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 /* 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 49 50 /* Each client has this additional data */ 51 struct lm77_data { 52 struct device *hwmon_dev; 53 struct mutex update_lock; 54 char valid; 55 unsigned long last_updated; /* In jiffies */ 56 int temp_input; /* Temperatures */ 57 int temp_crit; 58 int temp_min; 59 int temp_max; 60 int temp_hyst; 61 u8 alarms; 62 }; 63 64 static int lm77_probe(struct i2c_client *client, 65 const struct i2c_device_id *id); 66 static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info); 67 static void lm77_init_client(struct i2c_client *client); 68 static int lm77_remove(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); 71 72 static struct lm77_data *lm77_update_device(struct device *dev); 73 74 75 static const struct i2c_device_id lm77_id[] = { 76 { "lm77", 0 }, 77 { } 78 }; 79 MODULE_DEVICE_TABLE(i2c, lm77_id); 80 81 /* This is the driver that will be inserted */ 82 static struct i2c_driver lm77_driver = { 83 .class = I2C_CLASS_HWMON, 84 .driver = { 85 .name = "lm77", 86 }, 87 .probe = lm77_probe, 88 .remove = lm77_remove, 89 .id_table = lm77_id, 90 .detect = lm77_detect, 91 .address_list = normal_i2c, 92 }; 93 94 /* straight from the datasheet */ 95 #define LM77_TEMP_MIN (-55000) 96 #define LM77_TEMP_MAX 125000 97 98 /* In the temperature registers, the low 3 bits are not part of the 99 temperature values; they are the status bits. */ 100 static inline s16 LM77_TEMP_TO_REG(int temp) 101 { 102 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 103 return (ntemp / 500) * 8; 104 } 105 106 static inline int LM77_TEMP_FROM_REG(s16 reg) 107 { 108 return (reg / 8) * 500; 109 } 110 111 /* sysfs stuff */ 112 113 /* read routines for temperature limits */ 114 #define show(value) \ 115 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 116 { \ 117 struct lm77_data *data = lm77_update_device(dev); \ 118 return sprintf(buf, "%d\n", data->value); \ 119 } 120 121 show(temp_input); 122 show(temp_crit); 123 show(temp_min); 124 show(temp_max); 125 126 /* read routines for hysteresis values */ 127 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 128 { 129 struct lm77_data *data = lm77_update_device(dev); 130 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); 131 } 132 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 133 { 134 struct lm77_data *data = lm77_update_device(dev); 135 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 136 } 137 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 138 { 139 struct lm77_data *data = lm77_update_device(dev); 140 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); 141 } 142 143 /* write routines */ 144 #define set(value, reg) \ 145 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 146 { \ 147 struct i2c_client *client = to_i2c_client(dev); \ 148 struct lm77_data *data = i2c_get_clientdata(client); \ 149 long val = simple_strtol(buf, NULL, 10); \ 150 \ 151 mutex_lock(&data->update_lock); \ 152 data->value = val; \ 153 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 154 mutex_unlock(&data->update_lock); \ 155 return count; \ 156 } 157 158 set(temp_min, LM77_REG_TEMP_MIN); 159 set(temp_max, LM77_REG_TEMP_MAX); 160 161 /* hysteresis is stored as a relative value on the chip, so it has to be 162 converted first */ 163 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 164 { 165 struct i2c_client *client = to_i2c_client(dev); 166 struct lm77_data *data = i2c_get_clientdata(client); 167 unsigned long val = simple_strtoul(buf, NULL, 10); 168 169 mutex_lock(&data->update_lock); 170 data->temp_hyst = data->temp_crit - val; 171 lm77_write_value(client, LM77_REG_TEMP_HYST, 172 LM77_TEMP_TO_REG(data->temp_hyst)); 173 mutex_unlock(&data->update_lock); 174 return count; 175 } 176 177 /* preserve hysteresis when setting T_crit */ 178 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 179 { 180 struct i2c_client *client = to_i2c_client(dev); 181 struct lm77_data *data = i2c_get_clientdata(client); 182 long val = simple_strtoul(buf, NULL, 10); 183 int oldcrithyst; 184 185 mutex_lock(&data->update_lock); 186 oldcrithyst = data->temp_crit - data->temp_hyst; 187 data->temp_crit = val; 188 data->temp_hyst = data->temp_crit - oldcrithyst; 189 lm77_write_value(client, LM77_REG_TEMP_CRIT, 190 LM77_TEMP_TO_REG(data->temp_crit)); 191 lm77_write_value(client, LM77_REG_TEMP_HYST, 192 LM77_TEMP_TO_REG(data->temp_hyst)); 193 mutex_unlock(&data->update_lock); 194 return count; 195 } 196 197 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 198 char *buf) 199 { 200 int bitnr = to_sensor_dev_attr(attr)->index; 201 struct lm77_data *data = lm77_update_device(dev); 202 return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1); 203 } 204 205 static DEVICE_ATTR(temp1_input, S_IRUGO, 206 show_temp_input, NULL); 207 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, 208 show_temp_crit, set_temp_crit); 209 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 210 show_temp_min, set_temp_min); 211 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 212 show_temp_max, set_temp_max); 213 214 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, 215 show_temp_crit_hyst, set_temp_crit_hyst); 216 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, 217 show_temp_min_hyst, NULL); 218 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, 219 show_temp_max_hyst, NULL); 220 221 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 222 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 223 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 224 225 static struct attribute *lm77_attributes[] = { 226 &dev_attr_temp1_input.attr, 227 &dev_attr_temp1_crit.attr, 228 &dev_attr_temp1_min.attr, 229 &dev_attr_temp1_max.attr, 230 &dev_attr_temp1_crit_hyst.attr, 231 &dev_attr_temp1_min_hyst.attr, 232 &dev_attr_temp1_max_hyst.attr, 233 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 234 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 235 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 236 NULL 237 }; 238 239 static const struct attribute_group lm77_group = { 240 .attrs = lm77_attributes, 241 }; 242 243 /* Return 0 if detection is successful, -ENODEV otherwise */ 244 static int lm77_detect(struct i2c_client *new_client, 245 struct i2c_board_info *info) 246 { 247 struct i2c_adapter *adapter = new_client->adapter; 248 int i, cur, conf, hyst, crit, min, max; 249 250 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 251 I2C_FUNC_SMBUS_WORD_DATA)) 252 return -ENODEV; 253 254 /* Here comes the remaining detection. Since the LM77 has no 255 register dedicated to identification, we have to rely on the 256 following tricks: 257 258 1. the high 4 bits represent the sign and thus they should 259 always be the same 260 2. the high 3 bits are unused in the configuration register 261 3. addresses 0x06 and 0x07 return the last read value 262 4. registers cycling over 8-address boundaries 263 264 Word-sized registers are high-byte first. */ 265 266 /* addresses cycling */ 267 cur = i2c_smbus_read_word_data(new_client, 0); 268 conf = i2c_smbus_read_byte_data(new_client, 1); 269 hyst = i2c_smbus_read_word_data(new_client, 2); 270 crit = i2c_smbus_read_word_data(new_client, 3); 271 min = i2c_smbus_read_word_data(new_client, 4); 272 max = i2c_smbus_read_word_data(new_client, 5); 273 for (i = 8; i <= 0xff; i += 8) { 274 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 275 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 276 || i2c_smbus_read_word_data(new_client, i + 3) != crit 277 || i2c_smbus_read_word_data(new_client, i + 4) != min 278 || i2c_smbus_read_word_data(new_client, i + 5) != max) 279 return -ENODEV; 280 } 281 282 /* sign bits */ 283 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) 284 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) 285 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) 286 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) 287 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) 288 return -ENODEV; 289 290 /* unused bits */ 291 if (conf & 0xe0) 292 return -ENODEV; 293 294 /* 0x06 and 0x07 return the last read value */ 295 cur = i2c_smbus_read_word_data(new_client, 0); 296 if (i2c_smbus_read_word_data(new_client, 6) != cur 297 || i2c_smbus_read_word_data(new_client, 7) != cur) 298 return -ENODEV; 299 hyst = i2c_smbus_read_word_data(new_client, 2); 300 if (i2c_smbus_read_word_data(new_client, 6) != hyst 301 || i2c_smbus_read_word_data(new_client, 7) != hyst) 302 return -ENODEV; 303 min = i2c_smbus_read_word_data(new_client, 4); 304 if (i2c_smbus_read_word_data(new_client, 6) != min 305 || i2c_smbus_read_word_data(new_client, 7) != min) 306 return -ENODEV; 307 308 strlcpy(info->type, "lm77", I2C_NAME_SIZE); 309 310 return 0; 311 } 312 313 static int lm77_probe(struct i2c_client *new_client, 314 const struct i2c_device_id *id) 315 { 316 struct lm77_data *data; 317 int err; 318 319 data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL); 320 if (!data) { 321 err = -ENOMEM; 322 goto exit; 323 } 324 325 i2c_set_clientdata(new_client, data); 326 data->valid = 0; 327 mutex_init(&data->update_lock); 328 329 /* Initialize the LM77 chip */ 330 lm77_init_client(new_client); 331 332 /* Register sysfs hooks */ 333 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group))) 334 goto exit_free; 335 336 data->hwmon_dev = hwmon_device_register(&new_client->dev); 337 if (IS_ERR(data->hwmon_dev)) { 338 err = PTR_ERR(data->hwmon_dev); 339 goto exit_remove; 340 } 341 342 return 0; 343 344 exit_remove: 345 sysfs_remove_group(&new_client->dev.kobj, &lm77_group); 346 exit_free: 347 kfree(data); 348 exit: 349 return err; 350 } 351 352 static int lm77_remove(struct i2c_client *client) 353 { 354 struct lm77_data *data = i2c_get_clientdata(client); 355 hwmon_device_unregister(data->hwmon_dev); 356 sysfs_remove_group(&client->dev.kobj, &lm77_group); 357 kfree(data); 358 return 0; 359 } 360 361 /* All registers are word-sized, except for the configuration register. 362 The LM77 uses the high-byte first convention. */ 363 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 364 { 365 if (reg == LM77_REG_CONF) 366 return i2c_smbus_read_byte_data(client, reg); 367 else 368 return swab16(i2c_smbus_read_word_data(client, reg)); 369 } 370 371 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 372 { 373 if (reg == LM77_REG_CONF) 374 return i2c_smbus_write_byte_data(client, reg, value); 375 else 376 return i2c_smbus_write_word_data(client, reg, swab16(value)); 377 } 378 379 static void lm77_init_client(struct i2c_client *client) 380 { 381 /* Initialize the LM77 chip - turn off shutdown mode */ 382 int conf = lm77_read_value(client, LM77_REG_CONF); 383 if (conf & 1) 384 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 385 } 386 387 static struct lm77_data *lm77_update_device(struct device *dev) 388 { 389 struct i2c_client *client = to_i2c_client(dev); 390 struct lm77_data *data = i2c_get_clientdata(client); 391 392 mutex_lock(&data->update_lock); 393 394 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 395 || !data->valid) { 396 dev_dbg(&client->dev, "Starting lm77 update\n"); 397 data->temp_input = 398 LM77_TEMP_FROM_REG(lm77_read_value(client, 399 LM77_REG_TEMP)); 400 data->temp_hyst = 401 LM77_TEMP_FROM_REG(lm77_read_value(client, 402 LM77_REG_TEMP_HYST)); 403 data->temp_crit = 404 LM77_TEMP_FROM_REG(lm77_read_value(client, 405 LM77_REG_TEMP_CRIT)); 406 data->temp_min = 407 LM77_TEMP_FROM_REG(lm77_read_value(client, 408 LM77_REG_TEMP_MIN)); 409 data->temp_max = 410 LM77_TEMP_FROM_REG(lm77_read_value(client, 411 LM77_REG_TEMP_MAX)); 412 data->alarms = 413 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 414 data->last_updated = jiffies; 415 data->valid = 1; 416 } 417 418 mutex_unlock(&data->update_lock); 419 420 return data; 421 } 422 423 static int __init sensors_lm77_init(void) 424 { 425 return i2c_add_driver(&lm77_driver); 426 } 427 428 static void __exit sensors_lm77_exit(void) 429 { 430 i2c_del_driver(&lm77_driver); 431 } 432 433 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 434 MODULE_DESCRIPTION("LM77 driver"); 435 MODULE_LICENSE("GPL"); 436 437 module_init(sensors_lm77_init); 438 module_exit(sensors_lm77_exit); 439