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/err.h>
36 /* Addresses to scan */
37 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END };
39 /* Insmod parameters */
40 I2C_CLIENT_INSMOD_1(lm77);
42 /* The LM77 registers */
43 #define LM77_REG_TEMP 0x00
44 #define LM77_REG_CONF 0x01
45 #define LM77_REG_TEMP_HYST 0x02
46 #define LM77_REG_TEMP_CRIT 0x03
47 #define LM77_REG_TEMP_MIN 0x04
48 #define LM77_REG_TEMP_MAX 0x05
50 /* Each client has this additional data */
52 struct i2c_client client;
53 struct class_device *class_dev;
54 struct semaphore update_lock;
56 unsigned long last_updated; /* In jiffies */
57 int temp_input; /* Temperatures */
65 static int lm77_attach_adapter(struct i2c_adapter *adapter);
66 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind);
67 static void lm77_init_client(struct i2c_client *client);
68 static int lm77_detach_client(struct i2c_client *client);
69 static u16 lm77_read_value(struct i2c_client *client, u8 reg);
70 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
72 static struct lm77_data *lm77_update_device(struct device *dev);
75 /* This is the driver that will be inserted */
76 static struct i2c_driver lm77_driver = {
79 .attach_adapter = lm77_attach_adapter,
80 .detach_client = lm77_detach_client,
83 /* straight from the datasheet */
84 #define LM77_TEMP_MIN (-55000)
85 #define LM77_TEMP_MAX 125000
87 /* In the temperature registers, the low 3 bits are not part of the
88 temperature values; they are the status bits. */
89 static inline u16 LM77_TEMP_TO_REG(int temp)
91 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
92 return (u16)((ntemp / 500) * 8);
95 static inline int LM77_TEMP_FROM_REG(u16 reg)
97 return ((int)reg / 8) * 500;
102 /* read routines for temperature limits */
103 #define show(value) \
104 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
106 struct lm77_data *data = lm77_update_device(dev); \
107 return sprintf(buf, "%d\n", data->value); \
116 /* read routines for hysteresis values */
117 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
119 struct lm77_data *data = lm77_update_device(dev);
120 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
122 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
124 struct lm77_data *data = lm77_update_device(dev);
125 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
127 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
129 struct lm77_data *data = lm77_update_device(dev);
130 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
134 #define set(value, reg) \
135 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \
137 struct i2c_client *client = to_i2c_client(dev); \
138 struct lm77_data *data = i2c_get_clientdata(client); \
139 long val = simple_strtoul(buf, NULL, 10); \
141 down(&data->update_lock); \
143 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \
144 up(&data->update_lock); \
148 set(temp_min, LM77_REG_TEMP_MIN);
149 set(temp_max, LM77_REG_TEMP_MAX);
151 /* hysteresis is stored as a relative value on the chip, so it has to be
153 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
155 struct i2c_client *client = to_i2c_client(dev);
156 struct lm77_data *data = i2c_get_clientdata(client);
157 unsigned long val = simple_strtoul(buf, NULL, 10);
159 down(&data->update_lock);
160 data->temp_hyst = data->temp_crit - val;
161 lm77_write_value(client, LM77_REG_TEMP_HYST,
162 LM77_TEMP_TO_REG(data->temp_hyst));
163 up(&data->update_lock);
167 /* preserve hysteresis when setting T_crit */
168 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
170 struct i2c_client *client = to_i2c_client(dev);
171 struct lm77_data *data = i2c_get_clientdata(client);
172 long val = simple_strtoul(buf, NULL, 10);
175 down(&data->update_lock);
176 oldcrithyst = data->temp_crit - data->temp_hyst;
177 data->temp_crit = val;
178 data->temp_hyst = data->temp_crit - oldcrithyst;
179 lm77_write_value(client, LM77_REG_TEMP_CRIT,
180 LM77_TEMP_TO_REG(data->temp_crit));
181 lm77_write_value(client, LM77_REG_TEMP_HYST,
182 LM77_TEMP_TO_REG(data->temp_hyst));
183 up(&data->update_lock);
187 static DEVICE_ATTR(temp1_input, S_IRUGO,
188 show_temp_input, NULL);
189 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
190 show_temp_crit, set_temp_crit);
191 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
192 show_temp_min, set_temp_min);
193 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
194 show_temp_max, set_temp_max);
196 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
197 show_temp_crit_hyst, set_temp_crit_hyst);
198 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
199 show_temp_min_hyst, NULL);
200 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
201 show_temp_max_hyst, NULL);
203 static DEVICE_ATTR(alarms, S_IRUGO,
206 static int lm77_attach_adapter(struct i2c_adapter *adapter)
208 if (!(adapter->class & I2C_CLASS_HWMON))
210 return i2c_probe(adapter, &addr_data, lm77_detect);
213 /* This function is called by i2c_probe */
214 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind)
216 struct i2c_client *new_client;
217 struct lm77_data *data;
219 const char *name = "";
221 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
222 I2C_FUNC_SMBUS_WORD_DATA))
225 /* OK. For now, we presume we have a valid client. We now create the
226 client structure, even though we cannot fill it completely yet.
227 But it allows us to access lm77_{read,write}_value. */
228 if (!(data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL))) {
233 new_client = &data->client;
234 i2c_set_clientdata(new_client, data);
235 new_client->addr = address;
236 new_client->adapter = adapter;
237 new_client->driver = &lm77_driver;
238 new_client->flags = 0;
240 /* Here comes the remaining detection. Since the LM77 has no
241 register dedicated to identification, we have to rely on the
244 1. the high 4 bits represent the sign and thus they should
246 2. the high 3 bits are unused in the configuration register
247 3. addresses 0x06 and 0x07 return the last read value
248 4. registers cycling over 8-address boundaries
250 Word-sized registers are high-byte first. */
252 int i, cur, conf, hyst, crit, min, max;
254 /* addresses cycling */
255 cur = i2c_smbus_read_word_data(new_client, 0);
256 conf = i2c_smbus_read_byte_data(new_client, 1);
257 hyst = i2c_smbus_read_word_data(new_client, 2);
258 crit = i2c_smbus_read_word_data(new_client, 3);
259 min = i2c_smbus_read_word_data(new_client, 4);
260 max = i2c_smbus_read_word_data(new_client, 5);
261 for (i = 8; i <= 0xff; i += 8)
262 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
263 || i2c_smbus_read_word_data(new_client, i + 2) != hyst
264 || i2c_smbus_read_word_data(new_client, i + 3) != crit
265 || i2c_smbus_read_word_data(new_client, i + 4) != min
266 || i2c_smbus_read_word_data(new_client, i + 5) != max)
270 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
271 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
272 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
273 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
274 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
281 /* 0x06 and 0x07 return the last read value */
282 cur = i2c_smbus_read_word_data(new_client, 0);
283 if (i2c_smbus_read_word_data(new_client, 6) != cur
284 || i2c_smbus_read_word_data(new_client, 7) != cur)
286 hyst = i2c_smbus_read_word_data(new_client, 2);
287 if (i2c_smbus_read_word_data(new_client, 6) != hyst
288 || i2c_smbus_read_word_data(new_client, 7) != hyst)
290 min = i2c_smbus_read_word_data(new_client, 4);
291 if (i2c_smbus_read_word_data(new_client, 6) != min
292 || i2c_smbus_read_word_data(new_client, 7) != min)
297 /* Determine the chip type - only one kind supported! */
305 /* Fill in the remaining client fields and put it into the global list */
306 strlcpy(new_client->name, name, I2C_NAME_SIZE);
308 init_MUTEX(&data->update_lock);
310 /* Tell the I2C layer a new client has arrived */
311 if ((err = i2c_attach_client(new_client)))
314 /* Initialize the LM77 chip */
315 lm77_init_client(new_client);
317 /* Register sysfs hooks */
318 data->class_dev = hwmon_device_register(&new_client->dev);
319 if (IS_ERR(data->class_dev)) {
320 err = PTR_ERR(data->class_dev);
324 device_create_file(&new_client->dev, &dev_attr_temp1_input);
325 device_create_file(&new_client->dev, &dev_attr_temp1_crit);
326 device_create_file(&new_client->dev, &dev_attr_temp1_min);
327 device_create_file(&new_client->dev, &dev_attr_temp1_max);
328 device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
329 device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
330 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
331 device_create_file(&new_client->dev, &dev_attr_alarms);
335 i2c_detach_client(new_client);
342 static int lm77_detach_client(struct i2c_client *client)
344 struct lm77_data *data = i2c_get_clientdata(client);
345 hwmon_device_unregister(data->class_dev);
346 i2c_detach_client(client);
351 /* All registers are word-sized, except for the configuration register.
352 The LM77 uses the high-byte first convention. */
353 static u16 lm77_read_value(struct i2c_client *client, u8 reg)
355 if (reg == LM77_REG_CONF)
356 return i2c_smbus_read_byte_data(client, reg);
358 return swab16(i2c_smbus_read_word_data(client, reg));
361 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
363 if (reg == LM77_REG_CONF)
364 return i2c_smbus_write_byte_data(client, reg, value);
366 return i2c_smbus_write_word_data(client, reg, swab16(value));
369 static void lm77_init_client(struct i2c_client *client)
371 /* Initialize the LM77 chip - turn off shutdown mode */
372 int conf = lm77_read_value(client, LM77_REG_CONF);
374 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
377 static struct lm77_data *lm77_update_device(struct device *dev)
379 struct i2c_client *client = to_i2c_client(dev);
380 struct lm77_data *data = i2c_get_clientdata(client);
382 down(&data->update_lock);
384 if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
386 dev_dbg(&client->dev, "Starting lm77 update\n");
388 LM77_TEMP_FROM_REG(lm77_read_value(client,
391 LM77_TEMP_FROM_REG(lm77_read_value(client,
392 LM77_REG_TEMP_HYST));
394 LM77_TEMP_FROM_REG(lm77_read_value(client,
395 LM77_REG_TEMP_CRIT));
397 LM77_TEMP_FROM_REG(lm77_read_value(client,
400 LM77_TEMP_FROM_REG(lm77_read_value(client,
403 lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
404 data->last_updated = jiffies;
408 up(&data->update_lock);
413 static int __init sensors_lm77_init(void)
415 return i2c_add_driver(&lm77_driver);
418 static void __exit sensors_lm77_exit(void)
420 i2c_del_driver(&lm77_driver);
423 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
424 MODULE_DESCRIPTION("LM77 driver");
425 MODULE_LICENSE("GPL");
427 module_init(sensors_lm77_init);
428 module_exit(sensors_lm77_exit);