2 lm77.c - Part of lm_sensors, Linux kernel modules for hardware
5 Copyright (c) 2004 Andras BALI <drewie@freemail.hu>
7 Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77
8 is a temperature sensor and thermal window comparator with 0.5 deg
9 resolution made by National Semiconductor. Complete datasheet can be
10 obtained at their site:
11 http://www.national.com/pf/LM/LM77.html
13 This program is free software; you can redistribute it and/or modify
14 it under the terms of the GNU General Public License as published by
15 the Free Software Foundation; either version 2 of the License, or
16 (at your option) any later version.
18 This program is distributed in the hope that it will be useful,
19 but WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 GNU General Public License for more details.
23 You should have received a copy of the GNU General Public License
24 along with this program; if not, write to the Free Software
25 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/jiffies.h>
32 #include <linux/i2c.h>
33 #include <linux/hwmon.h>
34 #include <linux/hwmon-sysfs.h>
35 #include <linux/err.h>
36 #include <linux/mutex.h>
38 /* Addresses to scan */
39 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
42 /* Insmod parameters */
43 I2C_CLIENT_INSMOD_1(lm77);
45 /* The LM77 registers */
46 #define LM77_REG_TEMP 0x00
47 #define LM77_REG_CONF 0x01
48 #define LM77_REG_TEMP_HYST 0x02
49 #define LM77_REG_TEMP_CRIT 0x03
50 #define LM77_REG_TEMP_MIN 0x04
51 #define LM77_REG_TEMP_MAX 0x05
53 /* Each client has this additional data */
55 struct device *hwmon_dev;
56 struct mutex update_lock;
58 unsigned long last_updated; /* In jiffies */
59 int temp_input; /* Temperatures */
67 static int lm77_probe(struct i2c_client *client,
68 const struct i2c_device_id *id);
69 static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info);
70 static void lm77_init_client(struct i2c_client *client);
71 static int lm77_remove(struct i2c_client *client);
72 static u16 lm77_read_value(struct i2c_client *client, u8 reg);
73 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
75 static struct lm77_data *lm77_update_device(struct device *dev);
78 static const struct i2c_device_id lm77_id[] = {
82 MODULE_DEVICE_TABLE(i2c, lm77_id);
84 /* This is the driver that will be inserted */
85 static struct i2c_driver lm77_driver = {
86 .class = I2C_CLASS_HWMON,
91 .remove = lm77_remove,
93 .detect = lm77_detect,
94 .address_data = &addr_data,
97 /* straight from the datasheet */
98 #define LM77_TEMP_MIN (-55000)
99 #define LM77_TEMP_MAX 125000
101 /* In the temperature registers, the low 3 bits are not part of the
102 temperature values; they are the status bits. */
103 static inline s16 LM77_TEMP_TO_REG(int temp)
105 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
106 return (ntemp / 500) * 8;
109 static inline int LM77_TEMP_FROM_REG(s16 reg)
111 return (reg / 8) * 500;
116 /* read routines for temperature limits */
117 #define show(value) \
118 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
120 struct lm77_data *data = lm77_update_device(dev); \
121 return sprintf(buf, "%d\n", data->value); \
129 /* read routines for hysteresis values */
130 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
132 struct lm77_data *data = lm77_update_device(dev);
133 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
135 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
137 struct lm77_data *data = lm77_update_device(dev);
138 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
140 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
142 struct lm77_data *data = lm77_update_device(dev);
143 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
147 #define set(value, reg) \
148 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \
150 struct i2c_client *client = to_i2c_client(dev); \
151 struct lm77_data *data = i2c_get_clientdata(client); \
152 long val = simple_strtol(buf, NULL, 10); \
154 mutex_lock(&data->update_lock); \
156 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \
157 mutex_unlock(&data->update_lock); \
161 set(temp_min, LM77_REG_TEMP_MIN);
162 set(temp_max, LM77_REG_TEMP_MAX);
164 /* hysteresis is stored as a relative value on the chip, so it has to be
166 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
168 struct i2c_client *client = to_i2c_client(dev);
169 struct lm77_data *data = i2c_get_clientdata(client);
170 unsigned long val = simple_strtoul(buf, NULL, 10);
172 mutex_lock(&data->update_lock);
173 data->temp_hyst = data->temp_crit - val;
174 lm77_write_value(client, LM77_REG_TEMP_HYST,
175 LM77_TEMP_TO_REG(data->temp_hyst));
176 mutex_unlock(&data->update_lock);
180 /* preserve hysteresis when setting T_crit */
181 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
183 struct i2c_client *client = to_i2c_client(dev);
184 struct lm77_data *data = i2c_get_clientdata(client);
185 long val = simple_strtoul(buf, NULL, 10);
188 mutex_lock(&data->update_lock);
189 oldcrithyst = data->temp_crit - data->temp_hyst;
190 data->temp_crit = val;
191 data->temp_hyst = data->temp_crit - oldcrithyst;
192 lm77_write_value(client, LM77_REG_TEMP_CRIT,
193 LM77_TEMP_TO_REG(data->temp_crit));
194 lm77_write_value(client, LM77_REG_TEMP_HYST,
195 LM77_TEMP_TO_REG(data->temp_hyst));
196 mutex_unlock(&data->update_lock);
200 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
203 int bitnr = to_sensor_dev_attr(attr)->index;
204 struct lm77_data *data = lm77_update_device(dev);
205 return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
208 static DEVICE_ATTR(temp1_input, S_IRUGO,
209 show_temp_input, NULL);
210 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
211 show_temp_crit, set_temp_crit);
212 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
213 show_temp_min, set_temp_min);
214 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
215 show_temp_max, set_temp_max);
217 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
218 show_temp_crit_hyst, set_temp_crit_hyst);
219 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
220 show_temp_min_hyst, NULL);
221 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
222 show_temp_max_hyst, NULL);
224 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
225 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
226 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
228 static struct attribute *lm77_attributes[] = {
229 &dev_attr_temp1_input.attr,
230 &dev_attr_temp1_crit.attr,
231 &dev_attr_temp1_min.attr,
232 &dev_attr_temp1_max.attr,
233 &dev_attr_temp1_crit_hyst.attr,
234 &dev_attr_temp1_min_hyst.attr,
235 &dev_attr_temp1_max_hyst.attr,
236 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
237 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
238 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
242 static const struct attribute_group lm77_group = {
243 .attrs = lm77_attributes,
246 /* Return 0 if detection is successful, -ENODEV otherwise */
247 static int lm77_detect(struct i2c_client *new_client,
248 struct i2c_board_info *info)
250 struct i2c_adapter *adapter = new_client->adapter;
251 int i, cur, conf, hyst, crit, min, max;
253 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
254 I2C_FUNC_SMBUS_WORD_DATA))
257 /* Here comes the remaining detection. Since the LM77 has no
258 register dedicated to identification, we have to rely on the
261 1. the high 4 bits represent the sign and thus they should
263 2. the high 3 bits are unused in the configuration register
264 3. addresses 0x06 and 0x07 return the last read value
265 4. registers cycling over 8-address boundaries
267 Word-sized registers are high-byte first. */
269 /* addresses cycling */
270 cur = i2c_smbus_read_word_data(new_client, 0);
271 conf = i2c_smbus_read_byte_data(new_client, 1);
272 hyst = i2c_smbus_read_word_data(new_client, 2);
273 crit = i2c_smbus_read_word_data(new_client, 3);
274 min = i2c_smbus_read_word_data(new_client, 4);
275 max = i2c_smbus_read_word_data(new_client, 5);
276 for (i = 8; i <= 0xff; i += 8) {
277 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
278 || i2c_smbus_read_word_data(new_client, i + 2) != hyst
279 || i2c_smbus_read_word_data(new_client, i + 3) != crit
280 || i2c_smbus_read_word_data(new_client, i + 4) != min
281 || i2c_smbus_read_word_data(new_client, i + 5) != max)
286 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
287 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
288 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
289 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
290 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
297 /* 0x06 and 0x07 return the last read value */
298 cur = i2c_smbus_read_word_data(new_client, 0);
299 if (i2c_smbus_read_word_data(new_client, 6) != cur
300 || i2c_smbus_read_word_data(new_client, 7) != cur)
302 hyst = i2c_smbus_read_word_data(new_client, 2);
303 if (i2c_smbus_read_word_data(new_client, 6) != hyst
304 || i2c_smbus_read_word_data(new_client, 7) != hyst)
306 min = i2c_smbus_read_word_data(new_client, 4);
307 if (i2c_smbus_read_word_data(new_client, 6) != min
308 || i2c_smbus_read_word_data(new_client, 7) != min)
311 strlcpy(info->type, "lm77", I2C_NAME_SIZE);
316 static int lm77_probe(struct i2c_client *new_client,
317 const struct i2c_device_id *id)
319 struct lm77_data *data;
322 data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
328 i2c_set_clientdata(new_client, data);
330 mutex_init(&data->update_lock);
332 /* Initialize the LM77 chip */
333 lm77_init_client(new_client);
335 /* Register sysfs hooks */
336 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
339 data->hwmon_dev = hwmon_device_register(&new_client->dev);
340 if (IS_ERR(data->hwmon_dev)) {
341 err = PTR_ERR(data->hwmon_dev);
348 sysfs_remove_group(&new_client->dev.kobj, &lm77_group);
355 static int lm77_remove(struct i2c_client *client)
357 struct lm77_data *data = i2c_get_clientdata(client);
358 hwmon_device_unregister(data->hwmon_dev);
359 sysfs_remove_group(&client->dev.kobj, &lm77_group);
364 /* All registers are word-sized, except for the configuration register.
365 The LM77 uses the high-byte first convention. */
366 static u16 lm77_read_value(struct i2c_client *client, u8 reg)
368 if (reg == LM77_REG_CONF)
369 return i2c_smbus_read_byte_data(client, reg);
371 return swab16(i2c_smbus_read_word_data(client, reg));
374 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
376 if (reg == LM77_REG_CONF)
377 return i2c_smbus_write_byte_data(client, reg, value);
379 return i2c_smbus_write_word_data(client, reg, swab16(value));
382 static void lm77_init_client(struct i2c_client *client)
384 /* Initialize the LM77 chip - turn off shutdown mode */
385 int conf = lm77_read_value(client, LM77_REG_CONF);
387 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
390 static struct lm77_data *lm77_update_device(struct device *dev)
392 struct i2c_client *client = to_i2c_client(dev);
393 struct lm77_data *data = i2c_get_clientdata(client);
395 mutex_lock(&data->update_lock);
397 if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
399 dev_dbg(&client->dev, "Starting lm77 update\n");
401 LM77_TEMP_FROM_REG(lm77_read_value(client,
404 LM77_TEMP_FROM_REG(lm77_read_value(client,
405 LM77_REG_TEMP_HYST));
407 LM77_TEMP_FROM_REG(lm77_read_value(client,
408 LM77_REG_TEMP_CRIT));
410 LM77_TEMP_FROM_REG(lm77_read_value(client,
413 LM77_TEMP_FROM_REG(lm77_read_value(client,
416 lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
417 data->last_updated = jiffies;
421 mutex_unlock(&data->update_lock);
426 static int __init sensors_lm77_init(void)
428 return i2c_add_driver(&lm77_driver);
431 static void __exit sensors_lm77_exit(void)
433 i2c_del_driver(&lm77_driver);
436 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
437 MODULE_DESCRIPTION("LM77 driver");
438 MODULE_LICENSE("GPL");
440 module_init(sensors_lm77_init);
441 module_exit(sensors_lm77_exit);