1 /* 2 lm77.c - Part of lm_sensors, Linux kernel modules for hardware 3 monitoring 4 5 Copyright (c) 2004 Andras BALI <drewie@freemail.hu> 6 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 12 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. 17 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. 22 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. 26 */ 27 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> 37 38 /* Addresses to scan */ 39 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 40 I2C_CLIENT_END }; 41 42 /* Insmod parameters */ 43 I2C_CLIENT_INSMOD_1(lm77); 44 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 52 53 /* Each client has this additional data */ 54 struct lm77_data { 55 struct device *hwmon_dev; 56 struct mutex update_lock; 57 char valid; 58 unsigned long last_updated; /* In jiffies */ 59 int temp_input; /* Temperatures */ 60 int temp_crit; 61 int temp_min; 62 int temp_max; 63 int temp_hyst; 64 u8 alarms; 65 }; 66 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); 74 75 static struct lm77_data *lm77_update_device(struct device *dev); 76 77 78 static const struct i2c_device_id lm77_id[] = { 79 { "lm77", lm77 }, 80 { } 81 }; 82 MODULE_DEVICE_TABLE(i2c, lm77_id); 83 84 /* This is the driver that will be inserted */ 85 static struct i2c_driver lm77_driver = { 86 .class = I2C_CLASS_HWMON, 87 .driver = { 88 .name = "lm77", 89 }, 90 .probe = lm77_probe, 91 .remove = lm77_remove, 92 .id_table = lm77_id, 93 .detect = lm77_detect, 94 .address_data = &addr_data, 95 }; 96 97 /* straight from the datasheet */ 98 #define LM77_TEMP_MIN (-55000) 99 #define LM77_TEMP_MAX 125000 100 101 /* 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) 104 { 105 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 106 return (ntemp / 500) * 8; 107 } 108 109 static inline int LM77_TEMP_FROM_REG(s16 reg) 110 { 111 return (reg / 8) * 500; 112 } 113 114 /* sysfs stuff */ 115 116 /* read routines for temperature limits */ 117 #define show(value) \ 118 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 119 { \ 120 struct lm77_data *data = lm77_update_device(dev); \ 121 return sprintf(buf, "%d\n", data->value); \ 122 } 123 124 show(temp_input); 125 show(temp_crit); 126 show(temp_min); 127 show(temp_max); 128 129 /* read routines for hysteresis values */ 130 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 131 { 132 struct lm77_data *data = lm77_update_device(dev); 133 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); 134 } 135 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 136 { 137 struct lm77_data *data = lm77_update_device(dev); 138 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 139 } 140 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 141 { 142 struct lm77_data *data = lm77_update_device(dev); 143 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); 144 } 145 146 /* write routines */ 147 #define set(value, reg) \ 148 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 149 { \ 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); \ 153 \ 154 mutex_lock(&data->update_lock); \ 155 data->value = val; \ 156 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 157 mutex_unlock(&data->update_lock); \ 158 return count; \ 159 } 160 161 set(temp_min, LM77_REG_TEMP_MIN); 162 set(temp_max, LM77_REG_TEMP_MAX); 163 164 /* hysteresis is stored as a relative value on the chip, so it has to be 165 converted first */ 166 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 167 { 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); 171 172 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); 177 return count; 178 } 179 180 /* 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) 182 { 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); 186 int oldcrithyst; 187 188 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); 197 return count; 198 } 199 200 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 201 char *buf) 202 { 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); 206 } 207 208 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); 216 217 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); 223 224 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); 227 228 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, 239 NULL 240 }; 241 242 static const struct attribute_group lm77_group = { 243 .attrs = lm77_attributes, 244 }; 245 246 /* Return 0 if detection is successful, -ENODEV otherwise */ 247 static int lm77_detect(struct i2c_client *new_client, 248 struct i2c_board_info *info) 249 { 250 struct i2c_adapter *adapter = new_client->adapter; 251 int i, cur, conf, hyst, crit, min, max; 252 253 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 254 I2C_FUNC_SMBUS_WORD_DATA)) 255 return -ENODEV; 256 257 /* Here comes the remaining detection. Since the LM77 has no 258 register dedicated to identification, we have to rely on the 259 following tricks: 260 261 1. the high 4 bits represent the sign and thus they should 262 always be the same 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 266 267 Word-sized registers are high-byte first. */ 268 269 /* 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) 282 return -ENODEV; 283 } 284 285 /* sign bits */ 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)) 291 return -ENODEV; 292 293 /* unused bits */ 294 if (conf & 0xe0) 295 return -ENODEV; 296 297 /* 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) 301 return -ENODEV; 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) 305 return -ENODEV; 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) 309 return -ENODEV; 310 311 strlcpy(info->type, "lm77", I2C_NAME_SIZE); 312 313 return 0; 314 } 315 316 static int lm77_probe(struct i2c_client *new_client, 317 const struct i2c_device_id *id) 318 { 319 struct lm77_data *data; 320 int err; 321 322 data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL); 323 if (!data) { 324 err = -ENOMEM; 325 goto exit; 326 } 327 328 i2c_set_clientdata(new_client, data); 329 data->valid = 0; 330 mutex_init(&data->update_lock); 331 332 /* Initialize the LM77 chip */ 333 lm77_init_client(new_client); 334 335 /* Register sysfs hooks */ 336 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group))) 337 goto exit_free; 338 339 data->hwmon_dev = hwmon_device_register(&new_client->dev); 340 if (IS_ERR(data->hwmon_dev)) { 341 err = PTR_ERR(data->hwmon_dev); 342 goto exit_remove; 343 } 344 345 return 0; 346 347 exit_remove: 348 sysfs_remove_group(&new_client->dev.kobj, &lm77_group); 349 exit_free: 350 kfree(data); 351 exit: 352 return err; 353 } 354 355 static int lm77_remove(struct i2c_client *client) 356 { 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); 360 kfree(data); 361 return 0; 362 } 363 364 /* 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) 367 { 368 if (reg == LM77_REG_CONF) 369 return i2c_smbus_read_byte_data(client, reg); 370 else 371 return swab16(i2c_smbus_read_word_data(client, reg)); 372 } 373 374 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 375 { 376 if (reg == LM77_REG_CONF) 377 return i2c_smbus_write_byte_data(client, reg, value); 378 else 379 return i2c_smbus_write_word_data(client, reg, swab16(value)); 380 } 381 382 static void lm77_init_client(struct i2c_client *client) 383 { 384 /* Initialize the LM77 chip - turn off shutdown mode */ 385 int conf = lm77_read_value(client, LM77_REG_CONF); 386 if (conf & 1) 387 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 388 } 389 390 static struct lm77_data *lm77_update_device(struct device *dev) 391 { 392 struct i2c_client *client = to_i2c_client(dev); 393 struct lm77_data *data = i2c_get_clientdata(client); 394 395 mutex_lock(&data->update_lock); 396 397 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 398 || !data->valid) { 399 dev_dbg(&client->dev, "Starting lm77 update\n"); 400 data->temp_input = 401 LM77_TEMP_FROM_REG(lm77_read_value(client, 402 LM77_REG_TEMP)); 403 data->temp_hyst = 404 LM77_TEMP_FROM_REG(lm77_read_value(client, 405 LM77_REG_TEMP_HYST)); 406 data->temp_crit = 407 LM77_TEMP_FROM_REG(lm77_read_value(client, 408 LM77_REG_TEMP_CRIT)); 409 data->temp_min = 410 LM77_TEMP_FROM_REG(lm77_read_value(client, 411 LM77_REG_TEMP_MIN)); 412 data->temp_max = 413 LM77_TEMP_FROM_REG(lm77_read_value(client, 414 LM77_REG_TEMP_MAX)); 415 data->alarms = 416 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 417 data->last_updated = jiffies; 418 data->valid = 1; 419 } 420 421 mutex_unlock(&data->update_lock); 422 423 return data; 424 } 425 426 static int __init sensors_lm77_init(void) 427 { 428 return i2c_add_driver(&lm77_driver); 429 } 430 431 static void __exit sensors_lm77_exit(void) 432 { 433 i2c_del_driver(&lm77_driver); 434 } 435 436 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 437 MODULE_DESCRIPTION("LM77 driver"); 438 MODULE_LICENSE("GPL"); 439 440 module_init(sensors_lm77_init); 441 module_exit(sensors_lm77_exit); 442