drivers/hwmon/tmp108.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Texas Instruments TMP108 SMBus temperature sensor driver
   3  *
   4  * Copyright (C) 2016 John Muir <john@jmuir.com>
   5  */
   6
   7 #include <linux/delay.h>
   8 #include <linux/device.h>
   9 #include <linux/err.h>
  10 #include <linux/hwmon.h>
  11 #include <linux/hwmon-sysfs.h>
  12 #include <linux/module.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of.h>
  15 #include <linux/i2c.h>
  16 #include <linux/init.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/regmap.h>
  19 #include <linux/slab.h>
  20
  21 #define DRIVER_NAME "tmp108"
  22
  23 #define TMP108_REG_TEMP         0x00
  24 #define TMP108_REG_CONF         0x01
  25 #define TMP108_REG_TLOW         0x02
  26 #define TMP108_REG_THIGH        0x03
  27
  28 #define TMP108_TEMP_MIN_MC      -50000 /* Minimum millicelcius. */
  29 #define TMP108_TEMP_MAX_MC      127937 /* Maximum millicelcius. */
  30
  31 /* Configuration register bits.
  32  * Note: these bit definitions are byte swapped.
  33  */
  34 #define TMP108_CONF_M0          0x0100 /* Sensor mode. */
  35 #define TMP108_CONF_M1          0x0200
  36 #define TMP108_CONF_TM          0x0400 /* Thermostat mode. */
  37 #define TMP108_CONF_FL          0x0800 /* Watchdog flag - TLOW */
  38 #define TMP108_CONF_FH          0x1000 /* Watchdog flag - THIGH */
  39 #define TMP108_CONF_CR0         0x2000 /* Conversion rate. */
  40 #define TMP108_CONF_CR1         0x4000
  41 #define TMP108_CONF_ID          0x8000
  42 #define TMP108_CONF_HYS0        0x0010 /* Hysteresis. */
  43 #define TMP108_CONF_HYS1        0x0020
  44 #define TMP108_CONF_POL         0x0080 /* Polarity of alert. */
  45
  46 /* Defaults set by the hardware upon reset. */
  47 #define TMP108_CONF_DEFAULTS            (TMP108_CONF_CR0 | TMP108_CONF_TM |\
  48                                          TMP108_CONF_HYS0 | TMP108_CONF_M1)
  49 /* These bits are read-only. */
  50 #define TMP108_CONF_READ_ONLY           (TMP108_CONF_FL | TMP108_CONF_FH |\
  51                                          TMP108_CONF_ID)
  52
  53 #define TMP108_CONF_MODE_MASK           (TMP108_CONF_M0|TMP108_CONF_M1)
  54 #define TMP108_MODE_SHUTDOWN            0x0000
  55 #define TMP108_MODE_ONE_SHOT            TMP108_CONF_M0
  56 #define TMP108_MODE_CONTINUOUS          TMP108_CONF_M1          /* Default */
  57                                         /* When M1 is set, M0 is ignored. */
  58
  59 #define TMP108_CONF_CONVRATE_MASK       (TMP108_CONF_CR0|TMP108_CONF_CR1)
  60 #define TMP108_CONVRATE_0P25HZ          0x0000
  61 #define TMP108_CONVRATE_1HZ             TMP108_CONF_CR0         /* Default */
  62 #define TMP108_CONVRATE_4HZ             TMP108_CONF_CR1
  63 #define TMP108_CONVRATE_16HZ            (TMP108_CONF_CR0|TMP108_CONF_CR1)
  64
  65 #define TMP108_CONF_HYSTERESIS_MASK     (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
  66 #define TMP108_HYSTERESIS_0C            0x0000
  67 #define TMP108_HYSTERESIS_1C            TMP108_CONF_HYS0        /* Default */
  68 #define TMP108_HYSTERESIS_2C            TMP108_CONF_HYS1
  69 #define TMP108_HYSTERESIS_4C            (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
  70
  71 #define TMP108_CONVERSION_TIME_MS       30      /* in milli-seconds */
  72
  73 struct tmp108 {
  74         struct regmap *regmap;
  75         u16 orig_config;
  76         unsigned long ready_time;
  77 };
  78
  79 /* convert 12-bit TMP108 register value to milliCelsius */
  80 static inline int tmp108_temp_reg_to_mC(s16 val)
  81 {
  82         return (val & ~0x0f) * 1000 / 256;
  83 }
  84
  85 /* convert milliCelsius to left adjusted 12-bit TMP108 register value */
  86 static inline u16 tmp108_mC_to_temp_reg(int val)
  87 {
  88         return (val * 256) / 1000;
  89 }
  90
  91 static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
  92                        u32 attr, int channel, long *temp)
  93 {
  94         struct tmp108 *tmp108 = dev_get_drvdata(dev);
  95         unsigned int regval;
  96         int err, hyst;
  97
  98         if (type == hwmon_chip) {
  99                 if (attr == hwmon_chip_update_interval) {
 100                         err = regmap_read(tmp108->regmap, TMP108_REG_CONF,
 101                                           &regval);
 102                         if (err < 0)
 103                                 return err;
 104                         switch (regval & TMP108_CONF_CONVRATE_MASK) {
 105                         case TMP108_CONVRATE_0P25HZ:
 106                         default:
 107                                 *temp = 4000;
 108                                 break;
 109                         case TMP108_CONVRATE_1HZ:
 110                                 *temp = 1000;
 111                                 break;
 112                         case TMP108_CONVRATE_4HZ:
 113                                 *temp = 250;
 114                                 break;
 115                         case TMP108_CONVRATE_16HZ:
 116                                 *temp = 63;
 117                                 break;
 118                         }
 119                         return 0;
 120                 }
 121                 return -EOPNOTSUPP;
 122         }
 123
 124         switch (attr) {
 125         case hwmon_temp_input:
 126                 /* Is it too early to return a conversion ? */
 127                 if (time_before(jiffies, tmp108->ready_time)) {
 128                         dev_dbg(dev, "%s: Conversion not ready yet..\n",
 129                                 __func__);
 130                         return -EAGAIN;
 131                 }
 132                 err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, &regval);
 133                 if (err < 0)
 134                         return err;
 135                 *temp = tmp108_temp_reg_to_mC(regval);
 136                 break;
 137         case hwmon_temp_min:
 138         case hwmon_temp_max:
 139                 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ?
 140                                   TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
 141                 if (err < 0)
 142                         return err;
 143                 *temp = tmp108_temp_reg_to_mC(regval);
 144                 break;
 145         case hwmon_temp_min_alarm:
 146         case hwmon_temp_max_alarm:
 147                 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
 148                 if (err < 0)
 149                         return err;
 150                 *temp = !!(regval & (attr == hwmon_temp_min_alarm ?
 151                                      TMP108_CONF_FL : TMP108_CONF_FH));
 152                 break;
 153         case hwmon_temp_min_hyst:
 154         case hwmon_temp_max_hyst:
 155                 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
 156                 if (err < 0)
 157                         return err;
 158                 switch (regval & TMP108_CONF_HYSTERESIS_MASK) {
 159                 case TMP108_HYSTERESIS_0C:
 160                 default:
 161                         hyst = 0;
 162                         break;
 163                 case TMP108_HYSTERESIS_1C:
 164                         hyst = 1000;
 165                         break;
 166                 case TMP108_HYSTERESIS_2C:
 167                         hyst = 2000;
 168                         break;
 169                 case TMP108_HYSTERESIS_4C:
 170                         hyst = 4000;
 171                         break;
 172                 }
 173                 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ?
 174                                   TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
 175                 if (err < 0)
 176                         return err;
 177                 *temp = tmp108_temp_reg_to_mC(regval);
 178                 if (attr == hwmon_temp_min_hyst)
 179                         *temp += hyst;
 180                 else
 181                         *temp -= hyst;
 182                 break;
 183         default:
 184                 return -EOPNOTSUPP;
 185         }
 186
 187         return 0;
 188 }
 189
 190 static int tmp108_write(struct device *dev, enum hwmon_sensor_types type,
 191                         u32 attr, int channel, long temp)
 192 {
 193         struct tmp108 *tmp108 = dev_get_drvdata(dev);
 194         u32 regval, mask;
 195         int err;
 196
 197         if (type == hwmon_chip) {
 198                 if (attr == hwmon_chip_update_interval) {
 199                         if (temp < 156)
 200                                 mask = TMP108_CONVRATE_16HZ;
 201                         else if (temp < 625)
 202                                 mask = TMP108_CONVRATE_4HZ;
 203                         else if (temp < 2500)
 204                                 mask = TMP108_CONVRATE_1HZ;
 205                         else
 206                                 mask = TMP108_CONVRATE_0P25HZ;
 207                         return regmap_update_bits(tmp108->regmap,
 208                                                   TMP108_REG_CONF,
 209                                                   TMP108_CONF_CONVRATE_MASK,
 210                                                   mask);
 211                 }
 212                 return -EOPNOTSUPP;
 213         }
 214
 215         switch (attr) {
 216         case hwmon_temp_min:
 217         case hwmon_temp_max:
 218                 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
 219                 return regmap_write(tmp108->regmap,
 220                                     attr == hwmon_temp_min ?
 221                                         TMP108_REG_TLOW : TMP108_REG_THIGH,
 222                                     tmp108_mC_to_temp_reg(temp));
 223         case hwmon_temp_min_hyst:
 224         case hwmon_temp_max_hyst:
 225                 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
 226                 err = regmap_read(tmp108->regmap,
 227                                   attr == hwmon_temp_min_hyst ?
 228                                         TMP108_REG_TLOW : TMP108_REG_THIGH,
 229                                   &regval);
 230                 if (err < 0)
 231                         return err;
 232                 if (attr == hwmon_temp_min_hyst)
 233                         temp -= tmp108_temp_reg_to_mC(regval);
 234                 else
 235                         temp = tmp108_temp_reg_to_mC(regval) - temp;
 236                 if (temp < 500)
 237                         mask = TMP108_HYSTERESIS_0C;
 238                 else if (temp < 1500)
 239                         mask = TMP108_HYSTERESIS_1C;
 240                 else if (temp < 3000)
 241                         mask = TMP108_HYSTERESIS_2C;
 242                 else
 243                         mask = TMP108_HYSTERESIS_4C;
 244                 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 245                                           TMP108_CONF_HYSTERESIS_MASK, mask);
 246         default:
 247                 return -EOPNOTSUPP;
 248         }
 249 }
 250
 251 static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type,
 252                                  u32 attr, int channel)
 253 {
 254         if (type == hwmon_chip && attr == hwmon_chip_update_interval)
 255                 return 0644;
 256
 257         if (type != hwmon_temp)
 258                 return 0;
 259
 260         switch (attr) {
 261         case hwmon_temp_input:
 262         case hwmon_temp_min_alarm:
 263         case hwmon_temp_max_alarm:
 264                 return 0444;
 265         case hwmon_temp_min:
 266         case hwmon_temp_max:
 267         case hwmon_temp_min_hyst:
 268         case hwmon_temp_max_hyst:
 269                 return 0644;
 270         default:
 271                 return 0;
 272         }
 273 }
 274
 275 static const struct hwmon_channel_info *tmp108_info[] = {
 276         HWMON_CHANNEL_INFO(chip,
 277                            HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
 278         HWMON_CHANNEL_INFO(temp,
 279                            HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
 280                            HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
 281                            HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM),
 282         NULL
 283 };
 284
 285 static const struct hwmon_ops tmp108_hwmon_ops = {
 286         .is_visible = tmp108_is_visible,
 287         .read = tmp108_read,
 288         .write = tmp108_write,
 289 };
 290
 291 static const struct hwmon_chip_info tmp108_chip_info = {
 292         .ops = &tmp108_hwmon_ops,
 293         .info = tmp108_info,
 294 };
 295
 296 static void tmp108_restore_config(void *data)
 297 {
 298         struct tmp108 *tmp108 = data;
 299
 300         regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config);
 301 }
 302
 303 static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg)
 304 {
 305         return reg != TMP108_REG_TEMP;
 306 }
 307
 308 static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg)
 309 {
 310         /* Configuration register must be volatile to enable FL and FH. */
 311         return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF;
 312 }
 313
 314 static const struct regmap_config tmp108_regmap_config = {
 315         .reg_bits = 8,
 316         .val_bits = 16,
 317         .max_register = TMP108_REG_THIGH,
 318         .writeable_reg = tmp108_is_writeable_reg,
 319         .volatile_reg = tmp108_is_volatile_reg,
 320         .val_format_endian = REGMAP_ENDIAN_BIG,
 321         .cache_type = REGCACHE_RBTREE,
 322         .use_single_read = true,
 323         .use_single_write = true,
 324 };
 325
 326 static int tmp108_probe(struct i2c_client *client)
 327 {
 328         struct device *dev = &client->dev;
 329         struct device *hwmon_dev;
 330         struct tmp108 *tmp108;
 331         int err;
 332         u32 config;
 333
 334         if (!i2c_check_functionality(client->adapter,
 335                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 336                 dev_err(dev,
 337                         "adapter doesn't support SMBus word transactions\n");
 338                 return -ENODEV;
 339         }
 340
 341         tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL);
 342         if (!tmp108)
 343                 return -ENOMEM;
 344
 345         dev_set_drvdata(dev, tmp108);
 346
 347         tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config);
 348         if (IS_ERR(tmp108->regmap)) {
 349                 err = PTR_ERR(tmp108->regmap);
 350                 dev_err(dev, "regmap init failed: %d", err);
 351                 return err;
 352         }
 353
 354         err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config);
 355         if (err < 0) {
 356                 dev_err(dev, "error reading config register: %d", err);
 357                 return err;
 358         }
 359         tmp108->orig_config = config;
 360
 361         /* Only continuous mode is supported. */
 362         config &= ~TMP108_CONF_MODE_MASK;
 363         config |= TMP108_MODE_CONTINUOUS;
 364
 365         /* Only comparator mode is supported. */
 366         config &= ~TMP108_CONF_TM;
 367
 368         err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config);
 369         if (err < 0) {
 370                 dev_err(dev, "error writing config register: %d", err);
 371                 return err;
 372         }
 373
 374         tmp108->ready_time = jiffies;
 375         if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
 376             TMP108_MODE_SHUTDOWN)
 377                 tmp108->ready_time +=
 378                         msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
 379
 380         err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
 381         if (err) {
 382                 dev_err(dev, "add action or reset failed: %d", err);
 383                 return err;
 384         }
 385
 386         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 387                                                          tmp108,
 388                                                          &tmp108_chip_info,
 389                                                          NULL);
 390         return PTR_ERR_OR_ZERO(hwmon_dev);
 391 }
 392
 393 static int tmp108_suspend(struct device *dev)
 394 {
 395         struct tmp108 *tmp108 = dev_get_drvdata(dev);
 396
 397         return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 398                                   TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN);
 399 }
 400
 401 static int tmp108_resume(struct device *dev)
 402 {
 403         struct tmp108 *tmp108 = dev_get_drvdata(dev);
 404         int err;
 405
 406         err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
 407                                  TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
 408         tmp108->ready_time = jiffies +
 409                              msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
 410         return err;
 411 }
 412
 413 static DEFINE_SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume);
 414
 415 static const struct i2c_device_id tmp108_i2c_ids[] = {
 416         { "tmp108", 0 },
 417         { }
 418 };
 419 MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids);
 420
 421 #ifdef CONFIG_OF
 422 static const struct of_device_id tmp108_of_ids[] = {
 423         { .compatible = "ti,tmp108", },
 424         {}
 425 };
 426 MODULE_DEVICE_TABLE(of, tmp108_of_ids);
 427 #endif
 428
 429 static struct i2c_driver tmp108_driver = {
 430         .driver = {
 431                 .name   = DRIVER_NAME,
 432                 .pm     = pm_sleep_ptr(&tmp108_dev_pm_ops),
 433                 .of_match_table = of_match_ptr(tmp108_of_ids),
 434         },
 435         .probe_new      = tmp108_probe,
 436         .id_table       = tmp108_i2c_ids,
 437 };
 438
 439 module_i2c_driver(tmp108_driver);
 440
 441 MODULE_AUTHOR("John Muir <john@jmuir.com>");
 442 MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver");
 443 MODULE_LICENSE("GPL");