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 <[email protected]>
   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/of_device.h>
  30 #include <linux/of.h>
  31 #include <linux/regmap.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         max31725,
  51         mcp980x,
  52         stds75,
  53         stlm75,
  54         tcn75,
  55         tmp100,
  56         tmp101,
  57         tmp105,
  58         tmp112,
  59         tmp175,
  60         tmp275,
  61         tmp75,
  62         tmp75b,
  63         tmp75c,
  64 };
  65
  66 /* Addresses scanned */
  67 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  68                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  69
  70 /* The LM75 registers */
  71 #define LM75_REG_TEMP           0x00
  72 #define LM75_REG_CONF           0x01
  73 #define LM75_REG_HYST           0x02
  74 #define LM75_REG_MAX            0x03
  75
  76 /* Each client has this additional data */
  77 struct lm75_data {
  78         struct i2c_client       *client;
  79         struct regmap           *regmap;
  80         u8                      orig_conf;
  81         u8                      resolution;     /* In bits, between 9 and 16 */
  82         u8                      resolution_limits;
  83         unsigned int            sample_time;    /* In ms */
  84 };
  85
  86 /*-----------------------------------------------------------------------*/
  87
  88 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
  89 {
  90         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
  91 }
  92
  93 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
  94                      u32 attr, int channel, long *val)
  95 {
  96         struct lm75_data *data = dev_get_drvdata(dev);
  97         unsigned int regval;
  98         int err, reg;
  99
 100         switch (type) {
 101         case hwmon_chip:
 102                 switch (attr) {
 103                 case hwmon_chip_update_interval:
 104                         *val = data->sample_time;
 105                         break;
 106                 default:
 107                         return -EINVAL;
 108                 }
 109                 break;
 110         case hwmon_temp:
 111                 switch (attr) {
 112                 case hwmon_temp_input:
 113                         reg = LM75_REG_TEMP;
 114                         break;
 115                 case hwmon_temp_max:
 116                         reg = LM75_REG_MAX;
 117                         break;
 118                 case hwmon_temp_max_hyst:
 119                         reg = LM75_REG_HYST;
 120                         break;
 121                 default:
 122                         return -EINVAL;
 123                 }
 124                 err = regmap_read(data->regmap, reg, &regval);
 125                 if (err < 0)
 126                         return err;
 127
 128                 *val = lm75_reg_to_mc(regval, data->resolution);
 129                 break;
 130         default:
 131                 return -EINVAL;
 132         }
 133         return 0;
 134 }
 135
 136 static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
 137                       u32 attr, int channel, long temp)
 138 {
 139         struct lm75_data *data = dev_get_drvdata(dev);
 140         u8 resolution;
 141         int reg;
 142
 143         if (type != hwmon_temp)
 144                 return -EINVAL;
 145
 146         switch (attr) {
 147         case hwmon_temp_max:
 148                 reg = LM75_REG_MAX;
 149                 break;
 150         case hwmon_temp_max_hyst:
 151                 reg = LM75_REG_HYST;
 152                 break;
 153         default:
 154                 return -EINVAL;
 155         }
 156
 157         /*
 158          * Resolution of limit registers is assumed to be the same as the
 159          * temperature input register resolution unless given explicitly.
 160          */
 161         if (data->resolution_limits)
 162                 resolution = data->resolution_limits;
 163         else
 164                 resolution = data->resolution;
 165
 166         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 167         temp = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 168                                  1000) << (16 - resolution);
 169
 170         return regmap_write(data->regmap, reg, temp);
 171 }
 172
 173 static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
 174                                u32 attr, int channel)
 175 {
 176         switch (type) {
 177         case hwmon_chip:
 178                 switch (attr) {
 179                 case hwmon_chip_update_interval:
 180                         return 0444;
 181                 }
 182                 break;
 183         case hwmon_temp:
 184                 switch (attr) {
 185                 case hwmon_temp_input:
 186                         return 0444;
 187                 case hwmon_temp_max:
 188                 case hwmon_temp_max_hyst:
 189                         return 0644;
 190                 }
 191                 break;
 192         default:
 193                 break;
 194         }
 195         return 0;
 196 }
 197
 198 static const struct hwmon_channel_info *lm75_info[] = {
 199         HWMON_CHANNEL_INFO(chip,
 200                            HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
 201         HWMON_CHANNEL_INFO(temp,
 202                            HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
 203         NULL
 204 };
 205
 206 static const struct hwmon_ops lm75_hwmon_ops = {
 207         .is_visible = lm75_is_visible,
 208         .read = lm75_read,
 209         .write = lm75_write,
 210 };
 211
 212 static const struct hwmon_chip_info lm75_chip_info = {
 213         .ops = &lm75_hwmon_ops,
 214         .info = lm75_info,
 215 };
 216
 217 static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
 218 {
 219         return reg != LM75_REG_TEMP;
 220 }
 221
 222 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
 223 {
 224         return reg == LM75_REG_TEMP;
 225 }
 226
 227 static const struct regmap_config lm75_regmap_config = {
 228         .reg_bits = 8,
 229         .val_bits = 16,
 230         .max_register = LM75_REG_MAX,
 231         .writeable_reg = lm75_is_writeable_reg,
 232         .volatile_reg = lm75_is_volatile_reg,
 233         .val_format_endian = REGMAP_ENDIAN_BIG,
 234         .cache_type = REGCACHE_RBTREE,
 235         .use_single_read = true,
 236         .use_single_write = true,
 237 };
 238
 239 static void lm75_remove(void *data)
 240 {
 241         struct lm75_data *lm75 = data;
 242         struct i2c_client *client = lm75->client;
 243
 244         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 245 }
 246
 247 static int
 248 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 249 {
 250         struct device *dev = &client->dev;
 251         struct device *hwmon_dev;
 252         struct lm75_data *data;
 253         int status, err;
 254         u8 set_mask, clr_mask;
 255         int new;
 256         enum lm75_type kind;
 257
 258         if (client->dev.of_node)
 259                 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
 260         else
 261                 kind = id->driver_data;
 262
 263         if (!i2c_check_functionality(client->adapter,
 264                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 265                 return -EIO;
 266
 267         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 268         if (!data)
 269                 return -ENOMEM;
 270
 271         data->client = client;
 272
 273         data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
 274         if (IS_ERR(data->regmap))
 275                 return PTR_ERR(data->regmap);
 276
 277         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 278          * Then tweak to be more precise when appropriate.
 279          */
 280         set_mask = 0;
 281         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 282
 283         switch (kind) {
 284         case adt75:
 285                 clr_mask |= 1 << 5;             /* not one-shot mode */
 286                 data->resolution = 12;
 287                 data->sample_time = MSEC_PER_SEC / 8;
 288                 break;
 289         case ds1775:
 290         case ds75:
 291         case stds75:
 292                 clr_mask |= 3 << 5;
 293                 set_mask |= 2 << 5;             /* 11-bit mode */
 294                 data->resolution = 11;
 295                 data->sample_time = MSEC_PER_SEC;
 296                 break;
 297         case stlm75:
 298                 data->resolution = 9;
 299                 data->sample_time = MSEC_PER_SEC / 5;
 300                 break;
 301         case ds7505:
 302                 set_mask |= 3 << 5;             /* 12-bit mode */
 303                 data->resolution = 12;
 304                 data->sample_time = MSEC_PER_SEC / 4;
 305                 break;
 306         case g751:
 307         case lm75:
 308         case lm75a:
 309                 data->resolution = 9;
 310                 data->sample_time = MSEC_PER_SEC / 2;
 311                 break;
 312         case lm75b:
 313                 data->resolution = 11;
 314                 data->sample_time = MSEC_PER_SEC / 4;
 315                 break;
 316         case max6625:
 317                 data->resolution = 9;
 318                 data->sample_time = MSEC_PER_SEC / 4;
 319                 break;
 320         case max6626:
 321                 data->resolution = 12;
 322                 data->resolution_limits = 9;
 323                 data->sample_time = MSEC_PER_SEC / 4;
 324                 break;
 325         case max31725:
 326                 data->resolution = 16;
 327                 data->sample_time = MSEC_PER_SEC / 8;
 328                 break;
 329         case tcn75:
 330                 data->resolution = 9;
 331                 data->sample_time = MSEC_PER_SEC / 8;
 332                 break;
 333         case mcp980x:
 334                 data->resolution_limits = 9;
 335                 /* fall through */
 336         case tmp100:
 337         case tmp101:
 338                 set_mask |= 3 << 5;             /* 12-bit mode */
 339                 data->resolution = 12;
 340                 data->sample_time = MSEC_PER_SEC;
 341                 clr_mask |= 1 << 7;             /* not one-shot mode */
 342                 break;
 343         case tmp112:
 344                 set_mask |= 3 << 5;             /* 12-bit mode */
 345                 clr_mask |= 1 << 7;             /* not one-shot mode */
 346                 data->resolution = 12;
 347                 data->sample_time = MSEC_PER_SEC / 4;
 348                 break;
 349         case tmp105:
 350         case tmp175:
 351         case tmp275:
 352         case tmp75:
 353                 set_mask |= 3 << 5;             /* 12-bit mode */
 354                 clr_mask |= 1 << 7;             /* not one-shot mode */
 355                 data->resolution = 12;
 356                 data->sample_time = MSEC_PER_SEC / 2;
 357                 break;
 358         case tmp75b:  /* not one-shot mode, Conversion rate 37Hz */
 359                 clr_mask |= 1 << 15 | 0x3 << 13;
 360                 data->resolution = 12;
 361                 data->sample_time = MSEC_PER_SEC / 37;
 362                 break;
 363         case tmp75c:
 364                 clr_mask |= 1 << 5;             /* not one-shot mode */
 365                 data->resolution = 12;
 366                 data->sample_time = MSEC_PER_SEC / 4;
 367                 break;
 368         }
 369
 370         /* configure as specified */
 371         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 372         if (status < 0) {
 373                 dev_dbg(dev, "Can't read config? %d\n", status);
 374                 return status;
 375         }
 376         data->orig_conf = status;
 377         new = status & ~clr_mask;
 378         new |= set_mask;
 379         if (status != new)
 380                 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
 381
 382         err = devm_add_action_or_reset(dev, lm75_remove, data);
 383         if (err)
 384                 return err;
 385
 386         dev_dbg(dev, "Config %02x\n", new);
 387
 388         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 389                                                          data, &lm75_chip_info,
 390                                                          NULL);
 391         if (IS_ERR(hwmon_dev))
 392                 return PTR_ERR(hwmon_dev);
 393
 394         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 395
 396         return 0;
 397 }
 398
 399 static const struct i2c_device_id lm75_ids[] = {
 400         { "adt75", adt75, },
 401         { "ds1775", ds1775, },
 402         { "ds75", ds75, },
 403         { "ds7505", ds7505, },
 404         { "g751", g751, },
 405         { "lm75", lm75, },
 406         { "lm75a", lm75a, },
 407         { "lm75b", lm75b, },
 408         { "max6625", max6625, },
 409         { "max6626", max6626, },
 410         { "max31725", max31725, },
 411         { "max31726", max31725, },
 412         { "mcp980x", mcp980x, },
 413         { "stds75", stds75, },
 414         { "stlm75", stlm75, },
 415         { "tcn75", tcn75, },
 416         { "tmp100", tmp100, },
 417         { "tmp101", tmp101, },
 418         { "tmp105", tmp105, },
 419         { "tmp112", tmp112, },
 420         { "tmp175", tmp175, },
 421         { "tmp275", tmp275, },
 422         { "tmp75", tmp75, },
 423         { "tmp75b", tmp75b, },
 424         { "tmp75c", tmp75c, },
 425         { /* LIST END */ }
 426 };
 427 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 428
 429 static const struct of_device_id __maybe_unused lm75_of_match[] = {
 430         {
 431                 .compatible = "adi,adt75",
 432                 .data = (void *)adt75
 433         },
 434         {
 435                 .compatible = "dallas,ds1775",
 436                 .data = (void *)ds1775
 437         },
 438         {
 439                 .compatible = "dallas,ds75",
 440                 .data = (void *)ds75
 441         },
 442         {
 443                 .compatible = "dallas,ds7505",
 444                 .data = (void *)ds7505
 445         },
 446         {
 447                 .compatible = "gmt,g751",
 448                 .data = (void *)g751
 449         },
 450         {
 451                 .compatible = "national,lm75",
 452                 .data = (void *)lm75
 453         },
 454         {
 455                 .compatible = "national,lm75a",
 456                 .data = (void *)lm75a
 457         },
 458         {
 459                 .compatible = "national,lm75b",
 460                 .data = (void *)lm75b
 461         },
 462         {
 463                 .compatible = "maxim,max6625",
 464                 .data = (void *)max6625
 465         },
 466         {
 467                 .compatible = "maxim,max6626",
 468                 .data = (void *)max6626
 469         },
 470         {
 471                 .compatible = "maxim,max31725",
 472                 .data = (void *)max31725
 473         },
 474         {
 475                 .compatible = "maxim,max31726",
 476                 .data = (void *)max31725
 477         },
 478         {
 479                 .compatible = "maxim,mcp980x",
 480                 .data = (void *)mcp980x
 481         },
 482         {
 483                 .compatible = "st,stds75",
 484                 .data = (void *)stds75
 485         },
 486         {
 487                 .compatible = "st,stlm75",
 488                 .data = (void *)stlm75
 489         },
 490         {
 491                 .compatible = "microchip,tcn75",
 492                 .data = (void *)tcn75
 493         },
 494         {
 495                 .compatible = "ti,tmp100",
 496                 .data = (void *)tmp100
 497         },
 498         {
 499                 .compatible = "ti,tmp101",
 500                 .data = (void *)tmp101
 501         },
 502         {
 503                 .compatible = "ti,tmp105",
 504                 .data = (void *)tmp105
 505         },
 506         {
 507                 .compatible = "ti,tmp112",
 508                 .data = (void *)tmp112
 509         },
 510         {
 511                 .compatible = "ti,tmp175",
 512                 .data = (void *)tmp175
 513         },
 514         {
 515                 .compatible = "ti,tmp275",
 516                 .data = (void *)tmp275
 517         },
 518         {
 519                 .compatible = "ti,tmp75",
 520                 .data = (void *)tmp75
 521         },
 522         {
 523                 .compatible = "ti,tmp75b",
 524                 .data = (void *)tmp75b
 525         },
 526         {
 527                 .compatible = "ti,tmp75c",
 528                 .data = (void *)tmp75c
 529         },
 530         { },
 531 };
 532 MODULE_DEVICE_TABLE(of, lm75_of_match);
 533
 534 #define LM75A_ID 0xA1
 535
 536 /* Return 0 if detection is successful, -ENODEV otherwise */
 537 static int lm75_detect(struct i2c_client *new_client,
 538                        struct i2c_board_info *info)
 539 {
 540         struct i2c_adapter *adapter = new_client->adapter;
 541         int i;
 542         int conf, hyst, os;
 543         bool is_lm75a = 0;
 544
 545         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 546                                      I2C_FUNC_SMBUS_WORD_DATA))
 547                 return -ENODEV;
 548
 549         /*
 550          * Now, we do the remaining detection. There is no identification-
 551          * dedicated register so we have to rely on several tricks:
 552          * unused bits, registers cycling over 8-address boundaries,
 553          * addresses 0x04-0x07 returning the last read value.
 554          * The cycling+unused addresses combination is not tested,
 555          * since it would significantly slow the detection down and would
 556          * hardly add any value.
 557          *
 558          * The National Semiconductor LM75A is different than earlier
 559          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 560          * revision, with 1 being the only revision in existence) in
 561          * register 7, and unused registers return 0xff rather than the
 562          * last read value.
 563          *
 564          * Note that this function only detects the original National
 565          * Semiconductor LM75 and the LM75A. Clones from other vendors
 566          * aren't detected, on purpose, because they are typically never
 567          * found on PC hardware. They are found on embedded designs where
 568          * they can be instantiated explicitly so detection is not needed.
 569          * The absence of identification registers on all these clones
 570          * would make their exhaustive detection very difficult and weak,
 571          * and odds are that the driver would bind to unsupported devices.
 572          */
 573
 574         /* Unused bits */
 575         conf = i2c_smbus_read_byte_data(new_client, 1);
 576         if (conf & 0xe0)
 577                 return -ENODEV;
 578
 579         /* First check for LM75A */
 580         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 581                 /* LM75A returns 0xff on unused registers so
 582                    just to be sure we check for that too. */
 583                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 584                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 585                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 586                         return -ENODEV;
 587                 is_lm75a = 1;
 588                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 589                 os = i2c_smbus_read_byte_data(new_client, 3);
 590         } else { /* Traditional style LM75 detection */
 591                 /* Unused addresses */
 592                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 593                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 594                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 595                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 596                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 597                         return -ENODEV;
 598                 os = i2c_smbus_read_byte_data(new_client, 3);
 599                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 600                  || i2c_smbus_read_byte_data(new_client, 5) != os
 601                  || i2c_smbus_read_byte_data(new_client, 6) != os
 602                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 603                         return -ENODEV;
 604         }
 605         /*
 606          * It is very unlikely that this is a LM75 if both
 607          * hysteresis and temperature limit registers are 0.
 608          */
 609         if (hyst == 0 && os == 0)
 610                 return -ENODEV;
 611
 612         /* Addresses cycling */
 613         for (i = 8; i <= 248; i += 40) {
 614                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 615                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 616                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 617                         return -ENODEV;
 618                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 619                                 != LM75A_ID)
 620                         return -ENODEV;
 621         }
 622
 623         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 624
 625         return 0;
 626 }
 627
 628 #ifdef CONFIG_PM
 629 static int lm75_suspend(struct device *dev)
 630 {
 631         int status;
 632         struct i2c_client *client = to_i2c_client(dev);
 633         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 634         if (status < 0) {
 635                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 636                 return status;
 637         }
 638         status = status | LM75_SHUTDOWN;
 639         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 640         return 0;
 641 }
 642
 643 static int lm75_resume(struct device *dev)
 644 {
 645         int status;
 646         struct i2c_client *client = to_i2c_client(dev);
 647         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 648         if (status < 0) {
 649                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 650                 return status;
 651         }
 652         status = status & ~LM75_SHUTDOWN;
 653         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 654         return 0;
 655 }
 656
 657 static const struct dev_pm_ops lm75_dev_pm_ops = {
 658         .suspend        = lm75_suspend,
 659         .resume         = lm75_resume,
 660 };
 661 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 662 #else
 663 #define LM75_DEV_PM_OPS NULL
 664 #endif /* CONFIG_PM */
 665
 666 static struct i2c_driver lm75_driver = {
 667         .class          = I2C_CLASS_HWMON,
 668         .driver = {
 669                 .name   = "lm75",
 670                 .of_match_table = of_match_ptr(lm75_of_match),
 671                 .pm     = LM75_DEV_PM_OPS,
 672         },
 673         .probe          = lm75_probe,
 674         .id_table       = lm75_ids,
 675         .detect         = lm75_detect,
 676         .address_list   = normal_i2c,
 677 };
 678
 679 module_i2c_driver(lm75_driver);
 680
 681 MODULE_AUTHOR("Frodo Looijaard <[email protected]>");
 682 MODULE_DESCRIPTION("LM75 driver");
 683 MODULE_LICENSE("GPL");