1 /* 2 * lm75.c - Part of lm_sensors, Linux kernel modules for hardware 3 * monitoring 4 * Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #include <linux/module.h> 22 #include <linux/init.h> 23 #include <linux/slab.h> 24 #include <linux/jiffies.h> 25 #include <linux/i2c.h> 26 #include <linux/hwmon.h> 27 #include <linux/hwmon-sysfs.h> 28 #include <linux/err.h> 29 #include <linux/mutex.h> 30 #include "lm75.h" 31 32 33 /* 34 * This driver handles the LM75 and compatible digital temperature sensors. 35 */ 36 37 enum lm75_type { /* keep sorted in alphabetical order */ 38 adt75, 39 ds1775, 40 ds75, 41 lm75, 42 lm75a, 43 max6625, 44 max6626, 45 mcp980x, 46 stds75, 47 tcn75, 48 tmp100, 49 tmp101, 50 tmp105, 51 tmp175, 52 tmp275, 53 tmp75, 54 }; 55 56 /* Addresses scanned */ 57 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 58 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; 59 60 61 /* The LM75 registers */ 62 #define LM75_REG_CONF 0x01 63 static const u8 LM75_REG_TEMP[3] = { 64 0x00, /* input */ 65 0x03, /* max */ 66 0x02, /* hyst */ 67 }; 68 69 /* Each client has this additional data */ 70 struct lm75_data { 71 struct device *hwmon_dev; 72 struct mutex update_lock; 73 u8 orig_conf; 74 char valid; /* !=0 if registers are valid */ 75 unsigned long last_updated; /* In jiffies */ 76 u16 temp[3]; /* Register values, 77 0 = input 78 1 = max 79 2 = hyst */ 80 }; 81 82 static int lm75_read_value(struct i2c_client *client, u8 reg); 83 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); 84 static struct lm75_data *lm75_update_device(struct device *dev); 85 86 87 /*-----------------------------------------------------------------------*/ 88 89 /* sysfs attributes for hwmon */ 90 91 static ssize_t show_temp(struct device *dev, struct device_attribute *da, 92 char *buf) 93 { 94 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 95 struct lm75_data *data = lm75_update_device(dev); 96 return sprintf(buf, "%d\n", 97 LM75_TEMP_FROM_REG(data->temp[attr->index])); 98 } 99 100 static ssize_t set_temp(struct device *dev, struct device_attribute *da, 101 const char *buf, size_t count) 102 { 103 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 104 struct i2c_client *client = to_i2c_client(dev); 105 struct lm75_data *data = i2c_get_clientdata(client); 106 int nr = attr->index; 107 long temp; 108 int error; 109 110 error = strict_strtol(buf, 10, &temp); 111 if (error) 112 return error; 113 114 mutex_lock(&data->update_lock); 115 data->temp[nr] = LM75_TEMP_TO_REG(temp); 116 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); 117 mutex_unlock(&data->update_lock); 118 return count; 119 } 120 121 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 122 show_temp, set_temp, 1); 123 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, 124 show_temp, set_temp, 2); 125 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); 126 127 static struct attribute *lm75_attributes[] = { 128 &sensor_dev_attr_temp1_input.dev_attr.attr, 129 &sensor_dev_attr_temp1_max.dev_attr.attr, 130 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 131 132 NULL 133 }; 134 135 static const struct attribute_group lm75_group = { 136 .attrs = lm75_attributes, 137 }; 138 139 /*-----------------------------------------------------------------------*/ 140 141 /* device probe and removal */ 142 143 static int 144 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id) 145 { 146 struct lm75_data *data; 147 int status; 148 u8 set_mask, clr_mask; 149 int new; 150 151 if (!i2c_check_functionality(client->adapter, 152 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 153 return -EIO; 154 155 data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL); 156 if (!data) 157 return -ENOMEM; 158 159 i2c_set_clientdata(client, data); 160 mutex_init(&data->update_lock); 161 162 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range. 163 * Then tweak to be more precise when appropriate. 164 */ 165 set_mask = 0; 166 clr_mask = (1 << 0) /* continuous conversions */ 167 | (1 << 6) | (1 << 5); /* 9-bit mode */ 168 169 /* configure as specified */ 170 status = lm75_read_value(client, LM75_REG_CONF); 171 if (status < 0) { 172 dev_dbg(&client->dev, "Can't read config? %d\n", status); 173 goto exit_free; 174 } 175 data->orig_conf = status; 176 new = status & ~clr_mask; 177 new |= set_mask; 178 if (status != new) 179 lm75_write_value(client, LM75_REG_CONF, new); 180 dev_dbg(&client->dev, "Config %02x\n", new); 181 182 /* Register sysfs hooks */ 183 status = sysfs_create_group(&client->dev.kobj, &lm75_group); 184 if (status) 185 goto exit_free; 186 187 data->hwmon_dev = hwmon_device_register(&client->dev); 188 if (IS_ERR(data->hwmon_dev)) { 189 status = PTR_ERR(data->hwmon_dev); 190 goto exit_remove; 191 } 192 193 dev_info(&client->dev, "%s: sensor '%s'\n", 194 dev_name(data->hwmon_dev), client->name); 195 196 return 0; 197 198 exit_remove: 199 sysfs_remove_group(&client->dev.kobj, &lm75_group); 200 exit_free: 201 kfree(data); 202 return status; 203 } 204 205 static int lm75_remove(struct i2c_client *client) 206 { 207 struct lm75_data *data = i2c_get_clientdata(client); 208 209 hwmon_device_unregister(data->hwmon_dev); 210 sysfs_remove_group(&client->dev.kobj, &lm75_group); 211 lm75_write_value(client, LM75_REG_CONF, data->orig_conf); 212 kfree(data); 213 return 0; 214 } 215 216 static const struct i2c_device_id lm75_ids[] = { 217 { "adt75", adt75, }, 218 { "ds1775", ds1775, }, 219 { "ds75", ds75, }, 220 { "lm75", lm75, }, 221 { "lm75a", lm75a, }, 222 { "max6625", max6625, }, 223 { "max6626", max6626, }, 224 { "mcp980x", mcp980x, }, 225 { "stds75", stds75, }, 226 { "tcn75", tcn75, }, 227 { "tmp100", tmp100, }, 228 { "tmp101", tmp101, }, 229 { "tmp105", tmp105, }, 230 { "tmp175", tmp175, }, 231 { "tmp275", tmp275, }, 232 { "tmp75", tmp75, }, 233 { /* LIST END */ } 234 }; 235 MODULE_DEVICE_TABLE(i2c, lm75_ids); 236 237 #define LM75A_ID 0xA1 238 239 /* Return 0 if detection is successful, -ENODEV otherwise */ 240 static int lm75_detect(struct i2c_client *new_client, 241 struct i2c_board_info *info) 242 { 243 struct i2c_adapter *adapter = new_client->adapter; 244 int i; 245 int conf, hyst, os; 246 bool is_lm75a = 0; 247 248 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 249 I2C_FUNC_SMBUS_WORD_DATA)) 250 return -ENODEV; 251 252 /* 253 * Now, we do the remaining detection. There is no identification- 254 * dedicated register so we have to rely on several tricks: 255 * unused bits, registers cycling over 8-address boundaries, 256 * addresses 0x04-0x07 returning the last read value. 257 * The cycling+unused addresses combination is not tested, 258 * since it would significantly slow the detection down and would 259 * hardly add any value. 260 * 261 * The National Semiconductor LM75A is different than earlier 262 * LM75s. It has an ID byte of 0xaX (where X is the chip 263 * revision, with 1 being the only revision in existence) in 264 * register 7, and unused registers return 0xff rather than the 265 * last read value. 266 * 267 * Note that this function only detects the original National 268 * Semiconductor LM75 and the LM75A. Clones from other vendors 269 * aren't detected, on purpose, because they are typically never 270 * found on PC hardware. They are found on embedded designs where 271 * they can be instantiated explicitly so detection is not needed. 272 * The absence of identification registers on all these clones 273 * would make their exhaustive detection very difficult and weak, 274 * and odds are that the driver would bind to unsupported devices. 275 */ 276 277 /* Unused bits */ 278 conf = i2c_smbus_read_byte_data(new_client, 1); 279 if (conf & 0xe0) 280 return -ENODEV; 281 282 /* First check for LM75A */ 283 if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) { 284 /* LM75A returns 0xff on unused registers so 285 just to be sure we check for that too. */ 286 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff 287 || i2c_smbus_read_byte_data(new_client, 5) != 0xff 288 || i2c_smbus_read_byte_data(new_client, 6) != 0xff) 289 return -ENODEV; 290 is_lm75a = 1; 291 hyst = i2c_smbus_read_byte_data(new_client, 2); 292 os = i2c_smbus_read_byte_data(new_client, 3); 293 } else { /* Traditional style LM75 detection */ 294 /* Unused addresses */ 295 hyst = i2c_smbus_read_byte_data(new_client, 2); 296 if (i2c_smbus_read_byte_data(new_client, 4) != hyst 297 || i2c_smbus_read_byte_data(new_client, 5) != hyst 298 || i2c_smbus_read_byte_data(new_client, 6) != hyst 299 || i2c_smbus_read_byte_data(new_client, 7) != hyst) 300 return -ENODEV; 301 os = i2c_smbus_read_byte_data(new_client, 3); 302 if (i2c_smbus_read_byte_data(new_client, 4) != os 303 || i2c_smbus_read_byte_data(new_client, 5) != os 304 || i2c_smbus_read_byte_data(new_client, 6) != os 305 || i2c_smbus_read_byte_data(new_client, 7) != os) 306 return -ENODEV; 307 } 308 309 /* Addresses cycling */ 310 for (i = 8; i <= 248; i += 40) { 311 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 312 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst 313 || i2c_smbus_read_byte_data(new_client, i + 3) != os) 314 return -ENODEV; 315 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7) 316 != LM75A_ID) 317 return -ENODEV; 318 } 319 320 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); 321 322 return 0; 323 } 324 325 #ifdef CONFIG_PM 326 static int lm75_suspend(struct device *dev) 327 { 328 int status; 329 struct i2c_client *client = to_i2c_client(dev); 330 status = lm75_read_value(client, LM75_REG_CONF); 331 if (status < 0) { 332 dev_dbg(&client->dev, "Can't read config? %d\n", status); 333 return status; 334 } 335 status = status | LM75_SHUTDOWN; 336 lm75_write_value(client, LM75_REG_CONF, status); 337 return 0; 338 } 339 340 static int lm75_resume(struct device *dev) 341 { 342 int status; 343 struct i2c_client *client = to_i2c_client(dev); 344 status = lm75_read_value(client, LM75_REG_CONF); 345 if (status < 0) { 346 dev_dbg(&client->dev, "Can't read config? %d\n", status); 347 return status; 348 } 349 status = status & ~LM75_SHUTDOWN; 350 lm75_write_value(client, LM75_REG_CONF, status); 351 return 0; 352 } 353 354 static const struct dev_pm_ops lm75_dev_pm_ops = { 355 .suspend = lm75_suspend, 356 .resume = lm75_resume, 357 }; 358 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops) 359 #else 360 #define LM75_DEV_PM_OPS NULL 361 #endif /* CONFIG_PM */ 362 363 static struct i2c_driver lm75_driver = { 364 .class = I2C_CLASS_HWMON, 365 .driver = { 366 .name = "lm75", 367 .pm = LM75_DEV_PM_OPS, 368 }, 369 .probe = lm75_probe, 370 .remove = lm75_remove, 371 .id_table = lm75_ids, 372 .detect = lm75_detect, 373 .address_list = normal_i2c, 374 }; 375 376 /*-----------------------------------------------------------------------*/ 377 378 /* register access */ 379 380 /* 381 * All registers are word-sized, except for the configuration register. 382 * LM75 uses a high-byte first convention, which is exactly opposite to 383 * the SMBus standard. 384 */ 385 static int lm75_read_value(struct i2c_client *client, u8 reg) 386 { 387 int value; 388 389 if (reg == LM75_REG_CONF) 390 return i2c_smbus_read_byte_data(client, reg); 391 392 value = i2c_smbus_read_word_data(client, reg); 393 return (value < 0) ? value : swab16(value); 394 } 395 396 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 397 { 398 if (reg == LM75_REG_CONF) 399 return i2c_smbus_write_byte_data(client, reg, value); 400 else 401 return i2c_smbus_write_word_data(client, reg, swab16(value)); 402 } 403 404 static struct lm75_data *lm75_update_device(struct device *dev) 405 { 406 struct i2c_client *client = to_i2c_client(dev); 407 struct lm75_data *data = i2c_get_clientdata(client); 408 409 mutex_lock(&data->update_lock); 410 411 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 412 || !data->valid) { 413 int i; 414 dev_dbg(&client->dev, "Starting lm75 update\n"); 415 416 for (i = 0; i < ARRAY_SIZE(data->temp); i++) { 417 int status; 418 419 status = lm75_read_value(client, LM75_REG_TEMP[i]); 420 if (status < 0) 421 dev_dbg(&client->dev, "reg %d, err %d\n", 422 LM75_REG_TEMP[i], status); 423 else 424 data->temp[i] = status; 425 } 426 data->last_updated = jiffies; 427 data->valid = 1; 428 } 429 430 mutex_unlock(&data->update_lock); 431 432 return data; 433 } 434 435 /*-----------------------------------------------------------------------*/ 436 437 /* module glue */ 438 439 static int __init sensors_lm75_init(void) 440 { 441 return i2c_add_driver(&lm75_driver); 442 } 443 444 static void __exit sensors_lm75_exit(void) 445 { 446 i2c_del_driver(&lm75_driver); 447 } 448 449 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 450 MODULE_DESCRIPTION("LM75 driver"); 451 MODULE_LICENSE("GPL"); 452 453 module_init(sensors_lm75_init); 454 module_exit(sensors_lm75_exit); 455