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 = devm_kzalloc(&client->dev, 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 return status; 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 return status; 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 return status; 205 } 206 207 static int lm75_remove(struct i2c_client *client) 208 { 209 struct lm75_data *data = i2c_get_clientdata(client); 210 211 hwmon_device_unregister(data->hwmon_dev); 212 sysfs_remove_group(&client->dev.kobj, &lm75_group); 213 lm75_write_value(client, LM75_REG_CONF, data->orig_conf); 214 return 0; 215 } 216 217 static const struct i2c_device_id lm75_ids[] = { 218 { "adt75", adt75, }, 219 { "ds1775", ds1775, }, 220 { "ds75", ds75, }, 221 { "lm75", lm75, }, 222 { "lm75a", lm75a, }, 223 { "max6625", max6625, }, 224 { "max6626", max6626, }, 225 { "mcp980x", mcp980x, }, 226 { "stds75", stds75, }, 227 { "tcn75", tcn75, }, 228 { "tmp100", tmp100, }, 229 { "tmp101", tmp101, }, 230 { "tmp105", tmp105, }, 231 { "tmp175", tmp175, }, 232 { "tmp275", tmp275, }, 233 { "tmp75", tmp75, }, 234 { /* LIST END */ } 235 }; 236 MODULE_DEVICE_TABLE(i2c, lm75_ids); 237 238 #define LM75A_ID 0xA1 239 240 /* Return 0 if detection is successful, -ENODEV otherwise */ 241 static int lm75_detect(struct i2c_client *new_client, 242 struct i2c_board_info *info) 243 { 244 struct i2c_adapter *adapter = new_client->adapter; 245 int i; 246 int conf, hyst, os; 247 bool is_lm75a = 0; 248 249 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 250 I2C_FUNC_SMBUS_WORD_DATA)) 251 return -ENODEV; 252 253 /* 254 * Now, we do the remaining detection. There is no identification- 255 * dedicated register so we have to rely on several tricks: 256 * unused bits, registers cycling over 8-address boundaries, 257 * addresses 0x04-0x07 returning the last read value. 258 * The cycling+unused addresses combination is not tested, 259 * since it would significantly slow the detection down and would 260 * hardly add any value. 261 * 262 * The National Semiconductor LM75A is different than earlier 263 * LM75s. It has an ID byte of 0xaX (where X is the chip 264 * revision, with 1 being the only revision in existence) in 265 * register 7, and unused registers return 0xff rather than the 266 * last read value. 267 * 268 * Note that this function only detects the original National 269 * Semiconductor LM75 and the LM75A. Clones from other vendors 270 * aren't detected, on purpose, because they are typically never 271 * found on PC hardware. They are found on embedded designs where 272 * they can be instantiated explicitly so detection is not needed. 273 * The absence of identification registers on all these clones 274 * would make their exhaustive detection very difficult and weak, 275 * and odds are that the driver would bind to unsupported devices. 276 */ 277 278 /* Unused bits */ 279 conf = i2c_smbus_read_byte_data(new_client, 1); 280 if (conf & 0xe0) 281 return -ENODEV; 282 283 /* First check for LM75A */ 284 if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) { 285 /* LM75A returns 0xff on unused registers so 286 just to be sure we check for that too. */ 287 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff 288 || i2c_smbus_read_byte_data(new_client, 5) != 0xff 289 || i2c_smbus_read_byte_data(new_client, 6) != 0xff) 290 return -ENODEV; 291 is_lm75a = 1; 292 hyst = i2c_smbus_read_byte_data(new_client, 2); 293 os = i2c_smbus_read_byte_data(new_client, 3); 294 } else { /* Traditional style LM75 detection */ 295 /* Unused addresses */ 296 hyst = i2c_smbus_read_byte_data(new_client, 2); 297 if (i2c_smbus_read_byte_data(new_client, 4) != hyst 298 || i2c_smbus_read_byte_data(new_client, 5) != hyst 299 || i2c_smbus_read_byte_data(new_client, 6) != hyst 300 || i2c_smbus_read_byte_data(new_client, 7) != hyst) 301 return -ENODEV; 302 os = i2c_smbus_read_byte_data(new_client, 3); 303 if (i2c_smbus_read_byte_data(new_client, 4) != os 304 || i2c_smbus_read_byte_data(new_client, 5) != os 305 || i2c_smbus_read_byte_data(new_client, 6) != os 306 || i2c_smbus_read_byte_data(new_client, 7) != os) 307 return -ENODEV; 308 } 309 310 /* Addresses cycling */ 311 for (i = 8; i <= 248; i += 40) { 312 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 313 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst 314 || i2c_smbus_read_byte_data(new_client, i + 3) != os) 315 return -ENODEV; 316 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7) 317 != LM75A_ID) 318 return -ENODEV; 319 } 320 321 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); 322 323 return 0; 324 } 325 326 #ifdef CONFIG_PM 327 static int lm75_suspend(struct device *dev) 328 { 329 int status; 330 struct i2c_client *client = to_i2c_client(dev); 331 status = lm75_read_value(client, LM75_REG_CONF); 332 if (status < 0) { 333 dev_dbg(&client->dev, "Can't read config? %d\n", status); 334 return status; 335 } 336 status = status | LM75_SHUTDOWN; 337 lm75_write_value(client, LM75_REG_CONF, status); 338 return 0; 339 } 340 341 static int lm75_resume(struct device *dev) 342 { 343 int status; 344 struct i2c_client *client = to_i2c_client(dev); 345 status = lm75_read_value(client, LM75_REG_CONF); 346 if (status < 0) { 347 dev_dbg(&client->dev, "Can't read config? %d\n", status); 348 return status; 349 } 350 status = status & ~LM75_SHUTDOWN; 351 lm75_write_value(client, LM75_REG_CONF, status); 352 return 0; 353 } 354 355 static const struct dev_pm_ops lm75_dev_pm_ops = { 356 .suspend = lm75_suspend, 357 .resume = lm75_resume, 358 }; 359 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops) 360 #else 361 #define LM75_DEV_PM_OPS NULL 362 #endif /* CONFIG_PM */ 363 364 static struct i2c_driver lm75_driver = { 365 .class = I2C_CLASS_HWMON, 366 .driver = { 367 .name = "lm75", 368 .pm = LM75_DEV_PM_OPS, 369 }, 370 .probe = lm75_probe, 371 .remove = lm75_remove, 372 .id_table = lm75_ids, 373 .detect = lm75_detect, 374 .address_list = normal_i2c, 375 }; 376 377 /*-----------------------------------------------------------------------*/ 378 379 /* register access */ 380 381 /* 382 * All registers are word-sized, except for the configuration register. 383 * LM75 uses a high-byte first convention, which is exactly opposite to 384 * the SMBus standard. 385 */ 386 static int lm75_read_value(struct i2c_client *client, u8 reg) 387 { 388 if (reg == LM75_REG_CONF) 389 return i2c_smbus_read_byte_data(client, reg); 390 else 391 return i2c_smbus_read_word_swapped(client, reg); 392 } 393 394 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 395 { 396 if (reg == LM75_REG_CONF) 397 return i2c_smbus_write_byte_data(client, reg, value); 398 else 399 return i2c_smbus_write_word_swapped(client, reg, value); 400 } 401 402 static struct lm75_data *lm75_update_device(struct device *dev) 403 { 404 struct i2c_client *client = to_i2c_client(dev); 405 struct lm75_data *data = i2c_get_clientdata(client); 406 struct lm75_data *ret = data; 407 408 mutex_lock(&data->update_lock); 409 410 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 411 || !data->valid) { 412 int i; 413 dev_dbg(&client->dev, "Starting lm75 update\n"); 414 415 for (i = 0; i < ARRAY_SIZE(data->temp); i++) { 416 int status; 417 418 status = lm75_read_value(client, LM75_REG_TEMP[i]); 419 if (unlikely(status < 0)) { 420 dev_dbg(dev, 421 "LM75: Failed to read value: reg %d, error %d\n", 422 LM75_REG_TEMP[i], status); 423 ret = ERR_PTR(status); 424 data->valid = 0; 425 goto abort; 426 } 427 data->temp[i] = status; 428 } 429 data->last_updated = jiffies; 430 data->valid = 1; 431 } 432 433 abort: 434 mutex_unlock(&data->update_lock); 435 return ret; 436 } 437 438 module_i2c_driver(lm75_driver); 439 440 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 441 MODULE_DESCRIPTION("LM75 driver"); 442 MODULE_LICENSE("GPL"); 443