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 97 if (IS_ERR(data)) 98 return PTR_ERR(data); 99 100 return sprintf(buf, "%d\n", 101 LM75_TEMP_FROM_REG(data->temp[attr->index])); 102 } 103 104 static ssize_t set_temp(struct device *dev, struct device_attribute *da, 105 const char *buf, size_t count) 106 { 107 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 108 struct i2c_client *client = to_i2c_client(dev); 109 struct lm75_data *data = i2c_get_clientdata(client); 110 int nr = attr->index; 111 long temp; 112 int error; 113 114 error = kstrtol(buf, 10, &temp); 115 if (error) 116 return error; 117 118 mutex_lock(&data->update_lock); 119 data->temp[nr] = LM75_TEMP_TO_REG(temp); 120 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); 121 mutex_unlock(&data->update_lock); 122 return count; 123 } 124 125 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 126 show_temp, set_temp, 1); 127 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, 128 show_temp, set_temp, 2); 129 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); 130 131 static struct attribute *lm75_attributes[] = { 132 &sensor_dev_attr_temp1_input.dev_attr.attr, 133 &sensor_dev_attr_temp1_max.dev_attr.attr, 134 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 135 136 NULL 137 }; 138 139 static const struct attribute_group lm75_group = { 140 .attrs = lm75_attributes, 141 }; 142 143 /*-----------------------------------------------------------------------*/ 144 145 /* device probe and removal */ 146 147 static int 148 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id) 149 { 150 struct lm75_data *data; 151 int status; 152 u8 set_mask, clr_mask; 153 int new; 154 155 if (!i2c_check_functionality(client->adapter, 156 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 157 return -EIO; 158 159 data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL); 160 if (!data) 161 return -ENOMEM; 162 163 i2c_set_clientdata(client, data); 164 mutex_init(&data->update_lock); 165 166 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range. 167 * Then tweak to be more precise when appropriate. 168 */ 169 set_mask = 0; 170 clr_mask = (1 << 0) /* continuous conversions */ 171 | (1 << 6) | (1 << 5); /* 9-bit mode */ 172 173 /* configure as specified */ 174 status = lm75_read_value(client, LM75_REG_CONF); 175 if (status < 0) { 176 dev_dbg(&client->dev, "Can't read config? %d\n", status); 177 goto exit_free; 178 } 179 data->orig_conf = status; 180 new = status & ~clr_mask; 181 new |= set_mask; 182 if (status != new) 183 lm75_write_value(client, LM75_REG_CONF, new); 184 dev_dbg(&client->dev, "Config %02x\n", new); 185 186 /* Register sysfs hooks */ 187 status = sysfs_create_group(&client->dev.kobj, &lm75_group); 188 if (status) 189 goto exit_free; 190 191 data->hwmon_dev = hwmon_device_register(&client->dev); 192 if (IS_ERR(data->hwmon_dev)) { 193 status = PTR_ERR(data->hwmon_dev); 194 goto exit_remove; 195 } 196 197 dev_info(&client->dev, "%s: sensor '%s'\n", 198 dev_name(data->hwmon_dev), client->name); 199 200 return 0; 201 202 exit_remove: 203 sysfs_remove_group(&client->dev.kobj, &lm75_group); 204 exit_free: 205 kfree(data); 206 return status; 207 } 208 209 static int lm75_remove(struct i2c_client *client) 210 { 211 struct lm75_data *data = i2c_get_clientdata(client); 212 213 hwmon_device_unregister(data->hwmon_dev); 214 sysfs_remove_group(&client->dev.kobj, &lm75_group); 215 lm75_write_value(client, LM75_REG_CONF, data->orig_conf); 216 kfree(data); 217 return 0; 218 } 219 220 static const struct i2c_device_id lm75_ids[] = { 221 { "adt75", adt75, }, 222 { "ds1775", ds1775, }, 223 { "ds75", ds75, }, 224 { "lm75", lm75, }, 225 { "lm75a", lm75a, }, 226 { "max6625", max6625, }, 227 { "max6626", max6626, }, 228 { "mcp980x", mcp980x, }, 229 { "stds75", stds75, }, 230 { "tcn75", tcn75, }, 231 { "tmp100", tmp100, }, 232 { "tmp101", tmp101, }, 233 { "tmp105", tmp105, }, 234 { "tmp175", tmp175, }, 235 { "tmp275", tmp275, }, 236 { "tmp75", tmp75, }, 237 { /* LIST END */ } 238 }; 239 MODULE_DEVICE_TABLE(i2c, lm75_ids); 240 241 #define LM75A_ID 0xA1 242 243 /* Return 0 if detection is successful, -ENODEV otherwise */ 244 static int lm75_detect(struct i2c_client *new_client, 245 struct i2c_board_info *info) 246 { 247 struct i2c_adapter *adapter = new_client->adapter; 248 int i; 249 int conf, hyst, os; 250 bool is_lm75a = 0; 251 252 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 253 I2C_FUNC_SMBUS_WORD_DATA)) 254 return -ENODEV; 255 256 /* 257 * Now, we do the remaining detection. There is no identification- 258 * dedicated register so we have to rely on several tricks: 259 * unused bits, registers cycling over 8-address boundaries, 260 * addresses 0x04-0x07 returning the last read value. 261 * The cycling+unused addresses combination is not tested, 262 * since it would significantly slow the detection down and would 263 * hardly add any value. 264 * 265 * The National Semiconductor LM75A is different than earlier 266 * LM75s. It has an ID byte of 0xaX (where X is the chip 267 * revision, with 1 being the only revision in existence) in 268 * register 7, and unused registers return 0xff rather than the 269 * last read value. 270 * 271 * Note that this function only detects the original National 272 * Semiconductor LM75 and the LM75A. Clones from other vendors 273 * aren't detected, on purpose, because they are typically never 274 * found on PC hardware. They are found on embedded designs where 275 * they can be instantiated explicitly so detection is not needed. 276 * The absence of identification registers on all these clones 277 * would make their exhaustive detection very difficult and weak, 278 * and odds are that the driver would bind to unsupported devices. 279 */ 280 281 /* Unused bits */ 282 conf = i2c_smbus_read_byte_data(new_client, 1); 283 if (conf & 0xe0) 284 return -ENODEV; 285 286 /* First check for LM75A */ 287 if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) { 288 /* LM75A returns 0xff on unused registers so 289 just to be sure we check for that too. */ 290 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff 291 || i2c_smbus_read_byte_data(new_client, 5) != 0xff 292 || i2c_smbus_read_byte_data(new_client, 6) != 0xff) 293 return -ENODEV; 294 is_lm75a = 1; 295 hyst = i2c_smbus_read_byte_data(new_client, 2); 296 os = i2c_smbus_read_byte_data(new_client, 3); 297 } else { /* Traditional style LM75 detection */ 298 /* Unused addresses */ 299 hyst = i2c_smbus_read_byte_data(new_client, 2); 300 if (i2c_smbus_read_byte_data(new_client, 4) != hyst 301 || i2c_smbus_read_byte_data(new_client, 5) != hyst 302 || i2c_smbus_read_byte_data(new_client, 6) != hyst 303 || i2c_smbus_read_byte_data(new_client, 7) != hyst) 304 return -ENODEV; 305 os = i2c_smbus_read_byte_data(new_client, 3); 306 if (i2c_smbus_read_byte_data(new_client, 4) != os 307 || i2c_smbus_read_byte_data(new_client, 5) != os 308 || i2c_smbus_read_byte_data(new_client, 6) != os 309 || i2c_smbus_read_byte_data(new_client, 7) != os) 310 return -ENODEV; 311 } 312 313 /* Addresses cycling */ 314 for (i = 8; i <= 248; i += 40) { 315 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 316 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst 317 || i2c_smbus_read_byte_data(new_client, i + 3) != os) 318 return -ENODEV; 319 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7) 320 != LM75A_ID) 321 return -ENODEV; 322 } 323 324 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); 325 326 return 0; 327 } 328 329 #ifdef CONFIG_PM 330 static int lm75_suspend(struct device *dev) 331 { 332 int status; 333 struct i2c_client *client = to_i2c_client(dev); 334 status = lm75_read_value(client, LM75_REG_CONF); 335 if (status < 0) { 336 dev_dbg(&client->dev, "Can't read config? %d\n", status); 337 return status; 338 } 339 status = status | LM75_SHUTDOWN; 340 lm75_write_value(client, LM75_REG_CONF, status); 341 return 0; 342 } 343 344 static int lm75_resume(struct device *dev) 345 { 346 int status; 347 struct i2c_client *client = to_i2c_client(dev); 348 status = lm75_read_value(client, LM75_REG_CONF); 349 if (status < 0) { 350 dev_dbg(&client->dev, "Can't read config? %d\n", status); 351 return status; 352 } 353 status = status & ~LM75_SHUTDOWN; 354 lm75_write_value(client, LM75_REG_CONF, status); 355 return 0; 356 } 357 358 static const struct dev_pm_ops lm75_dev_pm_ops = { 359 .suspend = lm75_suspend, 360 .resume = lm75_resume, 361 }; 362 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops) 363 #else 364 #define LM75_DEV_PM_OPS NULL 365 #endif /* CONFIG_PM */ 366 367 static struct i2c_driver lm75_driver = { 368 .class = I2C_CLASS_HWMON, 369 .driver = { 370 .name = "lm75", 371 .pm = LM75_DEV_PM_OPS, 372 }, 373 .probe = lm75_probe, 374 .remove = lm75_remove, 375 .id_table = lm75_ids, 376 .detect = lm75_detect, 377 .address_list = normal_i2c, 378 }; 379 380 /*-----------------------------------------------------------------------*/ 381 382 /* register access */ 383 384 /* 385 * All registers are word-sized, except for the configuration register. 386 * LM75 uses a high-byte first convention, which is exactly opposite to 387 * the SMBus standard. 388 */ 389 static int lm75_read_value(struct i2c_client *client, u8 reg) 390 { 391 if (reg == LM75_REG_CONF) 392 return i2c_smbus_read_byte_data(client, reg); 393 else 394 return i2c_smbus_read_word_swapped(client, reg); 395 } 396 397 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 398 { 399 if (reg == LM75_REG_CONF) 400 return i2c_smbus_write_byte_data(client, reg, value); 401 else 402 return i2c_smbus_write_word_swapped(client, reg, value); 403 } 404 405 static struct lm75_data *lm75_update_device(struct device *dev) 406 { 407 struct i2c_client *client = to_i2c_client(dev); 408 struct lm75_data *data = i2c_get_clientdata(client); 409 struct lm75_data *ret = data; 410 411 mutex_lock(&data->update_lock); 412 413 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 414 || !data->valid) { 415 int i; 416 dev_dbg(&client->dev, "Starting lm75 update\n"); 417 418 for (i = 0; i < ARRAY_SIZE(data->temp); i++) { 419 int status; 420 421 status = lm75_read_value(client, LM75_REG_TEMP[i]); 422 if (unlikely(status < 0)) { 423 dev_dbg(dev, 424 "LM75: Failed to read value: reg %d, error %d\n", 425 LM75_REG_TEMP[i], status); 426 ret = ERR_PTR(status); 427 data->valid = 0; 428 goto abort; 429 } 430 data->temp[i] = status; 431 } 432 data->last_updated = jiffies; 433 data->valid = 1; 434 } 435 436 abort: 437 mutex_unlock(&data->update_lock); 438 return ret; 439 } 440 441 module_i2c_driver(lm75_driver); 442 443 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 444 MODULE_DESCRIPTION("LM75 driver"); 445 MODULE_LICENSE("GPL"); 446