drivers/hwmon/tmp108.c

   1 /* Texas Instruments TMP108 SMBus temperature sensor driver
   2  *
   3  * Copyright (C) 2016 John Muir <john@jmuir.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/device.h>
  18 #include <linux/err.h>
  19 #include <linux/hwmon.h>
  20 #include <linux/hwmon-sysfs.h>
  21 #include <linux/module.h>
  22 #include <linux/mutex.h>
  23 #include <linux/of.h>
  24 #include <linux/i2c.h>
  25 #include <linux/init.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/regmap.h>
  28 #include <linux/slab.h>
  29
  30 #define DRIVER_NAME "tmp108"
  31
  32 #define TMP108_REG_TEMP         0x00
  33 #define TMP108_REG_CONF         0x01
  34 #define TMP108_REG_TLOW         0x02
  35 #define TMP108_REG_THIGH        0x03
  36
  37 #define TMP108_TEMP_MIN_MC      -50000 /* Minimum millicelcius. */
  38 #define TMP108_TEMP_MAX_MC      127937 /* Maximum millicelcius. */
  39
  40 /* Configuration register bits.
  41  * Note: these bit definitions are byte swapped.
  42  */
  43 #define TMP108_CONF_M0          0x0100 /* Sensor mode. */
  44 #define TMP108_CONF_M1          0x0200
  45 #define TMP108_CONF_TM          0x0400 /* Thermostat mode. */
  46 #define TMP108_CONF_FL          0x0800 /* Watchdog flag - TLOW */
  47 #define TMP108_CONF_FH          0x1000 /* Watchdog flag - THIGH */
  48 #define TMP108_CONF_CR0         0x2000 /* Conversion rate. */
  49 #define TMP108_CONF_CR1         0x4000
  50 #define TMP108_CONF_ID          0x8000
  51 #define TMP108_CONF_HYS0        0x0010 /* Hysteresis. */
  52 #define TMP108_CONF_HYS1        0x0020
  53 #define TMP108_CONF_POL         0x0080 /* Polarity of alert. */
  54
  55 /* Defaults set by the hardware upon reset. */
  56 #define TMP108_CONF_DEFAULTS            (TMP108_CONF_CR0 | TMP108_CONF_TM |\
  57                                          TMP108_CONF_HYS0 | TMP108_CONF_M1)
  58 /* These bits are read-only. */
  59 #define TMP108_CONF_READ_ONLY           (TMP108_CONF_FL | TMP108_CONF_FH |\
  60                                          TMP108_CONF_ID)
  61
  62 #define TMP108_CONF_MODE_MASK           (TMP108_CONF_M0|TMP108_CONF_M1)
  63 #define TMP108_MODE_SHUTDOWN            0x0000
  64 #define TMP108_MODE_ONE_SHOT            TMP108_CONF_M0
  65 #define TMP108_MODE_CONTINUOUS          TMP108_CONF_M1          /* Default */
  66                                         /* When M1 is set, M0 is ignored. */
  67
  68 #define TMP108_CONF_CONVRATE_MASK       (TMP108_CONF_CR0|TMP108_CONF_CR1)
  69 #define TMP108_CONVRATE_0P25HZ          0x0000
  70 #define TMP108_CONVRATE_1HZ             TMP108_CONF_CR0         /* Default */
  71 #define TMP108_CONVRATE_4HZ             TMP108_CONF_CR1
  72 #define TMP108_CONVRATE_16HZ            (TMP108_CONF_CR0|TMP108_CONF_CR1)
  73
  74 #define TMP108_CONF_HYSTERESIS_MASK     (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
  75 #define TMP108_HYSTERESIS_0C            0x0000
  76 #define TMP108_HYSTERESIS_1C            TMP108_CONF_HYS0        /* Default */
  77 #define TMP108_HYSTERESIS_2C            TMP108_CONF_HYS1
  78 #define TMP108_HYSTERESIS_4C            (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
  79
  80 #define TMP108_CONVERSION_TIME_MS       30      /* in milli-seconds */
  81
  82 struct tmp108 {
  83         struct regmap *regmap;
  84         u16 orig_config;
  85         unsigned long ready_time;
  86 };
  87
  88 /* convert 12-bit TMP108 register value to milliCelsius */
  89 static inline int tmp108_temp_reg_to_mC(s16 val)
  90 {
  91         return (val & ~0x0f) * 1000 / 256;
  92 }
  93
  94 /* convert milliCelsius to left adjusted 12-bit TMP108 register value */
  95 static inline u16 tmp108_mC_to_temp_reg(int val)
  96 {
  97         return (val * 256) / 1000;
  98 }
  99
 100 static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
 101                        u32 attr, int channel, long *temp)
 102 {
 103         struct tmp108 *tmp108 = dev_get_drvdata(dev);
 104         unsigned int regval;
 105         int err, hyst;
 106
 107         if (type == hwmon_chip) {
 108                 if (attr == hwmon_chip_update_interval) {
 109                         err = regmap_read(tmp108->regmap, TMP108_REG_CONF,
 110                                           &regval);
 111                         if (err < 0)
 112                                 return err;
 113                         switch (regval & TMP108_CONF_CONVRATE_MASK) {
 114                         case TMP108_CONVRATE_0P25HZ:
 115                         default:
 116                                 *temp = 4000;
 117                                 break;
 118                         case TMP108_CONVRATE_1HZ:
 119                                 *temp = 1000;
 120                                 break;
 121                         case TMP108_CONVRATE_4HZ:
 122                                 *temp = 250;
 123                                 break;
 124                         case TMP108_CONVRATE_16HZ:
 125                                 *temp = 63;
 126                                 break;
 127                         }
 128                         return 0;
 129                 }
 130                 return -EOPNOTSUPP;
 131         }
 132
 133         switch (attr) {
 134         case hwmon_temp_input:
 135                 /* Is it too early to return a conversion ? */
 136                 if (time_before(jiffies, tmp108->ready_time)) {
 137                         dev_dbg(dev, "%s: Conversion not ready yet..\n",
 138                                 __func__);
 139                         return -EAGAIN;
 140                 }
 141                 err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, &regval);
 142                 if (err < 0)
 143                         return err;
 144                 *temp = tmp108_temp_reg_to_mC(regval);
 145                 break;
 146         case hwmon_temp_min:
 147         case hwmon_temp_max:
 148                 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ?
 149                                   TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
 150                 if (err < 0)
 151                         return err;
 152                 *temp = tmp108_temp_reg_to_mC(regval);
 153                 break;
 154         case hwmon_temp_min_alarm:
 155         case hwmon_temp_max_alarm:
 156                 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
 157                 if (err < 0)
 158                         return err;
 159                 *temp = !!(regval & (attr == hwmon_temp_min_alarm ?
 160                                      TMP108_CONF_FL : TMP108_CONF_FH));
 161                 break;
 162         case hwmon_temp_min_hyst:
 163         case hwmon_temp_max_hyst:
 164                 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
 165                 if (err < 0)
 166                         return err;
 167                 switch (regval & TMP108_CONF_HYSTERESIS_MASK) {
 168                 case TMP108_HYSTERESIS_0C:
 169                 default:
 170                         hyst = 0;
 171                         break;
 172                 case TMP108_HYSTERESIS_1C:
 173                         hyst = 1000;
 174                         break;
 175                 case TMP108_HYSTERESIS_2C:
 176                         hyst = 2000;
 177                         break;
 178                 case TMP108_HYSTERESIS_4C:
 179                         hyst = 4000;
 180                         break;
 181                 }
 182                 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ?
 183                                   TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
 184                 if (err < 0)
 185                         return err;
 186                 *temp = tmp108_temp_reg_to_mC(regval);
 187                 if (attr == hwmon_temp_min_hyst)
 188                         *temp += hyst;
 189                 else
 190                         *temp -= hyst;
 191                 break;
 192         default:
 193                 return -EOPNOTSUPP;
 194         }
 195
 196         return 0;
 197 }
 198
 199 static int tmp108_write(struct device *dev, enum hwmon_sensor_types type,
 200                         u32 attr, int channel, long temp)
 201 {
 202         struct tmp108 *tmp108 = dev_get_drvdata(dev);
 203         u32 regval, mask;
 204         int err;
 205
 206         if (type == hwmon_chip) {
 207                 if (attr == hwmon_chip_update_interval) {
 208                         if (temp < 156)
 209                                 mask = TMP108_CONVRATE_16HZ;
 210                         else if (temp < 625)
 211                                 mask = TMP108_CONVRATE_4HZ;
 212                         else if (temp < 2500)
 213                                 mask = TMP108_CONVRATE_1HZ;
 214                         else
 215                                 mask = TMP108_CONVRATE_0P25HZ;
 216                         return regmap_update_bits(tmp108->regmap,
 217                                                   TMP108_REG_CONF,
 218                                                   TMP108_CONF_CONVRATE_MASK,
 219                                                   mask);
 220                 }
 221                 return -EOPNOTSUPP;
 222         }
 223
 224         switch (attr) {
 225         case hwmon_temp_min:
 226         case hwmon_temp_max:
 227                 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
 228                 return regmap_write(tmp108->regmap,
 229                                     attr == hwmon_temp_min ?
 230                                         TMP108_REG_TLOW : TMP108_REG_THIGH,
 231                                     tmp108_mC_to_temp_reg(temp));
 232         case hwmon_temp_min_hyst:
 233         case hwmon_temp_max_hyst:
 234                 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
 235                 err = regmap_read(tmp108->regmap,
 236                                   attr == hwmon_temp_min_hyst ?
 237                                         TMP108_REG_TLOW : TMP108_REG_THIGH,
 238                                   &regval);
 239                 if (err < 0)
 240                         return err;
 241                 if (attr == hwmon_temp_min_hyst)
 242                         temp -= tmp108_temp_reg_to_mC(regval);
 243                 else
 244                         temp = tmp108_temp_reg_to_mC(regval) - temp;
 245                 if (temp < 500)
 246                         mask = TMP108_HYSTERESIS_0C;
 247                 else if (temp < 1500)
 248                         mask = TMP108_HYSTERESIS_1C;
 249                 else if (temp < 3000)
 250                         mask = TMP108_HYSTERESIS_2C;
 251                 else
 252                         mask = TMP108_HYSTERESIS_4C;
 253                 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 254                                           TMP108_CONF_HYSTERESIS_MASK, mask);
 255         default:
 256                 return -EOPNOTSUPP;
 257         }
 258 }
 259
 260 static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type,
 261                                  u32 attr, int channel)
 262 {
 263         if (type == hwmon_chip && attr == hwmon_chip_update_interval)
 264                 return 0644;
 265
 266         if (type != hwmon_temp)
 267                 return 0;
 268
 269         switch (attr) {
 270         case hwmon_temp_input:
 271         case hwmon_temp_min_alarm:
 272         case hwmon_temp_max_alarm:
 273                 return 0444;
 274         case hwmon_temp_min:
 275         case hwmon_temp_max:
 276         case hwmon_temp_min_hyst:
 277         case hwmon_temp_max_hyst:
 278                 return 0644;
 279         default:
 280                 return 0;
 281         }
 282 }
 283
 284 static u32 tmp108_chip_config[] = {
 285         HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
 286         0
 287 };
 288
 289 static const struct hwmon_channel_info tmp108_chip = {
 290         .type = hwmon_chip,
 291         .config = tmp108_chip_config,
 292 };
 293
 294 static u32 tmp108_temp_config[] = {
 295         HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_MIN_HYST
 296                 | HWMON_T_MAX_HYST | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
 297         0
 298 };
 299
 300 static const struct hwmon_channel_info tmp108_temp = {
 301         .type = hwmon_temp,
 302         .config = tmp108_temp_config,
 303 };
 304
 305 static const struct hwmon_channel_info *tmp108_info[] = {
 306         &tmp108_chip,
 307         &tmp108_temp,
 308         NULL
 309 };
 310
 311 static const struct hwmon_ops tmp108_hwmon_ops = {
 312         .is_visible = tmp108_is_visible,
 313         .read = tmp108_read,
 314         .write = tmp108_write,
 315 };
 316
 317 static const struct hwmon_chip_info tmp108_chip_info = {
 318         .ops = &tmp108_hwmon_ops,
 319         .info = tmp108_info,
 320 };
 321
 322 static void tmp108_restore_config(void *data)
 323 {
 324         struct tmp108 *tmp108 = data;
 325
 326         regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config);
 327 }
 328
 329 static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg)
 330 {
 331         return reg != TMP108_REG_TEMP;
 332 }
 333
 334 static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg)
 335 {
 336         /* Configuration register must be volatile to enable FL and FH. */
 337         return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF;
 338 }
 339
 340 static const struct regmap_config tmp108_regmap_config = {
 341         .reg_bits = 8,
 342         .val_bits = 16,
 343         .max_register = TMP108_REG_THIGH,
 344         .writeable_reg = tmp108_is_writeable_reg,
 345         .volatile_reg = tmp108_is_volatile_reg,
 346         .val_format_endian = REGMAP_ENDIAN_BIG,
 347         .cache_type = REGCACHE_RBTREE,
 348         .use_single_rw = true,
 349 };
 350
 351 static int tmp108_probe(struct i2c_client *client,
 352                         const struct i2c_device_id *id)
 353 {
 354         struct device *dev = &client->dev;
 355         struct device *hwmon_dev;
 356         struct tmp108 *tmp108;
 357         int err;
 358         u32 config;
 359
 360         if (!i2c_check_functionality(client->adapter,
 361                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 362                 dev_err(dev,
 363                         "adapter doesn't support SMBus word transactions\n");
 364                 return -ENODEV;
 365         }
 366
 367         tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL);
 368         if (!tmp108)
 369                 return -ENOMEM;
 370
 371         dev_set_drvdata(dev, tmp108);
 372
 373         tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config);
 374         if (IS_ERR(tmp108->regmap)) {
 375                 err = PTR_ERR(tmp108->regmap);
 376                 dev_err(dev, "regmap init failed: %d", err);
 377                 return err;
 378         }
 379
 380         err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config);
 381         if (err < 0) {
 382                 dev_err(dev, "error reading config register: %d", err);
 383                 return err;
 384         }
 385         tmp108->orig_config = config;
 386
 387         /* Only continuous mode is supported. */
 388         config &= ~TMP108_CONF_MODE_MASK;
 389         config |= TMP108_MODE_CONTINUOUS;
 390
 391         /* Only comparator mode is supported. */
 392         config &= ~TMP108_CONF_TM;
 393
 394         err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config);
 395         if (err < 0) {
 396                 dev_err(dev, "error writing config register: %d", err);
 397                 return err;
 398         }
 399
 400         tmp108->ready_time = jiffies;
 401         if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
 402             TMP108_MODE_SHUTDOWN)
 403                 tmp108->ready_time +=
 404                         msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
 405
 406         err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
 407         if (err) {
 408                 dev_err(dev, "add action or reset failed: %d", err);
 409                 return err;
 410         }
 411
 412         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 413                                                          tmp108,
 414                                                          &tmp108_chip_info,
 415                                                          NULL);
 416         return PTR_ERR_OR_ZERO(hwmon_dev);
 417 }
 418
 419 static int __maybe_unused tmp108_suspend(struct device *dev)
 420 {
 421         struct tmp108 *tmp108 = dev_get_drvdata(dev);
 422
 423         return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 424                                   TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN);
 425 }
 426
 427 static int __maybe_unused tmp108_resume(struct device *dev)
 428 {
 429         struct tmp108 *tmp108 = dev_get_drvdata(dev);
 430         int err;
 431
 432         err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 433                                  TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
 434         tmp108->ready_time = jiffies +
 435                              msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
 436         return err;
 437 }
 438
 439 static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume);
 440
 441 static const struct i2c_device_id tmp108_i2c_ids[] = {
 442         { "tmp108", 0 },
 443         { }
 444 };
 445 MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids);
 446
 447 #ifdef CONFIG_OF
 448 static const struct of_device_id tmp108_of_ids[] = {
 449         { .compatible = "ti,tmp108", },
 450         {}
 451 };
 452 MODULE_DEVICE_TABLE(of, tmp108_of_ids);
 453 #endif
 454
 455 static struct i2c_driver tmp108_driver = {
 456         .driver = {
 457                 .name   = DRIVER_NAME,
 458                 .pm     = &tmp108_dev_pm_ops,
 459                 .of_match_table = of_match_ptr(tmp108_of_ids),
 460         },
 461         .probe          = tmp108_probe,
 462         .id_table       = tmp108_i2c_ids,
 463 };
 464
 465 module_i2c_driver(tmp108_driver);
 466
 467 MODULE_AUTHOR("John Muir <john@jmuir.com>");
 468 MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver");
 469 MODULE_LICENSE("GPL");