root/drivers/hwmon/lm75.c

DEFINITIONS

1. lm75_reg_to_mc
2. lm75_write_config
3. lm75_read
4. lm75_write_temp
5. lm75_update_interval
6. lm75_write_chip
7. lm75_write
8. lm75_is_visible
9. lm75_is_writeable_reg
10. lm75_is_volatile_reg
11. lm75_remove
12. lm75_probe
13. lm75_detect
14. lm75_suspend
15. lm75_resume

   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 <linux/util_macros.h>
  20 #include "lm75.h"
  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         pct2075,
  40         stds75,
  41         stlm75,
  42         tcn75,
  43         tmp100,
  44         tmp101,
  45         tmp105,
  46         tmp112,
  47         tmp175,
  48         tmp275,
  49         tmp75,
  50         tmp75b,
  51         tmp75c,
  52 };
  53 
  54 /**
  55  * struct lm75_params - lm75 configuration parameters.
  56  * @set_mask:           Bits to set in configuration register when configuring
  57  *                      the chip.
  58  * @clr_mask:           Bits to clear in configuration register when configuring
  59  *                      the chip.
  60  * @default_resolution: Default number of bits to represent the temperature
  61  *                      value.
  62  * @resolution_limits:  Limit register resolution. Optional. Should be set if
  63  *                      the resolution of limit registers does not match the
  64  *                      resolution of the temperature register.
  65  * @resolutions:        List of resolutions associated with sample times.
  66  *                      Optional. Should be set if num_sample_times is larger
  67  *                      than 1, and if the resolution changes with sample times.
  68  *                      If set, number of entries must match num_sample_times.
  69  * @default_sample_time:Sample time to be set by default.
  70  * @num_sample_times:   Number of possible sample times to be set. Optional.
  71  *                      Should be set if the number of sample times is larger
  72  *                      than one.
  73  * @sample_times:       All the possible sample times to be set. Mandatory if
  74  *                      num_sample_times is larger than 1. If set, number of
  75  *                      entries must match num_sample_times.
  76  */
  77 
  78 struct lm75_params {
  79         u8                      set_mask;
  80         u8                      clr_mask;
  81         u8                      default_resolution;
  82         u8                      resolution_limits;
  83         const u8                *resolutions;
  84         unsigned int            default_sample_time;
  85         u8                      num_sample_times;
  86         const unsigned int      *sample_times;
  87 };
  88 
  89 /* Addresses scanned */
  90 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  91                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  92 
  93 /* The LM75 registers */
  94 #define LM75_REG_TEMP           0x00
  95 #define LM75_REG_CONF           0x01
  96 #define LM75_REG_HYST           0x02
  97 #define LM75_REG_MAX            0x03
  98 #define PCT2075_REG_IDLE        0x04
  99 
 100 /* Each client has this additional data */
 101 struct lm75_data {
 102         struct i2c_client               *client;
 103         struct regmap                   *regmap;
 104         u8                              orig_conf;
 105         u8                              current_conf;
 106         u8                              resolution;     /* In bits, 9 to 16 */
 107         unsigned int                    sample_time;    /* In ms */
 108         enum lm75_type                  kind;
 109         const struct lm75_params        *params;
 110 };
 111 
 112 /*-----------------------------------------------------------------------*/
 113 
 114 static const u8 lm75_sample_set_masks[] = { 0 << 5, 1 << 5, 2 << 5, 3 << 5 };
 115 
 116 #define LM75_SAMPLE_CLEAR_MASK  (3 << 5)
 117 
 118 /* The structure below stores the configuration values of the supported devices.
 119  * In case of being supported multiple configurations, the default one must
 120  * always be the first element of the array
 121  */
 122 static const struct lm75_params device_params[] = {
 123         [adt75] = {
 124                 .clr_mask = 1 << 5,     /* not one-shot mode */
 125                 .default_resolution = 12,
 126                 .default_sample_time = MSEC_PER_SEC / 10,
 127         },
 128         [ds1775] = {
 129                 .clr_mask = 3 << 5,
 130                 .set_mask = 2 << 5,     /* 11-bit mode */
 131                 .default_resolution = 11,
 132                 .default_sample_time = 500,
 133                 .num_sample_times = 4,
 134                 .sample_times = (unsigned int []){ 125, 250, 500, 1000 },
 135                 .resolutions = (u8 []) {9, 10, 11, 12 },
 136         },
 137         [ds75] = {
 138                 .clr_mask = 3 << 5,
 139                 .set_mask = 2 << 5,     /* 11-bit mode */
 140                 .default_resolution = 11,
 141                 .default_sample_time = 600,
 142                 .num_sample_times = 4,
 143                 .sample_times = (unsigned int []){ 150, 300, 600, 1200 },
 144                 .resolutions = (u8 []) {9, 10, 11, 12 },
 145         },
 146         [stds75] = {
 147                 .clr_mask = 3 << 5,
 148                 .set_mask = 2 << 5,     /* 11-bit mode */
 149                 .default_resolution = 11,
 150                 .default_sample_time = 600,
 151                 .num_sample_times = 4,
 152                 .sample_times = (unsigned int []){ 150, 300, 600, 1200 },
 153                 .resolutions = (u8 []) {9, 10, 11, 12 },
 154         },
 155         [stlm75] = {
 156                 .default_resolution = 9,
 157                 .default_sample_time = MSEC_PER_SEC / 6,
 158         },
 159         [ds7505] = {
 160                 .set_mask = 3 << 5,     /* 12-bit mode*/
 161                 .default_resolution = 12,
 162                 .default_sample_time = 200,
 163                 .num_sample_times = 4,
 164                 .sample_times = (unsigned int []){ 25, 50, 100, 200 },
 165                 .resolutions = (u8 []) {9, 10, 11, 12 },
 166         },
 167         [g751] = {
 168                 .default_resolution = 9,
 169                 .default_sample_time = MSEC_PER_SEC / 10,
 170         },
 171         [lm75] = {
 172                 .default_resolution = 9,
 173                 .default_sample_time = MSEC_PER_SEC / 10,
 174         },
 175         [lm75a] = {
 176                 .default_resolution = 9,
 177                 .default_sample_time = MSEC_PER_SEC / 10,
 178         },
 179         [lm75b] = {
 180                 .default_resolution = 11,
 181                 .default_sample_time = MSEC_PER_SEC / 10,
 182         },
 183         [max6625] = {
 184                 .default_resolution = 9,
 185                 .default_sample_time = MSEC_PER_SEC / 7,
 186         },
 187         [max6626] = {
 188                 .default_resolution = 12,
 189                 .default_sample_time = MSEC_PER_SEC / 7,
 190                 .resolution_limits = 9,
 191         },
 192         [max31725] = {
 193                 .default_resolution = 16,
 194                 .default_sample_time = MSEC_PER_SEC / 20,
 195         },
 196         [tcn75] = {
 197                 .default_resolution = 9,
 198                 .default_sample_time = MSEC_PER_SEC / 18,
 199         },
 200         [pct2075] = {
 201                 .default_resolution = 11,
 202                 .default_sample_time = MSEC_PER_SEC / 10,
 203                 .num_sample_times = 31,
 204                 .sample_times = (unsigned int []){ 100, 200, 300, 400, 500, 600,
 205                 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700,
 206                 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700,
 207                 2800, 2900, 3000, 3100 },
 208         },
 209         [mcp980x] = {
 210                 .set_mask = 3 << 5,     /* 12-bit mode */
 211                 .clr_mask = 1 << 7,     /* not one-shot mode */
 212                 .default_resolution = 12,
 213                 .resolution_limits = 9,
 214                 .default_sample_time = 240,
 215                 .num_sample_times = 4,
 216                 .sample_times = (unsigned int []){ 30, 60, 120, 240 },
 217                 .resolutions = (u8 []) {9, 10, 11, 12 },
 218         },
 219         [tmp100] = {
 220                 .set_mask = 3 << 5,     /* 12-bit mode */
 221                 .clr_mask = 1 << 7,     /* not one-shot mode */
 222                 .default_resolution = 12,
 223                 .default_sample_time = 320,
 224                 .num_sample_times = 4,
 225                 .sample_times = (unsigned int []){ 40, 80, 160, 320 },
 226                 .resolutions = (u8 []) {9, 10, 11, 12 },
 227         },
 228         [tmp101] = {
 229                 .set_mask = 3 << 5,     /* 12-bit mode */
 230                 .clr_mask = 1 << 7,     /* not one-shot mode */
 231                 .default_resolution = 12,
 232                 .default_sample_time = 320,
 233                 .num_sample_times = 4,
 234                 .sample_times = (unsigned int []){ 40, 80, 160, 320 },
 235                 .resolutions = (u8 []) {9, 10, 11, 12 },
 236         },
 237         [tmp105] = {
 238                 .set_mask = 3 << 5,     /* 12-bit mode */
 239                 .clr_mask = 1 << 7,     /* not one-shot mode*/
 240                 .default_resolution = 12,
 241                 .default_sample_time = 220,
 242                 .num_sample_times = 4,
 243                 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
 244                 .resolutions = (u8 []) {9, 10, 11, 12 },
 245         },
 246         [tmp112] = {
 247                 .set_mask = 3 << 5,     /* 8 samples / second */
 248                 .clr_mask = 1 << 7,     /* no one-shot mode*/
 249                 .default_resolution = 12,
 250                 .default_sample_time = 125,
 251                 .num_sample_times = 4,
 252                 .sample_times = (unsigned int []){ 125, 250, 1000, 4000 },
 253         },
 254         [tmp175] = {
 255                 .set_mask = 3 << 5,     /* 12-bit mode */
 256                 .clr_mask = 1 << 7,     /* not one-shot mode*/
 257                 .default_resolution = 12,
 258                 .default_sample_time = 220,
 259                 .num_sample_times = 4,
 260                 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
 261                 .resolutions = (u8 []) {9, 10, 11, 12 },
 262         },
 263         [tmp275] = {
 264                 .set_mask = 3 << 5,     /* 12-bit mode */
 265                 .clr_mask = 1 << 7,     /* not one-shot mode*/
 266                 .default_resolution = 12,
 267                 .default_sample_time = 220,
 268                 .num_sample_times = 4,
 269                 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
 270                 .resolutions = (u8 []) {9, 10, 11, 12 },
 271         },
 272         [tmp75] = {
 273                 .set_mask = 3 << 5,     /* 12-bit mode */
 274                 .clr_mask = 1 << 7,     /* not one-shot mode*/
 275                 .default_resolution = 12,
 276                 .default_sample_time = 220,
 277                 .num_sample_times = 4,
 278                 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
 279                 .resolutions = (u8 []) {9, 10, 11, 12 },
 280         },
 281         [tmp75b] = { /* not one-shot mode, Conversion rate 37Hz */
 282                 .clr_mask = 1 << 7 | 3 << 5,
 283                 .default_resolution = 12,
 284                 .default_sample_time = MSEC_PER_SEC / 37,
 285                 .sample_times = (unsigned int []){ MSEC_PER_SEC / 37,
 286                         MSEC_PER_SEC / 18,
 287                         MSEC_PER_SEC / 9, MSEC_PER_SEC / 4 },
 288                 .num_sample_times = 4,
 289         },
 290         [tmp75c] = {
 291                 .clr_mask = 1 << 5,     /*not one-shot mode*/
 292                 .default_resolution = 12,
 293                 .default_sample_time = MSEC_PER_SEC / 12,
 294         }
 295 };
 296 
 297 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
 298 {
 299         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
 300 }
 301 
 302 static int lm75_write_config(struct lm75_data *data, u8 set_mask,
 303                              u8 clr_mask)
 304 {
 305         u8 value;
 306 
 307         clr_mask |= LM75_SHUTDOWN;
 308         value = data->current_conf & ~clr_mask;
 309         value |= set_mask;
 310 
 311         if (data->current_conf != value) {
 312                 s32 err;
 313 
 314                 err = i2c_smbus_write_byte_data(data->client, LM75_REG_CONF,
 315                                                 value);
 316                 if (err)
 317                         return err;
 318                 data->current_conf = value;
 319         }
 320         return 0;
 321 }
 322 
 323 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
 324                      u32 attr, int channel, long *val)
 325 {
 326         struct lm75_data *data = dev_get_drvdata(dev);
 327         unsigned int regval;
 328         int err, reg;
 329 
 330         switch (type) {
 331         case hwmon_chip:
 332                 switch (attr) {
 333                 case hwmon_chip_update_interval:
 334                         *val = data->sample_time;
 335                         break;
 336                 default:
 337                         return -EINVAL;
 338                 }
 339                 break;
 340         case hwmon_temp:
 341                 switch (attr) {
 342                 case hwmon_temp_input:
 343                         reg = LM75_REG_TEMP;
 344                         break;
 345                 case hwmon_temp_max:
 346                         reg = LM75_REG_MAX;
 347                         break;
 348                 case hwmon_temp_max_hyst:
 349                         reg = LM75_REG_HYST;
 350                         break;
 351                 default:
 352                         return -EINVAL;
 353                 }
 354                 err = regmap_read(data->regmap, reg, &regval);
 355                 if (err < 0)
 356                         return err;
 357 
 358                 *val = lm75_reg_to_mc(regval, data->resolution);
 359                 break;
 360         default:
 361                 return -EINVAL;
 362         }
 363         return 0;
 364 }
 365 
 366 static int lm75_write_temp(struct device *dev, u32 attr, long temp)
 367 {
 368         struct lm75_data *data = dev_get_drvdata(dev);
 369         u8 resolution;
 370         int reg;
 371 
 372         switch (attr) {
 373         case hwmon_temp_max:
 374                 reg = LM75_REG_MAX;
 375                 break;
 376         case hwmon_temp_max_hyst:
 377                 reg = LM75_REG_HYST;
 378                 break;
 379         default:
 380                 return -EINVAL;
 381         }
 382 
 383         /*
 384          * Resolution of limit registers is assumed to be the same as the
 385          * temperature input register resolution unless given explicitly.
 386          */
 387         if (data->params->resolution_limits)
 388                 resolution = data->params->resolution_limits;
 389         else
 390                 resolution = data->resolution;
 391 
 392         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 393         temp = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 394                                  1000) << (16 - resolution);
 395 
 396         return regmap_write(data->regmap, reg, (u16)temp);
 397 }
 398 
 399 static int lm75_update_interval(struct device *dev, long val)
 400 {
 401         struct lm75_data *data = dev_get_drvdata(dev);
 402         unsigned int reg;
 403         u8 index;
 404         s32 err;
 405 
 406         index = find_closest(val, data->params->sample_times,
 407                              (int)data->params->num_sample_times);
 408 
 409         switch (data->kind) {
 410         default:
 411                 err = lm75_write_config(data, lm75_sample_set_masks[index],
 412                                         LM75_SAMPLE_CLEAR_MASK);
 413                 if (err)
 414                         return err;
 415 
 416                 data->sample_time = data->params->sample_times[index];
 417                 if (data->params->resolutions)
 418                         data->resolution = data->params->resolutions[index];
 419                 break;
 420         case tmp112:
 421                 err = regmap_read(data->regmap, LM75_REG_CONF, &reg);
 422                 if (err < 0)
 423                         return err;
 424                 reg &= ~0x00c0;
 425                 reg |= (3 - index) << 6;
 426                 err = regmap_write(data->regmap, LM75_REG_CONF, reg);
 427                 if (err < 0)
 428                         return err;
 429                 data->sample_time = data->params->sample_times[index];
 430                 break;
 431         case pct2075:
 432                 err = i2c_smbus_write_byte_data(data->client, PCT2075_REG_IDLE,
 433                                                 index + 1);
 434                 if (err)
 435                         return err;
 436                 data->sample_time = data->params->sample_times[index];
 437                 break;
 438         }
 439         return 0;
 440 }
 441 
 442 static int lm75_write_chip(struct device *dev, u32 attr, long val)
 443 {
 444         switch (attr) {
 445         case hwmon_chip_update_interval:
 446                 return lm75_update_interval(dev, val);
 447         default:
 448                 return -EINVAL;
 449         }
 450         return 0;
 451 }
 452 
 453 static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
 454                       u32 attr, int channel, long val)
 455 {
 456         switch (type) {
 457         case hwmon_chip:
 458                 return lm75_write_chip(dev, attr, val);
 459         case hwmon_temp:
 460                 return lm75_write_temp(dev, attr, val);
 461         default:
 462                 return -EINVAL;
 463         }
 464         return 0;
 465 }
 466 
 467 static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
 468                                u32 attr, int channel)
 469 {
 470         const struct lm75_data *config_data = data;
 471 
 472         switch (type) {
 473         case hwmon_chip:
 474                 switch (attr) {
 475                 case hwmon_chip_update_interval:
 476                         if (config_data->params->num_sample_times > 1)
 477                                 return 0644;
 478                         return 0444;
 479                 }
 480                 break;
 481         case hwmon_temp:
 482                 switch (attr) {
 483                 case hwmon_temp_input:
 484                         return 0444;
 485                 case hwmon_temp_max:
 486                 case hwmon_temp_max_hyst:
 487                         return 0644;
 488                 }
 489                 break;
 490         default:
 491                 break;
 492         }
 493         return 0;
 494 }
 495 
 496 static const struct hwmon_channel_info *lm75_info[] = {
 497         HWMON_CHANNEL_INFO(chip,
 498                            HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
 499         HWMON_CHANNEL_INFO(temp,
 500                            HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
 501         NULL
 502 };
 503 
 504 static const struct hwmon_ops lm75_hwmon_ops = {
 505         .is_visible = lm75_is_visible,
 506         .read = lm75_read,
 507         .write = lm75_write,
 508 };
 509 
 510 static const struct hwmon_chip_info lm75_chip_info = {
 511         .ops = &lm75_hwmon_ops,
 512         .info = lm75_info,
 513 };
 514 
 515 static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
 516 {
 517         return reg != LM75_REG_TEMP;
 518 }
 519 
 520 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
 521 {
 522         return reg == LM75_REG_TEMP || reg == LM75_REG_CONF;
 523 }
 524 
 525 static const struct regmap_config lm75_regmap_config = {
 526         .reg_bits = 8,
 527         .val_bits = 16,
 528         .max_register = PCT2075_REG_IDLE,
 529         .writeable_reg = lm75_is_writeable_reg,
 530         .volatile_reg = lm75_is_volatile_reg,
 531         .val_format_endian = REGMAP_ENDIAN_BIG,
 532         .cache_type = REGCACHE_RBTREE,
 533         .use_single_read = true,
 534         .use_single_write = true,
 535 };
 536 
 537 static void lm75_remove(void *data)
 538 {
 539         struct lm75_data *lm75 = data;
 540         struct i2c_client *client = lm75->client;
 541 
 542         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 543 }
 544 
 545 static int
 546 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 547 {
 548         struct device *dev = &client->dev;
 549         struct device *hwmon_dev;
 550         struct lm75_data *data;
 551         int status, err;
 552         enum lm75_type kind;
 553 
 554         if (client->dev.of_node)
 555                 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
 556         else
 557                 kind = id->driver_data;
 558 
 559         if (!i2c_check_functionality(client->adapter,
 560                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 561                 return -EIO;
 562 
 563         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 564         if (!data)
 565                 return -ENOMEM;
 566 
 567         data->client = client;
 568         data->kind = kind;
 569 
 570         data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
 571         if (IS_ERR(data->regmap))
 572                 return PTR_ERR(data->regmap);
 573 
 574         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 575          * Then tweak to be more precise when appropriate.
 576          */
 577 
 578         data->params = &device_params[data->kind];
 579 
 580         /* Save default sample time and resolution*/
 581         data->sample_time = data->params->default_sample_time;
 582         data->resolution = data->params->default_resolution;
 583 
 584         /* Cache original configuration */
 585         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 586         if (status < 0) {
 587                 dev_dbg(dev, "Can't read config? %d\n", status);
 588                 return status;
 589         }
 590         data->orig_conf = status;
 591         data->current_conf = status;
 592 
 593         err = lm75_write_config(data, data->params->set_mask,
 594                                 data->params->clr_mask);
 595         if (err)
 596                 return err;
 597 
 598         err = devm_add_action_or_reset(dev, lm75_remove, data);
 599         if (err)
 600                 return err;
 601 
 602         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 603                                                          data, &lm75_chip_info,
 604                                                          NULL);
 605         if (IS_ERR(hwmon_dev))
 606                 return PTR_ERR(hwmon_dev);
 607 
 608         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 609 
 610         return 0;
 611 }
 612 
 613 static const struct i2c_device_id lm75_ids[] = {
 614         { "adt75", adt75, },
 615         { "ds1775", ds1775, },
 616         { "ds75", ds75, },
 617         { "ds7505", ds7505, },
 618         { "g751", g751, },
 619         { "lm75", lm75, },
 620         { "lm75a", lm75a, },
 621         { "lm75b", lm75b, },
 622         { "max6625", max6625, },
 623         { "max6626", max6626, },
 624         { "max31725", max31725, },
 625         { "max31726", max31725, },
 626         { "mcp980x", mcp980x, },
 627         { "pct2075", pct2075, },
 628         { "stds75", stds75, },
 629         { "stlm75", stlm75, },
 630         { "tcn75", tcn75, },
 631         { "tmp100", tmp100, },
 632         { "tmp101", tmp101, },
 633         { "tmp105", tmp105, },
 634         { "tmp112", tmp112, },
 635         { "tmp175", tmp175, },
 636         { "tmp275", tmp275, },
 637         { "tmp75", tmp75, },
 638         { "tmp75b", tmp75b, },
 639         { "tmp75c", tmp75c, },
 640         { /* LIST END */ }
 641 };
 642 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 643 
 644 static const struct of_device_id __maybe_unused lm75_of_match[] = {
 645         {
 646                 .compatible = "adi,adt75",
 647                 .data = (void *)adt75
 648         },
 649         {
 650                 .compatible = "dallas,ds1775",
 651                 .data = (void *)ds1775
 652         },
 653         {
 654                 .compatible = "dallas,ds75",
 655                 .data = (void *)ds75
 656         },
 657         {
 658                 .compatible = "dallas,ds7505",
 659                 .data = (void *)ds7505
 660         },
 661         {
 662                 .compatible = "gmt,g751",
 663                 .data = (void *)g751
 664         },
 665         {
 666                 .compatible = "national,lm75",
 667                 .data = (void *)lm75
 668         },
 669         {
 670                 .compatible = "national,lm75a",
 671                 .data = (void *)lm75a
 672         },
 673         {
 674                 .compatible = "national,lm75b",
 675                 .data = (void *)lm75b
 676         },
 677         {
 678                 .compatible = "maxim,max6625",
 679                 .data = (void *)max6625
 680         },
 681         {
 682                 .compatible = "maxim,max6626",
 683                 .data = (void *)max6626
 684         },
 685         {
 686                 .compatible = "maxim,max31725",
 687                 .data = (void *)max31725
 688         },
 689         {
 690                 .compatible = "maxim,max31726",
 691                 .data = (void *)max31725
 692         },
 693         {
 694                 .compatible = "maxim,mcp980x",
 695                 .data = (void *)mcp980x
 696         },
 697         {
 698                 .compatible = "nxp,pct2075",
 699                 .data = (void *)pct2075
 700         },
 701         {
 702                 .compatible = "st,stds75",
 703                 .data = (void *)stds75
 704         },
 705         {
 706                 .compatible = "st,stlm75",
 707                 .data = (void *)stlm75
 708         },
 709         {
 710                 .compatible = "microchip,tcn75",
 711                 .data = (void *)tcn75
 712         },
 713         {
 714                 .compatible = "ti,tmp100",
 715                 .data = (void *)tmp100
 716         },
 717         {
 718                 .compatible = "ti,tmp101",
 719                 .data = (void *)tmp101
 720         },
 721         {
 722                 .compatible = "ti,tmp105",
 723                 .data = (void *)tmp105
 724         },
 725         {
 726                 .compatible = "ti,tmp112",
 727                 .data = (void *)tmp112
 728         },
 729         {
 730                 .compatible = "ti,tmp175",
 731                 .data = (void *)tmp175
 732         },
 733         {
 734                 .compatible = "ti,tmp275",
 735                 .data = (void *)tmp275
 736         },
 737         {
 738                 .compatible = "ti,tmp75",
 739                 .data = (void *)tmp75
 740         },
 741         {
 742                 .compatible = "ti,tmp75b",
 743                 .data = (void *)tmp75b
 744         },
 745         {
 746                 .compatible = "ti,tmp75c",
 747                 .data = (void *)tmp75c
 748         },
 749         { },
 750 };
 751 MODULE_DEVICE_TABLE(of, lm75_of_match);
 752 
 753 #define LM75A_ID 0xA1
 754 
 755 /* Return 0 if detection is successful, -ENODEV otherwise */
 756 static int lm75_detect(struct i2c_client *new_client,
 757                        struct i2c_board_info *info)
 758 {
 759         struct i2c_adapter *adapter = new_client->adapter;
 760         int i;
 761         int conf, hyst, os;
 762         bool is_lm75a = 0;
 763 
 764         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 765                                      I2C_FUNC_SMBUS_WORD_DATA))
 766                 return -ENODEV;
 767 
 768         /*
 769          * Now, we do the remaining detection. There is no identification-
 770          * dedicated register so we have to rely on several tricks:
 771          * unused bits, registers cycling over 8-address boundaries,
 772          * addresses 0x04-0x07 returning the last read value.
 773          * The cycling+unused addresses combination is not tested,
 774          * since it would significantly slow the detection down and would
 775          * hardly add any value.
 776          *
 777          * The National Semiconductor LM75A is different than earlier
 778          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 779          * revision, with 1 being the only revision in existence) in
 780          * register 7, and unused registers return 0xff rather than the
 781          * last read value.
 782          *
 783          * Note that this function only detects the original National
 784          * Semiconductor LM75 and the LM75A. Clones from other vendors
 785          * aren't detected, on purpose, because they are typically never
 786          * found on PC hardware. They are found on embedded designs where
 787          * they can be instantiated explicitly so detection is not needed.
 788          * The absence of identification registers on all these clones
 789          * would make their exhaustive detection very difficult and weak,
 790          * and odds are that the driver would bind to unsupported devices.
 791          */
 792 
 793         /* Unused bits */
 794         conf = i2c_smbus_read_byte_data(new_client, 1);
 795         if (conf & 0xe0)
 796                 return -ENODEV;
 797 
 798         /* First check for LM75A */
 799         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 800                 /* LM75A returns 0xff on unused registers so
 801                    just to be sure we check for that too. */
 802                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 803                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 804                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 805                         return -ENODEV;
 806                 is_lm75a = 1;
 807                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 808                 os = i2c_smbus_read_byte_data(new_client, 3);
 809         } else { /* Traditional style LM75 detection */
 810                 /* Unused addresses */
 811                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 812                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 813                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 814                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 815                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 816                         return -ENODEV;
 817                 os = i2c_smbus_read_byte_data(new_client, 3);
 818                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 819                  || i2c_smbus_read_byte_data(new_client, 5) != os
 820                  || i2c_smbus_read_byte_data(new_client, 6) != os
 821                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 822                         return -ENODEV;
 823         }
 824         /*
 825          * It is very unlikely that this is a LM75 if both
 826          * hysteresis and temperature limit registers are 0.
 827          */
 828         if (hyst == 0 && os == 0)
 829                 return -ENODEV;
 830 
 831         /* Addresses cycling */
 832         for (i = 8; i <= 248; i += 40) {
 833                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 834                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 835                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 836                         return -ENODEV;
 837                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 838                                 != LM75A_ID)
 839                         return -ENODEV;
 840         }
 841 
 842         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 843 
 844         return 0;
 845 }
 846 
 847 #ifdef CONFIG_PM
 848 static int lm75_suspend(struct device *dev)
 849 {
 850         int status;
 851         struct i2c_client *client = to_i2c_client(dev);
 852         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 853         if (status < 0) {
 854                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 855                 return status;
 856         }
 857         status = status | LM75_SHUTDOWN;
 858         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 859         return 0;
 860 }
 861 
 862 static int lm75_resume(struct device *dev)
 863 {
 864         int status;
 865         struct i2c_client *client = to_i2c_client(dev);
 866         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 867         if (status < 0) {
 868                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 869                 return status;
 870         }
 871         status = status & ~LM75_SHUTDOWN;
 872         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 873         return 0;
 874 }
 875 
 876 static const struct dev_pm_ops lm75_dev_pm_ops = {
 877         .suspend        = lm75_suspend,
 878         .resume         = lm75_resume,
 879 };
 880 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 881 #else
 882 #define LM75_DEV_PM_OPS NULL
 883 #endif /* CONFIG_PM */
 884 
 885 static struct i2c_driver lm75_driver = {
 886         .class          = I2C_CLASS_HWMON,
 887         .driver = {
 888                 .name   = "lm75",
 889                 .of_match_table = of_match_ptr(lm75_of_match),
 890                 .pm     = LM75_DEV_PM_OPS,
 891         },
 892         .probe          = lm75_probe,
 893         .id_table       = lm75_ids,
 894         .detect         = lm75_detect,
 895         .address_list   = normal_i2c,
 896 };
 897 
 898 module_i2c_driver(lm75_driver);
 899 
 900 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 901 MODULE_DESCRIPTION("LM75 driver");
 902 MODULE_LICENSE("GPL");