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         max6625,
  48         max6626,
  49         mcp980x,
  50         stds75,
  51         tcn75,
  52         tmp100,
  53         tmp101,
  54         tmp105,
  55         tmp112,
  56         tmp175,
  57         tmp275,
  58         tmp75,
  59 };
  60
  61 /* Addresses scanned */
  62 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  63                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  64
  65
  66 /* The LM75 registers */
  67 #define LM75_REG_CONF           0x01
  68 static const u8 LM75_REG_TEMP[3] = {
  69         0x00,           /* input */
  70         0x03,           /* max */
  71         0x02,           /* hyst */
  72 };
  73
  74 /* Each client has this additional data */
  75 struct lm75_data {
  76         struct i2c_client       *client;
  77         struct device           *hwmon_dev;
  78         struct thermal_zone_device      *tz;
  79         struct mutex            update_lock;
  80         u8                      orig_conf;
  81         u8                      resolution;     /* In bits, between 9 and 12 */
  82         u8                      resolution_limits;
  83         char                    valid;          /* !=0 if registers are valid */
  84         unsigned long           last_updated;   /* In jiffies */
  85         unsigned long           sample_time;    /* In jiffies */
  86         s16                     temp[3];        /* Register values,
  87                                                    0 = input
  88                                                    1 = max
  89                                                    2 = hyst */
  90 };
  91
  92 static int lm75_read_value(struct i2c_client *client, u8 reg);
  93 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  94 static struct lm75_data *lm75_update_device(struct device *dev);
  95
  96
  97 /*-----------------------------------------------------------------------*/
  98
  99 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
 100 {
 101         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
 102 }
 103
 104 /* sysfs attributes for hwmon */
 105
 106 static int lm75_read_temp(void *dev, long *temp)
 107 {
 108         struct lm75_data *data = lm75_update_device(dev);
 109
 110         if (IS_ERR(data))
 111                 return PTR_ERR(data);
 112
 113         *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
 114
 115         return 0;
 116 }
 117
 118 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 119                          char *buf)
 120 {
 121         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 122         struct lm75_data *data = lm75_update_device(dev);
 123
 124         if (IS_ERR(data))
 125                 return PTR_ERR(data);
 126
 127         return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
 128                                                     data->resolution));
 129 }
 130
 131 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 132                         const char *buf, size_t count)
 133 {
 134         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 135         struct lm75_data *data = dev_get_drvdata(dev);
 136         struct i2c_client *client = data->client;
 137         int nr = attr->index;
 138         long temp;
 139         int error;
 140         u8 resolution;
 141
 142         error = kstrtol(buf, 10, &temp);
 143         if (error)
 144                 return error;
 145
 146         /*
 147          * Resolution of limit registers is assumed to be the same as the
 148          * temperature input register resolution unless given explicitly.
 149          */
 150         if (attr->index && data->resolution_limits)
 151                 resolution = data->resolution_limits;
 152         else
 153                 resolution = data->resolution;
 154
 155         mutex_lock(&data->update_lock);
 156         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 157         data->temp[nr] = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 158                                            1000) << (16 - resolution);
 159         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 160         mutex_unlock(&data->update_lock);
 161         return count;
 162 }
 163
 164 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 165                         show_temp, set_temp, 1);
 166 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 167                         show_temp, set_temp, 2);
 168 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 169
 170 static struct attribute *lm75_attrs[] = {
 171         &sensor_dev_attr_temp1_input.dev_attr.attr,
 172         &sensor_dev_attr_temp1_max.dev_attr.attr,
 173         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 174
 175         NULL
 176 };
 177 ATTRIBUTE_GROUPS(lm75);
 178
 179 /*-----------------------------------------------------------------------*/
 180
 181 /* device probe and removal */
 182
 183 static int
 184 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 185 {
 186         struct device *dev = &client->dev;
 187         struct lm75_data *data;
 188         int status;
 189         u8 set_mask, clr_mask;
 190         int new;
 191         enum lm75_type kind = id->driver_data;
 192
 193         if (!i2c_check_functionality(client->adapter,
 194                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 195                 return -EIO;
 196
 197         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 198         if (!data)
 199                 return -ENOMEM;
 200
 201         data->client = client;
 202         i2c_set_clientdata(client, data);
 203         mutex_init(&data->update_lock);
 204
 205         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 206          * Then tweak to be more precise when appropriate.
 207          */
 208         set_mask = 0;
 209         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 210
 211         switch (kind) {
 212         case adt75:
 213                 clr_mask |= 1 << 5;             /* not one-shot mode */
 214                 data->resolution = 12;
 215                 data->sample_time = HZ / 8;
 216                 break;
 217         case ds1775:
 218         case ds75:
 219         case stds75:
 220                 clr_mask |= 3 << 5;
 221                 set_mask |= 2 << 5;             /* 11-bit mode */
 222                 data->resolution = 11;
 223                 data->sample_time = HZ;
 224                 break;
 225         case ds7505:
 226                 set_mask |= 3 << 5;             /* 12-bit mode */
 227                 data->resolution = 12;
 228                 data->sample_time = HZ / 4;
 229                 break;
 230         case g751:
 231         case lm75:
 232         case lm75a:
 233                 data->resolution = 9;
 234                 data->sample_time = HZ / 2;
 235                 break;
 236         case max6625:
 237                 data->resolution = 9;
 238                 data->sample_time = HZ / 4;
 239                 break;
 240         case max6626:
 241                 data->resolution = 12;
 242                 data->resolution_limits = 9;
 243                 data->sample_time = HZ / 4;
 244                 break;
 245         case tcn75:
 246                 data->resolution = 9;
 247                 data->sample_time = HZ / 8;
 248                 break;
 249         case mcp980x:
 250                 data->resolution_limits = 9;
 251                 /* fall through */
 252         case tmp100:
 253         case tmp101:
 254                 set_mask |= 3 << 5;             /* 12-bit mode */
 255                 data->resolution = 12;
 256                 data->sample_time = HZ;
 257                 clr_mask |= 1 << 7;             /* not one-shot mode */
 258                 break;
 259         case tmp112:
 260                 set_mask |= 3 << 5;             /* 12-bit mode */
 261                 clr_mask |= 1 << 7;             /* not one-shot mode */
 262                 data->resolution = 12;
 263                 data->sample_time = HZ / 4;
 264                 break;
 265         case tmp105:
 266         case tmp175:
 267         case tmp275:
 268         case tmp75:
 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 / 2;
 273                 break;
 274         }
 275
 276         /* configure as specified */
 277         status = lm75_read_value(client, LM75_REG_CONF);
 278         if (status < 0) {
 279                 dev_dbg(dev, "Can't read config? %d\n", status);
 280                 return status;
 281         }
 282         data->orig_conf = status;
 283         new = status & ~clr_mask;
 284         new |= set_mask;
 285         if (status != new)
 286                 lm75_write_value(client, LM75_REG_CONF, new);
 287         dev_dbg(dev, "Config %02x\n", new);
 288
 289         data->hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
 290                                                             data, lm75_groups);
 291         if (IS_ERR(data->hwmon_dev))
 292                 return PTR_ERR(data->hwmon_dev);
 293
 294         data->tz = thermal_zone_of_sensor_register(data->hwmon_dev,
 295                                                    0,
 296                                                    data->hwmon_dev,
 297                                                    lm75_read_temp, NULL);
 298         if (IS_ERR(data->tz))
 299                 data->tz = NULL;
 300
 301         dev_info(dev, "%s: sensor '%s'\n",
 302                  dev_name(data->hwmon_dev), client->name);
 303
 304         return 0;
 305 }
 306
 307 static int lm75_remove(struct i2c_client *client)
 308 {
 309         struct lm75_data *data = i2c_get_clientdata(client);
 310
 311         thermal_zone_of_sensor_unregister(data->hwmon_dev, data->tz);
 312         hwmon_device_unregister(data->hwmon_dev);
 313         lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
 314         return 0;
 315 }
 316
 317 static const struct i2c_device_id lm75_ids[] = {
 318         { "adt75", adt75, },
 319         { "ds1775", ds1775, },
 320         { "ds75", ds75, },
 321         { "ds7505", ds7505, },
 322         { "g751", g751, },
 323         { "lm75", lm75, },
 324         { "lm75a", lm75a, },
 325         { "max6625", max6625, },
 326         { "max6626", max6626, },
 327         { "mcp980x", mcp980x, },
 328         { "stds75", stds75, },
 329         { "tcn75", tcn75, },
 330         { "tmp100", tmp100, },
 331         { "tmp101", tmp101, },
 332         { "tmp105", tmp105, },
 333         { "tmp112", tmp112, },
 334         { "tmp175", tmp175, },
 335         { "tmp275", tmp275, },
 336         { "tmp75", tmp75, },
 337         { /* LIST END */ }
 338 };
 339 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 340
 341 #define LM75A_ID 0xA1
 342
 343 /* Return 0 if detection is successful, -ENODEV otherwise */
 344 static int lm75_detect(struct i2c_client *new_client,
 345                        struct i2c_board_info *info)
 346 {
 347         struct i2c_adapter *adapter = new_client->adapter;
 348         int i;
 349         int conf, hyst, os;
 350         bool is_lm75a = 0;
 351
 352         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 353                                      I2C_FUNC_SMBUS_WORD_DATA))
 354                 return -ENODEV;
 355
 356         /*
 357          * Now, we do the remaining detection. There is no identification-
 358          * dedicated register so we have to rely on several tricks:
 359          * unused bits, registers cycling over 8-address boundaries,
 360          * addresses 0x04-0x07 returning the last read value.
 361          * The cycling+unused addresses combination is not tested,
 362          * since it would significantly slow the detection down and would
 363          * hardly add any value.
 364          *
 365          * The National Semiconductor LM75A is different than earlier
 366          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 367          * revision, with 1 being the only revision in existence) in
 368          * register 7, and unused registers return 0xff rather than the
 369          * last read value.
 370          *
 371          * Note that this function only detects the original National
 372          * Semiconductor LM75 and the LM75A. Clones from other vendors
 373          * aren't detected, on purpose, because they are typically never
 374          * found on PC hardware. They are found on embedded designs where
 375          * they can be instantiated explicitly so detection is not needed.
 376          * The absence of identification registers on all these clones
 377          * would make their exhaustive detection very difficult and weak,
 378          * and odds are that the driver would bind to unsupported devices.
 379          */
 380
 381         /* Unused bits */
 382         conf = i2c_smbus_read_byte_data(new_client, 1);
 383         if (conf & 0xe0)
 384                 return -ENODEV;
 385
 386         /* First check for LM75A */
 387         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 388                 /* LM75A returns 0xff on unused registers so
 389                    just to be sure we check for that too. */
 390                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 391                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 392                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 393                         return -ENODEV;
 394                 is_lm75a = 1;
 395                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 396                 os = i2c_smbus_read_byte_data(new_client, 3);
 397         } else { /* Traditional style LM75 detection */
 398                 /* Unused addresses */
 399                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 400                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 401                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 402                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 403                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 404                         return -ENODEV;
 405                 os = i2c_smbus_read_byte_data(new_client, 3);
 406                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 407                  || i2c_smbus_read_byte_data(new_client, 5) != os
 408                  || i2c_smbus_read_byte_data(new_client, 6) != os
 409                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 410                         return -ENODEV;
 411         }
 412
 413         /* Addresses cycling */
 414         for (i = 8; i <= 248; i += 40) {
 415                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 416                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 417                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 418                         return -ENODEV;
 419                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 420                                 != LM75A_ID)
 421                         return -ENODEV;
 422         }
 423
 424         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 425
 426         return 0;
 427 }
 428
 429 #ifdef CONFIG_PM
 430 static int lm75_suspend(struct device *dev)
 431 {
 432         int status;
 433         struct i2c_client *client = to_i2c_client(dev);
 434         status = lm75_read_value(client, LM75_REG_CONF);
 435         if (status < 0) {
 436                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 437                 return status;
 438         }
 439         status = status | LM75_SHUTDOWN;
 440         lm75_write_value(client, LM75_REG_CONF, status);
 441         return 0;
 442 }
 443
 444 static int lm75_resume(struct device *dev)
 445 {
 446         int status;
 447         struct i2c_client *client = to_i2c_client(dev);
 448         status = lm75_read_value(client, LM75_REG_CONF);
 449         if (status < 0) {
 450                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 451                 return status;
 452         }
 453         status = status & ~LM75_SHUTDOWN;
 454         lm75_write_value(client, LM75_REG_CONF, status);
 455         return 0;
 456 }
 457
 458 static const struct dev_pm_ops lm75_dev_pm_ops = {
 459         .suspend        = lm75_suspend,
 460         .resume         = lm75_resume,
 461 };
 462 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 463 #else
 464 #define LM75_DEV_PM_OPS NULL
 465 #endif /* CONFIG_PM */
 466
 467 static struct i2c_driver lm75_driver = {
 468         .class          = I2C_CLASS_HWMON,
 469         .driver = {
 470                 .name   = "lm75",
 471                 .pm     = LM75_DEV_PM_OPS,
 472         },
 473         .probe          = lm75_probe,
 474         .remove         = lm75_remove,
 475         .id_table       = lm75_ids,
 476         .detect         = lm75_detect,
 477         .address_list   = normal_i2c,
 478 };
 479
 480 /*-----------------------------------------------------------------------*/
 481
 482 /* register access */
 483
 484 /*
 485  * All registers are word-sized, except for the configuration register.
 486  * LM75 uses a high-byte first convention, which is exactly opposite to
 487  * the SMBus standard.
 488  */
 489 static int lm75_read_value(struct i2c_client *client, u8 reg)
 490 {
 491         if (reg == LM75_REG_CONF)
 492                 return i2c_smbus_read_byte_data(client, reg);
 493         else
 494                 return i2c_smbus_read_word_swapped(client, reg);
 495 }
 496
 497 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 498 {
 499         if (reg == LM75_REG_CONF)
 500                 return i2c_smbus_write_byte_data(client, reg, value);
 501         else
 502                 return i2c_smbus_write_word_swapped(client, reg, value);
 503 }
 504
 505 static struct lm75_data *lm75_update_device(struct device *dev)
 506 {
 507         struct lm75_data *data = dev_get_drvdata(dev);
 508         struct i2c_client *client = data->client;
 509         struct lm75_data *ret = data;
 510
 511         mutex_lock(&data->update_lock);
 512
 513         if (time_after(jiffies, data->last_updated + data->sample_time)
 514             || !data->valid) {
 515                 int i;
 516                 dev_dbg(&client->dev, "Starting lm75 update\n");
 517
 518                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 519                         int status;
 520
 521                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 522                         if (unlikely(status < 0)) {
 523                                 dev_dbg(dev,
 524                                         "LM75: Failed to read value: reg %d, error %d\n",
 525                                         LM75_REG_TEMP[i], status);
 526                                 ret = ERR_PTR(status);
 527                                 data->valid = 0;
 528                                 goto abort;
 529                         }
 530                         data->temp[i] = status;
 531                 }
 532                 data->last_updated = jiffies;
 533                 data->valid = 1;
 534         }
 535
 536 abort:
 537         mutex_unlock(&data->update_lock);
 538         return ret;
 539 }
 540
 541 module_i2c_driver(lm75_driver);
 542
 543 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 544 MODULE_DESCRIPTION("LM75 driver");
 545 MODULE_LICENSE("GPL");