summaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/lm77.c
blob: 7cd516f888cc0fc26488b89f8fc63b8a37e2a485 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
/*
    lm77.c - Part of lm_sensors, Linux kernel modules for hardware
             monitoring

    Copyright (c) 2004  Andras BALI <drewie@freemail.hu>

    Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>.  The LM77
    is a temperature sensor and thermal window comparator with 0.5 deg
    resolution made by National Semiconductor.  Complete datasheet can be
    obtained at their site:
       http://www.national.com/pf/LM/LM77.html

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
						I2C_CLIENT_END };

/* The LM77 registers */
#define LM77_REG_TEMP		0x00
#define LM77_REG_CONF		0x01
#define LM77_REG_TEMP_HYST	0x02
#define LM77_REG_TEMP_CRIT	0x03
#define LM77_REG_TEMP_MIN	0x04
#define LM77_REG_TEMP_MAX	0x05

/* Each client has this additional data */
struct lm77_data {
	struct device 		*hwmon_dev;
	struct mutex		update_lock;
	char			valid;
	unsigned long		last_updated;	/* In jiffies */
	int			temp_input;	/* Temperatures */
	int			temp_crit;
	int			temp_min;
	int			temp_max;
	int			temp_hyst;
	u8			alarms;
};

static int lm77_probe(struct i2c_client *client,
		      const struct i2c_device_id *id);
static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info);
static void lm77_init_client(struct i2c_client *client);
static int lm77_remove(struct i2c_client *client);
static u16 lm77_read_value(struct i2c_client *client, u8 reg);
static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);

static struct lm77_data *lm77_update_device(struct device *dev);


static const struct i2c_device_id lm77_id[] = {
	{ "lm77", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, lm77_id);

/* This is the driver that will be inserted */
static struct i2c_driver lm77_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "lm77",
	},
	.probe		= lm77_probe,
	.remove		= lm77_remove,
	.id_table	= lm77_id,
	.detect		= lm77_detect,
	.address_list	= normal_i2c,
};

/* straight from the datasheet */
#define LM77_TEMP_MIN (-55000)
#define LM77_TEMP_MAX 125000

/* In the temperature registers, the low 3 bits are not part of the
   temperature values; they are the status bits. */
static inline s16 LM77_TEMP_TO_REG(int temp)
{
	int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
	return (ntemp / 500) * 8;
}

static inline int LM77_TEMP_FROM_REG(s16 reg)
{
	return (reg / 8) * 500;
}

/* sysfs stuff */

/* read routines for temperature limits */
#define show(value)	\
static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)	\
{								\
	struct lm77_data *data = lm77_update_device(dev);	\
	return sprintf(buf, "%d\n", data->value);		\
}

show(temp_input);
show(temp_crit);
show(temp_min);
show(temp_max);

/* read routines for hysteresis values */
static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
}
static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
}
static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
}

/* write routines */
#define set(value, reg)	\
static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)	\
{										\
	struct i2c_client *client = to_i2c_client(dev);				\
	struct lm77_data *data = i2c_get_clientdata(client);			\
	long val = simple_strtol(buf, NULL, 10);				\
										\
	mutex_lock(&data->update_lock);						\
	data->value = val;				\
	lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value));		\
	mutex_unlock(&data->update_lock);					\
	return count;								\
}

set(temp_min, LM77_REG_TEMP_MIN);
set(temp_max, LM77_REG_TEMP_MAX);

/* hysteresis is stored as a relative value on the chip, so it has to be
   converted first */
static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lm77_data *data = i2c_get_clientdata(client);
	unsigned long val = simple_strtoul(buf, NULL, 10);

	mutex_lock(&data->update_lock);
	data->temp_hyst = data->temp_crit - val;
	lm77_write_value(client, LM77_REG_TEMP_HYST,
			 LM77_TEMP_TO_REG(data->temp_hyst));
	mutex_unlock(&data->update_lock);
	return count;
}

/* preserve hysteresis when setting T_crit */
static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lm77_data *data = i2c_get_clientdata(client);
	long val = simple_strtoul(buf, NULL, 10);
	int oldcrithyst;
	
	mutex_lock(&data->update_lock);
	oldcrithyst = data->temp_crit - data->temp_hyst;
	data->temp_crit = val;
	data->temp_hyst = data->temp_crit - oldcrithyst;
	lm77_write_value(client, LM77_REG_TEMP_CRIT,
			 LM77_TEMP_TO_REG(data->temp_crit));
	lm77_write_value(client, LM77_REG_TEMP_HYST,
			 LM77_TEMP_TO_REG(data->temp_hyst));
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	int bitnr = to_sensor_dev_attr(attr)->index;
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
}

static DEVICE_ATTR(temp1_input, S_IRUGO,
		   show_temp_input, NULL);
static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
		   show_temp_crit, set_temp_crit);
static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
		   show_temp_min, set_temp_min);
static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
		   show_temp_max, set_temp_max);

static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
		   show_temp_crit_hyst, set_temp_crit_hyst);
static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
		   show_temp_min_hyst, NULL);
static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
		   show_temp_max_hyst, NULL);

static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);

static struct attribute *lm77_attributes[] = {
	&dev_attr_temp1_input.attr,
	&dev_attr_temp1_crit.attr,
	&dev_attr_temp1_min.attr,
	&dev_attr_temp1_max.attr,
	&dev_attr_temp1_crit_hyst.attr,
	&dev_attr_temp1_min_hyst.attr,
	&dev_attr_temp1_max_hyst.attr,
	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	NULL
};

static const struct attribute_group lm77_group = {
	.attrs = lm77_attributes,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm77_detect(struct i2c_client *new_client,
		       struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = new_client->adapter;
	int i, cur, conf, hyst, crit, min, max;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
				     I2C_FUNC_SMBUS_WORD_DATA))
		return -ENODEV;

	/* Here comes the remaining detection.  Since the LM77 has no
	   register dedicated to identification, we have to rely on the
	   following tricks:

	   1. the high 4 bits represent the sign and thus they should
	      always be the same
	   2. the high 3 bits are unused in the configuration register
	   3. addresses 0x06 and 0x07 return the last read value
	   4. registers cycling over 8-address boundaries

	   Word-sized registers are high-byte first. */

	/* addresses cycling */
	cur = i2c_smbus_read_word_data(new_client, 0);
	conf = i2c_smbus_read_byte_data(new_client, 1);
	hyst = i2c_smbus_read_word_data(new_client, 2);
	crit = i2c_smbus_read_word_data(new_client, 3);
	min = i2c_smbus_read_word_data(new_client, 4);
	max = i2c_smbus_read_word_data(new_client, 5);
	for (i = 8; i <= 0xff; i += 8) {
		if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
		 || i2c_smbus_read_word_data(new_client, i + 2) != hyst
		 || i2c_smbus_read_word_data(new_client, i + 3) != crit
		 || i2c_smbus_read_word_data(new_client, i + 4) != min
		 || i2c_smbus_read_word_data(new_client, i + 5) != max)
			return -ENODEV;
	}

	/* sign bits */
	if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
	 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
	 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
	 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
	 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
		return -ENODEV;

	/* unused bits */
	if (conf & 0xe0)
		return -ENODEV;

	/* 0x06 and 0x07 return the last read value */
	cur = i2c_smbus_read_word_data(new_client, 0);
	if (i2c_smbus_read_word_data(new_client, 6) != cur
	 || i2c_smbus_read_word_data(new_client, 7) != cur)
		return -ENODEV;
	hyst = i2c_smbus_read_word_data(new_client, 2);
	if (i2c_smbus_read_word_data(new_client, 6) != hyst
	 || i2c_smbus_read_word_data(new_client, 7) != hyst)
		return -ENODEV;
	min = i2c_smbus_read_word_data(new_client, 4);
	if (i2c_smbus_read_word_data(new_client, 6) != min
	 || i2c_smbus_read_word_data(new_client, 7) != min)
		return -ENODEV;

	strlcpy(info->type, "lm77", I2C_NAME_SIZE);

	return 0;
}

static int lm77_probe(struct i2c_client *new_client,
		      const struct i2c_device_id *id)
{
	struct lm77_data *data;
	int err;

	data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
	if (!data) {
		err = -ENOMEM;
		goto exit;
	}

	i2c_set_clientdata(new_client, data);
	data->valid = 0;
	mutex_init(&data->update_lock);

	/* Initialize the LM77 chip */
	lm77_init_client(new_client);

	/* Register sysfs hooks */
	if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
		goto exit_free;

	data->hwmon_dev = hwmon_device_register(&new_client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto exit_remove;
	}

	return 0;

exit_remove:
	sysfs_remove_group(&new_client->dev.kobj, &lm77_group);
exit_free:
	kfree(data);
exit:
	return err;
}

static int lm77_remove(struct i2c_client *client)
{
	struct lm77_data *data = i2c_get_clientdata(client);
	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &lm77_group);
	kfree(data);
	return 0;
}

/* All registers are word-sized, except for the configuration register.
   The LM77 uses the high-byte first convention. */
static u16 lm77_read_value(struct i2c_client *client, u8 reg)
{
	if (reg == LM77_REG_CONF)
		return i2c_smbus_read_byte_data(client, reg);
	else
		return i2c_smbus_read_word_swapped(client, reg);
}

static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
{
	if (reg == LM77_REG_CONF)
		return i2c_smbus_write_byte_data(client, reg, value);
	else
		return i2c_smbus_write_word_swapped(client, reg, value);
}

static void lm77_init_client(struct i2c_client *client)
{
	/* Initialize the LM77 chip - turn off shutdown mode */
	int conf = lm77_read_value(client, LM77_REG_CONF);
	if (conf & 1)
		lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
}

static struct lm77_data *lm77_update_device(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lm77_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	    || !data->valid) {
		dev_dbg(&client->dev, "Starting lm77 update\n");
		data->temp_input =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP));
		data->temp_hyst =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_HYST));
		data->temp_crit =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_CRIT));
		data->temp_min =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_MIN));
		data->temp_max =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_MAX));
		data->alarms =
			lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

module_i2c_driver(lm77_driver);

MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
MODULE_DESCRIPTION("LM77 driver");
MODULE_LICENSE("GPL");