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 ds1775, 39 ds75, 40 lm75, 41 lm75a, 42 max6625, 43 max6626, 44 mcp980x, 45 stds75, 46 tcn75, 47 tmp100, 48 tmp101, 49 tmp105, 50 tmp175, 51 tmp275, 52 tmp75, 53 }; 54 55 /* Addresses scanned */ 56 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 57 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; 58 59 60 /* The LM75 registers */ 61 #define LM75_REG_CONF 0x01 62 static const u8 LM75_REG_TEMP[3] = { 63 0x00, /* input */ 64 0x03, /* max */ 65 0x02, /* hyst */ 66 }; 67 68 /* Each client has this additional data */ 69 struct lm75_data { 70 struct device *hwmon_dev; 71 struct mutex update_lock; 72 u8 orig_conf; 73 char valid; /* !=0 if registers are valid */ 74 unsigned long last_updated; /* In jiffies */ 75 u16 temp[3]; /* Register values, 76 0 = input 77 1 = max 78 2 = hyst */ 79 }; 80 81 static int lm75_read_value(struct i2c_client *client, u8 reg); 82 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); 83 static struct lm75_data *lm75_update_device(struct device *dev); 84 85 86 /*-----------------------------------------------------------------------*/ 87 88 /* sysfs attributes for hwmon */ 89 90 static ssize_t show_temp(struct device *dev, struct device_attribute *da, 91 char *buf) 92 { 93 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 94 struct lm75_data *data = lm75_update_device(dev); 95 return sprintf(buf, "%d\n", 96 LM75_TEMP_FROM_REG(data->temp[attr->index])); 97 } 98 99 static ssize_t set_temp(struct device *dev, struct device_attribute *da, 100 const char *buf, size_t count) 101 { 102 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 103 struct i2c_client *client = to_i2c_client(dev); 104 struct lm75_data *data = i2c_get_clientdata(client); 105 int nr = attr->index; 106 long temp; 107 int error; 108 109 error = strict_strtol(buf, 10, &temp); 110 if (error) 111 return error; 112 113 mutex_lock(&data->update_lock); 114 data->temp[nr] = LM75_TEMP_TO_REG(temp); 115 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); 116 mutex_unlock(&data->update_lock); 117 return count; 118 } 119 120 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 121 show_temp, set_temp, 1); 122 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, 123 show_temp, set_temp, 2); 124 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); 125 126 static struct attribute *lm75_attributes[] = { 127 &sensor_dev_attr_temp1_input.dev_attr.attr, 128 &sensor_dev_attr_temp1_max.dev_attr.attr, 129 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 130 131 NULL 132 }; 133 134 static const struct attribute_group lm75_group = { 135 .attrs = lm75_attributes, 136 }; 137 138 /*-----------------------------------------------------------------------*/ 139 140 /* device probe and removal */ 141 142 static int 143 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id) 144 { 145 struct lm75_data *data; 146 int status; 147 u8 set_mask, clr_mask; 148 int new; 149 150 if (!i2c_check_functionality(client->adapter, 151 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 152 return -EIO; 153 154 data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL); 155 if (!data) 156 return -ENOMEM; 157 158 i2c_set_clientdata(client, data); 159 mutex_init(&data->update_lock); 160 161 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range. 162 * Then tweak to be more precise when appropriate. 163 */ 164 set_mask = 0; 165 clr_mask = (1 << 0) /* continuous conversions */ 166 | (1 << 6) | (1 << 5); /* 9-bit mode */ 167 168 /* configure as specified */ 169 status = lm75_read_value(client, LM75_REG_CONF); 170 if (status < 0) { 171 dev_dbg(&client->dev, "Can't read config? %d\n", status); 172 goto exit_free; 173 } 174 data->orig_conf = status; 175 new = status & ~clr_mask; 176 new |= set_mask; 177 if (status != new) 178 lm75_write_value(client, LM75_REG_CONF, new); 179 dev_dbg(&client->dev, "Config %02x\n", new); 180 181 /* Register sysfs hooks */ 182 status = sysfs_create_group(&client->dev.kobj, &lm75_group); 183 if (status) 184 goto exit_free; 185 186 data->hwmon_dev = hwmon_device_register(&client->dev); 187 if (IS_ERR(data->hwmon_dev)) { 188 status = PTR_ERR(data->hwmon_dev); 189 goto exit_remove; 190 } 191 192 dev_info(&client->dev, "%s: sensor '%s'\n", 193 dev_name(data->hwmon_dev), client->name); 194 195 return 0; 196 197 exit_remove: 198 sysfs_remove_group(&client->dev.kobj, &lm75_group); 199 exit_free: 200 kfree(data); 201 return status; 202 } 203 204 static int lm75_remove(struct i2c_client *client) 205 { 206 struct lm75_data *data = i2c_get_clientdata(client); 207 208 hwmon_device_unregister(data->hwmon_dev); 209 sysfs_remove_group(&client->dev.kobj, &lm75_group); 210 lm75_write_value(client, LM75_REG_CONF, data->orig_conf); 211 kfree(data); 212 return 0; 213 } 214 215 static const struct i2c_device_id lm75_ids[] = { 216 { "ds1775", ds1775, }, 217 { "ds75", ds75, }, 218 { "lm75", lm75, }, 219 { "lm75a", lm75a, }, 220 { "max6625", max6625, }, 221 { "max6626", max6626, }, 222 { "mcp980x", mcp980x, }, 223 { "stds75", stds75, }, 224 { "tcn75", tcn75, }, 225 { "tmp100", tmp100, }, 226 { "tmp101", tmp101, }, 227 { "tmp105", tmp105, }, 228 { "tmp175", tmp175, }, 229 { "tmp275", tmp275, }, 230 { "tmp75", tmp75, }, 231 { /* LIST END */ } 232 }; 233 MODULE_DEVICE_TABLE(i2c, lm75_ids); 234 235 /* Return 0 if detection is successful, -ENODEV otherwise */ 236 static int lm75_detect(struct i2c_client *new_client, 237 struct i2c_board_info *info) 238 { 239 struct i2c_adapter *adapter = new_client->adapter; 240 int i; 241 int cur, conf, hyst, os; 242 243 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 244 I2C_FUNC_SMBUS_WORD_DATA)) 245 return -ENODEV; 246 247 /* Now, we do the remaining detection. There is no identification- 248 dedicated register so we have to rely on several tricks: 249 unused bits, registers cycling over 8-address boundaries, 250 addresses 0x04-0x07 returning the last read value. 251 The cycling+unused addresses combination is not tested, 252 since it would significantly slow the detection down and would 253 hardly add any value. */ 254 255 /* Unused addresses */ 256 cur = i2c_smbus_read_word_data(new_client, 0); 257 conf = i2c_smbus_read_byte_data(new_client, 1); 258 hyst = i2c_smbus_read_word_data(new_client, 2); 259 if (i2c_smbus_read_word_data(new_client, 4) != hyst 260 || i2c_smbus_read_word_data(new_client, 5) != hyst 261 || i2c_smbus_read_word_data(new_client, 6) != hyst 262 || i2c_smbus_read_word_data(new_client, 7) != hyst) 263 return -ENODEV; 264 os = i2c_smbus_read_word_data(new_client, 3); 265 if (i2c_smbus_read_word_data(new_client, 4) != os 266 || i2c_smbus_read_word_data(new_client, 5) != os 267 || i2c_smbus_read_word_data(new_client, 6) != os 268 || i2c_smbus_read_word_data(new_client, 7) != os) 269 return -ENODEV; 270 271 /* Unused bits */ 272 if (conf & 0xe0) 273 return -ENODEV; 274 275 /* Addresses cycling */ 276 for (i = 8; i < 0xff; i += 8) { 277 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 278 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 279 || i2c_smbus_read_word_data(new_client, i + 3) != os) 280 return -ENODEV; 281 } 282 283 strlcpy(info->type, "lm75", I2C_NAME_SIZE); 284 285 return 0; 286 } 287 288 #ifdef CONFIG_PM 289 static int lm75_suspend(struct device *dev) 290 { 291 int status; 292 struct i2c_client *client = to_i2c_client(dev); 293 status = lm75_read_value(client, LM75_REG_CONF); 294 if (status < 0) { 295 dev_dbg(&client->dev, "Can't read config? %d\n", status); 296 return status; 297 } 298 status = status | LM75_SHUTDOWN; 299 lm75_write_value(client, LM75_REG_CONF, status); 300 return 0; 301 } 302 303 static int lm75_resume(struct device *dev) 304 { 305 int status; 306 struct i2c_client *client = to_i2c_client(dev); 307 status = lm75_read_value(client, LM75_REG_CONF); 308 if (status < 0) { 309 dev_dbg(&client->dev, "Can't read config? %d\n", status); 310 return status; 311 } 312 status = status & ~LM75_SHUTDOWN; 313 lm75_write_value(client, LM75_REG_CONF, status); 314 return 0; 315 } 316 317 static const struct dev_pm_ops lm75_dev_pm_ops = { 318 .suspend = lm75_suspend, 319 .resume = lm75_resume, 320 }; 321 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops) 322 #else 323 #define LM75_DEV_PM_OPS NULL 324 #endif /* CONFIG_PM */ 325 326 static struct i2c_driver lm75_driver = { 327 .class = I2C_CLASS_HWMON, 328 .driver = { 329 .name = "lm75", 330 .pm = LM75_DEV_PM_OPS, 331 }, 332 .probe = lm75_probe, 333 .remove = lm75_remove, 334 .id_table = lm75_ids, 335 .detect = lm75_detect, 336 .address_list = normal_i2c, 337 }; 338 339 /*-----------------------------------------------------------------------*/ 340 341 /* register access */ 342 343 /* 344 * All registers are word-sized, except for the configuration register. 345 * LM75 uses a high-byte first convention, which is exactly opposite to 346 * the SMBus standard. 347 */ 348 static int lm75_read_value(struct i2c_client *client, u8 reg) 349 { 350 int value; 351 352 if (reg == LM75_REG_CONF) 353 return i2c_smbus_read_byte_data(client, reg); 354 355 value = i2c_smbus_read_word_data(client, reg); 356 return (value < 0) ? value : swab16(value); 357 } 358 359 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 360 { 361 if (reg == LM75_REG_CONF) 362 return i2c_smbus_write_byte_data(client, reg, value); 363 else 364 return i2c_smbus_write_word_data(client, reg, swab16(value)); 365 } 366 367 static struct lm75_data *lm75_update_device(struct device *dev) 368 { 369 struct i2c_client *client = to_i2c_client(dev); 370 struct lm75_data *data = i2c_get_clientdata(client); 371 372 mutex_lock(&data->update_lock); 373 374 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 375 || !data->valid) { 376 int i; 377 dev_dbg(&client->dev, "Starting lm75 update\n"); 378 379 for (i = 0; i < ARRAY_SIZE(data->temp); i++) { 380 int status; 381 382 status = lm75_read_value(client, LM75_REG_TEMP[i]); 383 if (status < 0) 384 dev_dbg(&client->dev, "reg %d, err %d\n", 385 LM75_REG_TEMP[i], status); 386 else 387 data->temp[i] = status; 388 } 389 data->last_updated = jiffies; 390 data->valid = 1; 391 } 392 393 mutex_unlock(&data->update_lock); 394 395 return data; 396 } 397 398 /*-----------------------------------------------------------------------*/ 399 400 /* module glue */ 401 402 static int __init sensors_lm75_init(void) 403 { 404 return i2c_add_driver(&lm75_driver); 405 } 406 407 static void __exit sensors_lm75_exit(void) 408 { 409 i2c_del_driver(&lm75_driver); 410 } 411 412 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 413 MODULE_DESCRIPTION("LM75 driver"); 414 MODULE_LICENSE("GPL"); 415 416 module_init(sensors_lm75_init); 417 module_exit(sensors_lm75_exit); 418