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.h>
  30 #include <linux/regmap.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         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 /* sysfs attributes for hwmon */
  92
  93 static int lm75_read_temp(void *dev, int *temp)
  94 {
  95         struct lm75_data *data = dev_get_drvdata(dev);
  96         unsigned int _temp;
  97         int err;
  98
  99         err = regmap_read(data->regmap, LM75_REG_TEMP, &_temp);
 100         if (err < 0)
 101                 return err;
 102
 103         *temp = lm75_reg_to_mc(_temp, data->resolution);
 104
 105         return 0;
 106 }
 107
 108 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 109                          char *buf)
 110 {
 111         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 112         struct lm75_data *data = dev_get_drvdata(dev);
 113         unsigned int temp = 0;
 114         int err;
 115
 116         err = regmap_read(data->regmap, attr->index, &temp);
 117         if (err < 0)
 118                 return err;
 119
 120         return sprintf(buf, "%ld\n", lm75_reg_to_mc(temp, data->resolution));
 121 }
 122
 123 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 124                         const char *buf, size_t count)
 125 {
 126         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 127         struct lm75_data *data = dev_get_drvdata(dev);
 128         long temp;
 129         int error;
 130         u8 resolution;
 131
 132         error = kstrtol(buf, 10, &temp);
 133         if (error)
 134                 return error;
 135
 136         /*
 137          * Resolution of limit registers is assumed to be the same as the
 138          * temperature input register resolution unless given explicitly.
 139          */
 140         if (attr->index && data->resolution_limits)
 141                 resolution = data->resolution_limits;
 142         else
 143                 resolution = data->resolution;
 144
 145         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 146         temp = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 147                                  1000) << (16 - resolution);
 148         error = regmap_write(data->regmap, attr->index, temp);
 149         if (error < 0)
 150                 return error;
 151
 152         return count;
 153 }
 154
 155 static ssize_t show_update_interval(struct device *dev,
 156                                     struct device_attribute *da, char *buf)
 157 {
 158         struct lm75_data *data = dev_get_drvdata(dev);
 159
 160         return sprintf(buf, "%u\n", data->sample_time);
 161 }
 162
 163 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 164                         show_temp, set_temp, LM75_REG_MAX);
 165 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 166                         show_temp, set_temp, LM75_REG_HYST);
 167 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, LM75_REG_TEMP);
 168 static DEVICE_ATTR(update_interval, S_IRUGO, show_update_interval, NULL);
 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         &dev_attr_update_interval.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 bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
 189 {
 190         return reg != LM75_REG_TEMP;
 191 }
 192
 193 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
 194 {
 195         return reg == LM75_REG_TEMP;
 196 }
 197
 198 static const struct regmap_config lm75_regmap_config = {
 199         .reg_bits = 8,
 200         .val_bits = 16,
 201         .max_register = LM75_REG_MAX,
 202         .writeable_reg = lm75_is_writeable_reg,
 203         .volatile_reg = lm75_is_volatile_reg,
 204         .val_format_endian = REGMAP_ENDIAN_BIG,
 205         .cache_type = REGCACHE_RBTREE,
 206         .use_single_rw = true,
 207 };
 208
 209 static void lm75_remove(void *data)
 210 {
 211         struct lm75_data *lm75 = data;
 212         struct i2c_client *client = lm75->client;
 213
 214         i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
 215 }
 216
 217 static int
 218 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 219 {
 220         struct device *dev = &client->dev;
 221         struct device *hwmon_dev;
 222         struct lm75_data *data;
 223         int status, err;
 224         u8 set_mask, clr_mask;
 225         int new;
 226         enum lm75_type kind = id->driver_data;
 227
 228         if (!i2c_check_functionality(client->adapter,
 229                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 230                 return -EIO;
 231
 232         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 233         if (!data)
 234                 return -ENOMEM;
 235
 236         data->client = client;
 237
 238         data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
 239         if (IS_ERR(data->regmap))
 240                 return PTR_ERR(data->regmap);
 241
 242         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 243          * Then tweak to be more precise when appropriate.
 244          */
 245         set_mask = 0;
 246         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 247
 248         switch (kind) {
 249         case adt75:
 250                 clr_mask |= 1 << 5;             /* not one-shot mode */
 251                 data->resolution = 12;
 252                 data->sample_time = MSEC_PER_SEC / 8;
 253                 break;
 254         case ds1775:
 255         case ds75:
 256         case stds75:
 257                 clr_mask |= 3 << 5;
 258                 set_mask |= 2 << 5;             /* 11-bit mode */
 259                 data->resolution = 11;
 260                 data->sample_time = MSEC_PER_SEC;
 261                 break;
 262         case ds7505:
 263                 set_mask |= 3 << 5;             /* 12-bit mode */
 264                 data->resolution = 12;
 265                 data->sample_time = MSEC_PER_SEC / 4;
 266                 break;
 267         case g751:
 268         case lm75:
 269         case lm75a:
 270                 data->resolution = 9;
 271                 data->sample_time = MSEC_PER_SEC / 2;
 272                 break;
 273         case lm75b:
 274                 data->resolution = 11;
 275                 data->sample_time = MSEC_PER_SEC / 4;
 276                 break;
 277         case max6625:
 278                 data->resolution = 9;
 279                 data->sample_time = MSEC_PER_SEC / 4;
 280                 break;
 281         case max6626:
 282                 data->resolution = 12;
 283                 data->resolution_limits = 9;
 284                 data->sample_time = MSEC_PER_SEC / 4;
 285                 break;
 286         case tcn75:
 287                 data->resolution = 9;
 288                 data->sample_time = MSEC_PER_SEC / 8;
 289                 break;
 290         case mcp980x:
 291                 data->resolution_limits = 9;
 292                 /* fall through */
 293         case tmp100:
 294         case tmp101:
 295                 set_mask |= 3 << 5;             /* 12-bit mode */
 296                 data->resolution = 12;
 297                 data->sample_time = MSEC_PER_SEC;
 298                 clr_mask |= 1 << 7;             /* not one-shot mode */
 299                 break;
 300         case tmp112:
 301                 set_mask |= 3 << 5;             /* 12-bit mode */
 302                 clr_mask |= 1 << 7;             /* not one-shot mode */
 303                 data->resolution = 12;
 304                 data->sample_time = MSEC_PER_SEC / 4;
 305                 break;
 306         case tmp105:
 307         case tmp175:
 308         case tmp275:
 309         case tmp75:
 310                 set_mask |= 3 << 5;             /* 12-bit mode */
 311                 clr_mask |= 1 << 7;             /* not one-shot mode */
 312                 data->resolution = 12;
 313                 data->sample_time = MSEC_PER_SEC / 2;
 314                 break;
 315         case tmp75c:
 316                 clr_mask |= 1 << 5;             /* not one-shot mode */
 317                 data->resolution = 12;
 318                 data->sample_time = MSEC_PER_SEC / 4;
 319                 break;
 320         }
 321
 322         /* configure as specified */
 323         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 324         if (status < 0) {
 325                 dev_dbg(dev, "Can't read config? %d\n", status);
 326                 return status;
 327         }
 328         data->orig_conf = status;
 329         new = status & ~clr_mask;
 330         new |= set_mask;
 331         if (status != new)
 332                 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
 333
 334         err = devm_add_action_or_reset(dev, lm75_remove, data);
 335         if (err)
 336                 return err;
 337
 338         dev_dbg(dev, "Config %02x\n", new);
 339
 340         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 341                                                            data, lm75_groups);
 342         if (IS_ERR(hwmon_dev))
 343                 return PTR_ERR(hwmon_dev);
 344
 345         devm_thermal_zone_of_sensor_register(hwmon_dev, 0,
 346                                              hwmon_dev,
 347                                              &lm75_of_thermal_ops);
 348
 349         dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 350
 351         return 0;
 352 }
 353
 354 static const struct i2c_device_id lm75_ids[] = {
 355         { "adt75", adt75, },
 356         { "ds1775", ds1775, },
 357         { "ds75", ds75, },
 358         { "ds7505", ds7505, },
 359         { "g751", g751, },
 360         { "lm75", lm75, },
 361         { "lm75a", lm75a, },
 362         { "lm75b", lm75b, },
 363         { "max6625", max6625, },
 364         { "max6626", max6626, },
 365         { "mcp980x", mcp980x, },
 366         { "stds75", stds75, },
 367         { "tcn75", tcn75, },
 368         { "tmp100", tmp100, },
 369         { "tmp101", tmp101, },
 370         { "tmp105", tmp105, },
 371         { "tmp112", tmp112, },
 372         { "tmp175", tmp175, },
 373         { "tmp275", tmp275, },
 374         { "tmp75", tmp75, },
 375         { "tmp75c", tmp75c, },
 376         { /* LIST END */ }
 377 };
 378 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 379
 380 #define LM75A_ID 0xA1
 381
 382 /* Return 0 if detection is successful, -ENODEV otherwise */
 383 static int lm75_detect(struct i2c_client *new_client,
 384                        struct i2c_board_info *info)
 385 {
 386         struct i2c_adapter *adapter = new_client->adapter;
 387         int i;
 388         int conf, hyst, os;
 389         bool is_lm75a = 0;
 390
 391         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 392                                      I2C_FUNC_SMBUS_WORD_DATA))
 393                 return -ENODEV;
 394
 395         /*
 396          * Now, we do the remaining detection. There is no identification-
 397          * dedicated register so we have to rely on several tricks:
 398          * unused bits, registers cycling over 8-address boundaries,
 399          * addresses 0x04-0x07 returning the last read value.
 400          * The cycling+unused addresses combination is not tested,
 401          * since it would significantly slow the detection down and would
 402          * hardly add any value.
 403          *
 404          * The National Semiconductor LM75A is different than earlier
 405          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 406          * revision, with 1 being the only revision in existence) in
 407          * register 7, and unused registers return 0xff rather than the
 408          * last read value.
 409          *
 410          * Note that this function only detects the original National
 411          * Semiconductor LM75 and the LM75A. Clones from other vendors
 412          * aren't detected, on purpose, because they are typically never
 413          * found on PC hardware. They are found on embedded designs where
 414          * they can be instantiated explicitly so detection is not needed.
 415          * The absence of identification registers on all these clones
 416          * would make their exhaustive detection very difficult and weak,
 417          * and odds are that the driver would bind to unsupported devices.
 418          */
 419
 420         /* Unused bits */
 421         conf = i2c_smbus_read_byte_data(new_client, 1);
 422         if (conf & 0xe0)
 423                 return -ENODEV;
 424
 425         /* First check for LM75A */
 426         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 427                 /* LM75A returns 0xff on unused registers so
 428                    just to be sure we check for that too. */
 429                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 430                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 431                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 432                         return -ENODEV;
 433                 is_lm75a = 1;
 434                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 435                 os = i2c_smbus_read_byte_data(new_client, 3);
 436         } else { /* Traditional style LM75 detection */
 437                 /* Unused addresses */
 438                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 439                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 440                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 441                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 442                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 443                         return -ENODEV;
 444                 os = i2c_smbus_read_byte_data(new_client, 3);
 445                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 446                  || i2c_smbus_read_byte_data(new_client, 5) != os
 447                  || i2c_smbus_read_byte_data(new_client, 6) != os
 448                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 449                         return -ENODEV;
 450         }
 451         /*
 452          * It is very unlikely that this is a LM75 if both
 453          * hysteresis and temperature limit registers are 0.
 454          */
 455         if (hyst == 0 && os == 0)
 456                 return -ENODEV;
 457
 458         /* Addresses cycling */
 459         for (i = 8; i <= 248; i += 40) {
 460                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 461                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 462                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 463                         return -ENODEV;
 464                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 465                                 != LM75A_ID)
 466                         return -ENODEV;
 467         }
 468
 469         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 470
 471         return 0;
 472 }
 473
 474 #ifdef CONFIG_PM
 475 static int lm75_suspend(struct device *dev)
 476 {
 477         int status;
 478         struct i2c_client *client = to_i2c_client(dev);
 479         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 480         if (status < 0) {
 481                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 482                 return status;
 483         }
 484         status = status | LM75_SHUTDOWN;
 485         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 486         return 0;
 487 }
 488
 489 static int lm75_resume(struct device *dev)
 490 {
 491         int status;
 492         struct i2c_client *client = to_i2c_client(dev);
 493         status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 494         if (status < 0) {
 495                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 496                 return status;
 497         }
 498         status = status & ~LM75_SHUTDOWN;
 499         i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
 500         return 0;
 501 }
 502
 503 static const struct dev_pm_ops lm75_dev_pm_ops = {
 504         .suspend        = lm75_suspend,
 505         .resume         = lm75_resume,
 506 };
 507 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 508 #else
 509 #define LM75_DEV_PM_OPS NULL
 510 #endif /* CONFIG_PM */
 511
 512 static struct i2c_driver lm75_driver = {
 513         .class          = I2C_CLASS_HWMON,
 514         .driver = {
 515                 .name   = "lm75",
 516                 .pm     = LM75_DEV_PM_OPS,
 517         },
 518         .probe          = lm75_probe,
 519         .id_table       = lm75_ids,
 520         .detect         = lm75_detect,
 521         .address_list   = normal_i2c,
 522 };
 523
 524 module_i2c_driver(lm75_driver);
 525
 526 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 527 MODULE_DESCRIPTION("LM75 driver");
 528 MODULE_LICENSE("GPL");