aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/lm92.c
blob: 9bf278cf0bd03b705d1236c11a33fa2167891673 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * lm92 - Hardware monitoring driver
 * Copyright (C) 2005-2008  Jean Delvare <jdelvare@suse.de>
 *
 * Based on the lm90 driver, with some ideas taken from the lm_sensors
 * lm92 driver as well.
 *
 * The LM92 is a sensor chip made by National Semiconductor. It reports
 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
 * accuracy. Complete datasheet can be obtained from National's website
 * at:
 *   http://www.national.com/pf/LM/LM92.html
 *
 * This driver also supports the MAX6635 sensor chip made by Maxim.
 * This chip is compatible with the LM92, but has a lesser accuracy
 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
 * at:
 *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
 *
 * Since the LM92 was the first chipset supported by this driver, most
 * comments will refer to this chipset, but are actually general and
 * concern all supported chipsets, unless mentioned otherwise.
 *
 * Support could easily be added for the National Semiconductor LM76
 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
 * with the LM92.
 */

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

/*
 * The LM92 and MAX6635 have 2 two-state pins for address selection,
 * resulting in 4 possible addresses.
 */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
						I2C_CLIENT_END };
enum chips { lm92, max6635 };

/* The LM92 registers */
#define LM92_REG_CONFIG			0x01 /* 8-bit, RW */
#define LM92_REG_TEMP			0x00 /* 16-bit, RO */
#define LM92_REG_TEMP_HYST		0x02 /* 16-bit, RW */
#define LM92_REG_TEMP_CRIT		0x03 /* 16-bit, RW */
#define LM92_REG_TEMP_LOW		0x04 /* 16-bit, RW */
#define LM92_REG_TEMP_HIGH		0x05 /* 16-bit, RW */
#define LM92_REG_MAN_ID			0x07 /* 16-bit, RO, LM92 only */

/*
 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
 * left-justified in 16-bit registers. No rounding is done, with such
 * a resolution it's just not worth it. Note that the MAX6635 doesn't
 * make use of the 4 lower bits for limits (i.e. effective resolution
 * for limits is 1 degree Celsius).
 */
static inline int TEMP_FROM_REG(s16 reg)
{
	return reg / 8 * 625 / 10;
}

static inline s16 TEMP_TO_REG(long val)
{
	val = clamp_val(val, -60000, 160000);
	return val * 10 / 625 * 8;
}

/* Alarm flags are stored in the 3 LSB of the temperature register */
static inline u8 ALARMS_FROM_REG(s16 reg)
{
	return reg & 0x0007;
}

enum temp_index {
	t_input,
	t_crit,
	t_min,
	t_max,
	t_hyst,
	t_num_regs
};

static const u8 regs[t_num_regs] = {
	[t_input] = LM92_REG_TEMP,
	[t_crit] = LM92_REG_TEMP_CRIT,
	[t_min] = LM92_REG_TEMP_LOW,
	[t_max] = LM92_REG_TEMP_HIGH,
	[t_hyst] = LM92_REG_TEMP_HYST,
};

/* Client data (each client gets its own) */
struct lm92_data {
	struct i2c_client *client;
	struct mutex update_lock;
	char valid; /* zero until following fields are valid */
	unsigned long last_updated; /* in jiffies */

	/* registers values */
	s16 temp[t_num_regs];	/* index with enum temp_index */
};

/*
 * Sysfs attributes and callback functions
 */

static struct lm92_data *lm92_update_device(struct device *dev)
{
	struct lm92_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int i;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ) ||
	    !data->valid) {
		dev_dbg(&client->dev, "Updating lm92 data\n");
		for (i = 0; i < t_num_regs; i++) {
			data->temp[i] =
				i2c_smbus_read_word_swapped(client, regs[i]);
		}
		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
			 char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct lm92_data *data = lm92_update_device(dev);

	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
}

static ssize_t temp_store(struct device *dev,
			  struct device_attribute *devattr, const char *buf,
			  size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct lm92_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int nr = attr->index;
	long val;
	int err;

	err = kstrtol(buf, 10, &val);
	if (err)
		return err;

	mutex_lock(&data->update_lock);
	data->temp[nr] = TEMP_TO_REG(val);
	i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t temp_hyst_show(struct device *dev,
			      struct device_attribute *devattr, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct lm92_data *data = lm92_update_device(dev);

	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
		       - TEMP_FROM_REG(data->temp[t_hyst]));
}

static ssize_t temp1_min_hyst_show(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct lm92_data *data = lm92_update_device(dev);

	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
		       + TEMP_FROM_REG(data->temp[t_hyst]));
}

static ssize_t temp_hyst_store(struct device *dev,
			       struct device_attribute *devattr,
			       const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct lm92_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	long val;
	int err;

	err = kstrtol(buf, 10, &val);
	if (err)
		return err;

	val = clamp_val(val, -120000, 220000);
	mutex_lock(&data->update_lock);
	data->temp[t_hyst] =
		TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
	i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
				     data->temp[t_hyst]);
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t alarms_show(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	struct lm92_data *data = lm92_update_device(dev);

	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
}

static ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	int bitnr = to_sensor_dev_attr(attr)->index;
	struct lm92_data *data = lm92_update_device(dev);
	return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1);
}

static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input);
static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit);
static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit);
static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min);
static DEVICE_ATTR_RO(temp1_min_hyst);
static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max);
static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max);
static DEVICE_ATTR_RO(alarms);
static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2);
static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0);
static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1);

/*
 * Detection and registration
 */

static void lm92_init_client(struct i2c_client *client)
{
	u8 config;

	/* Start the conversions if needed */
	config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
	if (config & 0x01)
		i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
					  config & 0xFE);
}

static struct attribute *lm92_attrs[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp1_crit.dev_attr.attr,
	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
	&sensor_dev_attr_temp1_min.dev_attr.attr,
	&dev_attr_temp1_min_hyst.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
	&dev_attr_alarms.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
};
ATTRIBUTE_GROUPS(lm92);

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm92_detect(struct i2c_client *new_client,
		       struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = new_client->adapter;
	u8 config;
	u16 man_id;

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

	config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
	man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);

	if ((config & 0xe0) == 0x00 && man_id == 0x0180)
		pr_info("lm92: Found National Semiconductor LM92 chip\n");
	else
		return -ENODEV;

	strlcpy(info->type, "lm92", I2C_NAME_SIZE);

	return 0;
}

static int lm92_probe(struct i2c_client *new_client)
{
	struct device *hwmon_dev;
	struct lm92_data *data;

	data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->client = new_client;
	mutex_init(&data->update_lock);

	/* Initialize the chipset */
	lm92_init_client(new_client);

	hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
							   new_client->name,
							   data, lm92_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

/*
 * Module and driver stuff
 */

static const struct i2c_device_id lm92_id[] = {
	{ "lm92", lm92 },
	{ "max6635", max6635 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, lm92_id);

static struct i2c_driver lm92_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "lm92",
	},
	.probe_new	= lm92_probe,
	.id_table	= lm92_id,
	.detect		= lm92_detect,
	.address_list	= normal_i2c,
};

module_i2c_driver(lm92_driver);

MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("LM92/MAX6635 driver");
MODULE_LICENSE("GPL");