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, int kind, 70 struct i2c_board_info *info); 71 static void lm77_init_client(struct i2c_client *client); 72 static int lm77_remove(struct i2c_client *client); 73 static u16 lm77_read_value(struct i2c_client *client, u8 reg); 74 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value); 75 76 static struct lm77_data *lm77_update_device(struct device *dev); 77 78 79 static const struct i2c_device_id lm77_id[] = { 80 { "lm77", lm77 }, 81 { } 82 }; 83 MODULE_DEVICE_TABLE(i2c, lm77_id); 84 85 /* This is the driver that will be inserted */ 86 static struct i2c_driver lm77_driver = { 87 .class = I2C_CLASS_HWMON, 88 .driver = { 89 .name = "lm77", 90 }, 91 .probe = lm77_probe, 92 .remove = lm77_remove, 93 .id_table = lm77_id, 94 .detect = lm77_detect, 95 .address_data = &addr_data, 96 }; 97 98 /* straight from the datasheet */ 99 #define LM77_TEMP_MIN (-55000) 100 #define LM77_TEMP_MAX 125000 101 102 /* In the temperature registers, the low 3 bits are not part of the 103 temperature values; they are the status bits. */ 104 static inline s16 LM77_TEMP_TO_REG(int temp) 105 { 106 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 107 return (ntemp / 500) * 8; 108 } 109 110 static inline int LM77_TEMP_FROM_REG(s16 reg) 111 { 112 return (reg / 8) * 500; 113 } 114 115 /* sysfs stuff */ 116 117 /* read routines for temperature limits */ 118 #define show(value) \ 119 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 120 { \ 121 struct lm77_data *data = lm77_update_device(dev); \ 122 return sprintf(buf, "%d\n", data->value); \ 123 } 124 125 show(temp_input); 126 show(temp_crit); 127 show(temp_min); 128 show(temp_max); 129 130 /* read routines for hysteresis values */ 131 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 132 { 133 struct lm77_data *data = lm77_update_device(dev); 134 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); 135 } 136 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 137 { 138 struct lm77_data *data = lm77_update_device(dev); 139 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 140 } 141 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 142 { 143 struct lm77_data *data = lm77_update_device(dev); 144 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); 145 } 146 147 /* write routines */ 148 #define set(value, reg) \ 149 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 150 { \ 151 struct i2c_client *client = to_i2c_client(dev); \ 152 struct lm77_data *data = i2c_get_clientdata(client); \ 153 long val = simple_strtol(buf, NULL, 10); \ 154 \ 155 mutex_lock(&data->update_lock); \ 156 data->value = val; \ 157 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 158 mutex_unlock(&data->update_lock); \ 159 return count; \ 160 } 161 162 set(temp_min, LM77_REG_TEMP_MIN); 163 set(temp_max, LM77_REG_TEMP_MAX); 164 165 /* hysteresis is stored as a relative value on the chip, so it has to be 166 converted first */ 167 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 168 { 169 struct i2c_client *client = to_i2c_client(dev); 170 struct lm77_data *data = i2c_get_clientdata(client); 171 unsigned long val = simple_strtoul(buf, NULL, 10); 172 173 mutex_lock(&data->update_lock); 174 data->temp_hyst = data->temp_crit - val; 175 lm77_write_value(client, LM77_REG_TEMP_HYST, 176 LM77_TEMP_TO_REG(data->temp_hyst)); 177 mutex_unlock(&data->update_lock); 178 return count; 179 } 180 181 /* preserve hysteresis when setting T_crit */ 182 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 183 { 184 struct i2c_client *client = to_i2c_client(dev); 185 struct lm77_data *data = i2c_get_clientdata(client); 186 long val = simple_strtoul(buf, NULL, 10); 187 int oldcrithyst; 188 189 mutex_lock(&data->update_lock); 190 oldcrithyst = data->temp_crit - data->temp_hyst; 191 data->temp_crit = val; 192 data->temp_hyst = data->temp_crit - oldcrithyst; 193 lm77_write_value(client, LM77_REG_TEMP_CRIT, 194 LM77_TEMP_TO_REG(data->temp_crit)); 195 lm77_write_value(client, LM77_REG_TEMP_HYST, 196 LM77_TEMP_TO_REG(data->temp_hyst)); 197 mutex_unlock(&data->update_lock); 198 return count; 199 } 200 201 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 202 char *buf) 203 { 204 int bitnr = to_sensor_dev_attr(attr)->index; 205 struct lm77_data *data = lm77_update_device(dev); 206 return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1); 207 } 208 209 static DEVICE_ATTR(temp1_input, S_IRUGO, 210 show_temp_input, NULL); 211 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, 212 show_temp_crit, set_temp_crit); 213 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 214 show_temp_min, set_temp_min); 215 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 216 show_temp_max, set_temp_max); 217 218 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, 219 show_temp_crit_hyst, set_temp_crit_hyst); 220 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, 221 show_temp_min_hyst, NULL); 222 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, 223 show_temp_max_hyst, NULL); 224 225 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 226 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 227 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 228 229 static struct attribute *lm77_attributes[] = { 230 &dev_attr_temp1_input.attr, 231 &dev_attr_temp1_crit.attr, 232 &dev_attr_temp1_min.attr, 233 &dev_attr_temp1_max.attr, 234 &dev_attr_temp1_crit_hyst.attr, 235 &dev_attr_temp1_min_hyst.attr, 236 &dev_attr_temp1_max_hyst.attr, 237 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 238 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 239 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 240 NULL 241 }; 242 243 static const struct attribute_group lm77_group = { 244 .attrs = lm77_attributes, 245 }; 246 247 /* Return 0 if detection is successful, -ENODEV otherwise */ 248 static int lm77_detect(struct i2c_client *new_client, int kind, 249 struct i2c_board_info *info) 250 { 251 struct i2c_adapter *adapter = new_client->adapter; 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 if (kind < 0) { 269 int i, cur, conf, hyst, crit, min, max; 270 271 /* addresses cycling */ 272 cur = i2c_smbus_read_word_data(new_client, 0); 273 conf = i2c_smbus_read_byte_data(new_client, 1); 274 hyst = i2c_smbus_read_word_data(new_client, 2); 275 crit = i2c_smbus_read_word_data(new_client, 3); 276 min = i2c_smbus_read_word_data(new_client, 4); 277 max = i2c_smbus_read_word_data(new_client, 5); 278 for (i = 8; i <= 0xff; i += 8) 279 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 280 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 281 || i2c_smbus_read_word_data(new_client, i + 3) != crit 282 || i2c_smbus_read_word_data(new_client, i + 4) != min 283 || i2c_smbus_read_word_data(new_client, i + 5) != max) 284 return -ENODEV; 285 286 /* sign bits */ 287 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) 288 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) 289 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) 290 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) 291 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) 292 return -ENODEV; 293 294 /* unused bits */ 295 if (conf & 0xe0) 296 return -ENODEV; 297 298 /* 0x06 and 0x07 return the last read value */ 299 cur = i2c_smbus_read_word_data(new_client, 0); 300 if (i2c_smbus_read_word_data(new_client, 6) != cur 301 || i2c_smbus_read_word_data(new_client, 7) != cur) 302 return -ENODEV; 303 hyst = i2c_smbus_read_word_data(new_client, 2); 304 if (i2c_smbus_read_word_data(new_client, 6) != hyst 305 || i2c_smbus_read_word_data(new_client, 7) != hyst) 306 return -ENODEV; 307 min = i2c_smbus_read_word_data(new_client, 4); 308 if (i2c_smbus_read_word_data(new_client, 6) != min 309 || i2c_smbus_read_word_data(new_client, 7) != min) 310 return -ENODEV; 311 312 } 313 314 strlcpy(info->type, "lm77", I2C_NAME_SIZE); 315 316 return 0; 317 } 318 319 static int lm77_probe(struct i2c_client *new_client, 320 const struct i2c_device_id *id) 321 { 322 struct lm77_data *data; 323 int err; 324 325 data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL); 326 if (!data) { 327 err = -ENOMEM; 328 goto exit; 329 } 330 331 i2c_set_clientdata(new_client, data); 332 data->valid = 0; 333 mutex_init(&data->update_lock); 334 335 /* Initialize the LM77 chip */ 336 lm77_init_client(new_client); 337 338 /* Register sysfs hooks */ 339 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group))) 340 goto exit_free; 341 342 data->hwmon_dev = hwmon_device_register(&new_client->dev); 343 if (IS_ERR(data->hwmon_dev)) { 344 err = PTR_ERR(data->hwmon_dev); 345 goto exit_remove; 346 } 347 348 return 0; 349 350 exit_remove: 351 sysfs_remove_group(&new_client->dev.kobj, &lm77_group); 352 exit_free: 353 kfree(data); 354 exit: 355 return err; 356 } 357 358 static int lm77_remove(struct i2c_client *client) 359 { 360 struct lm77_data *data = i2c_get_clientdata(client); 361 hwmon_device_unregister(data->hwmon_dev); 362 sysfs_remove_group(&client->dev.kobj, &lm77_group); 363 kfree(data); 364 return 0; 365 } 366 367 /* All registers are word-sized, except for the configuration register. 368 The LM77 uses the high-byte first convention. */ 369 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 370 { 371 if (reg == LM77_REG_CONF) 372 return i2c_smbus_read_byte_data(client, reg); 373 else 374 return swab16(i2c_smbus_read_word_data(client, reg)); 375 } 376 377 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 378 { 379 if (reg == LM77_REG_CONF) 380 return i2c_smbus_write_byte_data(client, reg, value); 381 else 382 return i2c_smbus_write_word_data(client, reg, swab16(value)); 383 } 384 385 static void lm77_init_client(struct i2c_client *client) 386 { 387 /* Initialize the LM77 chip - turn off shutdown mode */ 388 int conf = lm77_read_value(client, LM77_REG_CONF); 389 if (conf & 1) 390 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 391 } 392 393 static struct lm77_data *lm77_update_device(struct device *dev) 394 { 395 struct i2c_client *client = to_i2c_client(dev); 396 struct lm77_data *data = i2c_get_clientdata(client); 397 398 mutex_lock(&data->update_lock); 399 400 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 401 || !data->valid) { 402 dev_dbg(&client->dev, "Starting lm77 update\n"); 403 data->temp_input = 404 LM77_TEMP_FROM_REG(lm77_read_value(client, 405 LM77_REG_TEMP)); 406 data->temp_hyst = 407 LM77_TEMP_FROM_REG(lm77_read_value(client, 408 LM77_REG_TEMP_HYST)); 409 data->temp_crit = 410 LM77_TEMP_FROM_REG(lm77_read_value(client, 411 LM77_REG_TEMP_CRIT)); 412 data->temp_min = 413 LM77_TEMP_FROM_REG(lm77_read_value(client, 414 LM77_REG_TEMP_MIN)); 415 data->temp_max = 416 LM77_TEMP_FROM_REG(lm77_read_value(client, 417 LM77_REG_TEMP_MAX)); 418 data->alarms = 419 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 420 data->last_updated = jiffies; 421 data->valid = 1; 422 } 423 424 mutex_unlock(&data->update_lock); 425 426 return data; 427 } 428 429 static int __init sensors_lm77_init(void) 430 { 431 return i2c_add_driver(&lm77_driver); 432 } 433 434 static void __exit sensors_lm77_exit(void) 435 { 436 i2c_del_driver(&lm77_driver); 437 } 438 439 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 440 MODULE_DESCRIPTION("LM77 driver"); 441 MODULE_LICENSE("GPL"); 442 443 module_init(sensors_lm77_init); 444 module_exit(sensors_lm77_exit); 445