580 			 * return the last read value, which in our case is
581 			 * those of the man_id register. Likewise, the config1
582 			 * register seems to lack a low nibble, so the value
583 			 * will be those of the previous read, so in our case
584 			 * those of the man_id register.
585 			 */
586 			if (chip_id == man_id
587 			 && (address == 0x4C || address == 0x4D)
588 			 && (reg_config1 & 0x1F) == (man_id & 0x0F)
589 			 && reg_convrate <= 0x09) {
590 			 	kind = max6657;
591 			} else
592 			/* The chip_id register of the MAX6680 and MAX6681
593 			 * holds the revision of the chip.
594 			 * the lowest bit of the config1 register is unused
595 			 * and should return zero when read, so should the
596 			 * second to last bit of config1 (software reset)
597 			 */
598 			if (chip_id == 0x01
599 			 && (reg_config1 & 0x03) == 0x00
600 			 && reg_convrate <= 0x07) {
601 			 	kind = max6680;
602 			}
603 		}
604 
605 		if (kind <= 0) { /* identification failed */
606 			dev_info(&adapter->dev,
607 			    "Unsupported chip (man_id=0x%02X, "
608 			    "chip_id=0x%02X).\n", man_id, chip_id);
609 			return -ENODEV;
610 		}
611 	}
612 
613 	/* Fill the i2c board info */
614 	if (kind == lm90) {
615 		name = "lm90";
616 	} else if (kind == adm1032) {
617 		name = "adm1032";
618 		/* The ADM1032 supports PEC, but only if combined
619 		   transactions are not used. */
620 		if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
621 			info->flags |= I2C_CLIENT_PEC;
622 	} else if (kind == lm99) {
623 		name = "lm99";
624 	} else if (kind == lm86) {
625 		name = "lm86";
626 	} else if (kind == max6657) {
627 		name = "max6657";
628 	} else if (kind == max6680) {
629 		name = "max6680";
630 	} else if (kind == adt7461) {
631 		name = "adt7461";
632 	}
633 	strlcpy(info->type, name, I2C_NAME_SIZE);
634 
635 	return 0;
636 }
637 
638 static int lm90_probe(struct i2c_client *new_client,
639 		      const struct i2c_device_id *id)
640 {
641 	struct i2c_adapter *adapter = to_i2c_adapter(new_client->dev.parent);
642 	struct lm90_data *data;
643 	int err;
644 
645 	data = kzalloc(sizeof(struct lm90_data), GFP_KERNEL);
646 	if (!data) {
647 		err = -ENOMEM;
648 		goto exit;
649 	}
650 	i2c_set_clientdata(new_client, data);
651 	mutex_init(&data->update_lock);
652 
653 	/* Set the device type */
654 	data->kind = id->driver_data;
655 	if (data->kind == adm1032) {
656 		if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
657 			new_client->flags &= ~I2C_CLIENT_PEC;
658 	}
659 
660 	/* Initialize the LM90 chip */
661 	lm90_init_client(new_client);
662 
663 	/* Register sysfs hooks */
664 	if ((err = sysfs_create_group(&new_client->dev.kobj, &lm90_group)))
665 		goto exit_free;
666 	if (new_client->flags & I2C_CLIENT_PEC) {
667 		if ((err = device_create_file(&new_client->dev,
668 					      &dev_attr_pec)))
669 			goto exit_remove_files;
670 	}
671 	if (data->kind != max6657) {
672 		if ((err = device_create_file(&new_client->dev,
673 				&sensor_dev_attr_temp2_offset.dev_attr)))
674 			goto exit_remove_files;
675 	}
676 
677 	data->hwmon_dev = hwmon_device_register(&new_client->dev);
678 	if (IS_ERR(data->hwmon_dev)) {
679 		err = PTR_ERR(data->hwmon_dev);
680 		goto exit_remove_files;
681 	}
682 
683 	return 0;
684 
685 exit_remove_files:
686 	sysfs_remove_group(&new_client->dev.kobj, &lm90_group);
687 	device_remove_file(&new_client->dev, &dev_attr_pec);
688 exit_free:
689 	kfree(data);
690 exit:
691 	return err;
692 }
693 
694 static void lm90_init_client(struct i2c_client *client)
695 {
696 	u8 config, config_orig;
697 	struct lm90_data *data = i2c_get_clientdata(client);
698 
699 	/*
700 	 * Start the conversions.
701 	 */
702 	i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE,
703 				  5); /* 2 Hz */
704 	if (lm90_read_reg(client, LM90_REG_R_CONFIG1, &config) < 0) {
705 		dev_warn(&client->dev, "Initialization failed!\n");
706 		return;
707 	}
708 	config_orig = config;
709 
710 	/*
711 	 * Put MAX6680/MAX8881 into extended resolution (bit 0x10,
712 	 * 0.125 degree resolution) and range (0x08, extend range
713 	 * to -64 degree) mode for the remote temperature sensor.
714 	 */
715 	if (data->kind == max6680) {
716 		config |= 0x18;
717 	}
718 
719 	config &= 0xBF;	/* run */
720 	if (config != config_orig) /* Only write if changed */
721 		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, config);
722 }
723 
724 static int lm90_remove(struct i2c_client *client)
725 {
726 	struct lm90_data *data = i2c_get_clientdata(client);
727 
728 	hwmon_device_unregister(data->hwmon_dev);
729 	sysfs_remove_group(&client->dev.kobj, &lm90_group);
730 	device_remove_file(&client->dev, &dev_attr_pec);
731 	if (data->kind != max6657)
732 		device_remove_file(&client->dev,
733 				   &sensor_dev_attr_temp2_offset.dev_attr);
734 
735 	kfree(data);
736 	return 0;
737 }
738 
739 static struct lm90_data *lm90_update_device(struct device *dev)
740 {
741 	struct i2c_client *client = to_i2c_client(dev);
742 	struct lm90_data *data = i2c_get_clientdata(client);
743 
744 	mutex_lock(&data->update_lock);
745 
746 	if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
747 		u8 oldh, newh, l;
748 
749 		dev_dbg(&client->dev, "Updating lm90 data.\n");
750 		lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP, &data->temp8[0]);
751 		lm90_read_reg(client, LM90_REG_R_LOCAL_LOW, &data->temp8[1]);
752 		lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH, &data->temp8[2]);
753 		lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT, &data->temp8[3]);
754 		lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]);
755 		lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
756 
757 		/*
758 		 * There is a trick here. We have to read two registers to
759 		 * have the remote sensor temperature, but we have to beware
760 		 * a conversion could occur inbetween the readings. The
761 		 * datasheet says we should either use the one-shot
762 		 * conversion register, which we don't want to do (disables
763 		 * hardware monitoring) or monitor the busy bit, which is
764 		 * impossible (we can't read the values and monitor that bit
765 		 * at the exact same time). So the solution used here is to
766 		 * read the high byte once, then the low byte, then the high
767 		 * byte again. If the new high byte matches the old one,
768 		 * then we have a valid reading. Else we have to read the low
769 		 * byte again, and now we believe we have a correct reading.
770 		 */
771 		if (lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &oldh) == 0
772 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0
773 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &newh) == 0
774 		 && (newh == oldh
775 		  || lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0))
776 			data->temp11[0] = (newh << 8) | l;
777 
778 		if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &newh) == 0
779 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL, &l) == 0)
780 			data->temp11[1] = (newh << 8) | l;
781 		if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &newh) == 0
782 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL, &l) == 0)
783 			data->temp11[2] = (newh << 8) | l;
784 		if (data->kind != max6657) {
785 			if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH,
786 					  &newh) == 0
787 			 && lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL,
788 					  &l) == 0)
789 				data->temp11[3] = (newh << 8) | l;
790 		}
791 		lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms);
792 
793 		data->last_updated = jiffies;
794 		data->valid = 1;
795 	}
796 
797 	mutex_unlock(&data->update_lock);
798 
799 	return data;
800 }
801 
802 static int __init sensors_lm90_init(void)
803 {
804 	return i2c_add_driver(&lm90_driver);
805 }
806 
807 static void __exit sensors_lm90_exit(void)
808 {
809 	i2c_del_driver(&lm90_driver);
810 }
811 
812 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
813 MODULE_DESCRIPTION("LM90/ADM1032 driver");
814 MODULE_LICENSE("GPL");
815 
816 module_init(sensors_lm90_init);
817 module_exit(sensors_lm90_exit);
818