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 <linux/of.h>
  31 #include <linux/thermal.h>
  32 #include "lm75.h"
  33
  34
  35 /*
  36  * This driver handles the LM75 and compatible digital temperature sensors.
  37  */
  38
  39 enum lm75_type {                /* keep sorted in alphabetical order */
  40         adt75,
  41         ds1775,
  42         ds75,
  43         ds7505,
  44         g751,
  45         lm75,
  46         lm75a,
  47         lm75b,
  48         max6625,
  49         max6626,
  50         mcp980x,
  51         stds75,
  52         tcn75,
  53         tmp100,
  54         tmp101,
  55         tmp105,
  56         tmp112,
  57         tmp175,
  58         tmp275,
  59         tmp75,
  60         tmp75c,
  61 };
  62
  63 /* Addresses scanned */
  64 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  65                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  66
  67
  68 /* The LM75 registers */
  69 #define LM75_REG_CONF           0x01
  70 static const u8 LM75_REG_TEMP[3] = {
  71         0x00,           /* input */
  72         0x03,           /* max */
  73         0x02,           /* hyst */
  74 };
  75
  76 /* Each client has this additional data */
  77 struct lm75_data {
  78         struct i2c_client       *client;
  79         struct mutex            update_lock;
  80         u8                      orig_conf;
  81         u8                      resolution;     /* In bits, between 9 and 12 */
  82         u8                      resolution_limits;
  83         char                    valid;          /* !=0 if registers are valid */
  84         unsigned long           last_updated;   /* In jiffies */
  85         unsigned long           sample_time;    /* In jiffies */
  86         s16                     temp[3];        /* Register values,
  87                                                    0 = input
  88                                                    1 = max
  89                                                    2 = hyst */
  90 };
  91
  92 static struct lm75_data *lm75_update_device(struct device *dev);
  93
  94
  95 /*-----------------------------------------------------------------------*/
  96
  97 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
  98 {
  99         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
 100 }
 101
 102 /* sysfs attributes for hwmon */
 103
 104 static int lm75_read_temp(void *dev, int *temp)
 105 {
 106         struct lm75_data *data = lm75_update_device(dev);
 107
 108         if (IS_ERR(data))
 109                 return PTR_ERR(data);
 110
 111         *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
 112
 113         return 0;
 114 }
 115
 116 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 117                          char *buf)
 118 {
 119         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 120         struct lm75_data *data = lm75_update_device(dev);
 121
 122         if (IS_ERR(data))
 123                 return PTR_ERR(data);
 124
 125         return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
 126                                                     data->resolution));
 127 }
 128
 129 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 130                         const char *buf, size_t count)
 131 {
 132         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 133         struct lm75_data *data = dev_get_drvdata(dev);
 134         struct i2c_client *client = data->client;
 135         int nr = attr->index;
 136         long temp;
 137         int error;
 138         u8 resolution;
 139
 140         error = kstrtol(buf, 10, &temp);
 141         if (error)
 142                 return error;
 143
 144         /*
 145          * Resolution of limit registers is assumed to be the same as the
 146          * temperature input register resolution unless given explicitly.
 147          */
 148         if (attr->index && data->resolution_limits)
 149                 resolution = data->resolution_limits;
 150         else
 151                 resolution = data->resolution;
 152
 153         mutex_lock(&data->update_lock);
 154         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 155         data->temp[nr] = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 156                                            1000) << (16 - resolution);
 157         i2c_smbus_write_word_swapped(client, LM75_REG_TEMP[nr], data->temp[nr]);
 158         mutex_unlock(&data->update_lock);
 159         return count;
 160 }
 161
 162 static ssize_t show_update_interval(struct device *dev,
 163                                     struct device_attribute *da, char *buf)
 164 {
 165         struct lm75_data *data = lm75_update_device(dev);
 166
 167         if (IS_ERR(data))
 168                 return PTR_ERR(data);
 169
 170         return sprintf(buf, "%u\n", jiffies_to_msecs(data->sample_time));
 171 }
 172
 173 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 174                         show_temp, set_temp, 1);
 175 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 176                         show_temp, set_temp, 2);
 177 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 178 static DEVICE_ATTR(update_interval, S_IRUGO, show_update_interval, NULL);
 179
 180 static struct attribute *lm75_attrs[] = {
 181         &sensor_dev_attr_temp1_input.dev_attr.attr,
 182         &sensor_dev_attr_temp1_max.dev_attr.attr,
 183         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 184         &dev_attr_update_interval.attr,
 185
 186         NULL
 187 };
 188 ATTRIBUTE_GROUPS(lm75);
 189
 190 static const struct thermal_zone_of_device_ops lm75_of_thermal_ops = {
 191         .get_temp = lm75_read_temp,
 192 };
 193
 194 /*-----------------------------------------------------------------------*/
 195
 196 /* device probe and removal */
 197
 198 static void lm75_remove(void *data)
 199 {
 200         struct lm75_data *lm75 = data;
 201         struct i2c_client *client = lm75->client;
 202
 203         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 204 }
 205
 206 static int
 207 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 208 {
 209         struct device *dev = &client->dev;
 210         struct device *hwmon_dev;
 211         struct lm75_data *data;
 212         int status;
 213         u8 set_mask, clr_mask;
 214         int new;
 215         enum lm75_type kind = id->driver_data;
 216
 217         if (!i2c_check_functionality(client->adapter,
 218                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 219                 return -EIO;
 220
 221         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 222         if (!data)
 223                 return -ENOMEM;
 224
 225         data->client = client;
 226         i2c_set_clientdata(client, data);
 227         mutex_init(&data->update_lock);
 228
 229         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 230          * Then tweak to be more precise when appropriate.
 231          */
 232         set_mask = 0;
 233         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 234
 235         switch (kind) {
 236         case adt75:
 237                 clr_mask |= 1 << 5;             /* not one-shot mode */
 238                 data->resolution = 12;
 239                 data->sample_time = HZ / 8;
 240                 break;
 241         case ds1775:
 242         case ds75:
 243         case stds75:
 244                 clr_mask |= 3 << 5;
 245                 set_mask |= 2 << 5;             /* 11-bit mode */
 246                 data->resolution = 11;
 247                 data->sample_time = HZ;
 248                 break;
 249         case ds7505:
 250                 set_mask |= 3 << 5;             /* 12-bit mode */
 251                 data->resolution = 12;
 252                 data->sample_time = HZ / 4;
 253                 break;
 254         case g751:
 255         case lm75:
 256         case lm75a:
 257                 data->resolution = 9;
 258                 data->sample_time = HZ / 2;
 259                 break;
 260         case lm75b:
 261                 data->resolution = 11;
 262                 data->sample_time = HZ / 4;
 263                 break;
 264         case max6625:
 265                 data->resolution = 9;
 266                 data->sample_time = HZ / 4;
 267                 break;
 268         case max6626:
 269                 data->resolution = 12;
 270                 data->resolution_limits = 9;
 271                 data->sample_time = HZ / 4;
 272                 break;
 273         case tcn75:
 274                 data->resolution = 9;
 275                 data->sample_time = HZ / 8;
 276                 break;
 277         case mcp980x:
 278                 data->resolution_limits = 9;
 279                 /* fall through */
 280         case tmp100:
 281         case tmp101:
 282                 set_mask |= 3 << 5;             /* 12-bit mode */
 283                 data->resolution = 12;
 284                 data->sample_time = HZ;
 285                 clr_mask |= 1 << 7;             /* not one-shot mode */
 286                 break;
 287         case tmp112:
 288                 set_mask |= 3 << 5;             /* 12-bit mode */
 289                 clr_mask |= 1 << 7;             /* not one-shot mode */
 290                 data->resolution = 12;
 291                 data->sample_time = HZ / 4;
 292                 break;
 293         case tmp105:
 294         case tmp175:
 295         case tmp275:
 296         case tmp75:
 297                 set_mask |= 3 << 5;             /* 12-bit mode */
 298                 clr_mask |= 1 << 7;             /* not one-shot mode */
 299                 data->resolution = 12;
 300                 data->sample_time = HZ / 2;
 301                 break;
 302         case tmp75c:
 303                 clr_mask |= 1 << 5;             /* not one-shot mode */
 304                 data->resolution = 12;
 305                 data->sample_time = HZ / 4;
 306                 break;
 307         }
 308
 309         /* configure as specified */
 310         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 311         if (status < 0) {
 312                 dev_dbg(dev, "Can't read config? %d\n", status);
 313                 return status;
 314         }
 315         data->orig_conf = status;
 316         new = status & ~clr_mask;
 317         new |= set_mask;
 318         if (status != new)
 319                 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
 320
 321         devm_add_action(dev, lm75_remove, data);
 322
 323         dev_dbg(dev, "Config %02x\n", new);
 324
 325         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 326                                                            data, lm75_groups);
 327         if (IS_ERR(hwmon_dev))
 328                 return PTR_ERR(hwmon_dev);
 329
 330         devm_thermal_zone_of_sensor_register(hwmon_dev, 0,
 331                                              hwmon_dev,
 332                                              &lm75_of_thermal_ops);
 333
 334         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 335
 336         return 0;
 337 }
 338
 339 static const struct i2c_device_id lm75_ids[] = {
 340         { "adt75", adt75, },
 341         { "ds1775", ds1775, },
 342         { "ds75", ds75, },
 343         { "ds7505", ds7505, },
 344         { "g751", g751, },
 345         { "lm75", lm75, },
 346         { "lm75a", lm75a, },
 347         { "lm75b", lm75b, },
 348         { "max6625", max6625, },
 349         { "max6626", max6626, },
 350         { "mcp980x", mcp980x, },
 351         { "stds75", stds75, },
 352         { "tcn75", tcn75, },
 353         { "tmp100", tmp100, },
 354         { "tmp101", tmp101, },
 355         { "tmp105", tmp105, },
 356         { "tmp112", tmp112, },
 357         { "tmp175", tmp175, },
 358         { "tmp275", tmp275, },
 359         { "tmp75", tmp75, },
 360         { "tmp75c", tmp75c, },
 361         { /* LIST END */ }
 362 };
 363 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 364
 365 #define LM75A_ID 0xA1
 366
 367 /* Return 0 if detection is successful, -ENODEV otherwise */
 368 static int lm75_detect(struct i2c_client *new_client,
 369                        struct i2c_board_info *info)
 370 {
 371         struct i2c_adapter *adapter = new_client->adapter;
 372         int i;
 373         int conf, hyst, os;
 374         bool is_lm75a = 0;
 375
 376         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 377                                      I2C_FUNC_SMBUS_WORD_DATA))
 378                 return -ENODEV;
 379
 380         /*
 381          * Now, we do the remaining detection. There is no identification-
 382          * dedicated register so we have to rely on several tricks:
 383          * unused bits, registers cycling over 8-address boundaries,
 384          * addresses 0x04-0x07 returning the last read value.
 385          * The cycling+unused addresses combination is not tested,
 386          * since it would significantly slow the detection down and would
 387          * hardly add any value.
 388          *
 389          * The National Semiconductor LM75A is different than earlier
 390          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 391          * revision, with 1 being the only revision in existence) in
 392          * register 7, and unused registers return 0xff rather than the
 393          * last read value.
 394          *
 395          * Note that this function only detects the original National
 396          * Semiconductor LM75 and the LM75A. Clones from other vendors
 397          * aren't detected, on purpose, because they are typically never
 398          * found on PC hardware. They are found on embedded designs where
 399          * they can be instantiated explicitly so detection is not needed.
 400          * The absence of identification registers on all these clones
 401          * would make their exhaustive detection very difficult and weak,
 402          * and odds are that the driver would bind to unsupported devices.
 403          */
 404
 405         /* Unused bits */
 406         conf = i2c_smbus_read_byte_data(new_client, 1);
 407         if (conf & 0xe0)
 408                 return -ENODEV;
 409
 410         /* First check for LM75A */
 411         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 412                 /* LM75A returns 0xff on unused registers so
 413                    just to be sure we check for that too. */
 414                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 415                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 416                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 417                         return -ENODEV;
 418                 is_lm75a = 1;
 419                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 420                 os = i2c_smbus_read_byte_data(new_client, 3);
 421         } else { /* Traditional style LM75 detection */
 422                 /* Unused addresses */
 423                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 424                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 425                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 426                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 427                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 428                         return -ENODEV;
 429                 os = i2c_smbus_read_byte_data(new_client, 3);
 430                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 431                  || i2c_smbus_read_byte_data(new_client, 5) != os
 432                  || i2c_smbus_read_byte_data(new_client, 6) != os
 433                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 434                         return -ENODEV;
 435         }
 436         /*
 437          * It is very unlikely that this is a LM75 if both
 438          * hysteresis and temperature limit registers are 0.
 439          */
 440         if (hyst == 0 && os == 0)
 441                 return -ENODEV;
 442
 443         /* Addresses cycling */
 444         for (i = 8; i <= 248; i += 40) {
 445                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 446                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 447                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 448                         return -ENODEV;
 449                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 450                                 != LM75A_ID)
 451                         return -ENODEV;
 452         }
 453
 454         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 455
 456         return 0;
 457 }
 458
 459 #ifdef CONFIG_PM
 460 static int lm75_suspend(struct device *dev)
 461 {
 462         int status;
 463         struct i2c_client *client = to_i2c_client(dev);
 464         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 465         if (status < 0) {
 466                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 467                 return status;
 468         }
 469         status = status | LM75_SHUTDOWN;
 470         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 471         return 0;
 472 }
 473
 474 static int lm75_resume(struct device *dev)
 475 {
 476         int status;
 477         struct i2c_client *client = to_i2c_client(dev);
 478         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 479         if (status < 0) {
 480                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 481                 return status;
 482         }
 483         status = status & ~LM75_SHUTDOWN;
 484         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 485         return 0;
 486 }
 487
 488 static const struct dev_pm_ops lm75_dev_pm_ops = {
 489         .suspend        = lm75_suspend,
 490         .resume         = lm75_resume,
 491 };
 492 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 493 #else
 494 #define LM75_DEV_PM_OPS NULL
 495 #endif /* CONFIG_PM */
 496
 497 static struct i2c_driver lm75_driver = {
 498         .class          = I2C_CLASS_HWMON,
 499         .driver = {
 500                 .name   = "lm75",
 501                 .pm     = LM75_DEV_PM_OPS,
 502         },
 503         .probe          = lm75_probe,
 504         .id_table       = lm75_ids,
 505         .detect         = lm75_detect,
 506         .address_list   = normal_i2c,
 507 };
 508
 509 /*-----------------------------------------------------------------------*/
 510
 511 static struct lm75_data *lm75_update_device(struct device *dev)
 512 {
 513         struct lm75_data *data = dev_get_drvdata(dev);
 514         struct i2c_client *client = data->client;
 515         struct lm75_data *ret = data;
 516
 517         mutex_lock(&data->update_lock);
 518
 519         if (time_after(jiffies, data->last_updated + data->sample_time)
 520             || !data->valid) {
 521                 int i;
 522                 dev_dbg(&client->dev, "Starting lm75 update\n");
 523
 524                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 525                         int status;
 526
 527                         status = i2c_smbus_read_word_swapped(client,
 528                                                              LM75_REG_TEMP[i]);
 529                         if (unlikely(status < 0)) {
 530                                 dev_dbg(dev,
 531                                         "LM75: Failed to read value: reg %d, error %d\n",
 532                                         LM75_REG_TEMP[i], status);
 533                                 ret = ERR_PTR(status);
 534                                 data->valid = 0;
 535                                 goto abort;
 536                         }
 537                         data->temp[i] = status;
 538                 }
 539                 data->last_updated = jiffies;
 540                 data->valid = 1;
 541         }
 542
 543 abort:
 544         mutex_unlock(&data->update_lock);
 545         return ret;
 546 }
 547
 548 module_i2c_driver(lm75_driver);
 549
 550 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 551 MODULE_DESCRIPTION("LM75 driver");
 552 MODULE_LICENSE("GPL");