xref: /openbmc/linux/drivers/hwmon/lm95245.c (revision db181ce0) 
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 i2c_client *client;
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 lm95245_data *data = dev_get_drvdata(dev);
144 	struct i2c_client *client = data->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 		for (i = 0; i < ARRAY_SIZE(lm95245_reg_address); i++)
153 			data->regs[i]
154 			  = i2c_smbus_read_byte_data(client,
155 						     lm95245_reg_address[i]);
156 		data->last_updated = jiffies;
157 		data->valid = 1;
158 	}
159 
160 	mutex_unlock(&data->update_lock);
161 
162 	return data;
163 }
164 
165 static unsigned long lm95245_read_conversion_rate(struct i2c_client *client)
166 {
167 	int rate;
168 	unsigned long interval;
169 
170 	rate = i2c_smbus_read_byte_data(client, LM95245_REG_RW_CONVERS_RATE);
171 
172 	switch (rate) {
173 	case RATE_CR0063:
174 		interval = 63;
175 		break;
176 	case RATE_CR0364:
177 		interval = 364;
178 		break;
179 	case RATE_CR1000:
180 		interval = 1000;
181 		break;
182 	case RATE_CR2500:
183 	default:
184 		interval = 2500;
185 		break;
186 	}
187 
188 	return interval;
189 }
190 
191 static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
192 			unsigned long interval)
193 {
194 	int rate;
195 
196 	if (interval <= 63) {
197 		interval = 63;
198 		rate = RATE_CR0063;
199 	} else if (interval <= 364) {
200 		interval = 364;
201 		rate = RATE_CR0364;
202 	} else if (interval <= 1000) {
203 		interval = 1000;
204 		rate = RATE_CR1000;
205 	} else {
206 		interval = 2500;
207 		rate = RATE_CR2500;
208 	}
209 
210 	i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONVERS_RATE, rate);
211 
212 	return interval;
213 }
214 
215 /* Sysfs stuff */
216 static ssize_t show_input(struct device *dev, struct device_attribute *attr,
217 			  char *buf)
218 {
219 	struct lm95245_data *data = lm95245_update_device(dev);
220 	int temp;
221 	int index = to_sensor_dev_attr(attr)->index;
222 
223 	/*
224 	 * Index 0 (Local temp) is always signed
225 	 * Index 2 (Remote temp) has both signed and unsigned data
226 	 * use signed calculation for remote if signed bit is set
227 	 */
228 	if (index == 0 || data->regs[index] & 0x80)
229 		temp = temp_from_reg_signed(data->regs[index],
230 			    data->regs[index + 1]);
231 	else
232 		temp = temp_from_reg_unsigned(data->regs[index + 2],
233 			    data->regs[index + 3]);
234 
235 	return snprintf(buf, PAGE_SIZE - 1, "%d\n", temp);
236 }
237 
238 static ssize_t show_limit(struct device *dev, struct device_attribute *attr,
239 			 char *buf)
240 {
241 	struct lm95245_data *data = lm95245_update_device(dev);
242 	int index = to_sensor_dev_attr(attr)->index;
243 
244 	return snprintf(buf, PAGE_SIZE - 1, "%d\n",
245 			data->regs[index] * 1000);
246 }
247 
248 static ssize_t set_limit(struct device *dev, struct device_attribute *attr,
249 			const char *buf, size_t count)
250 {
251 	struct lm95245_data *data = dev_get_drvdata(dev);
252 	int index = to_sensor_dev_attr(attr)->index;
253 	struct i2c_client *client = data->client;
254 	unsigned long val;
255 
256 	if (kstrtoul(buf, 10, &val) < 0)
257 		return -EINVAL;
258 
259 	val /= 1000;
260 
261 	val = clamp_val(val, 0, (index == 6 ? 127 : 255));
262 
263 	mutex_lock(&data->update_lock);
264 
265 	data->valid = 0;
266 
267 	i2c_smbus_write_byte_data(client, lm95245_reg_address[index], val);
268 
269 	mutex_unlock(&data->update_lock);
270 
271 	return count;
272 }
273 
274 static ssize_t show_crit_hyst(struct device *dev, struct device_attribute *attr,
275 			char *buf)
276 {
277 	struct lm95245_data *data = lm95245_update_device(dev);
278 	int index = to_sensor_dev_attr(attr)->index;
279 	int hyst = data->regs[index] - data->regs[8];
280 
281 	return snprintf(buf, PAGE_SIZE - 1, "%d\n", hyst * 1000);
282 }
283 
284 static ssize_t set_crit_hyst(struct device *dev, struct device_attribute *attr,
285 			const char *buf, size_t count)
286 {
287 	struct lm95245_data *data = dev_get_drvdata(dev);
288 	int index = to_sensor_dev_attr(attr)->index;
289 	struct i2c_client *client = data->client;
290 	unsigned long val;
291 	int hyst, limit;
292 
293 	if (kstrtoul(buf, 10, &val) < 0)
294 		return -EINVAL;
295 
296 	mutex_lock(&data->update_lock);
297 
298 	limit = i2c_smbus_read_byte_data(client, lm95245_reg_address[index]);
299 	hyst = limit - val / 1000;
300 	hyst = clamp_val(hyst, 0, 31);
301 	data->regs[8] = hyst;
302 
303 	/* shared crit hysteresis */
304 	i2c_smbus_write_byte_data(client, LM95245_REG_RW_COMMON_HYSTERESIS,
305 		hyst);
306 
307 	mutex_unlock(&data->update_lock);
308 
309 	return count;
310 }
311 
312 static ssize_t show_type(struct device *dev, struct device_attribute *attr,
313 			 char *buf)
314 {
315 	struct lm95245_data *data = dev_get_drvdata(dev);
316 
317 	return snprintf(buf, PAGE_SIZE - 1,
318 		data->config2 & CFG2_REMOTE_TT ? "1\n" : "2\n");
319 }
320 
321 static ssize_t set_type(struct device *dev, struct device_attribute *attr,
322 			const char *buf, size_t count)
323 {
324 	struct lm95245_data *data = dev_get_drvdata(dev);
325 	struct i2c_client *client = data->client;
326 	unsigned long val;
327 
328 	if (kstrtoul(buf, 10, &val) < 0)
329 		return -EINVAL;
330 	if (val != 1 && val != 2)
331 		return -EINVAL;
332 
333 	mutex_lock(&data->update_lock);
334 
335 	if (val == 1)
336 		data->config2 |= CFG2_REMOTE_TT;
337 	else
338 		data->config2 &= ~CFG2_REMOTE_TT;
339 
340 	data->valid = 0;
341 
342 	i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG2,
343 				  data->config2);
344 
345 	mutex_unlock(&data->update_lock);
346 
347 	return count;
348 }
349 
350 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
351 			 char *buf)
352 {
353 	struct lm95245_data *data = lm95245_update_device(dev);
354 	int index = to_sensor_dev_attr(attr)->index;
355 
356 	return snprintf(buf, PAGE_SIZE - 1, "%d\n",
357 			!!(data->regs[9] & index));
358 }
359 
360 static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
361 			     char *buf)
362 {
363 	struct lm95245_data *data = lm95245_update_device(dev);
364 
365 	return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->interval);
366 }
367 
368 static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
369 			    const char *buf, size_t count)
370 {
371 	struct lm95245_data *data = dev_get_drvdata(dev);
372 	struct i2c_client *client = data->client;
373 	unsigned long val;
374 
375 	if (kstrtoul(buf, 10, &val) < 0)
376 		return -EINVAL;
377 
378 	mutex_lock(&data->update_lock);
379 
380 	data->interval = lm95245_set_conversion_rate(client, val);
381 
382 	mutex_unlock(&data->update_lock);
383 
384 	return count;
385 }
386 
387 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
388 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
389 		set_limit, 6);
390 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_crit_hyst,
391 		set_crit_hyst, 6);
392 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
393 		STATUS1_LOC);
394 
395 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
396 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
397 		set_limit, 7);
398 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_crit_hyst, NULL, 7);
399 static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
400 		STATUS1_RTCRIT);
401 static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
402 		set_type, 0);
403 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
404 		STATUS1_DIODE_FAULT);
405 
406 static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
407 		set_interval);
408 
409 static struct attribute *lm95245_attrs[] = {
410 	&sensor_dev_attr_temp1_input.dev_attr.attr,
411 	&sensor_dev_attr_temp1_crit.dev_attr.attr,
412 	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
413 	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
414 	&sensor_dev_attr_temp2_input.dev_attr.attr,
415 	&sensor_dev_attr_temp2_crit.dev_attr.attr,
416 	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
417 	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
418 	&sensor_dev_attr_temp2_type.dev_attr.attr,
419 	&sensor_dev_attr_temp2_fault.dev_attr.attr,
420 	&dev_attr_update_interval.attr,
421 	NULL
422 };
423 ATTRIBUTE_GROUPS(lm95245);
424 
425 /* Return 0 if detection is successful, -ENODEV otherwise */
426 static int lm95245_detect(struct i2c_client *new_client,
427 			  struct i2c_board_info *info)
428 {
429 	struct i2c_adapter *adapter = new_client->adapter;
430 
431 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
432 		return -ENODEV;
433 
434 	if (i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID)
435 			!= MANUFACTURER_ID
436 		|| i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID)
437 			!= DEFAULT_REVISION)
438 		return -ENODEV;
439 
440 	strlcpy(info->type, DEVNAME, I2C_NAME_SIZE);
441 	return 0;
442 }
443 
444 static void lm95245_init_client(struct i2c_client *client,
445 				struct lm95245_data *data)
446 {
447 	data->interval = lm95245_read_conversion_rate(client);
448 
449 	data->config1 = i2c_smbus_read_byte_data(client,
450 		LM95245_REG_RW_CONFIG1);
451 	data->config2 = i2c_smbus_read_byte_data(client,
452 		LM95245_REG_RW_CONFIG2);
453 
454 	if (data->config1 & CFG_STOP) {
455 		/* Clear the standby bit */
456 		data->config1 &= ~CFG_STOP;
457 		i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
458 			data->config1);
459 	}
460 }
461 
462 static int lm95245_probe(struct i2c_client *client,
463 			 const struct i2c_device_id *id)
464 {
465 	struct device *dev = &client->dev;
466 	struct lm95245_data *data;
467 	struct device *hwmon_dev;
468 
469 	data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
470 	if (!data)
471 		return -ENOMEM;
472 
473 	data->client = client;
474 	mutex_init(&data->update_lock);
475 
476 	/* Initialize the LM95245 chip */
477 	lm95245_init_client(client, data);
478 
479 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
480 							   data,
481 							   lm95245_groups);
482 	return PTR_ERR_OR_ZERO(hwmon_dev);
483 }
484 
485 /* Driver data (common to all clients) */
486 static const struct i2c_device_id lm95245_id[] = {
487 	{ DEVNAME, 0 },
488 	{ }
489 };
490 MODULE_DEVICE_TABLE(i2c, lm95245_id);
491 
492 static struct i2c_driver lm95245_driver = {
493 	.class		= I2C_CLASS_HWMON,
494 	.driver = {
495 		.name	= DEVNAME,
496 	},
497 	.probe		= lm95245_probe,
498 	.id_table	= lm95245_id,
499 	.detect		= lm95245_detect,
500 	.address_list	= normal_i2c,
501 };
502 
503 module_i2c_driver(lm95245_driver);
504 
505 MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
506 MODULE_DESCRIPTION("LM95245 sensor driver");
507 MODULE_LICENSE("GPL");
508