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  * 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);