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/mutex.h>
  30 #include <linux/of.h>
  31 #include <linux/thermal.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 };
  61
  62 /* Addresses scanned */
  63 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  64                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  65
  66
  67 /* The LM75 registers */
  68 #define LM75_REG_CONF           0x01
  69 static const u8 LM75_REG_TEMP[3] = {
  70         0x00,           /* input */
  71         0x03,           /* max */
  72         0x02,           /* hyst */
  73 };
  74
  75 /* Each client has this additional data */
  76 struct lm75_data {
  77         struct i2c_client       *client;
  78         struct device           *hwmon_dev;
  79         struct thermal_zone_device      *tz;
  80         struct mutex            update_lock;
  81         u8                      orig_conf;
  82         u8                      resolution;     /* In bits, between 9 and 12 */
  83         u8                      resolution_limits;
  84         char                    valid;          /* !=0 if registers are valid */
  85         unsigned long           last_updated;   /* In jiffies */
  86         unsigned long           sample_time;    /* In jiffies */
  87         s16                     temp[3];        /* Register values,
  88                                                    0 = input
  89                                                    1 = max
  90                                                    2 = hyst */
  91 };
  92
  93 static int lm75_read_value(struct i2c_client *client, u8 reg);
  94 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  95 static struct lm75_data *lm75_update_device(struct device *dev);
  96
  97
  98 /*-----------------------------------------------------------------------*/
  99
 100 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
 101 {
 102         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
 103 }
 104
 105 /* sysfs attributes for hwmon */
 106
 107 static int lm75_read_temp(void *dev, long *temp)
 108 {
 109         struct lm75_data *data = lm75_update_device(dev);
 110
 111         if (IS_ERR(data))
 112                 return PTR_ERR(data);
 113
 114         *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
 115
 116         return 0;
 117 }
 118
 119 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 120                          char *buf)
 121 {
 122         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 123         struct lm75_data *data = lm75_update_device(dev);
 124
 125         if (IS_ERR(data))
 126                 return PTR_ERR(data);
 127
 128         return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
 129                                                     data->resolution));
 130 }
 131
 132 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 133                         const char *buf, size_t count)
 134 {
 135         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 136         struct lm75_data *data = dev_get_drvdata(dev);
 137         struct i2c_client *client = data->client;
 138         int nr = attr->index;
 139         long temp;
 140         int error;
 141         u8 resolution;
 142
 143         error = kstrtol(buf, 10, &temp);
 144         if (error)
 145                 return error;
 146
 147         /*
 148          * Resolution of limit registers is assumed to be the same as the
 149          * temperature input register resolution unless given explicitly.
 150          */
 151         if (attr->index && data->resolution_limits)
 152                 resolution = data->resolution_limits;
 153         else
 154                 resolution = data->resolution;
 155
 156         mutex_lock(&data->update_lock);
 157         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 158         data->temp[nr] = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 159                                            1000) << (16 - resolution);
 160         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 161         mutex_unlock(&data->update_lock);
 162         return count;
 163 }
 164
 165 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 166                         show_temp, set_temp, 1);
 167 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 168                         show_temp, set_temp, 2);
 169 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 170
 171 static struct attribute *lm75_attrs[] = {
 172         &sensor_dev_attr_temp1_input.dev_attr.attr,
 173         &sensor_dev_attr_temp1_max.dev_attr.attr,
 174         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 175
 176         NULL
 177 };
 178 ATTRIBUTE_GROUPS(lm75);
 179
 180 static const struct thermal_zone_of_device_ops lm75_of_thermal_ops = {
 181         .get_temp = lm75_read_temp,
 182 };
 183
 184 /*-----------------------------------------------------------------------*/
 185
 186 /* device probe and removal */
 187
 188 static int
 189 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 190 {
 191         struct device *dev = &client->dev;
 192         struct lm75_data *data;
 193         int status;
 194         u8 set_mask, clr_mask;
 195         int new;
 196         enum lm75_type kind = id->driver_data;
 197
 198         if (!i2c_check_functionality(client->adapter,
 199                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 200                 return -EIO;
 201
 202         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 203         if (!data)
 204                 return -ENOMEM;
 205
 206         data->client = client;
 207         i2c_set_clientdata(client, data);
 208         mutex_init(&data->update_lock);
 209
 210         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 211          * Then tweak to be more precise when appropriate.
 212          */
 213         set_mask = 0;
 214         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 215
 216         switch (kind) {
 217         case adt75:
 218                 clr_mask |= 1 << 5;             /* not one-shot mode */
 219                 data->resolution = 12;
 220                 data->sample_time = HZ / 8;
 221                 break;
 222         case ds1775:
 223         case ds75:
 224         case stds75:
 225                 clr_mask |= 3 << 5;
 226                 set_mask |= 2 << 5;             /* 11-bit mode */
 227                 data->resolution = 11;
 228                 data->sample_time = HZ;
 229                 break;
 230         case ds7505:
 231                 set_mask |= 3 << 5;             /* 12-bit mode */
 232                 data->resolution = 12;
 233                 data->sample_time = HZ / 4;
 234                 break;
 235         case g751:
 236         case lm75:
 237         case lm75a:
 238                 data->resolution = 9;
 239                 data->sample_time = HZ / 2;
 240                 break;
 241         case lm75b:
 242                 data->resolution = 11;
 243                 data->sample_time = HZ / 4;
 244                 break;
 245         case max6625:
 246                 data->resolution = 9;
 247                 data->sample_time = HZ / 4;
 248                 break;
 249         case max6626:
 250                 data->resolution = 12;
 251                 data->resolution_limits = 9;
 252                 data->sample_time = HZ / 4;
 253                 break;
 254         case tcn75:
 255                 data->resolution = 9;
 256                 data->sample_time = HZ / 8;
 257                 break;
 258         case mcp980x:
 259                 data->resolution_limits = 9;
 260                 /* fall through */
 261         case tmp100:
 262         case tmp101:
 263                 set_mask |= 3 << 5;             /* 12-bit mode */
 264                 data->resolution = 12;
 265                 data->sample_time = HZ;
 266                 clr_mask |= 1 << 7;             /* not one-shot mode */
 267                 break;
 268         case tmp112:
 269                 set_mask |= 3 << 5;             /* 12-bit mode */
 270                 clr_mask |= 1 << 7;             /* not one-shot mode */
 271                 data->resolution = 12;
 272                 data->sample_time = HZ / 4;
 273                 break;
 274         case tmp105:
 275         case tmp175:
 276         case tmp275:
 277         case tmp75:
 278                 set_mask |= 3 << 5;             /* 12-bit mode */
 279                 clr_mask |= 1 << 7;             /* not one-shot mode */
 280                 data->resolution = 12;
 281                 data->sample_time = HZ / 2;
 282                 break;
 283         }
 284
 285         /* configure as specified */
 286         status = lm75_read_value(client, LM75_REG_CONF);
 287         if (status < 0) {
 288                 dev_dbg(dev, "Can't read config? %d\n", status);
 289                 return status;
 290         }
 291         data->orig_conf = status;
 292         new = status & ~clr_mask;
 293         new |= set_mask;
 294         if (status != new)
 295                 lm75_write_value(client, LM75_REG_CONF, new);
 296         dev_dbg(dev, "Config %02x\n", new);
 297
 298         data->hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
 299                                                             data, lm75_groups);
 300         if (IS_ERR(data->hwmon_dev))
 301                 return PTR_ERR(data->hwmon_dev);
 302
 303         data->tz = thermal_zone_of_sensor_register(data->hwmon_dev, 0,
 304                                                    data->hwmon_dev,
 305                                                    &lm75_of_thermal_ops);
 306         if (IS_ERR(data->tz))
 307                 data->tz = NULL;
 308
 309         dev_info(dev, "%s: sensor '%s'\n",
 310                  dev_name(data->hwmon_dev), client->name);
 311
 312         return 0;
 313 }
 314
 315 static int lm75_remove(struct i2c_client *client)
 316 {
 317         struct lm75_data *data = i2c_get_clientdata(client);
 318
 319         thermal_zone_of_sensor_unregister(data->hwmon_dev, data->tz);
 320         hwmon_device_unregister(data->hwmon_dev);
 321         lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
 322         return 0;
 323 }
 324
 325 static const struct i2c_device_id lm75_ids[] = {
 326         { "adt75", adt75, },
 327         { "ds1775", ds1775, },
 328         { "ds75", ds75, },
 329         { "ds7505", ds7505, },
 330         { "g751", g751, },
 331         { "lm75", lm75, },
 332         { "lm75a", lm75a, },
 333         { "lm75b", lm75b, },
 334         { "max6625", max6625, },
 335         { "max6626", max6626, },
 336         { "mcp980x", mcp980x, },
 337         { "stds75", stds75, },
 338         { "tcn75", tcn75, },
 339         { "tmp100", tmp100, },
 340         { "tmp101", tmp101, },
 341         { "tmp105", tmp105, },
 342         { "tmp112", tmp112, },
 343         { "tmp175", tmp175, },
 344         { "tmp275", tmp275, },
 345         { "tmp75", tmp75, },
 346         { /* LIST END */ }
 347 };
 348 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 349
 350 #define LM75A_ID 0xA1
 351
 352 /* Return 0 if detection is successful, -ENODEV otherwise */
 353 static int lm75_detect(struct i2c_client *new_client,
 354                        struct i2c_board_info *info)
 355 {
 356         struct i2c_adapter *adapter = new_client->adapter;
 357         int i;
 358         int conf, hyst, os;
 359         bool is_lm75a = 0;
 360
 361         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 362                                      I2C_FUNC_SMBUS_WORD_DATA))
 363                 return -ENODEV;
 364
 365         /*
 366          * Now, we do the remaining detection. There is no identification-
 367          * dedicated register so we have to rely on several tricks:
 368          * unused bits, registers cycling over 8-address boundaries,
 369          * addresses 0x04-0x07 returning the last read value.
 370          * The cycling+unused addresses combination is not tested,
 371          * since it would significantly slow the detection down and would
 372          * hardly add any value.
 373          *
 374          * The National Semiconductor LM75A is different than earlier
 375          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 376          * revision, with 1 being the only revision in existence) in
 377          * register 7, and unused registers return 0xff rather than the
 378          * last read value.
 379          *
 380          * Note that this function only detects the original National
 381          * Semiconductor LM75 and the LM75A. Clones from other vendors
 382          * aren't detected, on purpose, because they are typically never
 383          * found on PC hardware. They are found on embedded designs where
 384          * they can be instantiated explicitly so detection is not needed.
 385          * The absence of identification registers on all these clones
 386          * would make their exhaustive detection very difficult and weak,
 387          * and odds are that the driver would bind to unsupported devices.
 388          */
 389
 390         /* Unused bits */
 391         conf = i2c_smbus_read_byte_data(new_client, 1);
 392         if (conf & 0xe0)
 393                 return -ENODEV;
 394
 395         /* First check for LM75A */
 396         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 397                 /* LM75A returns 0xff on unused registers so
 398                    just to be sure we check for that too. */
 399                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 400                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 401                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 402                         return -ENODEV;
 403                 is_lm75a = 1;
 404                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 405                 os = i2c_smbus_read_byte_data(new_client, 3);
 406         } else { /* Traditional style LM75 detection */
 407                 /* Unused addresses */
 408                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 409                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 410                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 411                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 412                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 413                         return -ENODEV;
 414                 os = i2c_smbus_read_byte_data(new_client, 3);
 415                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 416                  || i2c_smbus_read_byte_data(new_client, 5) != os
 417                  || i2c_smbus_read_byte_data(new_client, 6) != os
 418                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 419                         return -ENODEV;
 420         }
 421         /*
 422          * It is very unlikely that this is a LM75 if both
 423          * hysteresis and temperature limit registers are 0.
 424          */
 425         if (hyst == 0 && os == 0)
 426                 return -ENODEV;
 427
 428         /* Addresses cycling */
 429         for (i = 8; i <= 248; i += 40) {
 430                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 431                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 432                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 433                         return -ENODEV;
 434                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 435                                 != LM75A_ID)
 436                         return -ENODEV;
 437         }
 438
 439         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 440
 441         return 0;
 442 }
 443
 444 #ifdef CONFIG_PM
 445 static int lm75_suspend(struct device *dev)
 446 {
 447         int status;
 448         struct i2c_client *client = to_i2c_client(dev);
 449         status = lm75_read_value(client, LM75_REG_CONF);
 450         if (status < 0) {
 451                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 452                 return status;
 453         }
 454         status = status | LM75_SHUTDOWN;
 455         lm75_write_value(client, LM75_REG_CONF, status);
 456         return 0;
 457 }
 458
 459 static int lm75_resume(struct device *dev)
 460 {
 461         int status;
 462         struct i2c_client *client = to_i2c_client(dev);
 463         status = lm75_read_value(client, LM75_REG_CONF);
 464         if (status < 0) {
 465                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 466                 return status;
 467         }
 468         status = status & ~LM75_SHUTDOWN;
 469         lm75_write_value(client, LM75_REG_CONF, status);
 470         return 0;
 471 }
 472
 473 static const struct dev_pm_ops lm75_dev_pm_ops = {
 474         .suspend        = lm75_suspend,
 475         .resume         = lm75_resume,
 476 };
 477 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 478 #else
 479 #define LM75_DEV_PM_OPS NULL
 480 #endif /* CONFIG_PM */
 481
 482 static struct i2c_driver lm75_driver = {
 483         .class          = I2C_CLASS_HWMON,
 484         .driver = {
 485                 .name   = "lm75",
 486                 .pm     = LM75_DEV_PM_OPS,
 487         },
 488         .probe          = lm75_probe,
 489         .remove         = lm75_remove,
 490         .id_table       = lm75_ids,
 491         .detect         = lm75_detect,
 492         .address_list   = normal_i2c,
 493 };
 494
 495 /*-----------------------------------------------------------------------*/
 496
 497 /* register access */
 498
 499 /*
 500  * All registers are word-sized, except for the configuration register.
 501  * LM75 uses a high-byte first convention, which is exactly opposite to
 502  * the SMBus standard.
 503  */
 504 static int lm75_read_value(struct i2c_client *client, u8 reg)
 505 {
 506         if (reg == LM75_REG_CONF)
 507                 return i2c_smbus_read_byte_data(client, reg);
 508         else
 509                 return i2c_smbus_read_word_swapped(client, reg);
 510 }
 511
 512 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 513 {
 514         if (reg == LM75_REG_CONF)
 515                 return i2c_smbus_write_byte_data(client, reg, value);
 516         else
 517                 return i2c_smbus_write_word_swapped(client, reg, value);
 518 }
 519
 520 static struct lm75_data *lm75_update_device(struct device *dev)
 521 {
 522         struct lm75_data *data = dev_get_drvdata(dev);
 523         struct i2c_client *client = data->client;
 524         struct lm75_data *ret = data;
 525
 526         mutex_lock(&data->update_lock);
 527
 528         if (time_after(jiffies, data->last_updated + data->sample_time)
 529             || !data->valid) {
 530                 int i;
 531                 dev_dbg(&client->dev, "Starting lm75 update\n");
 532
 533                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 534                         int status;
 535
 536                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 537                         if (unlikely(status < 0)) {
 538                                 dev_dbg(dev,
 539                                         "LM75: Failed to read value: reg %d, error %d\n",
 540                                         LM75_REG_TEMP[i], status);
 541                                 ret = ERR_PTR(status);
 542                                 data->valid = 0;
 543                                 goto abort;
 544                         }
 545                         data->temp[i] = status;
 546                 }
 547                 data->last_updated = jiffies;
 548                 data->valid = 1;
 549         }
 550
 551 abort:
 552         mutex_unlock(&data->update_lock);
 553         return ret;
 554 }
 555
 556 module_i2c_driver(lm75_driver);
 557
 558 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 559 MODULE_DESCRIPTION("LM75 driver");
 560 MODULE_LICENSE("GPL");