xref: /openbmc/linux/drivers/hwmon/lm90.c (revision c21b37f6)
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.
45  *
46  * This driver also supports the MAX6680 and MAX6681, two other sensor
47  * chips made by Maxim. These are quite similar to the other Maxim
48  * chips. Complete datasheet can be obtained at:
49  *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3370
50  * The MAX6680 and MAX6681 only differ in the pinout so they can be
51  * treated identically.
52  *
53  * This driver also supports the ADT7461 chip from Analog Devices but
54  * only in its "compatability mode". If an ADT7461 chip is found but
55  * is configured in non-compatible mode (where its temperature
56  * register values are decoded differently) it is ignored by this
57  * driver. Complete datasheet can be obtained from Analog's website
58  * at:
59  *   http://www.analog.com/en/prod/0,2877,ADT7461,00.html
60  *
61  * Since the LM90 was the first chipset supported by this driver, most
62  * comments will refer to this chipset, but are actually general and
63  * concern all supported chipsets, unless mentioned otherwise.
64  *
65  * This program is free software; you can redistribute it and/or modify
66  * it under the terms of the GNU General Public License as published by
67  * the Free Software Foundation; either version 2 of the License, or
68  * (at your option) any later version.
69  *
70  * This program is distributed in the hope that it will be useful,
71  * but WITHOUT ANY WARRANTY; without even the implied warranty of
72  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
73  * GNU General Public License for more details.
74  *
75  * You should have received a copy of the GNU General Public License
76  * along with this program; if not, write to the Free Software
77  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
78  */
79 
80 #include <linux/module.h>
81 #include <linux/init.h>
82 #include <linux/slab.h>
83 #include <linux/jiffies.h>
84 #include <linux/i2c.h>
85 #include <linux/hwmon-sysfs.h>
86 #include <linux/hwmon.h>
87 #include <linux/err.h>
88 #include <linux/mutex.h>
89 #include <linux/sysfs.h>
90 
91 /*
92  * Addresses to scan
93  * Address is fully defined internally and cannot be changed except for
94  * MAX6659, MAX6680 and MAX6681.
95  * LM86, LM89, LM90, LM99, ADM1032, ADM1032-1, ADT7461, MAX6657 and MAX6658
96  * have address 0x4c.
97  * ADM1032-2, ADT7461-2, LM89-1, and LM99-1 have address 0x4d.
98  * MAX6659 can have address 0x4c, 0x4d or 0x4e (unsupported).
99  * MAX6680 and MAX6681 can have address 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
100  * 0x4c, 0x4d or 0x4e.
101  */
102 
103 static unsigned short normal_i2c[] = { 0x18, 0x19, 0x1a,
104 				       0x29, 0x2a, 0x2b,
105 				       0x4c, 0x4d, 0x4e,
106 				       I2C_CLIENT_END };
107 
108 /*
109  * Insmod parameters
110  */
111 
112 I2C_CLIENT_INSMOD_7(lm90, adm1032, lm99, lm86, max6657, adt7461, max6680);
113 
114 /*
115  * The LM90 registers
116  */
117 
118 #define LM90_REG_R_MAN_ID		0xFE
119 #define LM90_REG_R_CHIP_ID		0xFF
120 #define LM90_REG_R_CONFIG1		0x03
121 #define LM90_REG_W_CONFIG1		0x09
122 #define LM90_REG_R_CONFIG2		0xBF
123 #define LM90_REG_W_CONFIG2		0xBF
124 #define LM90_REG_R_CONVRATE		0x04
125 #define LM90_REG_W_CONVRATE		0x0A
126 #define LM90_REG_R_STATUS		0x02
127 #define LM90_REG_R_LOCAL_TEMP		0x00
128 #define LM90_REG_R_LOCAL_HIGH		0x05
129 #define LM90_REG_W_LOCAL_HIGH		0x0B
130 #define LM90_REG_R_LOCAL_LOW		0x06
131 #define LM90_REG_W_LOCAL_LOW		0x0C
132 #define LM90_REG_R_LOCAL_CRIT		0x20
133 #define LM90_REG_W_LOCAL_CRIT		0x20
134 #define LM90_REG_R_REMOTE_TEMPH		0x01
135 #define LM90_REG_R_REMOTE_TEMPL		0x10
136 #define LM90_REG_R_REMOTE_OFFSH		0x11
137 #define LM90_REG_W_REMOTE_OFFSH		0x11
138 #define LM90_REG_R_REMOTE_OFFSL		0x12
139 #define LM90_REG_W_REMOTE_OFFSL		0x12
140 #define LM90_REG_R_REMOTE_HIGHH		0x07
141 #define LM90_REG_W_REMOTE_HIGHH		0x0D
142 #define LM90_REG_R_REMOTE_HIGHL		0x13
143 #define LM90_REG_W_REMOTE_HIGHL		0x13
144 #define LM90_REG_R_REMOTE_LOWH		0x08
145 #define LM90_REG_W_REMOTE_LOWH		0x0E
146 #define LM90_REG_R_REMOTE_LOWL		0x14
147 #define LM90_REG_W_REMOTE_LOWL		0x14
148 #define LM90_REG_R_REMOTE_CRIT		0x19
149 #define LM90_REG_W_REMOTE_CRIT		0x19
150 #define LM90_REG_R_TCRIT_HYST		0x21
151 #define LM90_REG_W_TCRIT_HYST		0x21
152 
153 /*
154  * Conversions and various macros
155  * For local temperatures and limits, critical limits and the hysteresis
156  * value, the LM90 uses signed 8-bit values with LSB = 1 degree Celsius.
157  * For remote temperatures and limits, it uses signed 11-bit values with
158  * LSB = 0.125 degree Celsius, left-justified in 16-bit registers.
159  */
160 
161 #define TEMP1_FROM_REG(val)	((val) * 1000)
162 #define TEMP1_TO_REG(val)	((val) <= -128000 ? -128 : \
163 				 (val) >= 127000 ? 127 : \
164 				 (val) < 0 ? ((val) - 500) / 1000 : \
165 				 ((val) + 500) / 1000)
166 #define TEMP2_FROM_REG(val)	((val) / 32 * 125)
167 #define TEMP2_TO_REG(val)	((val) <= -128000 ? 0x8000 : \
168 				 (val) >= 127875 ? 0x7FE0 : \
169 				 (val) < 0 ? ((val) - 62) / 125 * 32 : \
170 				 ((val) + 62) / 125 * 32)
171 #define HYST_TO_REG(val)	((val) <= 0 ? 0 : (val) >= 30500 ? 31 : \
172 				 ((val) + 500) / 1000)
173 
174 /*
175  * ADT7461 is almost identical to LM90 except that attempts to write
176  * values that are outside the range 0 < temp < 127 are treated as
177  * the boundary value.
178  */
179 
180 #define TEMP1_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \
181 				 (val) >= 127000 ? 127 : \
182 				 ((val) + 500) / 1000)
183 #define TEMP2_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \
184 				 (val) >= 127750 ? 0x7FC0 : \
185 				 ((val) + 125) / 250 * 64)
186 
187 /*
188  * Functions declaration
189  */
190 
191 static int lm90_attach_adapter(struct i2c_adapter *adapter);
192 static int lm90_detect(struct i2c_adapter *adapter, int address,
193 	int kind);
194 static void lm90_init_client(struct i2c_client *client);
195 static int lm90_detach_client(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 struct i2c_driver lm90_driver = {
203 	.driver = {
204 		.name	= "lm90",
205 	},
206 	.id		= I2C_DRIVERID_LM90,
207 	.attach_adapter	= lm90_attach_adapter,
208 	.detach_client	= lm90_detach_client,
209 };
210 
211 /*
212  * Client data (each client gets its own)
213  */
214 
215 struct lm90_data {
216 	struct i2c_client client;
217 	struct class_device *class_dev;
218 	struct mutex update_lock;
219 	char valid; /* zero until following fields are valid */
220 	unsigned long last_updated; /* in jiffies */
221 	int kind;
222 
223 	/* registers values */
224 	s8 temp8[5];	/* 0: local input
225 			   1: local low limit
226 			   2: local high limit
227 			   3: local critical limit
228 			   4: remote critical limit */
229 	s16 temp11[3];	/* 0: remote input
230 			   1: remote low limit
231 			   2: remote high limit */
232 	u8 temp_hyst;
233 	u8 alarms; /* bitvector */
234 };
235 
236 /*
237  * Sysfs stuff
238  */
239 
240 static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
241 			  char *buf)
242 {
243 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
244 	struct lm90_data *data = lm90_update_device(dev);
245 	return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index]));
246 }
247 
248 static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
249 			 const char *buf, size_t count)
250 {
251 	static const u8 reg[4] = {
252 		LM90_REG_W_LOCAL_LOW,
253 		LM90_REG_W_LOCAL_HIGH,
254 		LM90_REG_W_LOCAL_CRIT,
255 		LM90_REG_W_REMOTE_CRIT,
256 	};
257 
258 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
259 	struct i2c_client *client = to_i2c_client(dev);
260 	struct lm90_data *data = i2c_get_clientdata(client);
261 	long val = simple_strtol(buf, NULL, 10);
262 	int nr = attr->index;
263 
264 	mutex_lock(&data->update_lock);
265 	if (data->kind == adt7461)
266 		data->temp8[nr] = TEMP1_TO_REG_ADT7461(val);
267 	else
268 		data->temp8[nr] = TEMP1_TO_REG(val);
269 	i2c_smbus_write_byte_data(client, reg[nr - 1], data->temp8[nr]);
270 	mutex_unlock(&data->update_lock);
271 	return count;
272 }
273 
274 static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
275 			   char *buf)
276 {
277 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
278 	struct lm90_data *data = lm90_update_device(dev);
279 	return sprintf(buf, "%d\n", TEMP2_FROM_REG(data->temp11[attr->index]));
280 }
281 
282 static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
283 			  const char *buf, size_t count)
284 {
285 	static const u8 reg[4] = {
286 		LM90_REG_W_REMOTE_LOWH,
287 		LM90_REG_W_REMOTE_LOWL,
288 		LM90_REG_W_REMOTE_HIGHH,
289 		LM90_REG_W_REMOTE_HIGHL,
290 	};
291 
292 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
293 	struct i2c_client *client = to_i2c_client(dev);
294 	struct lm90_data *data = i2c_get_clientdata(client);
295 	long val = simple_strtol(buf, NULL, 10);
296 	int nr = attr->index;
297 
298 	mutex_lock(&data->update_lock);
299 	if (data->kind == adt7461)
300 		data->temp11[nr] = TEMP2_TO_REG_ADT7461(val);
301 	else
302 		data->temp11[nr] = TEMP2_TO_REG(val);
303 	i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2],
304 				  data->temp11[nr] >> 8);
305 	i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2 + 1],
306 				  data->temp11[nr] & 0xff);
307 	mutex_unlock(&data->update_lock);
308 	return count;
309 }
310 
311 static ssize_t show_temphyst(struct device *dev, struct device_attribute *devattr,
312 			     char *buf)
313 {
314 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
315 	struct lm90_data *data = lm90_update_device(dev);
316 	return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index])
317 		       - TEMP1_FROM_REG(data->temp_hyst));
318 }
319 
320 static ssize_t set_temphyst(struct device *dev, struct device_attribute *dummy,
321 			    const char *buf, size_t count)
322 {
323 	struct i2c_client *client = to_i2c_client(dev);
324 	struct lm90_data *data = i2c_get_clientdata(client);
325 	long val = simple_strtol(buf, NULL, 10);
326 	long hyst;
327 
328 	mutex_lock(&data->update_lock);
329 	hyst = TEMP1_FROM_REG(data->temp8[3]) - val;
330 	i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,
331 				  HYST_TO_REG(hyst));
332 	mutex_unlock(&data->update_lock);
333 	return count;
334 }
335 
336 static ssize_t show_alarms(struct device *dev, struct device_attribute *dummy,
337 			   char *buf)
338 {
339 	struct lm90_data *data = lm90_update_device(dev);
340 	return sprintf(buf, "%d\n", data->alarms);
341 }
342 
343 static ssize_t show_alarm(struct device *dev, struct device_attribute
344 			  *devattr, char *buf)
345 {
346 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
347 	struct lm90_data *data = lm90_update_device(dev);
348 	int bitnr = attr->index;
349 
350 	return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
351 }
352 
353 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp8, NULL, 0);
354 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp11, NULL, 0);
355 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp8,
356 	set_temp8, 1);
357 static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_temp11,
358 	set_temp11, 1);
359 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp8,
360 	set_temp8, 2);
361 static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp11,
362 	set_temp11, 2);
363 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp8,
364 	set_temp8, 3);
365 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp8,
366 	set_temp8, 4);
367 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temphyst,
368 	set_temphyst, 3);
369 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_temphyst, NULL, 4);
370 
371 /* Individual alarm files */
372 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 0);
373 static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 1);
374 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
375 static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 3);
376 static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
377 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 5);
378 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
379 /* Raw alarm file for compatibility */
380 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
381 
382 static struct attribute *lm90_attributes[] = {
383 	&sensor_dev_attr_temp1_input.dev_attr.attr,
384 	&sensor_dev_attr_temp2_input.dev_attr.attr,
385 	&sensor_dev_attr_temp1_min.dev_attr.attr,
386 	&sensor_dev_attr_temp2_min.dev_attr.attr,
387 	&sensor_dev_attr_temp1_max.dev_attr.attr,
388 	&sensor_dev_attr_temp2_max.dev_attr.attr,
389 	&sensor_dev_attr_temp1_crit.dev_attr.attr,
390 	&sensor_dev_attr_temp2_crit.dev_attr.attr,
391 	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
392 	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
393 
394 	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
395 	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
396 	&sensor_dev_attr_temp2_fault.dev_attr.attr,
397 	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
398 	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
399 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
400 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
401 	&dev_attr_alarms.attr,
402 	NULL
403 };
404 
405 static const struct attribute_group lm90_group = {
406 	.attrs = lm90_attributes,
407 };
408 
409 /* pec used for ADM1032 only */
410 static ssize_t show_pec(struct device *dev, struct device_attribute *dummy,
411 			char *buf)
412 {
413 	struct i2c_client *client = to_i2c_client(dev);
414 	return sprintf(buf, "%d\n", !!(client->flags & I2C_CLIENT_PEC));
415 }
416 
417 static ssize_t set_pec(struct device *dev, struct device_attribute *dummy,
418 		       const char *buf, size_t count)
419 {
420 	struct i2c_client *client = to_i2c_client(dev);
421 	long val = simple_strtol(buf, NULL, 10);
422 
423 	switch (val) {
424 	case 0:
425 		client->flags &= ~I2C_CLIENT_PEC;
426 		break;
427 	case 1:
428 		client->flags |= I2C_CLIENT_PEC;
429 		break;
430 	default:
431 		return -EINVAL;
432 	}
433 
434 	return count;
435 }
436 
437 static DEVICE_ATTR(pec, S_IWUSR | S_IRUGO, show_pec, set_pec);
438 
439 /*
440  * Real code
441  */
442 
443 /* The ADM1032 supports PEC but not on write byte transactions, so we need
444    to explicitly ask for a transaction without PEC. */
445 static inline s32 adm1032_write_byte(struct i2c_client *client, u8 value)
446 {
447 	return i2c_smbus_xfer(client->adapter, client->addr,
448 			      client->flags & ~I2C_CLIENT_PEC,
449 			      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
450 }
451 
452 /* It is assumed that client->update_lock is held (unless we are in
453    detection or initialization steps). This matters when PEC is enabled,
454    because we don't want the address pointer to change between the write
455    byte and the read byte transactions. */
456 static int lm90_read_reg(struct i2c_client* client, u8 reg, u8 *value)
457 {
458 	int err;
459 
460  	if (client->flags & I2C_CLIENT_PEC) {
461  		err = adm1032_write_byte(client, reg);
462  		if (err >= 0)
463  			err = i2c_smbus_read_byte(client);
464  	} else
465  		err = i2c_smbus_read_byte_data(client, reg);
466 
467 	if (err < 0) {
468 		dev_warn(&client->dev, "Register %#02x read failed (%d)\n",
469 			 reg, err);
470 		return err;
471 	}
472 	*value = err;
473 
474 	return 0;
475 }
476 
477 static int lm90_attach_adapter(struct i2c_adapter *adapter)
478 {
479 	if (!(adapter->class & I2C_CLASS_HWMON))
480 		return 0;
481 	return i2c_probe(adapter, &addr_data, lm90_detect);
482 }
483 
484 /*
485  * The following function does more than just detection. If detection
486  * succeeds, it also registers the new chip.
487  */
488 static int lm90_detect(struct i2c_adapter *adapter, int address, int kind)
489 {
490 	struct i2c_client *new_client;
491 	struct lm90_data *data;
492 	int err = 0;
493 	const char *name = "";
494 
495 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
496 		goto exit;
497 
498 	if (!(data = kzalloc(sizeof(struct lm90_data), GFP_KERNEL))) {
499 		err = -ENOMEM;
500 		goto exit;
501 	}
502 
503 	/* The common I2C client data is placed right before the
504 	   LM90-specific data. */
505 	new_client = &data->client;
506 	i2c_set_clientdata(new_client, data);
507 	new_client->addr = address;
508 	new_client->adapter = adapter;
509 	new_client->driver = &lm90_driver;
510 	new_client->flags = 0;
511 
512 	/*
513 	 * Now we do the remaining detection. A negative kind means that
514 	 * the driver was loaded with no force parameter (default), so we
515 	 * must both detect and identify the chip. A zero kind means that
516 	 * the driver was loaded with the force parameter, the detection
517 	 * step shall be skipped. A positive kind means that the driver
518 	 * was loaded with the force parameter and a given kind of chip is
519 	 * requested, so both the detection and the identification steps
520 	 * are skipped.
521 	 */
522 
523 	/* Default to an LM90 if forced */
524 	if (kind == 0)
525 		kind = lm90;
526 
527 	if (kind < 0) { /* detection and identification */
528 		u8 man_id, chip_id, reg_config1, reg_convrate;
529 
530 		if (lm90_read_reg(new_client, LM90_REG_R_MAN_ID,
531 				  &man_id) < 0
532 		 || lm90_read_reg(new_client, LM90_REG_R_CHIP_ID,
533 		 		  &chip_id) < 0
534 		 || lm90_read_reg(new_client, LM90_REG_R_CONFIG1,
535 		 		  &reg_config1) < 0
536 		 || lm90_read_reg(new_client, LM90_REG_R_CONVRATE,
537 		 		  &reg_convrate) < 0)
538 			goto exit_free;
539 
540 		if ((address == 0x4C || address == 0x4D)
541 		 && man_id == 0x01) { /* National Semiconductor */
542 			u8 reg_config2;
543 
544 			if (lm90_read_reg(new_client, LM90_REG_R_CONFIG2,
545 					  &reg_config2) < 0)
546 				goto exit_free;
547 
548 			if ((reg_config1 & 0x2A) == 0x00
549 			 && (reg_config2 & 0xF8) == 0x00
550 			 && reg_convrate <= 0x09) {
551 				if (address == 0x4C
552 				 && (chip_id & 0xF0) == 0x20) { /* LM90 */
553 					kind = lm90;
554 				} else
555 				if ((chip_id & 0xF0) == 0x30) { /* LM89/LM99 */
556 					kind = lm99;
557 				} else
558 				if (address == 0x4C
559 				 && (chip_id & 0xF0) == 0x10) { /* LM86 */
560 					kind = lm86;
561 				}
562 			}
563 		} else
564 		if ((address == 0x4C || address == 0x4D)
565 		 && man_id == 0x41) { /* Analog Devices */
566 			if ((chip_id & 0xF0) == 0x40 /* ADM1032 */
567 			 && (reg_config1 & 0x3F) == 0x00
568 			 && reg_convrate <= 0x0A) {
569 				kind = adm1032;
570 			} else
571 			if (chip_id == 0x51 /* ADT7461 */
572 			 && (reg_config1 & 0x1F) == 0x00 /* check compat mode */
573 			 && reg_convrate <= 0x0A) {
574 				kind = adt7461;
575 			}
576 		} else
577 		if (man_id == 0x4D) { /* Maxim */
578 			/*
579 			 * The MAX6657, MAX6658 and MAX6659 do NOT have a
580 			 * chip_id register. Reading from that address will
581 			 * return the last read value, which in our case is
582 			 * those of the man_id register. Likewise, the config1
583 			 * register seems to lack a low nibble, so the value
584 			 * will be those of the previous read, so in our case
585 			 * those of the man_id register.
586 			 */
587 			if (chip_id == man_id
588 			 && (address == 0x4F || address == 0x4D)
589 			 && (reg_config1 & 0x1F) == (man_id & 0x0F)
590 			 && reg_convrate <= 0x09) {
591 			 	kind = max6657;
592 			} else
593 			/* The chip_id register of the MAX6680 and MAX6681
594 			 * holds the revision of the chip.
595 			 * the lowest bit of the config1 register is unused
596 			 * and should return zero when read, so should the
597 			 * second to last bit of config1 (software reset)
598 			 */
599 			if (chip_id == 0x01
600 			 && (reg_config1 & 0x03) == 0x00
601 			 && reg_convrate <= 0x07) {
602 			 	kind = max6680;
603 			}
604 		}
605 
606 		if (kind <= 0) { /* identification failed */
607 			dev_info(&adapter->dev,
608 			    "Unsupported chip (man_id=0x%02X, "
609 			    "chip_id=0x%02X).\n", man_id, chip_id);
610 			goto exit_free;
611 		}
612 	}
613 
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 			new_client->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 
634 	/* We can fill in the remaining client fields */
635 	strlcpy(new_client->name, name, I2C_NAME_SIZE);
636 	data->valid = 0;
637 	data->kind = kind;
638 	mutex_init(&data->update_lock);
639 
640 	/* Tell the I2C layer a new client has arrived */
641 	if ((err = i2c_attach_client(new_client)))
642 		goto exit_free;
643 
644 	/* Initialize the LM90 chip */
645 	lm90_init_client(new_client);
646 
647 	/* Register sysfs hooks */
648 	if ((err = sysfs_create_group(&new_client->dev.kobj, &lm90_group)))
649 		goto exit_detach;
650 	if (new_client->flags & I2C_CLIENT_PEC) {
651 		if ((err = device_create_file(&new_client->dev,
652 					      &dev_attr_pec)))
653 			goto exit_remove_files;
654 	}
655 
656 	data->class_dev = hwmon_device_register(&new_client->dev);
657 	if (IS_ERR(data->class_dev)) {
658 		err = PTR_ERR(data->class_dev);
659 		goto exit_remove_files;
660 	}
661 
662 	return 0;
663 
664 exit_remove_files:
665 	sysfs_remove_group(&new_client->dev.kobj, &lm90_group);
666 	device_remove_file(&new_client->dev, &dev_attr_pec);
667 exit_detach:
668 	i2c_detach_client(new_client);
669 exit_free:
670 	kfree(data);
671 exit:
672 	return err;
673 }
674 
675 static void lm90_init_client(struct i2c_client *client)
676 {
677 	u8 config, config_orig;
678 	struct lm90_data *data = i2c_get_clientdata(client);
679 
680 	/*
681 	 * Start the conversions.
682 	 */
683 	i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE,
684 				  5); /* 2 Hz */
685 	if (lm90_read_reg(client, LM90_REG_R_CONFIG1, &config) < 0) {
686 		dev_warn(&client->dev, "Initialization failed!\n");
687 		return;
688 	}
689 	config_orig = config;
690 
691 	/*
692 	 * Put MAX6680/MAX8881 into extended resolution (bit 0x10,
693 	 * 0.125 degree resolution) and range (0x08, extend range
694 	 * to -64 degree) mode for the remote temperature sensor.
695 	 */
696 	if (data->kind == max6680) {
697 		config |= 0x18;
698 	}
699 
700 	config &= 0xBF;	/* run */
701 	if (config != config_orig) /* Only write if changed */
702 		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, config);
703 }
704 
705 static int lm90_detach_client(struct i2c_client *client)
706 {
707 	struct lm90_data *data = i2c_get_clientdata(client);
708 	int err;
709 
710 	hwmon_device_unregister(data->class_dev);
711 	sysfs_remove_group(&client->dev.kobj, &lm90_group);
712 	device_remove_file(&client->dev, &dev_attr_pec);
713 
714 	if ((err = i2c_detach_client(client)))
715 		return err;
716 
717 	kfree(data);
718 	return 0;
719 }
720 
721 static struct lm90_data *lm90_update_device(struct device *dev)
722 {
723 	struct i2c_client *client = to_i2c_client(dev);
724 	struct lm90_data *data = i2c_get_clientdata(client);
725 
726 	mutex_lock(&data->update_lock);
727 
728 	if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
729 		u8 oldh, newh, l;
730 
731 		dev_dbg(&client->dev, "Updating lm90 data.\n");
732 		lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP, &data->temp8[0]);
733 		lm90_read_reg(client, LM90_REG_R_LOCAL_LOW, &data->temp8[1]);
734 		lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH, &data->temp8[2]);
735 		lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT, &data->temp8[3]);
736 		lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]);
737 		lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
738 
739 		/*
740 		 * There is a trick here. We have to read two registers to
741 		 * have the remote sensor temperature, but we have to beware
742 		 * a conversion could occur inbetween the readings. The
743 		 * datasheet says we should either use the one-shot
744 		 * conversion register, which we don't want to do (disables
745 		 * hardware monitoring) or monitor the busy bit, which is
746 		 * impossible (we can't read the values and monitor that bit
747 		 * at the exact same time). So the solution used here is to
748 		 * read the high byte once, then the low byte, then the high
749 		 * byte again. If the new high byte matches the old one,
750 		 * then we have a valid reading. Else we have to read the low
751 		 * byte again, and now we believe we have a correct reading.
752 		 */
753 		if (lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &oldh) == 0
754 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0
755 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &newh) == 0
756 		 && (newh == oldh
757 		  || lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0))
758 			data->temp11[0] = (newh << 8) | l;
759 
760 		if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &newh) == 0
761 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL, &l) == 0)
762 			data->temp11[1] = (newh << 8) | l;
763 		if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &newh) == 0
764 		 && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL, &l) == 0)
765 			data->temp11[2] = (newh << 8) | l;
766 		lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms);
767 
768 		data->last_updated = jiffies;
769 		data->valid = 1;
770 	}
771 
772 	mutex_unlock(&data->update_lock);
773 
774 	return data;
775 }
776 
777 static int __init sensors_lm90_init(void)
778 {
779 	return i2c_add_driver(&lm90_driver);
780 }
781 
782 static void __exit sensors_lm90_exit(void)
783 {
784 	i2c_del_driver(&lm90_driver);
785 }
786 
787 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
788 MODULE_DESCRIPTION("LM90/ADM1032 driver");
789 MODULE_LICENSE("GPL");
790 
791 module_init(sensors_lm90_init);
792 module_exit(sensors_lm90_exit);
793