drivers/iio/temperature/mlx90614.c

   1 /*
   2  * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
   3  *
   4  * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
   5  * Copyright (c) 2015 Essensium NV
   6  *
   7  * This file is subject to the terms and conditions of version 2 of
   8  * the GNU General Public License.  See the file COPYING in the main
   9  * directory of this archive for more details.
  10  *
  11  * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
  12  *
  13  * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
  14  *
  15  * To wake up from sleep mode, the SDA line must be held low while SCL is high
  16  * for at least 33ms.  This is achieved with an extra GPIO that can be connected
  17  * directly to the SDA line.  In normal operation, the GPIO is set as input and
  18  * will not interfere in I2C communication.  While the GPIO is driven low, the
  19  * i2c adapter is locked since it cannot be used by other clients.  The SCL line
  20  * always has a pull-up so we do not need an extra GPIO to drive it high.  If
  21  * the "wakeup" GPIO is not given, power management will be disabled.
  22  *
  23  * TODO: filter configuration
  24  */
  25
  26 #include <linux/err.h>
  27 #include <linux/i2c.h>
  28 #include <linux/module.h>
  29 #include <linux/delay.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/gpio/consumer.h>
  32 #include <linux/pm_runtime.h>
  33
  34 #include <linux/iio/iio.h>
  35
  36 #define MLX90614_OP_RAM         0x00
  37 #define MLX90614_OP_EEPROM      0x20
  38 #define MLX90614_OP_SLEEP       0xff
  39
  40 /* RAM offsets with 16-bit data, MSB first */
  41 #define MLX90614_RAW1   (MLX90614_OP_RAM | 0x04) /* raw data IR channel 1 */
  42 #define MLX90614_RAW2   (MLX90614_OP_RAM | 0x05) /* raw data IR channel 2 */
  43 #define MLX90614_TA     (MLX90614_OP_RAM | 0x06) /* ambient temperature */
  44 #define MLX90614_TOBJ1  (MLX90614_OP_RAM | 0x07) /* object 1 temperature */
  45 #define MLX90614_TOBJ2  (MLX90614_OP_RAM | 0x08) /* object 2 temperature */
  46
  47 /* EEPROM offsets with 16-bit data, MSB first */
  48 #define MLX90614_EMISSIVITY     (MLX90614_OP_EEPROM | 0x04) /* emissivity correction coefficient */
  49 #define MLX90614_CONFIG         (MLX90614_OP_EEPROM | 0x05) /* configuration register */
  50
  51 /* Control bits in configuration register */
  52 #define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */
  53 #define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT)
  54 #define MLX90614_CONFIG_DUAL_SHIFT 6 /* single (0) or dual (1) IR sensor */
  55 #define MLX90614_CONFIG_DUAL_MASK (1 << MLX90614_CONFIG_DUAL_SHIFT)
  56 #define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */
  57 #define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT)
  58 #define MLX90614_CONFIG_GAIN_SHIFT 11 /* gain */
  59 #define MLX90614_CONFIG_GAIN_MASK (0x7 << MLX90614_CONFIG_GAIN_SHIFT)
  60
  61 /* Timings (in ms) */
  62 #define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */
  63 #define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
  64 #define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
  65
  66 #define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */
  67
  68 struct mlx90614_data {
  69         struct i2c_client *client;
  70         struct mutex lock; /* for EEPROM access only */
  71         struct gpio_desc *wakeup_gpio; /* NULL to disable sleep/wake-up */
  72         unsigned long ready_timestamp; /* in jiffies */
  73 };
  74
  75 /*
  76  * Erase an address and write word.
  77  * The mutex must be locked before calling.
  78  */
  79 static s32 mlx90614_write_word(const struct i2c_client *client, u8 command,
  80                                u16 value)
  81 {
  82         /*
  83          * Note: The mlx90614 requires a PEC on writing but does not send us a
  84          * valid PEC on reading.  Hence, we cannot set I2C_CLIENT_PEC in
  85          * i2c_client.flags.  As a workaround, we use i2c_smbus_xfer here.
  86          */
  87         union i2c_smbus_data data;
  88         s32 ret;
  89
  90         dev_dbg(&client->dev, "Writing 0x%x to address 0x%x", value, command);
  91
  92         data.word = 0x0000; /* erase command */
  93         ret = i2c_smbus_xfer(client->adapter, client->addr,
  94                              client->flags | I2C_CLIENT_PEC,
  95                              I2C_SMBUS_WRITE, command,
  96                              I2C_SMBUS_WORD_DATA, &data);
  97         if (ret < 0)
  98                 return ret;
  99
 100         msleep(MLX90614_TIMING_EEPROM);
 101
 102         data.word = value; /* actual write */
 103         ret = i2c_smbus_xfer(client->adapter, client->addr,
 104                              client->flags | I2C_CLIENT_PEC,
 105                              I2C_SMBUS_WRITE, command,
 106                              I2C_SMBUS_WORD_DATA, &data);
 107
 108         msleep(MLX90614_TIMING_EEPROM);
 109
 110         return ret;
 111 }
 112
 113 #ifdef CONFIG_PM
 114 /*
 115  * If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since
 116  * the last wake-up.  This is normally only needed to get a valid temperature
 117  * reading.  EEPROM access does not need such delay.
 118  * Return 0 on success, <0 on error.
 119  */
 120 static int mlx90614_power_get(struct mlx90614_data *data, bool startup)
 121 {
 122         unsigned long now;
 123
 124         if (!data->wakeup_gpio)
 125                 return 0;
 126
 127         pm_runtime_get_sync(&data->client->dev);
 128
 129         if (startup) {
 130                 now = jiffies;
 131                 if (time_before(now, data->ready_timestamp) &&
 132                     msleep_interruptible(jiffies_to_msecs(
 133                                 data->ready_timestamp - now)) != 0) {
 134                         pm_runtime_put_autosuspend(&data->client->dev);
 135                         return -EINTR;
 136                 }
 137         }
 138
 139         return 0;
 140 }
 141
 142 static void mlx90614_power_put(struct mlx90614_data *data)
 143 {
 144         if (!data->wakeup_gpio)
 145                 return;
 146
 147         pm_runtime_mark_last_busy(&data->client->dev);
 148         pm_runtime_put_autosuspend(&data->client->dev);
 149 }
 150 #else
 151 static inline int mlx90614_power_get(struct mlx90614_data *data, bool startup)
 152 {
 153         return 0;
 154 }
 155
 156 static inline void mlx90614_power_put(struct mlx90614_data *data)
 157 {
 158 }
 159 #endif
 160
 161 static int mlx90614_read_raw(struct iio_dev *indio_dev,
 162                             struct iio_chan_spec const *channel, int *val,
 163                             int *val2, long mask)
 164 {
 165         struct mlx90614_data *data = iio_priv(indio_dev);
 166         u8 cmd;
 167         s32 ret;
 168
 169         switch (mask) {
 170         case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
 171                 switch (channel->channel2) {
 172                 case IIO_MOD_TEMP_AMBIENT:
 173                         cmd = MLX90614_TA;
 174                         break;
 175                 case IIO_MOD_TEMP_OBJECT:
 176                         switch (channel->channel) {
 177                         case 0:
 178                                 cmd = MLX90614_TOBJ1;
 179                                 break;
 180                         case 1:
 181                                 cmd = MLX90614_TOBJ2;
 182                                 break;
 183                         default:
 184                                 return -EINVAL;
 185                         }
 186                         break;
 187                 default:
 188                         return -EINVAL;
 189                 }
 190
 191                 ret = mlx90614_power_get(data, true);
 192                 if (ret < 0)
 193                         return ret;
 194                 ret = i2c_smbus_read_word_data(data->client, cmd);
 195                 mlx90614_power_put(data);
 196
 197                 if (ret < 0)
 198                         return ret;
 199
 200                 /* MSB is an error flag */
 201                 if (ret & 0x8000)
 202                         return -EIO;
 203
 204                 *val = ret;
 205                 return IIO_VAL_INT;
 206         case IIO_CHAN_INFO_OFFSET:
 207                 *val = -13657;
 208                 *val2 = 500000;
 209                 return IIO_VAL_INT_PLUS_MICRO;
 210         case IIO_CHAN_INFO_SCALE:
 211                 *val = 20;
 212                 return IIO_VAL_INT;
 213         case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
 214                 mlx90614_power_get(data, false);
 215                 mutex_lock(&data->lock);
 216                 ret = i2c_smbus_read_word_data(data->client,
 217                                                MLX90614_EMISSIVITY);
 218                 mutex_unlock(&data->lock);
 219                 mlx90614_power_put(data);
 220
 221                 if (ret < 0)
 222                         return ret;
 223
 224                 if (ret == 65535) {
 225                         *val = 1;
 226                         *val2 = 0;
 227                 } else {
 228                         *val = 0;
 229                         *val2 = ret * 15259; /* 1/65535 ~ 0.000015259 */
 230                 }
 231                 return IIO_VAL_INT_PLUS_NANO;
 232         default:
 233                 return -EINVAL;
 234         }
 235 }
 236
 237 static int mlx90614_write_raw(struct iio_dev *indio_dev,
 238                              struct iio_chan_spec const *channel, int val,
 239                              int val2, long mask)
 240 {
 241         struct mlx90614_data *data = iio_priv(indio_dev);
 242         s32 ret;
 243
 244         switch (mask) {
 245         case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
 246                 if (val < 0 || val2 < 0 || val > 1 || (val == 1 && val2 != 0))
 247                         return -EINVAL;
 248                 val = val * 65535 + val2 / 15259; /* 1/65535 ~ 0.000015259 */
 249
 250                 mlx90614_power_get(data, false);
 251                 mutex_lock(&data->lock);
 252                 ret = mlx90614_write_word(data->client, MLX90614_EMISSIVITY,
 253                                           val);
 254                 mutex_unlock(&data->lock);
 255                 mlx90614_power_put(data);
 256
 257                 return ret;
 258         default:
 259                 return -EINVAL;
 260         }
 261 }
 262
 263 static int mlx90614_write_raw_get_fmt(struct iio_dev *indio_dev,
 264                                      struct iio_chan_spec const *channel,
 265                                      long mask)
 266 {
 267         switch (mask) {
 268         case IIO_CHAN_INFO_CALIBEMISSIVITY:
 269                 return IIO_VAL_INT_PLUS_NANO;
 270         default:
 271                 return -EINVAL;
 272         }
 273 }
 274
 275 static const struct iio_chan_spec mlx90614_channels[] = {
 276         {
 277                 .type = IIO_TEMP,
 278                 .modified = 1,
 279                 .channel2 = IIO_MOD_TEMP_AMBIENT,
 280                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 281                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 282                     BIT(IIO_CHAN_INFO_SCALE),
 283         },
 284         {
 285                 .type = IIO_TEMP,
 286                 .modified = 1,
 287                 .channel2 = IIO_MOD_TEMP_OBJECT,
 288                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 289                     BIT(IIO_CHAN_INFO_CALIBEMISSIVITY),
 290                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 291                     BIT(IIO_CHAN_INFO_SCALE),
 292         },
 293         {
 294                 .type = IIO_TEMP,
 295                 .indexed = 1,
 296                 .modified = 1,
 297                 .channel = 1,
 298                 .channel2 = IIO_MOD_TEMP_OBJECT,
 299                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 300                     BIT(IIO_CHAN_INFO_CALIBEMISSIVITY),
 301                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 302                     BIT(IIO_CHAN_INFO_SCALE),
 303         },
 304 };
 305
 306 static const struct iio_info mlx90614_info = {
 307         .read_raw = mlx90614_read_raw,
 308         .write_raw = mlx90614_write_raw,
 309         .write_raw_get_fmt = mlx90614_write_raw_get_fmt,
 310         .driver_module = THIS_MODULE,
 311 };
 312
 313 #ifdef CONFIG_PM
 314 static int mlx90614_sleep(struct mlx90614_data *data)
 315 {
 316         s32 ret;
 317
 318         if (!data->wakeup_gpio) {
 319                 dev_dbg(&data->client->dev, "Sleep disabled");
 320                 return -ENOSYS;
 321         }
 322
 323         dev_dbg(&data->client->dev, "Requesting sleep");
 324
 325         mutex_lock(&data->lock);
 326         ret = i2c_smbus_xfer(data->client->adapter, data->client->addr,
 327                              data->client->flags | I2C_CLIENT_PEC,
 328                              I2C_SMBUS_WRITE, MLX90614_OP_SLEEP,
 329                              I2C_SMBUS_BYTE, NULL);
 330         mutex_unlock(&data->lock);
 331
 332         return ret;
 333 }
 334
 335 static int mlx90614_wakeup(struct mlx90614_data *data)
 336 {
 337         if (!data->wakeup_gpio) {
 338                 dev_dbg(&data->client->dev, "Wake-up disabled");
 339                 return -ENOSYS;
 340         }
 341
 342         dev_dbg(&data->client->dev, "Requesting wake-up");
 343
 344         i2c_lock_adapter(data->client->adapter);
 345         gpiod_direction_output(data->wakeup_gpio, 0);
 346         msleep(MLX90614_TIMING_WAKEUP);
 347         gpiod_direction_input(data->wakeup_gpio);
 348         i2c_unlock_adapter(data->client->adapter);
 349
 350         data->ready_timestamp = jiffies +
 351                         msecs_to_jiffies(MLX90614_TIMING_STARTUP);
 352
 353         /*
 354          * Quirk: the i2c controller may get confused right after the
 355          * wake-up signal has been sent.  As a workaround, do a dummy read.
 356          * If the read fails, the controller will probably be reset so that
 357          * further reads will work.
 358          */
 359         i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
 360
 361         return 0;
 362 }
 363
 364 /* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
 365 static struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
 366 {
 367         struct gpio_desc *gpio;
 368
 369         if (!i2c_check_functionality(client->adapter,
 370                                                 I2C_FUNC_SMBUS_WRITE_BYTE)) {
 371                 dev_info(&client->dev,
 372                          "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
 373                 return NULL;
 374         }
 375
 376         gpio = devm_gpiod_get_optional(&client->dev, "wakeup", GPIOD_IN);
 377
 378         if (IS_ERR(gpio)) {
 379                 dev_warn(&client->dev,
 380                          "gpio acquisition failed with error %ld, sleep disabled",
 381                          PTR_ERR(gpio));
 382                 return NULL;
 383         } else if (!gpio) {
 384                 dev_info(&client->dev,
 385                          "wakeup-gpio not found, sleep disabled");
 386         }
 387
 388         return gpio;
 389 }
 390 #else
 391 static inline int mlx90614_sleep(struct mlx90614_data *data)
 392 {
 393         return -ENOSYS;
 394 }
 395 static inline int mlx90614_wakeup(struct mlx90614_data *data)
 396 {
 397         return -ENOSYS;
 398 }
 399 static inline struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
 400 {
 401         return NULL;
 402 }
 403 #endif
 404
 405 /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
 406 static int mlx90614_probe_num_ir_sensors(struct i2c_client *client)
 407 {
 408         s32 ret;
 409
 410         ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
 411
 412         if (ret < 0)
 413                 return ret;
 414
 415         return (ret & MLX90614_CONFIG_DUAL_MASK) ? 1 : 0;
 416 }
 417
 418 static int mlx90614_probe(struct i2c_client *client,
 419                          const struct i2c_device_id *id)
 420 {
 421         struct iio_dev *indio_dev;
 422         struct mlx90614_data *data;
 423         int ret;
 424
 425         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 426                 return -ENODEV;
 427
 428         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 429         if (!indio_dev)
 430                 return -ENOMEM;
 431
 432         data = iio_priv(indio_dev);
 433         i2c_set_clientdata(client, indio_dev);
 434         data->client = client;
 435         mutex_init(&data->lock);
 436         data->wakeup_gpio = mlx90614_probe_wakeup(client);
 437
 438         mlx90614_wakeup(data);
 439
 440         indio_dev->dev.parent = &client->dev;
 441         indio_dev->name = id->name;
 442         indio_dev->modes = INDIO_DIRECT_MODE;
 443         indio_dev->info = &mlx90614_info;
 444
 445         ret = mlx90614_probe_num_ir_sensors(client);
 446         switch (ret) {
 447         case 0:
 448                 dev_dbg(&client->dev, "Found single sensor");
 449                 indio_dev->channels = mlx90614_channels;
 450                 indio_dev->num_channels = 2;
 451                 break;
 452         case 1:
 453                 dev_dbg(&client->dev, "Found dual sensor");
 454                 indio_dev->channels = mlx90614_channels;
 455                 indio_dev->num_channels = 3;
 456                 break;
 457         default:
 458                 return ret;
 459         }
 460
 461         if (data->wakeup_gpio) {
 462                 pm_runtime_set_autosuspend_delay(&client->dev,
 463                                                  MLX90614_AUTOSLEEP_DELAY);
 464                 pm_runtime_use_autosuspend(&client->dev);
 465                 pm_runtime_set_active(&client->dev);
 466                 pm_runtime_enable(&client->dev);
 467         }
 468
 469         return iio_device_register(indio_dev);
 470 }
 471
 472 static int mlx90614_remove(struct i2c_client *client)
 473 {
 474         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 475         struct mlx90614_data *data = iio_priv(indio_dev);
 476
 477         iio_device_unregister(indio_dev);
 478
 479         if (data->wakeup_gpio) {
 480                 pm_runtime_disable(&client->dev);
 481                 if (!pm_runtime_status_suspended(&client->dev))
 482                         mlx90614_sleep(data);
 483                 pm_runtime_set_suspended(&client->dev);
 484         }
 485
 486         return 0;
 487 }
 488
 489 static const struct i2c_device_id mlx90614_id[] = {
 490         { "mlx90614", 0 },
 491         { }
 492 };
 493 MODULE_DEVICE_TABLE(i2c, mlx90614_id);
 494
 495 #ifdef CONFIG_PM_SLEEP
 496 static int mlx90614_pm_suspend(struct device *dev)
 497 {
 498         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 499         struct mlx90614_data *data = iio_priv(indio_dev);
 500
 501         if (data->wakeup_gpio && pm_runtime_active(dev))
 502                 return mlx90614_sleep(data);
 503
 504         return 0;
 505 }
 506
 507 static int mlx90614_pm_resume(struct device *dev)
 508 {
 509         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 510         struct mlx90614_data *data = iio_priv(indio_dev);
 511         int err;
 512
 513         if (data->wakeup_gpio) {
 514                 err = mlx90614_wakeup(data);
 515                 if (err < 0)
 516                         return err;
 517
 518                 pm_runtime_disable(dev);
 519                 pm_runtime_set_active(dev);
 520                 pm_runtime_enable(dev);
 521         }
 522
 523         return 0;
 524 }
 525 #endif
 526
 527 #ifdef CONFIG_PM
 528 static int mlx90614_pm_runtime_suspend(struct device *dev)
 529 {
 530         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 531         struct mlx90614_data *data = iio_priv(indio_dev);
 532
 533         return mlx90614_sleep(data);
 534 }
 535
 536 static int mlx90614_pm_runtime_resume(struct device *dev)
 537 {
 538         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 539         struct mlx90614_data *data = iio_priv(indio_dev);
 540
 541         return mlx90614_wakeup(data);
 542 }
 543 #endif
 544
 545 static const struct dev_pm_ops mlx90614_pm_ops = {
 546         SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend, mlx90614_pm_resume)
 547         SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend,
 548                            mlx90614_pm_runtime_resume, NULL)
 549 };
 550
 551 static struct i2c_driver mlx90614_driver = {
 552         .driver = {
 553                 .name   = "mlx90614",
 554                 .owner  = THIS_MODULE,
 555                 .pm     = &mlx90614_pm_ops,
 556         },
 557         .probe = mlx90614_probe,
 558         .remove = mlx90614_remove,
 559         .id_table = mlx90614_id,
 560 };
 561 module_i2c_driver(mlx90614_driver);
 562
 563 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 564 MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
 565 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
 566 MODULE_LICENSE("GPL");