2 * lm92 - Hardware monitoring driver
3 * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
5 * Based on the lm90 driver, with some ideas taken from the lm_sensors
8 * The LM92 is a sensor chip made by National Semiconductor. It reports
9 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
10 * accuracy. Complete datasheet can be obtained from National's website
12 * http://www.national.com/pf/LM/LM92.html
14 * This driver also supports the MAX6635 sensor chip made by Maxim.
15 * This chip is compatible with the LM92, but has a lesser accuracy
16 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
18 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
20 * Since the LM92 was the first chipset supported by this driver, most
21 * comments will refer to this chipset, but are actually general and
22 * concern all supported chipsets, unless mentioned otherwise.
24 * Support could easily be added for the National Semiconductor LM76
25 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
28 * This program is free software; you can redistribute it and/or modify
29 * it under the terms of the GNU General Public License as published by
30 * the Free Software Foundation; either version 2 of the License, or
31 * (at your option) any later version.
33 * This program is distributed in the hope that it will be useful,
34 * but WITHOUT ANY WARRANTY; without even the implied warranty of
35 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
36 * GNU General Public License for more details.
39 #include <linux/module.h>
40 #include <linux/init.h>
41 #include <linux/slab.h>
42 #include <linux/i2c.h>
43 #include <linux/hwmon.h>
44 #include <linux/hwmon-sysfs.h>
45 #include <linux/err.h>
46 #include <linux/mutex.h>
47 #include <linux/jiffies.h>
50 * The LM92 and MAX6635 have 2 two-state pins for address selection,
51 * resulting in 4 possible addresses.
53 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
56 /* The LM92 registers */
57 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
58 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
59 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
60 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
61 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
62 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
63 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
66 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
67 * left-justified in 16-bit registers. No rounding is done, with such
68 * a resolution it's just not worth it. Note that the MAX6635 doesn't
69 * make use of the 4 lower bits for limits (i.e. effective resolution
70 * for limits is 1 degree Celsius).
72 static inline int TEMP_FROM_REG(s16 reg)
74 return reg / 8 * 625 / 10;
77 static inline s16 TEMP_TO_REG(long val)
79 val = clamp_val(val, -60000, 160000);
80 return val * 10 / 625 * 8;
83 /* Alarm flags are stored in the 3 LSB of the temperature register */
84 static inline u8 ALARMS_FROM_REG(s16 reg)
98 static const u8 regs[t_num_regs] = {
99 [t_input] = LM92_REG_TEMP,
100 [t_crit] = LM92_REG_TEMP_CRIT,
101 [t_min] = LM92_REG_TEMP_LOW,
102 [t_max] = LM92_REG_TEMP_HIGH,
103 [t_hyst] = LM92_REG_TEMP_HYST,
106 /* Client data (each client gets its own) */
108 struct i2c_client *client;
109 struct mutex update_lock;
110 char valid; /* zero until following fields are valid */
111 unsigned long last_updated; /* in jiffies */
113 /* registers values */
114 s16 temp[t_num_regs]; /* index with enum temp_index */
118 * Sysfs attributes and callback functions
121 static struct lm92_data *lm92_update_device(struct device *dev)
123 struct lm92_data *data = dev_get_drvdata(dev);
124 struct i2c_client *client = data->client;
127 mutex_lock(&data->update_lock);
129 if (time_after(jiffies, data->last_updated + HZ)
131 dev_dbg(&client->dev, "Updating lm92 data\n");
132 for (i = 0; i < t_num_regs; i++) {
134 i2c_smbus_read_word_swapped(client, regs[i]);
136 data->last_updated = jiffies;
140 mutex_unlock(&data->update_lock);
145 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
148 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
149 struct lm92_data *data = lm92_update_device(dev);
151 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
154 static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
155 const char *buf, size_t count)
157 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
158 struct lm92_data *data = dev_get_drvdata(dev);
159 struct i2c_client *client = data->client;
160 int nr = attr->index;
164 err = kstrtol(buf, 10, &val);
168 mutex_lock(&data->update_lock);
169 data->temp[nr] = TEMP_TO_REG(val);
170 i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
171 mutex_unlock(&data->update_lock);
175 static ssize_t show_temp_hyst(struct device *dev,
176 struct device_attribute *devattr, char *buf)
178 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
179 struct lm92_data *data = lm92_update_device(dev);
180 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
181 - TEMP_FROM_REG(data->temp[t_hyst]));
184 static ssize_t temp1_min_hyst_show(struct device *dev,
185 struct device_attribute *attr, char *buf)
187 struct lm92_data *data = lm92_update_device(dev);
188 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
189 + TEMP_FROM_REG(data->temp[t_hyst]));
192 static ssize_t set_temp_hyst(struct device *dev,
193 struct device_attribute *devattr,
194 const char *buf, size_t count)
196 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
197 struct lm92_data *data = dev_get_drvdata(dev);
198 struct i2c_client *client = data->client;
202 err = kstrtol(buf, 10, &val);
206 val = clamp_val(val, -120000, 220000);
207 mutex_lock(&data->update_lock);
209 TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
210 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
212 mutex_unlock(&data->update_lock);
216 static ssize_t alarms_show(struct device *dev, struct device_attribute *attr,
219 struct lm92_data *data = lm92_update_device(dev);
220 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
223 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
226 int bitnr = to_sensor_dev_attr(attr)->index;
227 struct lm92_data *data = lm92_update_device(dev);
228 return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1);
231 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input);
232 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp,
234 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst,
235 set_temp_hyst, t_crit);
236 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp,
238 static DEVICE_ATTR_RO(temp1_min_hyst);
239 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp,
241 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);
242 static DEVICE_ATTR_RO(alarms);
243 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
244 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
245 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
248 * Detection and registration
251 static void lm92_init_client(struct i2c_client *client)
255 /* Start the conversions if needed */
256 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
258 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
262 static struct attribute *lm92_attrs[] = {
263 &sensor_dev_attr_temp1_input.dev_attr.attr,
264 &sensor_dev_attr_temp1_crit.dev_attr.attr,
265 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
266 &sensor_dev_attr_temp1_min.dev_attr.attr,
267 &dev_attr_temp1_min_hyst.attr,
268 &sensor_dev_attr_temp1_max.dev_attr.attr,
269 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
270 &dev_attr_alarms.attr,
271 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
272 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
273 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
276 ATTRIBUTE_GROUPS(lm92);
278 /* Return 0 if detection is successful, -ENODEV otherwise */
279 static int lm92_detect(struct i2c_client *new_client,
280 struct i2c_board_info *info)
282 struct i2c_adapter *adapter = new_client->adapter;
286 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
287 | I2C_FUNC_SMBUS_WORD_DATA))
290 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
291 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
293 if ((config & 0xe0) == 0x00 && man_id == 0x0180)
294 pr_info("lm92: Found National Semiconductor LM92 chip\n");
298 strlcpy(info->type, "lm92", I2C_NAME_SIZE);
303 static int lm92_probe(struct i2c_client *new_client,
304 const struct i2c_device_id *id)
306 struct device *hwmon_dev;
307 struct lm92_data *data;
309 data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
314 data->client = new_client;
315 mutex_init(&data->update_lock);
317 /* Initialize the chipset */
318 lm92_init_client(new_client);
320 hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
323 return PTR_ERR_OR_ZERO(hwmon_dev);
328 * Module and driver stuff
331 static const struct i2c_device_id lm92_id[] = {
333 /* max6635 could be added here */
336 MODULE_DEVICE_TABLE(i2c, lm92_id);
338 static struct i2c_driver lm92_driver = {
339 .class = I2C_CLASS_HWMON,
345 .detect = lm92_detect,
346 .address_list = normal_i2c,
349 module_i2c_driver(lm92_driver);
351 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
352 MODULE_DESCRIPTION("LM92/MAX6635 driver");
353 MODULE_LICENSE("GPL");