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 * Only types which are _not_ listed in I2C_CLIENT_INSMOD_*() need to be 36 * listed here. We start at 9 since I2C_CLIENT_INSMOD_*() currently allow 37 * definition of up to 8 chip types (plus zero). 38 */ 39 40 enum lm75_type { /* keep sorted in alphabetical order */ 41 ds1775 = 9, 42 ds75, 43 /* lm75 -- in I2C_CLIENT_INSMOD_1() */ 44 lm75a, 45 max6625, 46 max6626, 47 mcp980x, 48 stds75, 49 tcn75, 50 tmp100, 51 tmp101, 52 tmp175, 53 tmp275, 54 tmp75, 55 }; 56 57 /* Addresses scanned */ 58 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 59 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; 60 61 /* Insmod parameters */ 62 I2C_CLIENT_INSMOD_1(lm75); 63 64 65 /* The LM75 registers */ 66 #define LM75_REG_CONF 0x01 67 static const u8 LM75_REG_TEMP[3] = { 68 0x00, /* input */ 69 0x03, /* max */ 70 0x02, /* hyst */ 71 }; 72 73 /* Each client has this additional data */ 74 struct lm75_data { 75 struct device *hwmon_dev; 76 struct mutex update_lock; 77 u8 orig_conf; 78 char valid; /* !=0 if registers are valid */ 79 unsigned long last_updated; /* In jiffies */ 80 u16 temp[3]; /* Register values, 81 0 = input 82 1 = max 83 2 = hyst */ 84 }; 85 86 static int lm75_read_value(struct i2c_client *client, u8 reg); 87 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); 88 static struct lm75_data *lm75_update_device(struct device *dev); 89 90 91 /*-----------------------------------------------------------------------*/ 92 93 /* sysfs attributes for hwmon */ 94 95 static ssize_t show_temp(struct device *dev, struct device_attribute *da, 96 char *buf) 97 { 98 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 99 struct lm75_data *data = lm75_update_device(dev); 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 = simple_strtol(buf, NULL, 10); 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 i2c_set_clientdata(client, NULL); 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 i2c_set_clientdata(client, NULL); 213 kfree(data); 214 return 0; 215 } 216 217 static const struct i2c_device_id lm75_ids[] = { 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 { "tmp175", tmp175, }, 230 { "tmp275", tmp275, }, 231 { "tmp75", tmp75, }, 232 { /* LIST END */ } 233 }; 234 MODULE_DEVICE_TABLE(i2c, lm75_ids); 235 236 /* Return 0 if detection is successful, -ENODEV otherwise */ 237 static int lm75_detect(struct i2c_client *new_client, int kind, 238 struct i2c_board_info *info) 239 { 240 struct i2c_adapter *adapter = new_client->adapter; 241 int i; 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 if (kind < 0) { 255 int cur, conf, hyst, os; 256 257 /* Unused addresses */ 258 cur = i2c_smbus_read_word_data(new_client, 0); 259 conf = i2c_smbus_read_byte_data(new_client, 1); 260 hyst = i2c_smbus_read_word_data(new_client, 2); 261 if (i2c_smbus_read_word_data(new_client, 4) != hyst 262 || i2c_smbus_read_word_data(new_client, 5) != hyst 263 || i2c_smbus_read_word_data(new_client, 6) != hyst 264 || i2c_smbus_read_word_data(new_client, 7) != hyst) 265 return -ENODEV; 266 os = i2c_smbus_read_word_data(new_client, 3); 267 if (i2c_smbus_read_word_data(new_client, 4) != os 268 || i2c_smbus_read_word_data(new_client, 5) != os 269 || i2c_smbus_read_word_data(new_client, 6) != os 270 || i2c_smbus_read_word_data(new_client, 7) != os) 271 return -ENODEV; 272 273 /* Unused bits */ 274 if (conf & 0xe0) 275 return -ENODEV; 276 277 /* Addresses cycling */ 278 for (i = 8; i < 0xff; i += 8) 279 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 280 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 281 || i2c_smbus_read_word_data(new_client, i + 3) != os) 282 return -ENODEV; 283 } 284 285 /* NOTE: we treat "force=..." and "force_lm75=..." the same. 286 * Only new-style driver binding distinguishes chip types. 287 */ 288 strlcpy(info->type, "lm75", I2C_NAME_SIZE); 289 290 return 0; 291 } 292 293 static struct i2c_driver lm75_driver = { 294 .class = I2C_CLASS_HWMON, 295 .driver = { 296 .name = "lm75", 297 }, 298 .probe = lm75_probe, 299 .remove = lm75_remove, 300 .id_table = lm75_ids, 301 .detect = lm75_detect, 302 .address_data = &addr_data, 303 }; 304 305 /*-----------------------------------------------------------------------*/ 306 307 /* register access */ 308 309 /* All registers are word-sized, except for the configuration register. 310 LM75 uses a high-byte first convention, which is exactly opposite to 311 the SMBus standard. */ 312 static int lm75_read_value(struct i2c_client *client, u8 reg) 313 { 314 int value; 315 316 if (reg == LM75_REG_CONF) 317 return i2c_smbus_read_byte_data(client, reg); 318 319 value = i2c_smbus_read_word_data(client, reg); 320 return (value < 0) ? value : swab16(value); 321 } 322 323 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 324 { 325 if (reg == LM75_REG_CONF) 326 return i2c_smbus_write_byte_data(client, reg, value); 327 else 328 return i2c_smbus_write_word_data(client, reg, swab16(value)); 329 } 330 331 static struct lm75_data *lm75_update_device(struct device *dev) 332 { 333 struct i2c_client *client = to_i2c_client(dev); 334 struct lm75_data *data = i2c_get_clientdata(client); 335 336 mutex_lock(&data->update_lock); 337 338 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 339 || !data->valid) { 340 int i; 341 dev_dbg(&client->dev, "Starting lm75 update\n"); 342 343 for (i = 0; i < ARRAY_SIZE(data->temp); i++) { 344 int status; 345 346 status = lm75_read_value(client, LM75_REG_TEMP[i]); 347 if (status < 0) 348 dev_dbg(&client->dev, "reg %d, err %d\n", 349 LM75_REG_TEMP[i], status); 350 else 351 data->temp[i] = status; 352 } 353 data->last_updated = jiffies; 354 data->valid = 1; 355 } 356 357 mutex_unlock(&data->update_lock); 358 359 return data; 360 } 361 362 /*-----------------------------------------------------------------------*/ 363 364 /* module glue */ 365 366 static int __init sensors_lm75_init(void) 367 { 368 return i2c_add_driver(&lm75_driver); 369 } 370 371 static void __exit sensors_lm75_exit(void) 372 { 373 i2c_del_driver(&lm75_driver); 374 } 375 376 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 377 MODULE_DESCRIPTION("LM75 driver"); 378 MODULE_LICENSE("GPL"); 379 380 module_init(sensors_lm75_init); 381 module_exit(sensors_lm75_exit); 382