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/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         tcn75,
  54         tmp100,
  55         tmp101,
  56         tmp105,
  57         tmp112,
  58         tmp175,
  59         tmp275,
  60         tmp75,
  61         tmp75c,
  62 };
  63
  64 /* Addresses scanned */
  65 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  66                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  67
  68 /* The LM75 registers */
  69 #define LM75_REG_TEMP           0x00
  70 #define LM75_REG_CONF           0x01
  71 #define LM75_REG_HYST           0x02
  72 #define LM75_REG_MAX            0x03
  73
  74 /* Each client has this additional data */
  75 struct lm75_data {
  76         struct i2c_client       *client;
  77         struct regmap           *regmap;
  78         u8                      orig_conf;
  79         u8                      resolution;     /* In bits, between 9 and 16 */
  80         u8                      resolution_limits;
  81         unsigned int            sample_time;    /* In ms */
  82 };
  83
  84 /*-----------------------------------------------------------------------*/
  85
  86 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
  87 {
  88         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
  89 }
  90
  91 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
  92                      u32 attr, int channel, long *val)
  93 {
  94         struct lm75_data *data = dev_get_drvdata(dev);
  95         unsigned int regval;
  96         int err, reg;
  97
  98         switch (type) {
  99         case hwmon_chip:
 100                 switch (attr) {
 101                 case hwmon_chip_update_interval:
 102                         *val = data->sample_time;
 103                         break;
 104                 default:
 105                         return -EINVAL;
 106                 }
 107                 break;
 108         case hwmon_temp:
 109                 switch (attr) {
 110                 case hwmon_temp_input:
 111                         reg = LM75_REG_TEMP;
 112                         break;
 113                 case hwmon_temp_max:
 114                         reg = LM75_REG_MAX;
 115                         break;
 116                 case hwmon_temp_max_hyst:
 117                         reg = LM75_REG_HYST;
 118                         break;
 119                 default:
 120                         return -EINVAL;
 121                 }
 122                 err = regmap_read(data->regmap, reg, &regval);
 123                 if (err < 0)
 124                         return err;
 125
 126                 *val = lm75_reg_to_mc(regval, data->resolution);
 127                 break;
 128         default:
 129                 return -EINVAL;
 130         }
 131         return 0;
 132 }
 133
 134 static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
 135                       u32 attr, int channel, long temp)
 136 {
 137         struct lm75_data *data = dev_get_drvdata(dev);
 138         u8 resolution;
 139         int reg;
 140
 141         if (type != hwmon_temp)
 142                 return -EINVAL;
 143
 144         switch (attr) {
 145         case hwmon_temp_max:
 146                 reg = LM75_REG_MAX;
 147                 break;
 148         case hwmon_temp_max_hyst:
 149                 reg = LM75_REG_HYST;
 150                 break;
 151         default:
 152                 return -EINVAL;
 153         }
 154
 155         /*
 156          * Resolution of limit registers is assumed to be the same as the
 157          * temperature input register resolution unless given explicitly.
 158          */
 159         if (data->resolution_limits)
 160                 resolution = data->resolution_limits;
 161         else
 162                 resolution = data->resolution;
 163
 164         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 165         temp = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 166                                  1000) << (16 - resolution);
 167
 168         return regmap_write(data->regmap, reg, temp);
 169 }
 170
 171 static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
 172                                u32 attr, int channel)
 173 {
 174         switch (type) {
 175         case hwmon_chip:
 176                 switch (attr) {
 177                 case hwmon_chip_update_interval:
 178                         return S_IRUGO;
 179                 }
 180                 break;
 181         case hwmon_temp:
 182                 switch (attr) {
 183                 case hwmon_temp_input:
 184                         return S_IRUGO;
 185                 case hwmon_temp_max:
 186                 case hwmon_temp_max_hyst:
 187                         return S_IRUGO | S_IWUSR;
 188                 }
 189                 break;
 190         default:
 191                 break;
 192         }
 193         return 0;
 194 }
 195
 196 /*-----------------------------------------------------------------------*/
 197
 198 /* device probe and removal */
 199
 200 /* chip configuration */
 201
 202 static const u32 lm75_chip_config[] = {
 203         HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
 204         0
 205 };
 206
 207 static const struct hwmon_channel_info lm75_chip = {
 208         .type = hwmon_chip,
 209         .config = lm75_chip_config,
 210 };
 211
 212 static const u32 lm75_temp_config[] = {
 213         HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
 214         0
 215 };
 216
 217 static const struct hwmon_channel_info lm75_temp = {
 218         .type = hwmon_temp,
 219         .config = lm75_temp_config,
 220 };
 221
 222 static const struct hwmon_channel_info *lm75_info[] = {
 223         &lm75_chip,
 224         &lm75_temp,
 225         NULL
 226 };
 227
 228 static const struct hwmon_ops lm75_hwmon_ops = {
 229         .is_visible = lm75_is_visible,
 230         .read = lm75_read,
 231         .write = lm75_write,
 232 };
 233
 234 static const struct hwmon_chip_info lm75_chip_info = {
 235         .ops = &lm75_hwmon_ops,
 236         .info = lm75_info,
 237 };
 238
 239 static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
 240 {
 241         return reg != LM75_REG_TEMP;
 242 }
 243
 244 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
 245 {
 246         return reg == LM75_REG_TEMP;
 247 }
 248
 249 static const struct regmap_config lm75_regmap_config = {
 250         .reg_bits = 8,
 251         .val_bits = 16,
 252         .max_register = LM75_REG_MAX,
 253         .writeable_reg = lm75_is_writeable_reg,
 254         .volatile_reg = lm75_is_volatile_reg,
 255         .val_format_endian = REGMAP_ENDIAN_BIG,
 256         .cache_type = REGCACHE_RBTREE,
 257         .use_single_read = true,
 258         .use_single_write = true,
 259 };
 260
 261 static void lm75_remove(void *data)
 262 {
 263         struct lm75_data *lm75 = data;
 264         struct i2c_client *client = lm75->client;
 265
 266         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 267 }
 268
 269 static int
 270 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 271 {
 272         struct device *dev = &client->dev;
 273         struct device *hwmon_dev;
 274         struct lm75_data *data;
 275         int status, err;
 276         u8 set_mask, clr_mask;
 277         int new;
 278         enum lm75_type kind;
 279
 280         if (client->dev.of_node)
 281                 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
 282         else
 283                 kind = id->driver_data;
 284
 285         if (!i2c_check_functionality(client->adapter,
 286                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 287                 return -EIO;
 288
 289         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 290         if (!data)
 291                 return -ENOMEM;
 292
 293         data->client = client;
 294
 295         data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
 296         if (IS_ERR(data->regmap))
 297                 return PTR_ERR(data->regmap);
 298
 299         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 300          * Then tweak to be more precise when appropriate.
 301          */
 302         set_mask = 0;
 303         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 304
 305         switch (kind) {
 306         case adt75:
 307                 clr_mask |= 1 << 5;             /* not one-shot mode */
 308                 data->resolution = 12;
 309                 data->sample_time = MSEC_PER_SEC / 8;
 310                 break;
 311         case ds1775:
 312         case ds75:
 313         case stds75:
 314                 clr_mask |= 3 << 5;
 315                 set_mask |= 2 << 5;             /* 11-bit mode */
 316                 data->resolution = 11;
 317                 data->sample_time = MSEC_PER_SEC;
 318                 break;
 319         case ds7505:
 320                 set_mask |= 3 << 5;             /* 12-bit mode */
 321                 data->resolution = 12;
 322                 data->sample_time = MSEC_PER_SEC / 4;
 323                 break;
 324         case g751:
 325         case lm75:
 326         case lm75a:
 327                 data->resolution = 9;
 328                 data->sample_time = MSEC_PER_SEC / 2;
 329                 break;
 330         case lm75b:
 331                 data->resolution = 11;
 332                 data->sample_time = MSEC_PER_SEC / 4;
 333                 break;
 334         case max6625:
 335                 data->resolution = 9;
 336                 data->sample_time = MSEC_PER_SEC / 4;
 337                 break;
 338         case max6626:
 339                 data->resolution = 12;
 340                 data->resolution_limits = 9;
 341                 data->sample_time = MSEC_PER_SEC / 4;
 342                 break;
 343         case max31725:
 344                 data->resolution = 16;
 345                 data->sample_time = MSEC_PER_SEC / 8;
 346                 break;
 347         case tcn75:
 348                 data->resolution = 9;
 349                 data->sample_time = MSEC_PER_SEC / 8;
 350                 break;
 351         case mcp980x:
 352                 data->resolution_limits = 9;
 353                 /* fall through */
 354         case tmp100:
 355         case tmp101:
 356                 set_mask |= 3 << 5;             /* 12-bit mode */
 357                 data->resolution = 12;
 358                 data->sample_time = MSEC_PER_SEC;
 359                 clr_mask |= 1 << 7;             /* not one-shot mode */
 360                 break;
 361         case tmp112:
 362                 set_mask |= 3 << 5;             /* 12-bit mode */
 363                 clr_mask |= 1 << 7;             /* not one-shot mode */
 364                 data->resolution = 12;
 365                 data->sample_time = MSEC_PER_SEC / 4;
 366                 break;
 367         case tmp105:
 368         case tmp175:
 369         case tmp275:
 370         case tmp75:
 371                 set_mask |= 3 << 5;             /* 12-bit mode */
 372                 clr_mask |= 1 << 7;             /* not one-shot mode */
 373                 data->resolution = 12;
 374                 data->sample_time = MSEC_PER_SEC / 2;
 375                 break;
 376         case tmp75c:
 377                 clr_mask |= 1 << 5;             /* not one-shot mode */
 378                 data->resolution = 12;
 379                 data->sample_time = MSEC_PER_SEC / 4;
 380                 break;
 381         }
 382
 383         /* configure as specified */
 384         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 385         if (status < 0) {
 386                 dev_dbg(dev, "Can't read config? %d\n", status);
 387                 return status;
 388         }
 389         data->orig_conf = status;
 390         new = status & ~clr_mask;
 391         new |= set_mask;
 392         if (status != new)
 393                 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
 394
 395         err = devm_add_action_or_reset(dev, lm75_remove, data);
 396         if (err)
 397                 return err;
 398
 399         dev_dbg(dev, "Config %02x\n", new);
 400
 401         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 402                                                          data, &lm75_chip_info,
 403                                                          NULL);
 404         if (IS_ERR(hwmon_dev))
 405                 return PTR_ERR(hwmon_dev);
 406
 407         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 408
 409         return 0;
 410 }
 411
 412 static const struct i2c_device_id lm75_ids[] = {
 413         { "adt75", adt75, },
 414         { "ds1775", ds1775, },
 415         { "ds75", ds75, },
 416         { "ds7505", ds7505, },
 417         { "g751", g751, },
 418         { "lm75", lm75, },
 419         { "lm75a", lm75a, },
 420         { "lm75b", lm75b, },
 421         { "max6625", max6625, },
 422         { "max6626", max6626, },
 423         { "max31725", max31725, },
 424         { "max31726", max31725, },
 425         { "mcp980x", mcp980x, },
 426         { "stds75", stds75, },
 427         { "tcn75", tcn75, },
 428         { "tmp100", tmp100, },
 429         { "tmp101", tmp101, },
 430         { "tmp105", tmp105, },
 431         { "tmp112", tmp112, },
 432         { "tmp175", tmp175, },
 433         { "tmp275", tmp275, },
 434         { "tmp75", tmp75, },
 435         { "tmp75c", tmp75c, },
 436         { /* LIST END */ }
 437 };
 438 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 439
 440 static const struct of_device_id lm75_of_match[] = {
 441         {
 442                 .compatible = "adi,adt75",
 443                 .data = (void *)adt75
 444         },
 445         {
 446                 .compatible = "dallas,ds1775",
 447                 .data = (void *)ds1775
 448         },
 449         {
 450                 .compatible = "dallas,ds75",
 451                 .data = (void *)ds75
 452         },
 453         {
 454                 .compatible = "dallas,ds7505",
 455                 .data = (void *)ds7505
 456         },
 457         {
 458                 .compatible = "gmt,g751",
 459                 .data = (void *)g751
 460         },
 461         {
 462                 .compatible = "national,lm75",
 463                 .data = (void *)lm75
 464         },
 465         {
 466                 .compatible = "national,lm75a",
 467                 .data = (void *)lm75a
 468         },
 469         {
 470                 .compatible = "national,lm75b",
 471                 .data = (void *)lm75b
 472         },
 473         {
 474                 .compatible = "maxim,max6625",
 475                 .data = (void *)max6625
 476         },
 477         {
 478                 .compatible = "maxim,max6626",
 479                 .data = (void *)max6626
 480         },
 481         {
 482                 .compatible = "maxim,max31725",
 483                 .data = (void *)max31725
 484         },
 485         {
 486                 .compatible = "maxim,max31726",
 487                 .data = (void *)max31725
 488         },
 489         {
 490                 .compatible = "maxim,mcp980x",
 491                 .data = (void *)mcp980x
 492         },
 493         {
 494                 .compatible = "st,stds75",
 495                 .data = (void *)stds75
 496         },
 497         {
 498                 .compatible = "microchip,tcn75",
 499                 .data = (void *)tcn75
 500         },
 501         {
 502                 .compatible = "ti,tmp100",
 503                 .data = (void *)tmp100
 504         },
 505         {
 506                 .compatible = "ti,tmp101",
 507                 .data = (void *)tmp101
 508         },
 509         {
 510                 .compatible = "ti,tmp105",
 511                 .data = (void *)tmp105
 512         },
 513         {
 514                 .compatible = "ti,tmp112",
 515                 .data = (void *)tmp112
 516         },
 517         {
 518                 .compatible = "ti,tmp175",
 519                 .data = (void *)tmp175
 520         },
 521         {
 522                 .compatible = "ti,tmp275",
 523                 .data = (void *)tmp275
 524         },
 525         {
 526                 .compatible = "ti,tmp75",
 527                 .data = (void *)tmp75
 528         },
 529         {
 530                 .compatible = "ti,tmp75c",
 531                 .data = (void *)tmp75c
 532         },
 533         { },
 534 };
 535 MODULE_DEVICE_TABLE(of, lm75_of_match);
 536
 537 #define LM75A_ID 0xA1
 538
 539 /* Return 0 if detection is successful, -ENODEV otherwise */
 540 static int lm75_detect(struct i2c_client *new_client,
 541                        struct i2c_board_info *info)
 542 {
 543         struct i2c_adapter *adapter = new_client->adapter;
 544         int i;
 545         int conf, hyst, os;
 546         bool is_lm75a = 0;
 547
 548         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 549                                      I2C_FUNC_SMBUS_WORD_DATA))
 550                 return -ENODEV;
 551
 552         /*
 553          * Now, we do the remaining detection. There is no identification-
 554          * dedicated register so we have to rely on several tricks:
 555          * unused bits, registers cycling over 8-address boundaries,
 556          * addresses 0x04-0x07 returning the last read value.
 557          * The cycling+unused addresses combination is not tested,
 558          * since it would significantly slow the detection down and would
 559          * hardly add any value.
 560          *
 561          * The National Semiconductor LM75A is different than earlier
 562          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 563          * revision, with 1 being the only revision in existence) in
 564          * register 7, and unused registers return 0xff rather than the
 565          * last read value.
 566          *
 567          * Note that this function only detects the original National
 568          * Semiconductor LM75 and the LM75A. Clones from other vendors
 569          * aren't detected, on purpose, because they are typically never
 570          * found on PC hardware. They are found on embedded designs where
 571          * they can be instantiated explicitly so detection is not needed.
 572          * The absence of identification registers on all these clones
 573          * would make their exhaustive detection very difficult and weak,
 574          * and odds are that the driver would bind to unsupported devices.
 575          */
 576
 577         /* Unused bits */
 578         conf = i2c_smbus_read_byte_data(new_client, 1);
 579         if (conf & 0xe0)
 580                 return -ENODEV;
 581
 582         /* First check for LM75A */
 583         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 584                 /* LM75A returns 0xff on unused registers so
 585                    just to be sure we check for that too. */
 586                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 587                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 588                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 589                         return -ENODEV;
 590                 is_lm75a = 1;
 591                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 592                 os = i2c_smbus_read_byte_data(new_client, 3);
 593         } else { /* Traditional style LM75 detection */
 594                 /* Unused addresses */
 595                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 596                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 597                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 598                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 599                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 600                         return -ENODEV;
 601                 os = i2c_smbus_read_byte_data(new_client, 3);
 602                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 603                  || i2c_smbus_read_byte_data(new_client, 5) != os
 604                  || i2c_smbus_read_byte_data(new_client, 6) != os
 605                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 606                         return -ENODEV;
 607         }
 608         /*
 609          * It is very unlikely that this is a LM75 if both
 610          * hysteresis and temperature limit registers are 0.
 611          */
 612         if (hyst == 0 && os == 0)
 613                 return -ENODEV;
 614
 615         /* Addresses cycling */
 616         for (i = 8; i <= 248; i += 40) {
 617                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 618                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 619                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 620                         return -ENODEV;
 621                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 622                                 != LM75A_ID)
 623                         return -ENODEV;
 624         }
 625
 626         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 627
 628         return 0;
 629 }
 630
 631 #ifdef CONFIG_PM
 632 static int lm75_suspend(struct device *dev)
 633 {
 634         int status;
 635         struct i2c_client *client = to_i2c_client(dev);
 636         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 637         if (status < 0) {
 638                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 639                 return status;
 640         }
 641         status = status | LM75_SHUTDOWN;
 642         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 643         return 0;
 644 }
 645
 646 static int lm75_resume(struct device *dev)
 647 {
 648         int status;
 649         struct i2c_client *client = to_i2c_client(dev);
 650         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 651         if (status < 0) {
 652                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 653                 return status;
 654         }
 655         status = status & ~LM75_SHUTDOWN;
 656         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 657         return 0;
 658 }
 659
 660 static const struct dev_pm_ops lm75_dev_pm_ops = {
 661         .suspend        = lm75_suspend,
 662         .resume         = lm75_resume,
 663 };
 664 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 665 #else
 666 #define LM75_DEV_PM_OPS NULL
 667 #endif /* CONFIG_PM */
 668
 669 static struct i2c_driver lm75_driver = {
 670         .class          = I2C_CLASS_HWMON,
 671         .driver = {
 672                 .name   = "lm75",
 673                 .of_match_table = of_match_ptr(lm75_of_match),
 674                 .pm     = LM75_DEV_PM_OPS,
 675         },
 676         .probe          = lm75_probe,
 677         .id_table       = lm75_ids,
 678         .detect         = lm75_detect,
 679         .address_list   = normal_i2c,
 680 };
 681
 682 module_i2c_driver(lm75_driver);
 683
 684 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 685 MODULE_DESCRIPTION("LM75 driver");
 686 MODULE_LICENSE("GPL");