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 int lm75_read_value(struct i2c_client *client, u8 reg);
  93 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  94 static struct lm75_data *lm75_update_device(struct device *dev);
  95
  96
  97 /*-----------------------------------------------------------------------*/
  98
  99 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
 100 {
 101         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
 102 }
 103
 104 /* sysfs attributes for hwmon */
 105
 106 static int lm75_read_temp(void *dev, int *temp)
 107 {
 108         struct lm75_data *data = lm75_update_device(dev);
 109
 110         if (IS_ERR(data))
 111                 return PTR_ERR(data);
 112
 113         *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
 114
 115         return 0;
 116 }
 117
 118 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 119                          char *buf)
 120 {
 121         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 122         struct lm75_data *data = lm75_update_device(dev);
 123
 124         if (IS_ERR(data))
 125                 return PTR_ERR(data);
 126
 127         return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
 128                                                     data->resolution));
 129 }
 130
 131 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 132                         const char *buf, size_t count)
 133 {
 134         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 135         struct lm75_data *data = dev_get_drvdata(dev);
 136         struct i2c_client *client = data->client;
 137         int nr = attr->index;
 138         long temp;
 139         int error;
 140         u8 resolution;
 141
 142         error = kstrtol(buf, 10, &temp);
 143         if (error)
 144                 return error;
 145
 146         /*
 147          * Resolution of limit registers is assumed to be the same as the
 148          * temperature input register resolution unless given explicitly.
 149          */
 150         if (attr->index && data->resolution_limits)
 151                 resolution = data->resolution_limits;
 152         else
 153                 resolution = data->resolution;
 154
 155         mutex_lock(&data->update_lock);
 156         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 157         data->temp[nr] = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 158                                            1000) << (16 - resolution);
 159         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 160         mutex_unlock(&data->update_lock);
 161         return count;
 162 }
 163
 164 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 165                         show_temp, set_temp, 1);
 166 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 167                         show_temp, set_temp, 2);
 168 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 169
 170 static struct attribute *lm75_attrs[] = {
 171         &sensor_dev_attr_temp1_input.dev_attr.attr,
 172         &sensor_dev_attr_temp1_max.dev_attr.attr,
 173         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 174
 175         NULL
 176 };
 177 ATTRIBUTE_GROUPS(lm75);
 178
 179 static const struct thermal_zone_of_device_ops lm75_of_thermal_ops = {
 180         .get_temp = lm75_read_temp,
 181 };
 182
 183 /*-----------------------------------------------------------------------*/
 184
 185 /* device probe and removal */
 186
 187 static void lm75_remove(void *data)
 188 {
 189         struct lm75_data *lm75 = data;
 190         struct i2c_client *client = lm75->client;
 191
 192         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 193 }
 194
 195 static int
 196 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 197 {
 198         struct device *dev = &client->dev;
 199         struct device *hwmon_dev;
 200         struct lm75_data *data;
 201         int status;
 202         u8 set_mask, clr_mask;
 203         int new;
 204         enum lm75_type kind = id->driver_data;
 205
 206         if (!i2c_check_functionality(client->adapter,
 207                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 208                 return -EIO;
 209
 210         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 211         if (!data)
 212                 return -ENOMEM;
 213
 214         data->client = client;
 215         i2c_set_clientdata(client, data);
 216         mutex_init(&data->update_lock);
 217
 218         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 219          * Then tweak to be more precise when appropriate.
 220          */
 221         set_mask = 0;
 222         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 223
 224         switch (kind) {
 225         case adt75:
 226                 clr_mask |= 1 << 5;             /* not one-shot mode */
 227                 data->resolution = 12;
 228                 data->sample_time = HZ / 8;
 229                 break;
 230         case ds1775:
 231         case ds75:
 232         case stds75:
 233                 clr_mask |= 3 << 5;
 234                 set_mask |= 2 << 5;             /* 11-bit mode */
 235                 data->resolution = 11;
 236                 data->sample_time = HZ;
 237                 break;
 238         case ds7505:
 239                 set_mask |= 3 << 5;             /* 12-bit mode */
 240                 data->resolution = 12;
 241                 data->sample_time = HZ / 4;
 242                 break;
 243         case g751:
 244         case lm75:
 245         case lm75a:
 246                 data->resolution = 9;
 247                 data->sample_time = HZ / 2;
 248                 break;
 249         case lm75b:
 250                 data->resolution = 11;
 251                 data->sample_time = HZ / 4;
 252                 break;
 253         case max6625:
 254                 data->resolution = 9;
 255                 data->sample_time = HZ / 4;
 256                 break;
 257         case max6626:
 258                 data->resolution = 12;
 259                 data->resolution_limits = 9;
 260                 data->sample_time = HZ / 4;
 261                 break;
 262         case tcn75:
 263                 data->resolution = 9;
 264                 data->sample_time = HZ / 8;
 265                 break;
 266         case mcp980x:
 267                 data->resolution_limits = 9;
 268                 /* fall through */
 269         case tmp100:
 270         case tmp101:
 271                 set_mask |= 3 << 5;             /* 12-bit mode */
 272                 data->resolution = 12;
 273                 data->sample_time = HZ;
 274                 clr_mask |= 1 << 7;             /* not one-shot mode */
 275                 break;
 276         case tmp112:
 277                 set_mask |= 3 << 5;             /* 12-bit mode */
 278                 clr_mask |= 1 << 7;             /* not one-shot mode */
 279                 data->resolution = 12;
 280                 data->sample_time = HZ / 4;
 281                 break;
 282         case tmp105:
 283         case tmp175:
 284         case tmp275:
 285         case tmp75:
 286                 set_mask |= 3 << 5;             /* 12-bit mode */
 287                 clr_mask |= 1 << 7;             /* not one-shot mode */
 288                 data->resolution = 12;
 289                 data->sample_time = HZ / 2;
 290                 break;
 291         case tmp75c:
 292                 clr_mask |= 1 << 5;             /* not one-shot mode */
 293                 data->resolution = 12;
 294                 data->sample_time = HZ / 4;
 295                 break;
 296         }
 297
 298         /* configure as specified */
 299         status = lm75_read_value(client, LM75_REG_CONF);
 300         if (status < 0) {
 301                 dev_dbg(dev, "Can't read config? %d\n", status);
 302                 return status;
 303         }
 304         data->orig_conf = status;
 305         new = status & ~clr_mask;
 306         new |= set_mask;
 307         if (status != new)
 308                 lm75_write_value(client, LM75_REG_CONF, new);
 309
 310         devm_add_action(dev, lm75_remove, data);
 311
 312         dev_dbg(dev, "Config %02x\n", new);
 313
 314         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 315                                                            data, lm75_groups);
 316         if (IS_ERR(hwmon_dev))
 317                 return PTR_ERR(hwmon_dev);
 318
 319         devm_thermal_zone_of_sensor_register(hwmon_dev, 0,
 320                                              hwmon_dev,
 321                                              &lm75_of_thermal_ops);
 322
 323         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 324
 325         return 0;
 326 }
 327
 328 static const struct i2c_device_id lm75_ids[] = {
 329         { "adt75", adt75, },
 330         { "ds1775", ds1775, },
 331         { "ds75", ds75, },
 332         { "ds7505", ds7505, },
 333         { "g751", g751, },
 334         { "lm75", lm75, },
 335         { "lm75a", lm75a, },
 336         { "lm75b", lm75b, },
 337         { "max6625", max6625, },
 338         { "max6626", max6626, },
 339         { "mcp980x", mcp980x, },
 340         { "stds75", stds75, },
 341         { "tcn75", tcn75, },
 342         { "tmp100", tmp100, },
 343         { "tmp101", tmp101, },
 344         { "tmp105", tmp105, },
 345         { "tmp112", tmp112, },
 346         { "tmp175", tmp175, },
 347         { "tmp275", tmp275, },
 348         { "tmp75", tmp75, },
 349         { "tmp75c", tmp75c, },
 350         { /* LIST END */ }
 351 };
 352 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 353
 354 #define LM75A_ID 0xA1
 355
 356 /* Return 0 if detection is successful, -ENODEV otherwise */
 357 static int lm75_detect(struct i2c_client *new_client,
 358                        struct i2c_board_info *info)
 359 {
 360         struct i2c_adapter *adapter = new_client->adapter;
 361         int i;
 362         int conf, hyst, os;
 363         bool is_lm75a = 0;
 364
 365         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 366                                      I2C_FUNC_SMBUS_WORD_DATA))
 367                 return -ENODEV;
 368
 369         /*
 370          * Now, we do the remaining detection. There is no identification-
 371          * dedicated register so we have to rely on several tricks:
 372          * unused bits, registers cycling over 8-address boundaries,
 373          * addresses 0x04-0x07 returning the last read value.
 374          * The cycling+unused addresses combination is not tested,
 375          * since it would significantly slow the detection down and would
 376          * hardly add any value.
 377          *
 378          * The National Semiconductor LM75A is different than earlier
 379          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 380          * revision, with 1 being the only revision in existence) in
 381          * register 7, and unused registers return 0xff rather than the
 382          * last read value.
 383          *
 384          * Note that this function only detects the original National
 385          * Semiconductor LM75 and the LM75A. Clones from other vendors
 386          * aren't detected, on purpose, because they are typically never
 387          * found on PC hardware. They are found on embedded designs where
 388          * they can be instantiated explicitly so detection is not needed.
 389          * The absence of identification registers on all these clones
 390          * would make their exhaustive detection very difficult and weak,
 391          * and odds are that the driver would bind to unsupported devices.
 392          */
 393
 394         /* Unused bits */
 395         conf = i2c_smbus_read_byte_data(new_client, 1);
 396         if (conf & 0xe0)
 397                 return -ENODEV;
 398
 399         /* First check for LM75A */
 400         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 401                 /* LM75A returns 0xff on unused registers so
 402                    just to be sure we check for that too. */
 403                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 404                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 405                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 406                         return -ENODEV;
 407                 is_lm75a = 1;
 408                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 409                 os = i2c_smbus_read_byte_data(new_client, 3);
 410         } else { /* Traditional style LM75 detection */
 411                 /* Unused addresses */
 412                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 413                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 414                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 415                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 416                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 417                         return -ENODEV;
 418                 os = i2c_smbus_read_byte_data(new_client, 3);
 419                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 420                  || i2c_smbus_read_byte_data(new_client, 5) != os
 421                  || i2c_smbus_read_byte_data(new_client, 6) != os
 422                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 423                         return -ENODEV;
 424         }
 425         /*
 426          * It is very unlikely that this is a LM75 if both
 427          * hysteresis and temperature limit registers are 0.
 428          */
 429         if (hyst == 0 && os == 0)
 430                 return -ENODEV;
 431
 432         /* Addresses cycling */
 433         for (i = 8; i <= 248; i += 40) {
 434                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 435                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 436                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 437                         return -ENODEV;
 438                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 439                                 != LM75A_ID)
 440                         return -ENODEV;
 441         }
 442
 443         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 444
 445         return 0;
 446 }
 447
 448 #ifdef CONFIG_PM
 449 static int lm75_suspend(struct device *dev)
 450 {
 451         int status;
 452         struct i2c_client *client = to_i2c_client(dev);
 453         status = lm75_read_value(client, LM75_REG_CONF);
 454         if (status < 0) {
 455                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 456                 return status;
 457         }
 458         status = status | LM75_SHUTDOWN;
 459         lm75_write_value(client, LM75_REG_CONF, status);
 460         return 0;
 461 }
 462
 463 static int lm75_resume(struct device *dev)
 464 {
 465         int status;
 466         struct i2c_client *client = to_i2c_client(dev);
 467         status = lm75_read_value(client, LM75_REG_CONF);
 468         if (status < 0) {
 469                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 470                 return status;
 471         }
 472         status = status & ~LM75_SHUTDOWN;
 473         lm75_write_value(client, LM75_REG_CONF, status);
 474         return 0;
 475 }
 476
 477 static const struct dev_pm_ops lm75_dev_pm_ops = {
 478         .suspend        = lm75_suspend,
 479         .resume         = lm75_resume,
 480 };
 481 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 482 #else
 483 #define LM75_DEV_PM_OPS NULL
 484 #endif /* CONFIG_PM */
 485
 486 static struct i2c_driver lm75_driver = {
 487         .class          = I2C_CLASS_HWMON,
 488         .driver = {
 489                 .name   = "lm75",
 490                 .pm     = LM75_DEV_PM_OPS,
 491         },
 492         .probe          = lm75_probe,
 493         .id_table       = lm75_ids,
 494         .detect         = lm75_detect,
 495         .address_list   = normal_i2c,
 496 };
 497
 498 /*-----------------------------------------------------------------------*/
 499
 500 /* register access */
 501
 502 /*
 503  * All registers are word-sized, except for the configuration register.
 504  * LM75 uses a high-byte first convention, which is exactly opposite to
 505  * the SMBus standard.
 506  */
 507 static int lm75_read_value(struct i2c_client *client, u8 reg)
 508 {
 509         if (reg == LM75_REG_CONF)
 510                 return i2c_smbus_read_byte_data(client, reg);
 511         else
 512                 return i2c_smbus_read_word_swapped(client, reg);
 513 }
 514
 515 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 516 {
 517         if (reg == LM75_REG_CONF)
 518                 return i2c_smbus_write_byte_data(client, reg, value);
 519         else
 520                 return i2c_smbus_write_word_swapped(client, reg, value);
 521 }
 522
 523 static struct lm75_data *lm75_update_device(struct device *dev)
 524 {
 525         struct lm75_data *data = dev_get_drvdata(dev);
 526         struct i2c_client *client = data->client;
 527         struct lm75_data *ret = data;
 528
 529         mutex_lock(&data->update_lock);
 530
 531         if (time_after(jiffies, data->last_updated + data->sample_time)
 532             || !data->valid) {
 533                 int i;
 534                 dev_dbg(&client->dev, "Starting lm75 update\n");
 535
 536                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 537                         int status;
 538
 539                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 540                         if (unlikely(status < 0)) {
 541                                 dev_dbg(dev,
 542                                         "LM75: Failed to read value: reg %d, error %d\n",
 543                                         LM75_REG_TEMP[i], status);
 544                                 ret = ERR_PTR(status);
 545                                 data->valid = 0;
 546                                 goto abort;
 547                         }
 548                         data->temp[i] = status;
 549                 }
 550                 data->last_updated = jiffies;
 551                 data->valid = 1;
 552         }
 553
 554 abort:
 555         mutex_unlock(&data->update_lock);
 556         return ret;
 557 }
 558
 559 module_i2c_driver(lm75_driver);
 560
 561 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 562 MODULE_DESCRIPTION("LM75 driver");
 563 MODULE_LICENSE("GPL");