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/err.h> 35 #include <linux/mutex.h> 36 37 /* Addresses to scan */ 38 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END }; 39 40 /* Insmod parameters */ 41 I2C_CLIENT_INSMOD_1(lm77); 42 43 /* The LM77 registers */ 44 #define LM77_REG_TEMP 0x00 45 #define LM77_REG_CONF 0x01 46 #define LM77_REG_TEMP_HYST 0x02 47 #define LM77_REG_TEMP_CRIT 0x03 48 #define LM77_REG_TEMP_MIN 0x04 49 #define LM77_REG_TEMP_MAX 0x05 50 51 /* Each client has this additional data */ 52 struct lm77_data { 53 struct i2c_client client; 54 struct class_device *class_dev; 55 struct mutex update_lock; 56 char valid; 57 unsigned long last_updated; /* In jiffies */ 58 int temp_input; /* Temperatures */ 59 int temp_crit; 60 int temp_min; 61 int temp_max; 62 int temp_hyst; 63 u8 alarms; 64 }; 65 66 static int lm77_attach_adapter(struct i2c_adapter *adapter); 67 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind); 68 static void lm77_init_client(struct i2c_client *client); 69 static int lm77_detach_client(struct i2c_client *client); 70 static u16 lm77_read_value(struct i2c_client *client, u8 reg); 71 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value); 72 73 static struct lm77_data *lm77_update_device(struct device *dev); 74 75 76 /* This is the driver that will be inserted */ 77 static struct i2c_driver lm77_driver = { 78 .driver = { 79 .name = "lm77", 80 }, 81 .attach_adapter = lm77_attach_adapter, 82 .detach_client = lm77_detach_client, 83 }; 84 85 /* straight from the datasheet */ 86 #define LM77_TEMP_MIN (-55000) 87 #define LM77_TEMP_MAX 125000 88 89 /* In the temperature registers, the low 3 bits are not part of the 90 temperature values; they are the status bits. */ 91 static inline s16 LM77_TEMP_TO_REG(int temp) 92 { 93 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 94 return (ntemp / 500) * 8; 95 } 96 97 static inline int LM77_TEMP_FROM_REG(s16 reg) 98 { 99 return (reg / 8) * 500; 100 } 101 102 /* sysfs stuff */ 103 104 /* read routines for temperature limits */ 105 #define show(value) \ 106 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 107 { \ 108 struct lm77_data *data = lm77_update_device(dev); \ 109 return sprintf(buf, "%d\n", data->value); \ 110 } 111 112 show(temp_input); 113 show(temp_crit); 114 show(temp_min); 115 show(temp_max); 116 show(alarms); 117 118 /* read routines for hysteresis values */ 119 static ssize_t show_temp_crit_hyst(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->temp_crit - data->temp_hyst); 123 } 124 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 125 { 126 struct lm77_data *data = lm77_update_device(dev); 127 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 128 } 129 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 130 { 131 struct lm77_data *data = lm77_update_device(dev); 132 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); 133 } 134 135 /* write routines */ 136 #define set(value, reg) \ 137 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 138 { \ 139 struct i2c_client *client = to_i2c_client(dev); \ 140 struct lm77_data *data = i2c_get_clientdata(client); \ 141 long val = simple_strtoul(buf, NULL, 10); \ 142 \ 143 mutex_lock(&data->update_lock); \ 144 data->value = val; \ 145 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 146 mutex_unlock(&data->update_lock); \ 147 return count; \ 148 } 149 150 set(temp_min, LM77_REG_TEMP_MIN); 151 set(temp_max, LM77_REG_TEMP_MAX); 152 153 /* hysteresis is stored as a relative value on the chip, so it has to be 154 converted first */ 155 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 156 { 157 struct i2c_client *client = to_i2c_client(dev); 158 struct lm77_data *data = i2c_get_clientdata(client); 159 unsigned long val = simple_strtoul(buf, NULL, 10); 160 161 mutex_lock(&data->update_lock); 162 data->temp_hyst = data->temp_crit - val; 163 lm77_write_value(client, LM77_REG_TEMP_HYST, 164 LM77_TEMP_TO_REG(data->temp_hyst)); 165 mutex_unlock(&data->update_lock); 166 return count; 167 } 168 169 /* preserve hysteresis when setting T_crit */ 170 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 171 { 172 struct i2c_client *client = to_i2c_client(dev); 173 struct lm77_data *data = i2c_get_clientdata(client); 174 long val = simple_strtoul(buf, NULL, 10); 175 int oldcrithyst; 176 177 mutex_lock(&data->update_lock); 178 oldcrithyst = data->temp_crit - data->temp_hyst; 179 data->temp_crit = val; 180 data->temp_hyst = data->temp_crit - oldcrithyst; 181 lm77_write_value(client, LM77_REG_TEMP_CRIT, 182 LM77_TEMP_TO_REG(data->temp_crit)); 183 lm77_write_value(client, LM77_REG_TEMP_HYST, 184 LM77_TEMP_TO_REG(data->temp_hyst)); 185 mutex_unlock(&data->update_lock); 186 return count; 187 } 188 189 static DEVICE_ATTR(temp1_input, S_IRUGO, 190 show_temp_input, NULL); 191 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, 192 show_temp_crit, set_temp_crit); 193 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 194 show_temp_min, set_temp_min); 195 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 196 show_temp_max, set_temp_max); 197 198 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, 199 show_temp_crit_hyst, set_temp_crit_hyst); 200 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, 201 show_temp_min_hyst, NULL); 202 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, 203 show_temp_max_hyst, NULL); 204 205 static DEVICE_ATTR(alarms, S_IRUGO, 206 show_alarms, NULL); 207 208 static int lm77_attach_adapter(struct i2c_adapter *adapter) 209 { 210 if (!(adapter->class & I2C_CLASS_HWMON)) 211 return 0; 212 return i2c_probe(adapter, &addr_data, lm77_detect); 213 } 214 215 static struct attribute *lm77_attributes[] = { 216 &dev_attr_temp1_input.attr, 217 &dev_attr_temp1_crit.attr, 218 &dev_attr_temp1_min.attr, 219 &dev_attr_temp1_max.attr, 220 &dev_attr_temp1_crit_hyst.attr, 221 &dev_attr_temp1_min_hyst.attr, 222 &dev_attr_temp1_max_hyst.attr, 223 &dev_attr_alarms.attr, 224 225 NULL 226 }; 227 228 static const struct attribute_group lm77_group = { 229 .attrs = lm77_attributes, 230 }; 231 232 /* This function is called by i2c_probe */ 233 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind) 234 { 235 struct i2c_client *new_client; 236 struct lm77_data *data; 237 int err = 0; 238 const char *name = ""; 239 240 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 241 I2C_FUNC_SMBUS_WORD_DATA)) 242 goto exit; 243 244 /* OK. For now, we presume we have a valid client. We now create the 245 client structure, even though we cannot fill it completely yet. 246 But it allows us to access lm77_{read,write}_value. */ 247 if (!(data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL))) { 248 err = -ENOMEM; 249 goto exit; 250 } 251 252 new_client = &data->client; 253 i2c_set_clientdata(new_client, data); 254 new_client->addr = address; 255 new_client->adapter = adapter; 256 new_client->driver = &lm77_driver; 257 new_client->flags = 0; 258 259 /* Here comes the remaining detection. Since the LM77 has no 260 register dedicated to identification, we have to rely on the 261 following tricks: 262 263 1. the high 4 bits represent the sign and thus they should 264 always be the same 265 2. the high 3 bits are unused in the configuration register 266 3. addresses 0x06 and 0x07 return the last read value 267 4. registers cycling over 8-address boundaries 268 269 Word-sized registers are high-byte first. */ 270 if (kind < 0) { 271 int i, cur, conf, hyst, crit, min, max; 272 273 /* addresses cycling */ 274 cur = i2c_smbus_read_word_data(new_client, 0); 275 conf = i2c_smbus_read_byte_data(new_client, 1); 276 hyst = i2c_smbus_read_word_data(new_client, 2); 277 crit = i2c_smbus_read_word_data(new_client, 3); 278 min = i2c_smbus_read_word_data(new_client, 4); 279 max = i2c_smbus_read_word_data(new_client, 5); 280 for (i = 8; i <= 0xff; i += 8) 281 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 282 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 283 || i2c_smbus_read_word_data(new_client, i + 3) != crit 284 || i2c_smbus_read_word_data(new_client, i + 4) != min 285 || i2c_smbus_read_word_data(new_client, i + 5) != max) 286 goto exit_free; 287 288 /* sign bits */ 289 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) 290 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) 291 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) 292 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) 293 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) 294 goto exit_free; 295 296 /* unused bits */ 297 if (conf & 0xe0) 298 goto exit_free; 299 300 /* 0x06 and 0x07 return the last read value */ 301 cur = i2c_smbus_read_word_data(new_client, 0); 302 if (i2c_smbus_read_word_data(new_client, 6) != cur 303 || i2c_smbus_read_word_data(new_client, 7) != cur) 304 goto exit_free; 305 hyst = i2c_smbus_read_word_data(new_client, 2); 306 if (i2c_smbus_read_word_data(new_client, 6) != hyst 307 || i2c_smbus_read_word_data(new_client, 7) != hyst) 308 goto exit_free; 309 min = i2c_smbus_read_word_data(new_client, 4); 310 if (i2c_smbus_read_word_data(new_client, 6) != min 311 || i2c_smbus_read_word_data(new_client, 7) != min) 312 goto exit_free; 313 314 } 315 316 /* Determine the chip type - only one kind supported! */ 317 if (kind <= 0) 318 kind = lm77; 319 320 if (kind == lm77) { 321 name = "lm77"; 322 } 323 324 /* Fill in the remaining client fields and put it into the global list */ 325 strlcpy(new_client->name, name, I2C_NAME_SIZE); 326 data->valid = 0; 327 mutex_init(&data->update_lock); 328 329 /* Tell the I2C layer a new client has arrived */ 330 if ((err = i2c_attach_client(new_client))) 331 goto exit_free; 332 333 /* Initialize the LM77 chip */ 334 lm77_init_client(new_client); 335 336 /* Register sysfs hooks */ 337 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group))) 338 goto exit_detach; 339 340 data->class_dev = hwmon_device_register(&new_client->dev); 341 if (IS_ERR(data->class_dev)) { 342 err = PTR_ERR(data->class_dev); 343 goto exit_remove; 344 } 345 346 return 0; 347 348 exit_remove: 349 sysfs_remove_group(&new_client->dev.kobj, &lm77_group); 350 exit_detach: 351 i2c_detach_client(new_client); 352 exit_free: 353 kfree(data); 354 exit: 355 return err; 356 } 357 358 static int lm77_detach_client(struct i2c_client *client) 359 { 360 struct lm77_data *data = i2c_get_clientdata(client); 361 hwmon_device_unregister(data->class_dev); 362 sysfs_remove_group(&client->dev.kobj, &lm77_group); 363 i2c_detach_client(client); 364 kfree(data); 365 return 0; 366 } 367 368 /* All registers are word-sized, except for the configuration register. 369 The LM77 uses the high-byte first convention. */ 370 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 371 { 372 if (reg == LM77_REG_CONF) 373 return i2c_smbus_read_byte_data(client, reg); 374 else 375 return swab16(i2c_smbus_read_word_data(client, reg)); 376 } 377 378 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 379 { 380 if (reg == LM77_REG_CONF) 381 return i2c_smbus_write_byte_data(client, reg, value); 382 else 383 return i2c_smbus_write_word_data(client, reg, swab16(value)); 384 } 385 386 static void lm77_init_client(struct i2c_client *client) 387 { 388 /* Initialize the LM77 chip - turn off shutdown mode */ 389 int conf = lm77_read_value(client, LM77_REG_CONF); 390 if (conf & 1) 391 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 392 } 393 394 static struct lm77_data *lm77_update_device(struct device *dev) 395 { 396 struct i2c_client *client = to_i2c_client(dev); 397 struct lm77_data *data = i2c_get_clientdata(client); 398 399 mutex_lock(&data->update_lock); 400 401 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 402 || !data->valid) { 403 dev_dbg(&client->dev, "Starting lm77 update\n"); 404 data->temp_input = 405 LM77_TEMP_FROM_REG(lm77_read_value(client, 406 LM77_REG_TEMP)); 407 data->temp_hyst = 408 LM77_TEMP_FROM_REG(lm77_read_value(client, 409 LM77_REG_TEMP_HYST)); 410 data->temp_crit = 411 LM77_TEMP_FROM_REG(lm77_read_value(client, 412 LM77_REG_TEMP_CRIT)); 413 data->temp_min = 414 LM77_TEMP_FROM_REG(lm77_read_value(client, 415 LM77_REG_TEMP_MIN)); 416 data->temp_max = 417 LM77_TEMP_FROM_REG(lm77_read_value(client, 418 LM77_REG_TEMP_MAX)); 419 data->alarms = 420 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 421 data->last_updated = jiffies; 422 data->valid = 1; 423 } 424 425 mutex_unlock(&data->update_lock); 426 427 return data; 428 } 429 430 static int __init sensors_lm77_init(void) 431 { 432 return i2c_add_driver(&lm77_driver); 433 } 434 435 static void __exit sensors_lm77_exit(void) 436 { 437 i2c_del_driver(&lm77_driver); 438 } 439 440 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 441 MODULE_DESCRIPTION("LM77 driver"); 442 MODULE_LICENSE("GPL"); 443 444 module_init(sensors_lm77_init); 445 module_exit(sensors_lm77_exit); 446