xref: /openbmc/linux/drivers/hwmon/lm95245.c (revision 8fdff1dc) 
1 /*
2  * Copyright (C) 2011 Alexander Stein <alexander.stein@systec-electronic.com>
3  *
4  * The LM95245 is a sensor chip made by National Semiconductors.
5  * It reports up to two temperatures (its own plus an external one).
6  * Complete datasheet can be obtained from National's website at:
7  *   http://www.national.com/ds.cgi/LM/LM95245.pdf
8  *
9  * This driver is based on lm95241.c
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  */
25 
26 #include <linux/module.h>
27 #include <linux/init.h>
28 #include <linux/slab.h>
29 #include <linux/jiffies.h>
30 #include <linux/i2c.h>
31 #include <linux/hwmon.h>
32 #include <linux/hwmon-sysfs.h>
33 #include <linux/err.h>
34 #include <linux/mutex.h>
35 #include <linux/sysfs.h>
36 
37 #define DEVNAME "lm95245"
38 
39 static const unsigned short normal_i2c[] = {
40 	0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };
41 
42 /* LM95245 registers */
43 /* general registers */
44 #define LM95245_REG_RW_CONFIG1		0x03
45 #define LM95245_REG_RW_CONVERS_RATE	0x04
46 #define LM95245_REG_W_ONE_SHOT		0x0F
47 
48 /* diode configuration */
49 #define LM95245_REG_RW_CONFIG2		0xBF
50 #define LM95245_REG_RW_REMOTE_OFFH	0x11
51 #define LM95245_REG_RW_REMOTE_OFFL	0x12
52 
53 /* status registers */
54 #define LM95245_REG_R_STATUS1		0x02
55 #define LM95245_REG_R_STATUS2		0x33
56 
57 /* limit registers */
58 #define LM95245_REG_RW_REMOTE_OS_LIMIT		0x07
59 #define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT	0x20
60 #define LM95245_REG_RW_REMOTE_TCRIT_LIMIT	0x19
61 #define LM95245_REG_RW_COMMON_HYSTERESIS	0x21
62 
63 /* temperature signed */
64 #define LM95245_REG_R_LOCAL_TEMPH_S	0x00
65 #define LM95245_REG_R_LOCAL_TEMPL_S	0x30
66 #define LM95245_REG_R_REMOTE_TEMPH_S	0x01
67 #define LM95245_REG_R_REMOTE_TEMPL_S	0x10
68 /* temperature unsigned */
69 #define LM95245_REG_R_REMOTE_TEMPH_U	0x31
70 #define LM95245_REG_R_REMOTE_TEMPL_U	0x32
71 
72 /* id registers */
73 #define LM95245_REG_R_MAN_ID		0xFE
74 #define LM95245_REG_R_CHIP_ID		0xFF
75 
76 /* LM95245 specific bitfields */
77 #define CFG_STOP		0x40
78 #define CFG_REMOTE_TCRIT_MASK	0x10
79 #define CFG_REMOTE_OS_MASK	0x08
80 #define CFG_LOCAL_TCRIT_MASK	0x04
81 #define CFG_LOCAL_OS_MASK	0x02
82 
83 #define CFG2_OS_A0		0x40
84 #define CFG2_DIODE_FAULT_OS	0x20
85 #define CFG2_DIODE_FAULT_TCRIT	0x10
86 #define CFG2_REMOTE_TT		0x08
87 #define CFG2_REMOTE_FILTER_DIS	0x00
88 #define CFG2_REMOTE_FILTER_EN	0x06
89 
90 /* conversation rate in ms */
91 #define RATE_CR0063	0x00
92 #define RATE_CR0364	0x01
93 #define RATE_CR1000	0x02
94 #define RATE_CR2500	0x03
95 
96 #define STATUS1_DIODE_FAULT	0x04
97 #define STATUS1_RTCRIT		0x02
98 #define STATUS1_LOC		0x01
99 
100 #define MANUFACTURER_ID		0x01
101 #define DEFAULT_REVISION	0xB3
102 
103 static const u8 lm95245_reg_address[] = {
104 	LM95245_REG_R_LOCAL_TEMPH_S,
105 	LM95245_REG_R_LOCAL_TEMPL_S,
106 	LM95245_REG_R_REMOTE_TEMPH_S,
107 	LM95245_REG_R_REMOTE_TEMPL_S,
108 	LM95245_REG_R_REMOTE_TEMPH_U,
109 	LM95245_REG_R_REMOTE_TEMPL_U,
110 	LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
111 	LM95245_REG_RW_REMOTE_TCRIT_LIMIT,
112 	LM95245_REG_RW_COMMON_HYSTERESIS,
113 	LM95245_REG_R_STATUS1,
114 };
115 
116 /* Client data (each client gets its own) */
117 struct lm95245_data {
118 	struct device *hwmon_dev;
119 	struct mutex update_lock;
120 	unsigned long last_updated;	/* in jiffies */
121 	unsigned long interval;	/* in msecs */
122 	bool valid;		/* zero until following fields are valid */
123 	/* registers values */
124 	u8 regs[ARRAY_SIZE(lm95245_reg_address)];
125 	u8 config1, config2;
126 };
127 
128 /* Conversions */
129 static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
130 {
131 	return val_h * 1000 + val_l * 1000 / 256;
132 }
133 
134 static int temp_from_reg_signed(u8 val_h, u8 val_l)
135 {
136 	if (val_h & 0x80)
137 		return (val_h - 0x100) * 1000;
138 	return temp_from_reg_unsigned(val_h, val_l);
139 }
140 
141 static struct lm95245_data *lm95245_update_device(struct device *dev)
142 {
143 	struct i2c_client *client = to_i2c_client(dev);
144 	struct lm95245_data *data = i2c_get_clientdata(client);
145 
146 	mutex_lock(&data->update_lock);
147 
148 	if (time_after(jiffies, data->last_updated
149 		+ msecs_to_jiffies(data->interval)) || !data->valid) {
150 		int i;
151 
152 		dev_dbg(&client->dev, "Updating lm95245 data.\n");
153 		for (i = 0; i < ARRAY_SIZE(lm95245_reg_address); i++)
154 			data->regs[i]
155 			  = i2c_smbus_read_byte_data(client,
156 						     lm95245_reg_address[i]);
157 		data->last_updated = jiffies;
158 		data->valid = 1;
159 	}
160 
161 	mutex_unlock(&data->update_lock);
162 
163 	return data;
164 }
165 
166 static unsigned long lm95245_read_conversion_rate(struct i2c_client *client)
167 {
168 	int rate;
169 	unsigned long interval;
170 
171 	rate = i2c_smbus_read_byte_data(client, LM95245_REG_RW_CONVERS_RATE);
172 
173 	switch (rate) {
174 	case RATE_CR0063:
175 		interval = 63;
176 		break;
177 	case RATE_CR0364:
178 		interval = 364;
179 		break;
180 	case RATE_CR1000:
181 		interval = 1000;
182 		break;
183 	case RATE_CR2500:
184 	default:
185 		interval = 2500;
186 		break;
187 	}
188 
189 	return interval;
190 }
191 
192 static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
193 			unsigned long interval)
194 {
195 	int rate;
196 
197 	if (interval <= 63) {
198 		interval = 63;
199 		rate = RATE_CR0063;
200 	} else if (interval <= 364) {
201 		interval = 364;
202 		rate = RATE_CR0364;
203 	} else if (interval <= 1000) {
204 		interval = 1000;
205 		rate = RATE_CR1000;
206 	} else {
207 		interval = 2500;
208 		rate = RATE_CR2500;
209 	}
210 
211 	i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONVERS_RATE, rate);
212 
213 	return interval;
214 }
215 
216 /* Sysfs stuff */
217 static ssize_t show_input(struct device *dev, struct device_attribute *attr,
218 			  char *buf)
219 {
220 	struct lm95245_data *data = lm95245_update_device(dev);
221 	int temp;
222 	int index = to_sensor_dev_attr(attr)->index;
223 
224 	/*
225 	 * Index 0 (Local temp) is always signed
226 	 * Index 2 (Remote temp) has both signed and unsigned data
227 	 * use signed calculation for remote if signed bit is set
228 	 */
229 	if (index == 0 || data->regs[index] & 0x80)
230 		temp = temp_from_reg_signed(data->regs[index],
231 			    data->regs[index + 1]);
232 	else
233 		temp = temp_from_reg_unsigned(data->regs[index + 2],
234 			    data->regs[index + 3]);
235 
236 	return snprintf(buf, PAGE_SIZE - 1, "%d\n", temp);
237 }
238 
239 static ssize_t show_limit(struct device *dev, struct device_attribute *attr,
240 			 char *buf)
241 {
242 	struct lm95245_data *data = lm95245_update_device(dev);
243 	int index = to_sensor_dev_attr(attr)->index;
244 
245 	return snprintf(buf, PAGE_SIZE - 1, "%d\n",
246 			data->regs[index] * 1000);
247 }
248 
249 static ssize_t set_limit(struct device *dev, struct device_attribute *attr,
250 			const char *buf, size_t count)
251 {
252 	struct i2c_client *client = to_i2c_client(dev);
253 	struct lm95245_data *data = i2c_get_clientdata(client);
254 	int index = to_sensor_dev_attr(attr)->index;
255 	unsigned long val;
256 
257 	if (kstrtoul(buf, 10, &val) < 0)
258 		return -EINVAL;
259 
260 	val /= 1000;
261 
262 	val = SENSORS_LIMIT(val, 0, (index == 6 ? 127 : 255));
263 
264 	mutex_lock(&data->update_lock);
265 
266 	data->valid = 0;
267 
268 	i2c_smbus_write_byte_data(client, lm95245_reg_address[index], val);
269 
270 	mutex_unlock(&data->update_lock);
271 
272 	return count;
273 }
274 
275 static ssize_t set_crit_hyst(struct device *dev, struct device_attribute *attr,
276 			const char *buf, size_t count)
277 {
278 	struct i2c_client *client = to_i2c_client(dev);
279 	struct lm95245_data *data = i2c_get_clientdata(client);
280 	unsigned long val;
281 
282 	if (kstrtoul(buf, 10, &val) < 0)
283 		return -EINVAL;
284 
285 	val /= 1000;
286 
287 	val = SENSORS_LIMIT(val, 0, 31);
288 
289 	mutex_lock(&data->update_lock);
290 
291 	data->valid = 0;
292 
293 	/* shared crit hysteresis */
294 	i2c_smbus_write_byte_data(client, LM95245_REG_RW_COMMON_HYSTERESIS,
295 		val);
296 
297 	mutex_unlock(&data->update_lock);
298 
299 	return count;
300 }
301 
302 static ssize_t show_type(struct device *dev, struct device_attribute *attr,
303 			 char *buf)
304 {
305 	struct i2c_client *client = to_i2c_client(dev);
306 	struct lm95245_data *data = i2c_get_clientdata(client);
307 
308 	return snprintf(buf, PAGE_SIZE - 1,
309 		data->config2 & CFG2_REMOTE_TT ? "1\n" : "2\n");
310 }
311 
312 static ssize_t set_type(struct device *dev, struct device_attribute *attr,
313 			const char *buf, size_t count)
314 {
315 	struct i2c_client *client = to_i2c_client(dev);
316 	struct lm95245_data *data = i2c_get_clientdata(client);
317 	unsigned long val;
318 
319 	if (kstrtoul(buf, 10, &val) < 0)
320 		return -EINVAL;
321 	if (val != 1 && val != 2)
322 		return -EINVAL;
323 
324 	mutex_lock(&data->update_lock);
325 
326 	if (val == 1)
327 		data->config2 |= CFG2_REMOTE_TT;
328 	else
329 		data->config2 &= ~CFG2_REMOTE_TT;
330 
331 	data->valid = 0;
332 
333 	i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG2,
334 				  data->config2);
335 
336 	mutex_unlock(&data->update_lock);
337 
338 	return count;
339 }
340 
341 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
342 			 char *buf)
343 {
344 	struct lm95245_data *data = lm95245_update_device(dev);
345 	int index = to_sensor_dev_attr(attr)->index;
346 
347 	return snprintf(buf, PAGE_SIZE - 1, "%d\n",
348 			!!(data->regs[9] & index));
349 }
350 
351 static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
352 			     char *buf)
353 {
354 	struct lm95245_data *data = lm95245_update_device(dev);
355 
356 	return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->interval);
357 }
358 
359 static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
360 			    const char *buf, size_t count)
361 {
362 	struct i2c_client *client = to_i2c_client(dev);
363 	struct lm95245_data *data = i2c_get_clientdata(client);
364 	unsigned long val;
365 
366 	if (kstrtoul(buf, 10, &val) < 0)
367 		return -EINVAL;
368 
369 	mutex_lock(&data->update_lock);
370 
371 	data->interval = lm95245_set_conversion_rate(client, val);
372 
373 	mutex_unlock(&data->update_lock);
374 
375 	return count;
376 }
377 
378 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
379 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
380 		set_limit, 6);
381 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
382 		set_crit_hyst, 8);
383 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
384 		STATUS1_LOC);
385 
386 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
387 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
388 		set_limit, 7);
389 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
390 		set_crit_hyst, 8);
391 static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
392 		STATUS1_RTCRIT);
393 static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
394 		set_type, 0);
395 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
396 		STATUS1_DIODE_FAULT);
397 
398 static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
399 		set_interval);
400 
401 static struct attribute *lm95245_attributes[] = {
402 	&sensor_dev_attr_temp1_input.dev_attr.attr,
403 	&sensor_dev_attr_temp1_crit.dev_attr.attr,
404 	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
405 	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
406 	&sensor_dev_attr_temp2_input.dev_attr.attr,
407 	&sensor_dev_attr_temp2_crit.dev_attr.attr,
408 	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
409 	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
410 	&sensor_dev_attr_temp2_type.dev_attr.attr,
411 	&sensor_dev_attr_temp2_fault.dev_attr.attr,
412 	&dev_attr_update_interval.attr,
413 	NULL
414 };
415 
416 static const struct attribute_group lm95245_group = {
417 	.attrs = lm95245_attributes,
418 };
419 
420 /* Return 0 if detection is successful, -ENODEV otherwise */
421 static int lm95245_detect(struct i2c_client *new_client,
422 			  struct i2c_board_info *info)
423 {
424 	struct i2c_adapter *adapter = new_client->adapter;
425 
426 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
427 		return -ENODEV;
428 
429 	if (i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID)
430 			!= MANUFACTURER_ID
431 		|| i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID)
432 			!= DEFAULT_REVISION)
433 		return -ENODEV;
434 
435 	strlcpy(info->type, DEVNAME, I2C_NAME_SIZE);
436 	return 0;
437 }
438 
439 static void lm95245_init_client(struct i2c_client *client)
440 {
441 	struct lm95245_data *data = i2c_get_clientdata(client);
442 
443 	data->valid = 0;
444 	data->interval = lm95245_read_conversion_rate(client);
445 
446 	data->config1 = i2c_smbus_read_byte_data(client,
447 		LM95245_REG_RW_CONFIG1);
448 	data->config2 = i2c_smbus_read_byte_data(client,
449 		LM95245_REG_RW_CONFIG2);
450 
451 	if (data->config1 & CFG_STOP) {
452 		/* Clear the standby bit */
453 		data->config1 &= ~CFG_STOP;
454 		i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
455 			data->config1);
456 	}
457 }
458 
459 static int lm95245_probe(struct i2c_client *new_client,
460 			 const struct i2c_device_id *id)
461 {
462 	struct lm95245_data *data;
463 	int err;
464 
465 	data = devm_kzalloc(&new_client->dev, sizeof(struct lm95245_data),
466 			    GFP_KERNEL);
467 	if (!data)
468 		return -ENOMEM;
469 
470 	i2c_set_clientdata(new_client, data);
471 	mutex_init(&data->update_lock);
472 
473 	/* Initialize the LM95245 chip */
474 	lm95245_init_client(new_client);
475 
476 	/* Register sysfs hooks */
477 	err = sysfs_create_group(&new_client->dev.kobj, &lm95245_group);
478 	if (err)
479 		return err;
480 
481 	data->hwmon_dev = hwmon_device_register(&new_client->dev);
482 	if (IS_ERR(data->hwmon_dev)) {
483 		err = PTR_ERR(data->hwmon_dev);
484 		goto exit_remove_files;
485 	}
486 
487 	return 0;
488 
489 exit_remove_files:
490 	sysfs_remove_group(&new_client->dev.kobj, &lm95245_group);
491 	return err;
492 }
493 
494 static int lm95245_remove(struct i2c_client *client)
495 {
496 	struct lm95245_data *data = i2c_get_clientdata(client);
497 
498 	hwmon_device_unregister(data->hwmon_dev);
499 	sysfs_remove_group(&client->dev.kobj, &lm95245_group);
500 
501 	return 0;
502 }
503 
504 /* Driver data (common to all clients) */
505 static const struct i2c_device_id lm95245_id[] = {
506 	{ DEVNAME, 0 },
507 	{ }
508 };
509 MODULE_DEVICE_TABLE(i2c, lm95245_id);
510 
511 static struct i2c_driver lm95245_driver = {
512 	.class		= I2C_CLASS_HWMON,
513 	.driver = {
514 		.name	= DEVNAME,
515 	},
516 	.probe		= lm95245_probe,
517 	.remove		= lm95245_remove,
518 	.id_table	= lm95245_id,
519 	.detect		= lm95245_detect,
520 	.address_list	= normal_i2c,
521 };
522 
523 module_i2c_driver(lm95245_driver);
524 
525 MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
526 MODULE_DESCRIPTION("LM95245 sensor driver");
527 MODULE_LICENSE("GPL");
528