drivers/hwmon/lm75.c

   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         tmp175,
  50         tmp275,
  51         tmp75,
  52 };
  53
  54 /* Addresses scanned */
  55 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  56                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  57
  58
  59 /* The LM75 registers */
  60 #define LM75_REG_CONF           0x01
  61 static const u8 LM75_REG_TEMP[3] = {
  62         0x00,           /* input */
  63         0x03,           /* max */
  64         0x02,           /* hyst */
  65 };
  66
  67 /* Each client has this additional data */
  68 struct lm75_data {
  69         struct device           *hwmon_dev;
  70         struct mutex            update_lock;
  71         u8                      orig_conf;
  72         char                    valid;          /* !=0 if registers are valid */
  73         unsigned long           last_updated;   /* In jiffies */
  74         u16                     temp[3];        /* Register values,
  75                                                    0 = input
  76                                                    1 = max
  77                                                    2 = hyst */
  78 };
  79
  80 static int lm75_read_value(struct i2c_client *client, u8 reg);
  81 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  82 static struct lm75_data *lm75_update_device(struct device *dev);
  83
  84
  85 /*-----------------------------------------------------------------------*/
  86
  87 /* sysfs attributes for hwmon */
  88
  89 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  90                          char *buf)
  91 {
  92         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  93         struct lm75_data *data = lm75_update_device(dev);
  94         return sprintf(buf, "%d\n",
  95                        LM75_TEMP_FROM_REG(data->temp[attr->index]));
  96 }
  97
  98 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
  99                         const char *buf, size_t count)
 100 {
 101         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 102         struct i2c_client *client = to_i2c_client(dev);
 103         struct lm75_data *data = i2c_get_clientdata(client);
 104         int nr = attr->index;
 105         long temp = simple_strtol(buf, NULL, 10);
 106
 107         mutex_lock(&data->update_lock);
 108         data->temp[nr] = LM75_TEMP_TO_REG(temp);
 109         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 110         mutex_unlock(&data->update_lock);
 111         return count;
 112 }
 113
 114 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 115                         show_temp, set_temp, 1);
 116 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 117                         show_temp, set_temp, 2);
 118 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 119
 120 static struct attribute *lm75_attributes[] = {
 121         &sensor_dev_attr_temp1_input.dev_attr.attr,
 122         &sensor_dev_attr_temp1_max.dev_attr.attr,
 123         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 124
 125         NULL
 126 };
 127
 128 static const struct attribute_group lm75_group = {
 129         .attrs = lm75_attributes,
 130 };
 131
 132 /*-----------------------------------------------------------------------*/
 133
 134 /* device probe and removal */
 135
 136 static int
 137 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 138 {
 139         struct lm75_data *data;
 140         int status;
 141         u8 set_mask, clr_mask;
 142         int new;
 143
 144         if (!i2c_check_functionality(client->adapter,
 145                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 146                 return -EIO;
 147
 148         data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
 149         if (!data)
 150                 return -ENOMEM;
 151
 152         i2c_set_clientdata(client, data);
 153         mutex_init(&data->update_lock);
 154
 155         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 156          * Then tweak to be more precise when appropriate.
 157          */
 158         set_mask = 0;
 159         clr_mask = (1 << 0)                     /* continuous conversions */
 160                 | (1 << 6) | (1 << 5);          /* 9-bit mode */
 161
 162         /* configure as specified */
 163         status = lm75_read_value(client, LM75_REG_CONF);
 164         if (status < 0) {
 165                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 166                 goto exit_free;
 167         }
 168         data->orig_conf = status;
 169         new = status & ~clr_mask;
 170         new |= set_mask;
 171         if (status != new)
 172                 lm75_write_value(client, LM75_REG_CONF, new);
 173         dev_dbg(&client->dev, "Config %02x\n", new);
 174
 175         /* Register sysfs hooks */
 176         status = sysfs_create_group(&client->dev.kobj, &lm75_group);
 177         if (status)
 178                 goto exit_free;
 179
 180         data->hwmon_dev = hwmon_device_register(&client->dev);
 181         if (IS_ERR(data->hwmon_dev)) {
 182                 status = PTR_ERR(data->hwmon_dev);
 183                 goto exit_remove;
 184         }
 185
 186         dev_info(&client->dev, "%s: sensor '%s'\n",
 187                  dev_name(data->hwmon_dev), client->name);
 188
 189         return 0;
 190
 191 exit_remove:
 192         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 193 exit_free:
 194         i2c_set_clientdata(client, NULL);
 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         i2c_set_clientdata(client, NULL);
 207         kfree(data);
 208         return 0;
 209 }
 210
 211 static const struct i2c_device_id lm75_ids[] = {
 212         { "ds1775", ds1775, },
 213         { "ds75", ds75, },
 214         { "lm75", lm75, },
 215         { "lm75a", lm75a, },
 216         { "max6625", max6625, },
 217         { "max6626", max6626, },
 218         { "mcp980x", mcp980x, },
 219         { "stds75", stds75, },
 220         { "tcn75", tcn75, },
 221         { "tmp100", tmp100, },
 222         { "tmp101", tmp101, },
 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);