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         mcp980x,
  51         stds75,
  52         tcn75,
  53         tmp100,
  54         tmp101,
  55         tmp105,
  56         tmp112,
  57         tmp175,
  58         tmp275,
  59         tmp75,
  60         tmp75c,
  61 };
  62
  63 /* Addresses scanned */
  64 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  65                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  66
  67
  68 /* The LM75 registers */
  69 #define LM75_REG_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 12 */
  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_rw = true,
 258 };
 259
 260 static void lm75_remove(void *data)
 261 {
 262         struct lm75_data *lm75 = data;
 263         struct i2c_client *client = lm75->client;
 264
 265         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 266 }
 267
 268 static int
 269 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 270 {
 271         struct device *dev = &client->dev;
 272         struct device *hwmon_dev;
 273         struct lm75_data *data;
 274         int status, err;
 275         u8 set_mask, clr_mask;
 276         int new;
 277         enum lm75_type kind;
 278
 279         if (client->dev.of_node)
 280                 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
 281         else
 282                 kind = id->driver_data;
 283
 284         if (!i2c_check_functionality(client->adapter,
 285                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 286                 return -EIO;
 287
 288         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 289         if (!data)
 290                 return -ENOMEM;
 291
 292         data->client = client;
 293
 294         data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
 295         if (IS_ERR(data->regmap))
 296                 return PTR_ERR(data->regmap);
 297
 298         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 299          * Then tweak to be more precise when appropriate.
 300          */
 301         set_mask = 0;
 302         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 303
 304         switch (kind) {
 305         case adt75:
 306                 clr_mask |= 1 << 5;             /* not one-shot mode */
 307                 data->resolution = 12;
 308                 data->sample_time = MSEC_PER_SEC / 8;
 309                 break;
 310         case ds1775:
 311         case ds75:
 312         case stds75:
 313                 clr_mask |= 3 << 5;
 314                 set_mask |= 2 << 5;             /* 11-bit mode */
 315                 data->resolution = 11;
 316                 data->sample_time = MSEC_PER_SEC;
 317                 break;
 318         case ds7505:
 319                 set_mask |= 3 << 5;             /* 12-bit mode */
 320                 data->resolution = 12;
 321                 data->sample_time = MSEC_PER_SEC / 4;
 322                 break;
 323         case g751:
 324         case lm75:
 325         case lm75a:
 326                 data->resolution = 9;
 327                 data->sample_time = MSEC_PER_SEC / 2;
 328                 break;
 329         case lm75b:
 330                 data->resolution = 11;
 331                 data->sample_time = MSEC_PER_SEC / 4;
 332                 break;
 333         case max6625:
 334                 data->resolution = 9;
 335                 data->sample_time = MSEC_PER_SEC / 4;
 336                 break;
 337         case max6626:
 338                 data->resolution = 12;
 339                 data->resolution_limits = 9;
 340                 data->sample_time = MSEC_PER_SEC / 4;
 341                 break;
 342         case tcn75:
 343                 data->resolution = 9;
 344                 data->sample_time = MSEC_PER_SEC / 8;
 345                 break;
 346         case mcp980x:
 347                 data->resolution_limits = 9;
 348                 /* fall through */
 349         case tmp100:
 350         case tmp101:
 351                 set_mask |= 3 << 5;             /* 12-bit mode */
 352                 data->resolution = 12;
 353                 data->sample_time = MSEC_PER_SEC;
 354                 clr_mask |= 1 << 7;             /* not one-shot mode */
 355                 break;
 356         case tmp112:
 357                 set_mask |= 3 << 5;             /* 12-bit mode */
 358                 clr_mask |= 1 << 7;             /* not one-shot mode */
 359                 data->resolution = 12;
 360                 data->sample_time = MSEC_PER_SEC / 4;
 361                 break;
 362         case tmp105:
 363         case tmp175:
 364         case tmp275:
 365         case tmp75:
 366                 set_mask |= 3 << 5;             /* 12-bit mode */
 367                 clr_mask |= 1 << 7;             /* not one-shot mode */
 368                 data->resolution = 12;
 369                 data->sample_time = MSEC_PER_SEC / 2;
 370                 break;
 371         case tmp75c:
 372                 clr_mask |= 1 << 5;             /* not one-shot mode */
 373                 data->resolution = 12;
 374                 data->sample_time = MSEC_PER_SEC / 4;
 375                 break;
 376         }
 377
 378         /* configure as specified */
 379         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 380         if (status < 0) {
 381                 dev_dbg(dev, "Can't read config? %d\n", status);
 382                 return status;
 383         }
 384         data->orig_conf = status;
 385         new = status & ~clr_mask;
 386         new |= set_mask;
 387         if (status != new)
 388                 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
 389
 390         err = devm_add_action_or_reset(dev, lm75_remove, data);
 391         if (err)
 392                 return err;
 393
 394         dev_dbg(dev, "Config %02x\n", new);
 395
 396         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 397                                                          data, &lm75_chip_info,
 398                                                          NULL);
 399         if (IS_ERR(hwmon_dev))
 400                 return PTR_ERR(hwmon_dev);
 401
 402         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 403
 404         return 0;
 405 }
 406
 407 static const struct i2c_device_id lm75_ids[] = {
 408         { "adt75", adt75, },
 409         { "ds1775", ds1775, },
 410         { "ds75", ds75, },
 411         { "ds7505", ds7505, },
 412         { "g751", g751, },
 413         { "lm75", lm75, },
 414         { "lm75a", lm75a, },
 415         { "lm75b", lm75b, },
 416         { "max6625", max6625, },
 417         { "max6626", max6626, },
 418         { "mcp980x", mcp980x, },
 419         { "stds75", stds75, },
 420         { "tcn75", tcn75, },
 421         { "tmp100", tmp100, },
 422         { "tmp101", tmp101, },
 423         { "tmp105", tmp105, },
 424         { "tmp112", tmp112, },
 425         { "tmp175", tmp175, },
 426         { "tmp275", tmp275, },
 427         { "tmp75", tmp75, },
 428         { "tmp75c", tmp75c, },
 429         { /* LIST END */ }
 430 };
 431 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 432
 433 static const struct of_device_id lm75_of_match[] = {
 434         {
 435                 .compatible = "adi,adt75",
 436                 .data = (void *)adt75
 437         },
 438         {
 439                 .compatible = "dallas,ds1775",
 440                 .data = (void *)ds1775
 441         },
 442         {
 443                 .compatible = "dallas,ds75",
 444                 .data = (void *)ds75
 445         },
 446         {
 447                 .compatible = "dallas,ds7505",
 448                 .data = (void *)ds7505
 449         },
 450         {
 451                 .compatible = "gmt,g751",
 452                 .data = (void *)g751
 453         },
 454         {
 455                 .compatible = "national,lm75",
 456                 .data = (void *)lm75
 457         },
 458         {
 459                 .compatible = "national,lm75a",
 460                 .data = (void *)lm75a
 461         },
 462         {
 463                 .compatible = "national,lm75b",
 464                 .data = (void *)lm75b
 465         },
 466         {
 467                 .compatible = "maxim,max6625",
 468                 .data = (void *)max6625
 469         },
 470         {
 471                 .compatible = "maxim,max6626",
 472                 .data = (void *)max6626
 473         },
 474         {
 475                 .compatible = "maxim,mcp980x",
 476                 .data = (void *)mcp980x
 477         },
 478         {
 479                 .compatible = "st,stds75",
 480                 .data = (void *)stds75
 481         },
 482         {
 483                 .compatible = "microchip,tcn75",
 484                 .data = (void *)tcn75
 485         },
 486         {
 487                 .compatible = "ti,tmp100",
 488                 .data = (void *)tmp100
 489         },
 490         {
 491                 .compatible = "ti,tmp101",
 492                 .data = (void *)tmp101
 493         },
 494         {
 495                 .compatible = "ti,tmp105",
 496                 .data = (void *)tmp105
 497         },
 498         {
 499                 .compatible = "ti,tmp112",
 500                 .data = (void *)tmp112
 501         },
 502         {
 503                 .compatible = "ti,tmp175",
 504                 .data = (void *)tmp175
 505         },
 506         {
 507                 .compatible = "ti,tmp275",
 508                 .data = (void *)tmp275
 509         },
 510         {
 511                 .compatible = "ti,tmp75",
 512                 .data = (void *)tmp75
 513         },
 514         {
 515                 .compatible = "ti,tmp75c",
 516                 .data = (void *)tmp75c
 517         },
 518         { },
 519 };
 520 MODULE_DEVICE_TABLE(of, lm75_of_match);
 521
 522 #define LM75A_ID 0xA1
 523
 524 /* Return 0 if detection is successful, -ENODEV otherwise */
 525 static int lm75_detect(struct i2c_client *new_client,
 526                        struct i2c_board_info *info)
 527 {
 528         struct i2c_adapter *adapter = new_client->adapter;
 529         int i;
 530         int conf, hyst, os;
 531         bool is_lm75a = 0;
 532
 533         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 534                                      I2C_FUNC_SMBUS_WORD_DATA))
 535                 return -ENODEV;
 536
 537         /*
 538          * Now, we do the remaining detection. There is no identification-
 539          * dedicated register so we have to rely on several tricks:
 540          * unused bits, registers cycling over 8-address boundaries,
 541          * addresses 0x04-0x07 returning the last read value.
 542          * The cycling+unused addresses combination is not tested,
 543          * since it would significantly slow the detection down and would
 544          * hardly add any value.
 545          *
 546          * The National Semiconductor LM75A is different than earlier
 547          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 548          * revision, with 1 being the only revision in existence) in
 549          * register 7, and unused registers return 0xff rather than the
 550          * last read value.
 551          *
 552          * Note that this function only detects the original National
 553          * Semiconductor LM75 and the LM75A. Clones from other vendors
 554          * aren't detected, on purpose, because they are typically never
 555          * found on PC hardware. They are found on embedded designs where
 556          * they can be instantiated explicitly so detection is not needed.
 557          * The absence of identification registers on all these clones
 558          * would make their exhaustive detection very difficult and weak,
 559          * and odds are that the driver would bind to unsupported devices.
 560          */
 561
 562         /* Unused bits */
 563         conf = i2c_smbus_read_byte_data(new_client, 1);
 564         if (conf & 0xe0)
 565                 return -ENODEV;
 566
 567         /* First check for LM75A */
 568         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 569                 /* LM75A returns 0xff on unused registers so
 570                    just to be sure we check for that too. */
 571                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 572                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 573                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 574                         return -ENODEV;
 575                 is_lm75a = 1;
 576                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 577                 os = i2c_smbus_read_byte_data(new_client, 3);
 578         } else { /* Traditional style LM75 detection */
 579                 /* Unused addresses */
 580                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 581                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 582                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 583                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 584                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 585                         return -ENODEV;
 586                 os = i2c_smbus_read_byte_data(new_client, 3);
 587                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 588                  || i2c_smbus_read_byte_data(new_client, 5) != os
 589                  || i2c_smbus_read_byte_data(new_client, 6) != os
 590                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 591                         return -ENODEV;
 592         }
 593         /*
 594          * It is very unlikely that this is a LM75 if both
 595          * hysteresis and temperature limit registers are 0.
 596          */
 597         if (hyst == 0 && os == 0)
 598                 return -ENODEV;
 599
 600         /* Addresses cycling */
 601         for (i = 8; i <= 248; i += 40) {
 602                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 603                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 604                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 605                         return -ENODEV;
 606                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 607                                 != LM75A_ID)
 608                         return -ENODEV;
 609         }
 610
 611         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 612
 613         return 0;
 614 }
 615
 616 #ifdef CONFIG_PM
 617 static int lm75_suspend(struct device *dev)
 618 {
 619         int status;
 620         struct i2c_client *client = to_i2c_client(dev);
 621         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 622         if (status < 0) {
 623                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 624                 return status;
 625         }
 626         status = status | LM75_SHUTDOWN;
 627         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 628         return 0;
 629 }
 630
 631 static int lm75_resume(struct device *dev)
 632 {
 633         int status;
 634         struct i2c_client *client = to_i2c_client(dev);
 635         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 636         if (status < 0) {
 637                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 638                 return status;
 639         }
 640         status = status & ~LM75_SHUTDOWN;
 641         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 642         return 0;
 643 }
 644
 645 static const struct dev_pm_ops lm75_dev_pm_ops = {
 646         .suspend        = lm75_suspend,
 647         .resume         = lm75_resume,
 648 };
 649 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 650 #else
 651 #define LM75_DEV_PM_OPS NULL
 652 #endif /* CONFIG_PM */
 653
 654 static struct i2c_driver lm75_driver = {
 655         .class          = I2C_CLASS_HWMON,
 656         .driver = {
 657                 .name   = "lm75",
 658                 .of_match_table = of_match_ptr(lm75_of_match),
 659                 .pm     = LM75_DEV_PM_OPS,
 660         },
 661         .probe          = lm75_probe,
 662         .id_table       = lm75_ids,
 663         .detect         = lm75_detect,
 664         .address_list   = normal_i2c,
 665 };
 666
 667 module_i2c_driver(lm75_driver);
 668
 669 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 670 MODULE_DESCRIPTION("LM75 driver");
 671 MODULE_LICENSE("GPL");