drivers/hwmon/lm75.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
   4  *       monitoring
   5  * Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/slab.h>
  11 #include <linux/jiffies.h>
  12 #include <linux/i2c.h>
  13 #include <linux/hwmon.h>
  14 #include <linux/hwmon-sysfs.h>
  15 #include <linux/err.h>
  16 #include <linux/of_device.h>
  17 #include <linux/of.h>
  18 #include <linux/regmap.h>
  19 #include "lm75.h"
  20
  21
  22 /*
  23  * This driver handles the LM75 and compatible digital temperature sensors.
  24  */
  25
  26 enum lm75_type {                /* keep sorted in alphabetical order */
  27         adt75,
  28         ds1775,
  29         ds75,
  30         ds7505,
  31         g751,
  32         lm75,
  33         lm75a,
  34         lm75b,
  35         max6625,
  36         max6626,
  37         max31725,
  38         mcp980x,
  39         stds75,
  40         stlm75,
  41         tcn75,
  42         tmp100,
  43         tmp101,
  44         tmp105,
  45         tmp112,
  46         tmp175,
  47         tmp275,
  48         tmp75,
  49         tmp75b,
  50         tmp75c,
  51 };
  52
  53 /* Addresses scanned */
  54 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  55                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  56
  57 /* The LM75 registers */
  58 #define LM75_REG_TEMP           0x00
  59 #define LM75_REG_CONF           0x01
  60 #define LM75_REG_HYST           0x02
  61 #define LM75_REG_MAX            0x03
  62
  63 /* Each client has this additional data */
  64 struct lm75_data {
  65         struct i2c_client       *client;
  66         struct regmap           *regmap;
  67         u8                      orig_conf;
  68         u8                      resolution;     /* In bits, between 9 and 16 */
  69         u8                      resolution_limits;
  70         unsigned int            sample_time;    /* In ms */
  71 };
  72
  73 /*-----------------------------------------------------------------------*/
  74
  75 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
  76 {
  77         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
  78 }
  79
  80 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
  81                      u32 attr, int channel, long *val)
  82 {
  83         struct lm75_data *data = dev_get_drvdata(dev);
  84         unsigned int regval;
  85         int err, reg;
  86
  87         switch (type) {
  88         case hwmon_chip:
  89                 switch (attr) {
  90                 case hwmon_chip_update_interval:
  91                         *val = data->sample_time;
  92                         break;
  93                 default:
  94                         return -EINVAL;
  95                 }
  96                 break;
  97         case hwmon_temp:
  98                 switch (attr) {
  99                 case hwmon_temp_input:
 100                         reg = LM75_REG_TEMP;
 101                         break;
 102                 case hwmon_temp_max:
 103                         reg = LM75_REG_MAX;
 104                         break;
 105                 case hwmon_temp_max_hyst:
 106                         reg = LM75_REG_HYST;
 107                         break;
 108                 default:
 109                         return -EINVAL;
 110                 }
 111                 err = regmap_read(data->regmap, reg, &regval);
 112                 if (err < 0)
 113                         return err;
 114
 115                 *val = lm75_reg_to_mc(regval, data->resolution);
 116                 break;
 117         default:
 118                 return -EINVAL;
 119         }
 120         return 0;
 121 }
 122
 123 static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
 124                       u32 attr, int channel, long temp)
 125 {
 126         struct lm75_data *data = dev_get_drvdata(dev);
 127         u8 resolution;
 128         int reg;
 129
 130         if (type != hwmon_temp)
 131                 return -EINVAL;
 132
 133         switch (attr) {
 134         case hwmon_temp_max:
 135                 reg = LM75_REG_MAX;
 136                 break;
 137         case hwmon_temp_max_hyst:
 138                 reg = LM75_REG_HYST;
 139                 break;
 140         default:
 141                 return -EINVAL;
 142         }
 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 (data->resolution_limits)
 149                 resolution = data->resolution_limits;
 150         else
 151                 resolution = data->resolution;
 152
 153         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 154         temp = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 155                                  1000) << (16 - resolution);
 156
 157         return regmap_write(data->regmap, reg, temp);
 158 }
 159
 160 static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
 161                                u32 attr, int channel)
 162 {
 163         switch (type) {
 164         case hwmon_chip:
 165                 switch (attr) {
 166                 case hwmon_chip_update_interval:
 167                         return 0444;
 168                 }
 169                 break;
 170         case hwmon_temp:
 171                 switch (attr) {
 172                 case hwmon_temp_input:
 173                         return 0444;
 174                 case hwmon_temp_max:
 175                 case hwmon_temp_max_hyst:
 176                         return 0644;
 177                 }
 178                 break;
 179         default:
 180                 break;
 181         }
 182         return 0;
 183 }
 184
 185 static const struct hwmon_channel_info *lm75_info[] = {
 186         HWMON_CHANNEL_INFO(chip,
 187                            HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
 188         HWMON_CHANNEL_INFO(temp,
 189                            HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
 190         NULL
 191 };
 192
 193 static const struct hwmon_ops lm75_hwmon_ops = {
 194         .is_visible = lm75_is_visible,
 195         .read = lm75_read,
 196         .write = lm75_write,
 197 };
 198
 199 static const struct hwmon_chip_info lm75_chip_info = {
 200         .ops = &lm75_hwmon_ops,
 201         .info = lm75_info,
 202 };
 203
 204 static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
 205 {
 206         return reg != LM75_REG_TEMP;
 207 }
 208
 209 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
 210 {
 211         return reg == LM75_REG_TEMP;
 212 }
 213
 214 static const struct regmap_config lm75_regmap_config = {
 215         .reg_bits = 8,
 216         .val_bits = 16,
 217         .max_register = LM75_REG_MAX,
 218         .writeable_reg = lm75_is_writeable_reg,
 219         .volatile_reg = lm75_is_volatile_reg,
 220         .val_format_endian = REGMAP_ENDIAN_BIG,
 221         .cache_type = REGCACHE_RBTREE,
 222         .use_single_read = true,
 223         .use_single_write = true,
 224 };
 225
 226 static void lm75_remove(void *data)
 227 {
 228         struct lm75_data *lm75 = data;
 229         struct i2c_client *client = lm75->client;
 230
 231         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 232 }
 233
 234 static int
 235 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 236 {
 237         struct device *dev = &client->dev;
 238         struct device *hwmon_dev;
 239         struct lm75_data *data;
 240         int status, err;
 241         u8 set_mask, clr_mask;
 242         int new;
 243         enum lm75_type kind;
 244
 245         if (client->dev.of_node)
 246                 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
 247         else
 248                 kind = id->driver_data;
 249
 250         if (!i2c_check_functionality(client->adapter,
 251                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 252                 return -EIO;
 253
 254         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 255         if (!data)
 256                 return -ENOMEM;
 257
 258         data->client = client;
 259
 260         data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
 261         if (IS_ERR(data->regmap))
 262                 return PTR_ERR(data->regmap);
 263
 264         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 265          * Then tweak to be more precise when appropriate.
 266          */
 267         set_mask = 0;
 268         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 269
 270         switch (kind) {
 271         case adt75:
 272                 clr_mask |= 1 << 5;             /* not one-shot mode */
 273                 data->resolution = 12;
 274                 data->sample_time = MSEC_PER_SEC / 8;
 275                 break;
 276         case ds1775:
 277         case ds75:
 278         case stds75:
 279                 clr_mask |= 3 << 5;
 280                 set_mask |= 2 << 5;             /* 11-bit mode */
 281                 data->resolution = 11;
 282                 data->sample_time = MSEC_PER_SEC;
 283                 break;
 284         case stlm75:
 285                 data->resolution = 9;
 286                 data->sample_time = MSEC_PER_SEC / 5;
 287                 break;
 288         case ds7505:
 289                 set_mask |= 3 << 5;             /* 12-bit mode */
 290                 data->resolution = 12;
 291                 data->sample_time = MSEC_PER_SEC / 4;
 292                 break;
 293         case g751:
 294         case lm75:
 295         case lm75a:
 296                 data->resolution = 9;
 297                 data->sample_time = MSEC_PER_SEC / 2;
 298                 break;
 299         case lm75b:
 300                 data->resolution = 11;
 301                 data->sample_time = MSEC_PER_SEC / 4;
 302                 break;
 303         case max6625:
 304                 data->resolution = 9;
 305                 data->sample_time = MSEC_PER_SEC / 4;
 306                 break;
 307         case max6626:
 308                 data->resolution = 12;
 309                 data->resolution_limits = 9;
 310                 data->sample_time = MSEC_PER_SEC / 4;
 311                 break;
 312         case max31725:
 313                 data->resolution = 16;
 314                 data->sample_time = MSEC_PER_SEC / 8;
 315                 break;
 316         case tcn75:
 317                 data->resolution = 9;
 318                 data->sample_time = MSEC_PER_SEC / 8;
 319                 break;
 320         case mcp980x:
 321                 data->resolution_limits = 9;
 322                 /* fall through */
 323         case tmp100:
 324         case tmp101:
 325                 set_mask |= 3 << 5;             /* 12-bit mode */
 326                 data->resolution = 12;
 327                 data->sample_time = MSEC_PER_SEC;
 328                 clr_mask |= 1 << 7;             /* not one-shot mode */
 329                 break;
 330         case tmp112:
 331                 set_mask |= 3 << 5;             /* 12-bit mode */
 332                 clr_mask |= 1 << 7;             /* not one-shot mode */
 333                 data->resolution = 12;
 334                 data->sample_time = MSEC_PER_SEC / 4;
 335                 break;
 336         case tmp105:
 337         case tmp175:
 338         case tmp275:
 339         case tmp75:
 340                 set_mask |= 3 << 5;             /* 12-bit mode */
 341                 clr_mask |= 1 << 7;             /* not one-shot mode */
 342                 data->resolution = 12;
 343                 data->sample_time = MSEC_PER_SEC / 2;
 344                 break;
 345         case tmp75b:  /* not one-shot mode, Conversion rate 37Hz */
 346                 clr_mask |= 1 << 15 | 0x3 << 13;
 347                 data->resolution = 12;
 348                 data->sample_time = MSEC_PER_SEC / 37;
 349                 break;
 350         case tmp75c:
 351                 clr_mask |= 1 << 5;             /* not one-shot mode */
 352                 data->resolution = 12;
 353                 data->sample_time = MSEC_PER_SEC / 4;
 354                 break;
 355         }
 356
 357         /* configure as specified */
 358         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 359         if (status < 0) {
 360                 dev_dbg(dev, "Can't read config? %d\n", status);
 361                 return status;
 362         }
 363         data->orig_conf = status;
 364         new = status & ~clr_mask;
 365         new |= set_mask;
 366         if (status != new)
 367                 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
 368
 369         err = devm_add_action_or_reset(dev, lm75_remove, data);
 370         if (err)
 371                 return err;
 372
 373         dev_dbg(dev, "Config %02x\n", new);
 374
 375         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 376                                                          data, &lm75_chip_info,
 377                                                          NULL);
 378         if (IS_ERR(hwmon_dev))
 379                 return PTR_ERR(hwmon_dev);
 380
 381         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 382
 383         return 0;
 384 }
 385
 386 static const struct i2c_device_id lm75_ids[] = {
 387         { "adt75", adt75, },
 388         { "ds1775", ds1775, },
 389         { "ds75", ds75, },
 390         { "ds7505", ds7505, },
 391         { "g751", g751, },
 392         { "lm75", lm75, },
 393         { "lm75a", lm75a, },
 394         { "lm75b", lm75b, },
 395         { "max6625", max6625, },
 396         { "max6626", max6626, },
 397         { "max31725", max31725, },
 398         { "max31726", max31725, },
 399         { "mcp980x", mcp980x, },
 400         { "stds75", stds75, },
 401         { "stlm75", stlm75, },
 402         { "tcn75", tcn75, },
 403         { "tmp100", tmp100, },
 404         { "tmp101", tmp101, },
 405         { "tmp105", tmp105, },
 406         { "tmp112", tmp112, },
 407         { "tmp175", tmp175, },
 408         { "tmp275", tmp275, },
 409         { "tmp75", tmp75, },
 410         { "tmp75b", tmp75b, },
 411         { "tmp75c", tmp75c, },
 412         { /* LIST END */ }
 413 };
 414 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 415
 416 static const struct of_device_id __maybe_unused lm75_of_match[] = {
 417         {
 418                 .compatible = "adi,adt75",
 419                 .data = (void *)adt75
 420         },
 421         {
 422                 .compatible = "dallas,ds1775",
 423                 .data = (void *)ds1775
 424         },
 425         {
 426                 .compatible = "dallas,ds75",
 427                 .data = (void *)ds75
 428         },
 429         {
 430                 .compatible = "dallas,ds7505",
 431                 .data = (void *)ds7505
 432         },
 433         {
 434                 .compatible = "gmt,g751",
 435                 .data = (void *)g751
 436         },
 437         {
 438                 .compatible = "national,lm75",
 439                 .data = (void *)lm75
 440         },
 441         {
 442                 .compatible = "national,lm75a",
 443                 .data = (void *)lm75a
 444         },
 445         {
 446                 .compatible = "national,lm75b",
 447                 .data = (void *)lm75b
 448         },
 449         {
 450                 .compatible = "maxim,max6625",
 451                 .data = (void *)max6625
 452         },
 453         {
 454                 .compatible = "maxim,max6626",
 455                 .data = (void *)max6626
 456         },
 457         {
 458                 .compatible = "maxim,max31725",
 459                 .data = (void *)max31725
 460         },
 461         {
 462                 .compatible = "maxim,max31726",
 463                 .data = (void *)max31725
 464         },
 465         {
 466                 .compatible = "maxim,mcp980x",
 467                 .data = (void *)mcp980x
 468         },
 469         {
 470                 .compatible = "st,stds75",
 471                 .data = (void *)stds75
 472         },
 473         {
 474                 .compatible = "st,stlm75",
 475                 .data = (void *)stlm75
 476         },
 477         {
 478                 .compatible = "microchip,tcn75",
 479                 .data = (void *)tcn75
 480         },
 481         {
 482                 .compatible = "ti,tmp100",
 483                 .data = (void *)tmp100
 484         },
 485         {
 486                 .compatible = "ti,tmp101",
 487                 .data = (void *)tmp101
 488         },
 489         {
 490                 .compatible = "ti,tmp105",
 491                 .data = (void *)tmp105
 492         },
 493         {
 494                 .compatible = "ti,tmp112",
 495                 .data = (void *)tmp112
 496         },
 497         {
 498                 .compatible = "ti,tmp175",
 499                 .data = (void *)tmp175
 500         },
 501         {
 502                 .compatible = "ti,tmp275",
 503                 .data = (void *)tmp275
 504         },
 505         {
 506                 .compatible = "ti,tmp75",
 507                 .data = (void *)tmp75
 508         },
 509         {
 510                 .compatible = "ti,tmp75b",
 511                 .data = (void *)tmp75b
 512         },
 513         {
 514                 .compatible = "ti,tmp75c",
 515                 .data = (void *)tmp75c
 516         },
 517         { },
 518 };
 519 MODULE_DEVICE_TABLE(of, lm75_of_match);
 520
 521 #define LM75A_ID 0xA1
 522
 523 /* Return 0 if detection is successful, -ENODEV otherwise */
 524 static int lm75_detect(struct i2c_client *new_client,
 525                        struct i2c_board_info *info)
 526 {
 527         struct i2c_adapter *adapter = new_client->adapter;
 528         int i;
 529         int conf, hyst, os;
 530         bool is_lm75a = 0;
 531
 532         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 533                                      I2C_FUNC_SMBUS_WORD_DATA))
 534                 return -ENODEV;
 535
 536         /*
 537          * Now, we do the remaining detection. There is no identification-
 538          * dedicated register so we have to rely on several tricks:
 539          * unused bits, registers cycling over 8-address boundaries,
 540          * addresses 0x04-0x07 returning the last read value.
 541          * The cycling+unused addresses combination is not tested,
 542          * since it would significantly slow the detection down and would
 543          * hardly add any value.
 544          *
 545          * The National Semiconductor LM75A is different than earlier
 546          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 547          * revision, with 1 being the only revision in existence) in
 548          * register 7, and unused registers return 0xff rather than the
 549          * last read value.
 550          *
 551          * Note that this function only detects the original National
 552          * Semiconductor LM75 and the LM75A. Clones from other vendors
 553          * aren't detected, on purpose, because they are typically never
 554          * found on PC hardware. They are found on embedded designs where
 555          * they can be instantiated explicitly so detection is not needed.
 556          * The absence of identification registers on all these clones
 557          * would make their exhaustive detection very difficult and weak,
 558          * and odds are that the driver would bind to unsupported devices.
 559          */
 560
 561         /* Unused bits */
 562         conf = i2c_smbus_read_byte_data(new_client, 1);
 563         if (conf & 0xe0)
 564                 return -ENODEV;
 565
 566         /* First check for LM75A */
 567         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 568                 /* LM75A returns 0xff on unused registers so
 569                    just to be sure we check for that too. */
 570                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 571                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 572                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 573                         return -ENODEV;
 574                 is_lm75a = 1;
 575                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 576                 os = i2c_smbus_read_byte_data(new_client, 3);
 577         } else { /* Traditional style LM75 detection */
 578                 /* Unused addresses */
 579                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 580                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 581                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 582                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 583                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 584                         return -ENODEV;
 585                 os = i2c_smbus_read_byte_data(new_client, 3);
 586                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 587                  || i2c_smbus_read_byte_data(new_client, 5) != os
 588                  || i2c_smbus_read_byte_data(new_client, 6) != os
 589                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 590                         return -ENODEV;
 591         }
 592         /*
 593          * It is very unlikely that this is a LM75 if both
 594          * hysteresis and temperature limit registers are 0.
 595          */
 596         if (hyst == 0 && os == 0)
 597                 return -ENODEV;
 598
 599         /* Addresses cycling */
 600         for (i = 8; i <= 248; i += 40) {
 601                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 602                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 603                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 604                         return -ENODEV;
 605                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 606                                 != LM75A_ID)
 607                         return -ENODEV;
 608         }
 609
 610         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 611
 612         return 0;
 613 }
 614
 615 #ifdef CONFIG_PM
 616 static int lm75_suspend(struct device *dev)
 617 {
 618         int status;
 619         struct i2c_client *client = to_i2c_client(dev);
 620         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 621         if (status < 0) {
 622                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 623                 return status;
 624         }
 625         status = status | LM75_SHUTDOWN;
 626         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 627         return 0;
 628 }
 629
 630 static int lm75_resume(struct device *dev)
 631 {
 632         int status;
 633         struct i2c_client *client = to_i2c_client(dev);
 634         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 635         if (status < 0) {
 636                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 637                 return status;
 638         }
 639         status = status & ~LM75_SHUTDOWN;
 640         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 641         return 0;
 642 }
 643
 644 static const struct dev_pm_ops lm75_dev_pm_ops = {
 645         .suspend        = lm75_suspend,
 646         .resume         = lm75_resume,
 647 };
 648 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 649 #else
 650 #define LM75_DEV_PM_OPS NULL
 651 #endif /* CONFIG_PM */
 652
 653 static struct i2c_driver lm75_driver = {
 654         .class          = I2C_CLASS_HWMON,
 655         .driver = {
 656                 .name   = "lm75",
 657                 .of_match_table = of_match_ptr(lm75_of_match),
 658                 .pm     = LM75_DEV_PM_OPS,
 659         },
 660         .probe          = lm75_probe,
 661         .id_table       = lm75_ids,
 662         .detect         = lm75_detect,
 663         .address_list   = normal_i2c,
 664 };
 665
 666 module_i2c_driver(lm75_driver);
 667
 668 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 669 MODULE_DESCRIPTION("LM75 driver");
 670 MODULE_LICENSE("GPL");