lm95245.c revision 7276d55e62f79f2b81d2c414e48de43edea5aa78 
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
39static 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
103static 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) */
117struct 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 */
129static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
130{
131	return val_h * 1000 + val_l * 1000 / 256;
132}
133
134static 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
141static 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
165static 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
191static 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 */
216static 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
238static 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
248static 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
274static 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
284static 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
312static 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
321static 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
350static 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
360static 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
368static 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
387static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
388static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
389		set_limit, 6);
390static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_crit_hyst,
391		set_crit_hyst, 6);
392static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
393		STATUS1_LOC);
394
395static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
396static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
397		set_limit, 7);
398static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_crit_hyst,
399		set_crit_hyst, 7);
400static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
401		STATUS1_RTCRIT);
402static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
403		set_type, 0);
404static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
405		STATUS1_DIODE_FAULT);
406
407static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
408		set_interval);
409
410static struct attribute *lm95245_attrs[] = {
411	&sensor_dev_attr_temp1_input.dev_attr.attr,
412	&sensor_dev_attr_temp1_crit.dev_attr.attr,
413	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
414	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
415	&sensor_dev_attr_temp2_input.dev_attr.attr,
416	&sensor_dev_attr_temp2_crit.dev_attr.attr,
417	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
418	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
419	&sensor_dev_attr_temp2_type.dev_attr.attr,
420	&sensor_dev_attr_temp2_fault.dev_attr.attr,
421	&dev_attr_update_interval.attr,
422	NULL
423};
424ATTRIBUTE_GROUPS(lm95245);
425
426/* Return 0 if detection is successful, -ENODEV otherwise */
427static int lm95245_detect(struct i2c_client *new_client,
428			  struct i2c_board_info *info)
429{
430	struct i2c_adapter *adapter = new_client->adapter;
431
432	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
433		return -ENODEV;
434
435	if (i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID)
436			!= MANUFACTURER_ID
437		|| i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID)
438			!= DEFAULT_REVISION)
439		return -ENODEV;
440
441	strlcpy(info->type, DEVNAME, I2C_NAME_SIZE);
442	return 0;
443}
444
445static void lm95245_init_client(struct i2c_client *client,
446				struct lm95245_data *data)
447{
448	data->interval = lm95245_read_conversion_rate(client);
449
450	data->config1 = i2c_smbus_read_byte_data(client,
451		LM95245_REG_RW_CONFIG1);
452	data->config2 = i2c_smbus_read_byte_data(client,
453		LM95245_REG_RW_CONFIG2);
454
455	if (data->config1 & CFG_STOP) {
456		/* Clear the standby bit */
457		data->config1 &= ~CFG_STOP;
458		i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
459			data->config1);
460	}
461}
462
463static int lm95245_probe(struct i2c_client *client,
464			 const struct i2c_device_id *id)
465{
466	struct device *dev = &client->dev;
467	struct lm95245_data *data;
468	struct device *hwmon_dev;
469
470	data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
471	if (!data)
472		return -ENOMEM;
473
474	data->client = client;
475	mutex_init(&data->update_lock);
476
477	/* Initialize the LM95245 chip */
478	lm95245_init_client(client, data);
479
480	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
481							   data,
482							   lm95245_groups);
483	return PTR_ERR_OR_ZERO(hwmon_dev);
484}
485
486/* Driver data (common to all clients) */
487static const struct i2c_device_id lm95245_id[] = {
488	{ DEVNAME, 0 },
489	{ }
490};
491MODULE_DEVICE_TABLE(i2c, lm95245_id);
492
493static struct i2c_driver lm95245_driver = {
494	.class		= I2C_CLASS_HWMON,
495	.driver = {
496		.name	= DEVNAME,
497	},
498	.probe		= lm95245_probe,
499	.id_table	= lm95245_id,
500	.detect		= lm95245_detect,
501	.address_list	= normal_i2c,
502};
503
504module_i2c_driver(lm95245_driver);
505
506MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
507MODULE_DESCRIPTION("LM95245 sensor driver");
508MODULE_LICENSE("GPL");
509