lm95245.c revision a8dd946c420781fd7a70fec8b75e0daf67c4a681 
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 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 */
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 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
166static 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
192static 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 */
217static 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
239static 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
249static 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
275static 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
302static 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
312static 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
341static 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
351static 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
359static 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
378static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
379static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
380		set_limit, 6);
381static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
382		set_crit_hyst, 8);
383static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
384		STATUS1_LOC);
385
386static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
387static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
388		set_limit, 7);
389static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
390		set_crit_hyst, 8);
391static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
392		STATUS1_RTCRIT);
393static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
394		set_type, 0);
395static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
396		STATUS1_DIODE_FAULT);
397
398static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
399		set_interval);
400
401static 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
416static const struct attribute_group lm95245_group = {
417	.attrs = lm95245_attributes,
418};
419
420/* Return 0 if detection is successful, -ENODEV otherwise */
421static 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
439static 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
459static 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
489exit_remove_files:
490	sysfs_remove_group(&new_client->dev.kobj, &lm95245_group);
491	return err;
492}
493
494static 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) */
505static const struct i2c_device_id lm95245_id[] = {
506	{ DEVNAME, 0 },
507	{ }
508};
509MODULE_DEVICE_TABLE(i2c, lm95245_id);
510
511static 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
523module_i2c_driver(lm95245_driver);
524
525MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
526MODULE_DESCRIPTION("LM95245 sensor driver");
527MODULE_LICENSE("GPL");
528