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 = simple_strtol(buf, NULL, 10); 107 108 mutex_lock(&data->update_lock); 109 data->temp[nr] = LM75_TEMP_TO_REG(temp); 110 lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); 111 mutex_unlock(&data->update_lock); 112 return count; 113 } 114 115 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 116 show_temp, set_temp, 1); 117 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, 118 show_temp, set_temp, 2); 119 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); 120 121 static struct attribute *lm75_attributes[] = { 122 &sensor_dev_attr_temp1_input.dev_attr.attr, 123 &sensor_dev_attr_temp1_max.dev_attr.attr, 124 &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, 125 126 NULL 127 }; 128 129 static const struct attribute_group lm75_group = { 130 .attrs = lm75_attributes, 131 }; 132 133 /*-----------------------------------------------------------------------*/ 134 135 /* device probe and removal */ 136 137 static int 138 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id) 139 { 140 struct lm75_data *data; 141 int status; 142 u8 set_mask, clr_mask; 143 int new; 144 145 if (!i2c_check_functionality(client->adapter, 146 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) 147 return -EIO; 148 149 data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL); 150 if (!data) 151 return -ENOMEM; 152 153 i2c_set_clientdata(client, data); 154 mutex_init(&data->update_lock); 155 156 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range. 157 * Then tweak to be more precise when appropriate. 158 */ 159 set_mask = 0; 160 clr_mask = (1 << 0) /* continuous conversions */ 161 | (1 << 6) | (1 << 5); /* 9-bit mode */ 162 163 /* configure as specified */ 164 status = lm75_read_value(client, LM75_REG_CONF); 165 if (status < 0) { 166 dev_dbg(&client->dev, "Can't read config? %d\n", status); 167 goto exit_free; 168 } 169 data->orig_conf = status; 170 new = status & ~clr_mask; 171 new |= set_mask; 172 if (status != new) 173 lm75_write_value(client, LM75_REG_CONF, new); 174 dev_dbg(&client->dev, "Config %02x\n", new); 175 176 /* Register sysfs hooks */ 177 status = sysfs_create_group(&client->dev.kobj, &lm75_group); 178 if (status) 179 goto exit_free; 180 181 data->hwmon_dev = hwmon_device_register(&client->dev); 182 if (IS_ERR(data->hwmon_dev)) { 183 status = PTR_ERR(data->hwmon_dev); 184 goto exit_remove; 185 } 186 187 dev_info(&client->dev, "%s: sensor '%s'\n", 188 dev_name(data->hwmon_dev), client->name); 189 190 return 0; 191 192 exit_remove: 193 sysfs_remove_group(&client->dev.kobj, &lm75_group); 194 exit_free: 195 kfree(data); 196 return status; 197 } 198 199 static int lm75_remove(struct i2c_client *client) 200 { 201 struct lm75_data *data = i2c_get_clientdata(client); 202 203 hwmon_device_unregister(data->hwmon_dev); 204 sysfs_remove_group(&client->dev.kobj, &lm75_group); 205 lm75_write_value(client, LM75_REG_CONF, data->orig_conf); 206 kfree(data); 207 return 0; 208 } 209 210 static const struct i2c_device_id lm75_ids[] = { 211 { "ds1775", ds1775, }, 212 { "ds75", ds75, }, 213 { "lm75", lm75, }, 214 { "lm75a", lm75a, }, 215 { "max6625", max6625, }, 216 { "max6626", max6626, }, 217 { "mcp980x", mcp980x, }, 218 { "stds75", stds75, }, 219 { "tcn75", tcn75, }, 220 { "tmp100", tmp100, }, 221 { "tmp101", tmp101, }, 222 { "tmp105", tmp105, }, 223 { "tmp175", tmp175, }, 224 { "tmp275", tmp275, }, 225 { "tmp75", tmp75, }, 226 { /* LIST END */ } 227 }; 228 MODULE_DEVICE_TABLE(i2c, lm75_ids); 229 230 /* Return 0 if detection is successful, -ENODEV otherwise */ 231 static int lm75_detect(struct i2c_client *new_client, 232 struct i2c_board_info *info) 233 { 234 struct i2c_adapter *adapter = new_client->adapter; 235 int i; 236 int cur, conf, hyst, os; 237 238 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 239 I2C_FUNC_SMBUS_WORD_DATA)) 240 return -ENODEV; 241 242 /* Now, we do the remaining detection. There is no identification- 243 dedicated register so we have to rely on several tricks: 244 unused bits, registers cycling over 8-address boundaries, 245 addresses 0x04-0x07 returning the last read value. 246 The cycling+unused addresses combination is not tested, 247 since it would significantly slow the detection down and would 248 hardly add any value. */ 249 250 /* Unused addresses */ 251 cur = i2c_smbus_read_word_data(new_client, 0); 252 conf = i2c_smbus_read_byte_data(new_client, 1); 253 hyst = i2c_smbus_read_word_data(new_client, 2); 254 if (i2c_smbus_read_word_data(new_client, 4) != hyst 255 || i2c_smbus_read_word_data(new_client, 5) != hyst 256 || i2c_smbus_read_word_data(new_client, 6) != hyst 257 || i2c_smbus_read_word_data(new_client, 7) != hyst) 258 return -ENODEV; 259 os = i2c_smbus_read_word_data(new_client, 3); 260 if (i2c_smbus_read_word_data(new_client, 4) != os 261 || i2c_smbus_read_word_data(new_client, 5) != os 262 || i2c_smbus_read_word_data(new_client, 6) != os 263 || i2c_smbus_read_word_data(new_client, 7) != os) 264 return -ENODEV; 265 266 /* Unused bits */ 267 if (conf & 0xe0) 268 return -ENODEV; 269 270 /* Addresses cycling */ 271 for (i = 8; i < 0xff; i += 8) { 272 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 273 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 274 || i2c_smbus_read_word_data(new_client, i + 3) != os) 275 return -ENODEV; 276 } 277 278 strlcpy(info->type, "lm75", I2C_NAME_SIZE); 279 280 return 0; 281 } 282 283 static struct i2c_driver lm75_driver = { 284 .class = I2C_CLASS_HWMON, 285 .driver = { 286 .name = "lm75", 287 }, 288 .probe = lm75_probe, 289 .remove = lm75_remove, 290 .id_table = lm75_ids, 291 .detect = lm75_detect, 292 .address_list = normal_i2c, 293 }; 294 295 /*-----------------------------------------------------------------------*/ 296 297 /* register access */ 298 299 /* All registers are word-sized, except for the configuration register. 300 LM75 uses a high-byte first convention, which is exactly opposite to 301 the SMBus standard. */ 302 static int lm75_read_value(struct i2c_client *client, u8 reg) 303 { 304 int value; 305 306 if (reg == LM75_REG_CONF) 307 return i2c_smbus_read_byte_data(client, reg); 308 309 value = i2c_smbus_read_word_data(client, reg); 310 return (value < 0) ? value : swab16(value); 311 } 312 313 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 314 { 315 if (reg == LM75_REG_CONF) 316 return i2c_smbus_write_byte_data(client, reg, value); 317 else 318 return i2c_smbus_write_word_data(client, reg, swab16(value)); 319 } 320 321 static struct lm75_data *lm75_update_device(struct device *dev) 322 { 323 struct i2c_client *client = to_i2c_client(dev); 324 struct lm75_data *data = i2c_get_clientdata(client); 325 326 mutex_lock(&data->update_lock); 327 328 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 329 || !data->valid) { 330 int i; 331 dev_dbg(&client->dev, "Starting lm75 update\n"); 332 333 for (i = 0; i < ARRAY_SIZE(data->temp); i++) { 334 int status; 335 336 status = lm75_read_value(client, LM75_REG_TEMP[i]); 337 if (status < 0) 338 dev_dbg(&client->dev, "reg %d, err %d\n", 339 LM75_REG_TEMP[i], status); 340 else 341 data->temp[i] = status; 342 } 343 data->last_updated = jiffies; 344 data->valid = 1; 345 } 346 347 mutex_unlock(&data->update_lock); 348 349 return data; 350 } 351 352 /*-----------------------------------------------------------------------*/ 353 354 /* module glue */ 355 356 static int __init sensors_lm75_init(void) 357 { 358 return i2c_add_driver(&lm75_driver); 359 } 360 361 static void __exit sensors_lm75_exit(void) 362 { 363 i2c_del_driver(&lm75_driver); 364 } 365 366 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 367 MODULE_DESCRIPTION("LM75 driver"); 368 MODULE_LICENSE("GPL"); 369 370 module_init(sensors_lm75_init); 371 module_exit(sensors_lm75_exit); 372