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 i2c_client client; 56 struct device *hwmon_dev; 57 struct mutex update_lock; 58 char valid; 59 unsigned long last_updated; /* In jiffies */ 60 int temp_input; /* Temperatures */ 61 int temp_crit; 62 int temp_min; 63 int temp_max; 64 int temp_hyst; 65 u8 alarms; 66 }; 67 68 static int lm77_attach_adapter(struct i2c_adapter *adapter); 69 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind); 70 static void lm77_init_client(struct i2c_client *client); 71 static int lm77_detach_client(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 /* This is the driver that will be inserted */ 79 static struct i2c_driver lm77_driver = { 80 .driver = { 81 .name = "lm77", 82 }, 83 .attach_adapter = lm77_attach_adapter, 84 .detach_client = lm77_detach_client, 85 }; 86 87 /* straight from the datasheet */ 88 #define LM77_TEMP_MIN (-55000) 89 #define LM77_TEMP_MAX 125000 90 91 /* In the temperature registers, the low 3 bits are not part of the 92 temperature values; they are the status bits. */ 93 static inline s16 LM77_TEMP_TO_REG(int temp) 94 { 95 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 96 return (ntemp / 500) * 8; 97 } 98 99 static inline int LM77_TEMP_FROM_REG(s16 reg) 100 { 101 return (reg / 8) * 500; 102 } 103 104 /* sysfs stuff */ 105 106 /* read routines for temperature limits */ 107 #define show(value) \ 108 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 109 { \ 110 struct lm77_data *data = lm77_update_device(dev); \ 111 return sprintf(buf, "%d\n", data->value); \ 112 } 113 114 show(temp_input); 115 show(temp_crit); 116 show(temp_min); 117 show(temp_max); 118 119 /* read routines for hysteresis values */ 120 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 121 { 122 struct lm77_data *data = lm77_update_device(dev); 123 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); 124 } 125 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 126 { 127 struct lm77_data *data = lm77_update_device(dev); 128 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 129 } 130 static ssize_t show_temp_max_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_max - data->temp_hyst); 134 } 135 136 /* write routines */ 137 #define set(value, reg) \ 138 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 139 { \ 140 struct i2c_client *client = to_i2c_client(dev); \ 141 struct lm77_data *data = i2c_get_clientdata(client); \ 142 long val = simple_strtol(buf, NULL, 10); \ 143 \ 144 mutex_lock(&data->update_lock); \ 145 data->value = val; \ 146 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 147 mutex_unlock(&data->update_lock); \ 148 return count; \ 149 } 150 151 set(temp_min, LM77_REG_TEMP_MIN); 152 set(temp_max, LM77_REG_TEMP_MAX); 153 154 /* hysteresis is stored as a relative value on the chip, so it has to be 155 converted first */ 156 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 157 { 158 struct i2c_client *client = to_i2c_client(dev); 159 struct lm77_data *data = i2c_get_clientdata(client); 160 unsigned long val = simple_strtoul(buf, NULL, 10); 161 162 mutex_lock(&data->update_lock); 163 data->temp_hyst = data->temp_crit - val; 164 lm77_write_value(client, LM77_REG_TEMP_HYST, 165 LM77_TEMP_TO_REG(data->temp_hyst)); 166 mutex_unlock(&data->update_lock); 167 return count; 168 } 169 170 /* preserve hysteresis when setting T_crit */ 171 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 172 { 173 struct i2c_client *client = to_i2c_client(dev); 174 struct lm77_data *data = i2c_get_clientdata(client); 175 long val = simple_strtoul(buf, NULL, 10); 176 int oldcrithyst; 177 178 mutex_lock(&data->update_lock); 179 oldcrithyst = data->temp_crit - data->temp_hyst; 180 data->temp_crit = val; 181 data->temp_hyst = data->temp_crit - oldcrithyst; 182 lm77_write_value(client, LM77_REG_TEMP_CRIT, 183 LM77_TEMP_TO_REG(data->temp_crit)); 184 lm77_write_value(client, LM77_REG_TEMP_HYST, 185 LM77_TEMP_TO_REG(data->temp_hyst)); 186 mutex_unlock(&data->update_lock); 187 return count; 188 } 189 190 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 191 char *buf) 192 { 193 int bitnr = to_sensor_dev_attr(attr)->index; 194 struct lm77_data *data = lm77_update_device(dev); 195 return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1); 196 } 197 198 static DEVICE_ATTR(temp1_input, S_IRUGO, 199 show_temp_input, NULL); 200 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, 201 show_temp_crit, set_temp_crit); 202 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 203 show_temp_min, set_temp_min); 204 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 205 show_temp_max, set_temp_max); 206 207 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, 208 show_temp_crit_hyst, set_temp_crit_hyst); 209 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, 210 show_temp_min_hyst, NULL); 211 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, 212 show_temp_max_hyst, NULL); 213 214 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 215 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 216 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 217 218 static int lm77_attach_adapter(struct i2c_adapter *adapter) 219 { 220 if (!(adapter->class & I2C_CLASS_HWMON)) 221 return 0; 222 return i2c_probe(adapter, &addr_data, lm77_detect); 223 } 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 /* This function is called by i2c_probe */ 244 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind) 245 { 246 struct i2c_client *new_client; 247 struct lm77_data *data; 248 int err = 0; 249 const char *name = ""; 250 251 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 252 I2C_FUNC_SMBUS_WORD_DATA)) 253 goto exit; 254 255 /* OK. For now, we presume we have a valid client. We now create the 256 client structure, even though we cannot fill it completely yet. 257 But it allows us to access lm77_{read,write}_value. */ 258 if (!(data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL))) { 259 err = -ENOMEM; 260 goto exit; 261 } 262 263 new_client = &data->client; 264 i2c_set_clientdata(new_client, data); 265 new_client->addr = address; 266 new_client->adapter = adapter; 267 new_client->driver = &lm77_driver; 268 new_client->flags = 0; 269 270 /* Here comes the remaining detection. Since the LM77 has no 271 register dedicated to identification, we have to rely on the 272 following tricks: 273 274 1. the high 4 bits represent the sign and thus they should 275 always be the same 276 2. the high 3 bits are unused in the configuration register 277 3. addresses 0x06 and 0x07 return the last read value 278 4. registers cycling over 8-address boundaries 279 280 Word-sized registers are high-byte first. */ 281 if (kind < 0) { 282 int i, cur, conf, hyst, crit, min, max; 283 284 /* addresses cycling */ 285 cur = i2c_smbus_read_word_data(new_client, 0); 286 conf = i2c_smbus_read_byte_data(new_client, 1); 287 hyst = i2c_smbus_read_word_data(new_client, 2); 288 crit = i2c_smbus_read_word_data(new_client, 3); 289 min = i2c_smbus_read_word_data(new_client, 4); 290 max = i2c_smbus_read_word_data(new_client, 5); 291 for (i = 8; i <= 0xff; i += 8) 292 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 293 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 294 || i2c_smbus_read_word_data(new_client, i + 3) != crit 295 || i2c_smbus_read_word_data(new_client, i + 4) != min 296 || i2c_smbus_read_word_data(new_client, i + 5) != max) 297 goto exit_free; 298 299 /* sign bits */ 300 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) 301 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) 302 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) 303 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) 304 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) 305 goto exit_free; 306 307 /* unused bits */ 308 if (conf & 0xe0) 309 goto exit_free; 310 311 /* 0x06 and 0x07 return the last read value */ 312 cur = i2c_smbus_read_word_data(new_client, 0); 313 if (i2c_smbus_read_word_data(new_client, 6) != cur 314 || i2c_smbus_read_word_data(new_client, 7) != cur) 315 goto exit_free; 316 hyst = i2c_smbus_read_word_data(new_client, 2); 317 if (i2c_smbus_read_word_data(new_client, 6) != hyst 318 || i2c_smbus_read_word_data(new_client, 7) != hyst) 319 goto exit_free; 320 min = i2c_smbus_read_word_data(new_client, 4); 321 if (i2c_smbus_read_word_data(new_client, 6) != min 322 || i2c_smbus_read_word_data(new_client, 7) != min) 323 goto exit_free; 324 325 } 326 327 /* Determine the chip type - only one kind supported! */ 328 if (kind <= 0) 329 kind = lm77; 330 331 if (kind == lm77) { 332 name = "lm77"; 333 } 334 335 /* Fill in the remaining client fields and put it into the global list */ 336 strlcpy(new_client->name, name, I2C_NAME_SIZE); 337 data->valid = 0; 338 mutex_init(&data->update_lock); 339 340 /* Tell the I2C layer a new client has arrived */ 341 if ((err = i2c_attach_client(new_client))) 342 goto exit_free; 343 344 /* Initialize the LM77 chip */ 345 lm77_init_client(new_client); 346 347 /* Register sysfs hooks */ 348 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group))) 349 goto exit_detach; 350 351 data->hwmon_dev = hwmon_device_register(&new_client->dev); 352 if (IS_ERR(data->hwmon_dev)) { 353 err = PTR_ERR(data->hwmon_dev); 354 goto exit_remove; 355 } 356 357 return 0; 358 359 exit_remove: 360 sysfs_remove_group(&new_client->dev.kobj, &lm77_group); 361 exit_detach: 362 i2c_detach_client(new_client); 363 exit_free: 364 kfree(data); 365 exit: 366 return err; 367 } 368 369 static int lm77_detach_client(struct i2c_client *client) 370 { 371 struct lm77_data *data = i2c_get_clientdata(client); 372 hwmon_device_unregister(data->hwmon_dev); 373 sysfs_remove_group(&client->dev.kobj, &lm77_group); 374 i2c_detach_client(client); 375 kfree(data); 376 return 0; 377 } 378 379 /* All registers are word-sized, except for the configuration register. 380 The LM77 uses the high-byte first convention. */ 381 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 382 { 383 if (reg == LM77_REG_CONF) 384 return i2c_smbus_read_byte_data(client, reg); 385 else 386 return swab16(i2c_smbus_read_word_data(client, reg)); 387 } 388 389 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 390 { 391 if (reg == LM77_REG_CONF) 392 return i2c_smbus_write_byte_data(client, reg, value); 393 else 394 return i2c_smbus_write_word_data(client, reg, swab16(value)); 395 } 396 397 static void lm77_init_client(struct i2c_client *client) 398 { 399 /* Initialize the LM77 chip - turn off shutdown mode */ 400 int conf = lm77_read_value(client, LM77_REG_CONF); 401 if (conf & 1) 402 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 403 } 404 405 static struct lm77_data *lm77_update_device(struct device *dev) 406 { 407 struct i2c_client *client = to_i2c_client(dev); 408 struct lm77_data *data = i2c_get_clientdata(client); 409 410 mutex_lock(&data->update_lock); 411 412 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 413 || !data->valid) { 414 dev_dbg(&client->dev, "Starting lm77 update\n"); 415 data->temp_input = 416 LM77_TEMP_FROM_REG(lm77_read_value(client, 417 LM77_REG_TEMP)); 418 data->temp_hyst = 419 LM77_TEMP_FROM_REG(lm77_read_value(client, 420 LM77_REG_TEMP_HYST)); 421 data->temp_crit = 422 LM77_TEMP_FROM_REG(lm77_read_value(client, 423 LM77_REG_TEMP_CRIT)); 424 data->temp_min = 425 LM77_TEMP_FROM_REG(lm77_read_value(client, 426 LM77_REG_TEMP_MIN)); 427 data->temp_max = 428 LM77_TEMP_FROM_REG(lm77_read_value(client, 429 LM77_REG_TEMP_MAX)); 430 data->alarms = 431 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 432 data->last_updated = jiffies; 433 data->valid = 1; 434 } 435 436 mutex_unlock(&data->update_lock); 437 438 return data; 439 } 440 441 static int __init sensors_lm77_init(void) 442 { 443 return i2c_add_driver(&lm77_driver); 444 } 445 446 static void __exit sensors_lm77_exit(void) 447 { 448 i2c_del_driver(&lm77_driver); 449 } 450 451 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 452 MODULE_DESCRIPTION("LM77 driver"); 453 MODULE_LICENSE("GPL"); 454 455 module_init(sensors_lm77_init); 456 module_exit(sensors_lm77_exit); 457