drivers/iio/chemical/ccs811.c

   1 /*
   2  * ccs811.c - Support for AMS CCS811 VOC Sensor
   3  *
   4  * Copyright (C) 2017 Narcisa Vasile <narcisaanamaria12@gmail.com>
   5  *
   6  * Datasheet: ams.com/content/download/951091/2269479/CCS811_DS000459_3-00.pdf
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * IIO driver for AMS CCS811 (I2C address 0x5A/0x5B set by ADDR Low/High)
  13  *
  14  * TODO:
  15  * 1. Make the drive mode selectable form userspace
  16  * 2. Add support for interrupts
  17  * 3. Adjust time to wait for data to be ready based on selected operation mode
  18  * 4. Read error register and put the information in logs
  19  */
  20
  21 #include <linux/delay.h>
  22 #include <linux/i2c.h>
  23 #include <linux/iio/iio.h>
  24 #include <linux/iio/buffer.h>
  25 #include <linux/iio/trigger.h>
  26 #include <linux/iio/triggered_buffer.h>
  27 #include <linux/iio/trigger_consumer.h>
  28 #include <linux/module.h>
  29
  30 #define CCS811_STATUS           0x00
  31 #define CCS811_MEAS_MODE        0x01
  32 #define CCS811_ALG_RESULT_DATA  0x02
  33 #define CCS811_RAW_DATA         0x03
  34 #define CCS811_HW_ID            0x20
  35 #define CCS811_HW_ID_VALUE      0x81
  36 #define CCS811_HW_VERSION       0x21
  37 #define CCS811_HW_VERSION_VALUE 0x10
  38 #define CCS811_HW_VERSION_MASK  0xF0
  39 #define CCS811_ERR              0xE0
  40 /* Used to transition from boot to application mode */
  41 #define CCS811_APP_START        0xF4
  42
  43 /* Status register flags */
  44 #define CCS811_STATUS_ERROR             BIT(0)
  45 #define CCS811_STATUS_DATA_READY        BIT(3)
  46 #define CCS811_STATUS_APP_VALID_MASK    BIT(4)
  47 #define CCS811_STATUS_APP_VALID_LOADED  BIT(4)
  48 /*
  49  * Value of FW_MODE bit of STATUS register describes the sensor's state:
  50  * 0: Firmware is in boot mode, this allows new firmware to be loaded
  51  * 1: Firmware is in application mode. CCS811 is ready to take ADC measurements
  52  */
  53 #define CCS811_STATUS_FW_MODE_MASK      BIT(7)
  54 #define CCS811_STATUS_FW_MODE_APPLICATION       BIT(7)
  55
  56 /* Measurement modes */
  57 #define CCS811_MODE_IDLE        0x00
  58 #define CCS811_MODE_IAQ_1SEC    0x10
  59 #define CCS811_MODE_IAQ_10SEC   0x20
  60 #define CCS811_MODE_IAQ_60SEC   0x30
  61 #define CCS811_MODE_RAW_DATA    0x40
  62
  63 #define CCS811_MEAS_MODE_INTERRUPT      BIT(3)
  64
  65 #define CCS811_VOLTAGE_MASK     0x3FF
  66
  67 struct ccs811_reading {
  68         __be16 co2;
  69         __be16 voc;
  70         u8 status;
  71         u8 error;
  72         __be16 raw_data;
  73 } __attribute__((__packed__));
  74
  75 struct ccs811_data {
  76         struct i2c_client *client;
  77         struct mutex lock; /* Protect readings */
  78         struct ccs811_reading buffer;
  79         struct iio_trigger *drdy_trig;
  80         bool drdy_trig_on;
  81 };
  82
  83 static const struct iio_chan_spec ccs811_channels[] = {
  84         {
  85                 .type = IIO_CURRENT,
  86                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  87                                       BIT(IIO_CHAN_INFO_SCALE),
  88                 .scan_index = -1,
  89         }, {
  90                 .type = IIO_VOLTAGE,
  91                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  92                                       BIT(IIO_CHAN_INFO_SCALE),
  93                 .scan_index = -1,
  94         }, {
  95                 .type = IIO_CONCENTRATION,
  96                 .channel2 = IIO_MOD_CO2,
  97                 .modified = 1,
  98                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  99                                       BIT(IIO_CHAN_INFO_SCALE),
 100                 .scan_index = 0,
 101                 .scan_type = {
 102                         .sign = 'u',
 103                         .realbits = 16,
 104                         .storagebits = 16,
 105                         .endianness = IIO_BE,
 106                 },
 107         }, {
 108                 .type = IIO_CONCENTRATION,
 109                 .channel2 = IIO_MOD_VOC,
 110                 .modified = 1,
 111                 .info_mask_separate =  BIT(IIO_CHAN_INFO_RAW) |
 112                                        BIT(IIO_CHAN_INFO_SCALE),
 113                 .scan_index = 1,
 114                 .scan_type = {
 115                         .sign = 'u',
 116                         .realbits = 16,
 117                         .storagebits = 16,
 118                         .endianness = IIO_BE,
 119                 },
 120         },
 121         IIO_CHAN_SOFT_TIMESTAMP(2),
 122 };
 123
 124 /*
 125  * The CCS811 powers-up in boot mode. A setup write to CCS811_APP_START will
 126  * transition the sensor to application mode.
 127  */
 128 static int ccs811_start_sensor_application(struct i2c_client *client)
 129 {
 130         int ret;
 131
 132         ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
 133         if (ret < 0)
 134                 return ret;
 135
 136         if ((ret & CCS811_STATUS_FW_MODE_APPLICATION))
 137                 return 0;
 138
 139         if ((ret & CCS811_STATUS_APP_VALID_MASK) !=
 140             CCS811_STATUS_APP_VALID_LOADED)
 141                 return -EIO;
 142
 143         ret = i2c_smbus_write_byte(client, CCS811_APP_START);
 144         if (ret < 0)
 145                 return ret;
 146
 147         ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
 148         if (ret < 0)
 149                 return ret;
 150
 151         if ((ret & CCS811_STATUS_FW_MODE_MASK) !=
 152             CCS811_STATUS_FW_MODE_APPLICATION) {
 153                 dev_err(&client->dev, "Application failed to start. Sensor is still in boot mode.\n");
 154                 return -EIO;
 155         }
 156
 157         return 0;
 158 }
 159
 160 static int ccs811_setup(struct i2c_client *client)
 161 {
 162         int ret;
 163
 164         ret = ccs811_start_sensor_application(client);
 165         if (ret < 0)
 166                 return ret;
 167
 168         return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
 169                                          CCS811_MODE_IAQ_1SEC);
 170 }
 171
 172 static int ccs811_get_measurement(struct ccs811_data *data)
 173 {
 174         int ret, tries = 11;
 175
 176         /* Maximum waiting time: 1s, as measurements are made every second */
 177         while (tries-- > 0) {
 178                 ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS);
 179                 if (ret < 0)
 180                         return ret;
 181
 182                 if ((ret & CCS811_STATUS_DATA_READY) || tries == 0)
 183                         break;
 184                 msleep(100);
 185         }
 186         if (!(ret & CCS811_STATUS_DATA_READY))
 187                 return -EIO;
 188
 189         return i2c_smbus_read_i2c_block_data(data->client,
 190                                             CCS811_ALG_RESULT_DATA, 8,
 191                                             (char *)&data->buffer);
 192 }
 193
 194 static int ccs811_read_raw(struct iio_dev *indio_dev,
 195                            struct iio_chan_spec const *chan,
 196                            int *val, int *val2, long mask)
 197 {
 198         struct ccs811_data *data = iio_priv(indio_dev);
 199         int ret;
 200
 201         switch (mask) {
 202         case IIO_CHAN_INFO_RAW:
 203                 ret = iio_device_claim_direct_mode(indio_dev);
 204                 if (ret)
 205                         return ret;
 206                 mutex_lock(&data->lock);
 207                 ret = ccs811_get_measurement(data);
 208                 if (ret < 0) {
 209                         mutex_unlock(&data->lock);
 210                         iio_device_release_direct_mode(indio_dev);
 211                         return ret;
 212                 }
 213
 214                 switch (chan->type) {
 215                 case IIO_VOLTAGE:
 216                         *val = be16_to_cpu(data->buffer.raw_data) &
 217                                            CCS811_VOLTAGE_MASK;
 218                         ret = IIO_VAL_INT;
 219                         break;
 220                 case IIO_CURRENT:
 221                         *val = be16_to_cpu(data->buffer.raw_data) >> 10;
 222                         ret = IIO_VAL_INT;
 223                         break;
 224                 case IIO_CONCENTRATION:
 225                         switch (chan->channel2) {
 226                         case IIO_MOD_CO2:
 227                                 *val = be16_to_cpu(data->buffer.co2);
 228                                 ret =  IIO_VAL_INT;
 229                                 break;
 230                         case IIO_MOD_VOC:
 231                                 *val = be16_to_cpu(data->buffer.voc);
 232                                 ret = IIO_VAL_INT;
 233                                 break;
 234                         default:
 235                                 ret = -EINVAL;
 236                         }
 237                         break;
 238                 default:
 239                         ret = -EINVAL;
 240                 }
 241                 mutex_unlock(&data->lock);
 242                 iio_device_release_direct_mode(indio_dev);
 243
 244                 return ret;
 245
 246         case IIO_CHAN_INFO_SCALE:
 247                 switch (chan->type) {
 248                 case IIO_VOLTAGE:
 249                         *val = 1;
 250                         *val2 = 612903;
 251                         return IIO_VAL_INT_PLUS_MICRO;
 252                 case IIO_CURRENT:
 253                         *val = 0;
 254                         *val2 = 1000;
 255                         return IIO_VAL_INT_PLUS_MICRO;
 256                 case IIO_CONCENTRATION:
 257                         switch (chan->channel2) {
 258                         case IIO_MOD_CO2:
 259                                 *val = 0;
 260                                 *val2 = 100;
 261                                 return IIO_VAL_INT_PLUS_MICRO;
 262                         case IIO_MOD_VOC:
 263                                 *val = 0;
 264                                 *val2 = 100;
 265                                 return IIO_VAL_INT_PLUS_NANO;
 266                         default:
 267                                 return -EINVAL;
 268                         }
 269                 default:
 270                         return -EINVAL;
 271                 }
 272         default:
 273                 return -EINVAL;
 274         }
 275 }
 276
 277 static const struct iio_info ccs811_info = {
 278         .read_raw = ccs811_read_raw,
 279 };
 280
 281 static int ccs811_set_trigger_state(struct iio_trigger *trig,
 282                                     bool state)
 283 {
 284         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 285         struct ccs811_data *data = iio_priv(indio_dev);
 286         int ret;
 287
 288         ret = i2c_smbus_read_byte_data(data->client, CCS811_MEAS_MODE);
 289         if (ret < 0)
 290                 return ret;
 291
 292         if (state)
 293                 ret |= CCS811_MEAS_MODE_INTERRUPT;
 294         else
 295                 ret &= ~CCS811_MEAS_MODE_INTERRUPT;
 296
 297         data->drdy_trig_on = state;
 298
 299         return i2c_smbus_write_byte_data(data->client, CCS811_MEAS_MODE, ret);
 300 }
 301
 302 static const struct iio_trigger_ops ccs811_trigger_ops = {
 303         .set_trigger_state = ccs811_set_trigger_state,
 304 };
 305
 306 static irqreturn_t ccs811_trigger_handler(int irq, void *p)
 307 {
 308         struct iio_poll_func *pf = p;
 309         struct iio_dev *indio_dev = pf->indio_dev;
 310         struct ccs811_data *data = iio_priv(indio_dev);
 311         struct i2c_client *client = data->client;
 312         s16 buf[8]; /* s16 eCO2 + s16 TVOC + padding + 8 byte timestamp */
 313         int ret;
 314
 315         ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, 4,
 316                                             (u8 *)&buf);
 317         if (ret != 4) {
 318                 dev_err(&client->dev, "cannot read sensor data\n");
 319                 goto err;
 320         }
 321
 322         iio_push_to_buffers_with_timestamp(indio_dev, buf,
 323                                            iio_get_time_ns(indio_dev));
 324
 325 err:
 326         iio_trigger_notify_done(indio_dev->trig);
 327
 328         return IRQ_HANDLED;
 329 }
 330
 331 static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private)
 332 {
 333         struct iio_dev *indio_dev = private;
 334         struct ccs811_data *data = iio_priv(indio_dev);
 335
 336         if (data->drdy_trig_on)
 337                 iio_trigger_poll(data->drdy_trig);
 338
 339         return IRQ_HANDLED;
 340 }
 341
 342 static int ccs811_probe(struct i2c_client *client,
 343                         const struct i2c_device_id *id)
 344 {
 345         struct iio_dev *indio_dev;
 346         struct ccs811_data *data;
 347         int ret;
 348
 349         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE
 350                                      | I2C_FUNC_SMBUS_BYTE_DATA
 351                                      | I2C_FUNC_SMBUS_READ_I2C_BLOCK))
 352                 return -EOPNOTSUPP;
 353
 354         /* Check hardware id (should be 0x81 for this family of devices) */
 355         ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
 356         if (ret < 0)
 357                 return ret;
 358
 359         if (ret != CCS811_HW_ID_VALUE) {
 360                 dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
 361                 return -ENODEV;
 362         }
 363
 364         ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
 365         if (ret < 0)
 366                 return ret;
 367
 368         if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
 369                 dev_err(&client->dev, "no CCS811 sensor\n");
 370                 return -ENODEV;
 371         }
 372
 373         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 374         if (!indio_dev)
 375                 return -ENOMEM;
 376
 377         ret = ccs811_setup(client);
 378         if (ret < 0)
 379                 return ret;
 380
 381         data = iio_priv(indio_dev);
 382         i2c_set_clientdata(client, indio_dev);
 383         data->client = client;
 384
 385         mutex_init(&data->lock);
 386
 387         indio_dev->dev.parent = &client->dev;
 388         indio_dev->name = id->name;
 389         indio_dev->info = &ccs811_info;
 390         indio_dev->modes = INDIO_DIRECT_MODE;
 391
 392         indio_dev->channels = ccs811_channels;
 393         indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);
 394
 395         if (client->irq > 0) {
 396                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 397                                                 ccs811_data_rdy_trigger_poll,
 398                                                 NULL,
 399                                                 IRQF_TRIGGER_FALLING |
 400                                                 IRQF_ONESHOT,
 401                                                 "ccs811_irq", indio_dev);
 402                 if (ret) {
 403                         dev_err(&client->dev, "irq request error %d\n", -ret);
 404                         goto err_poweroff;
 405                 }
 406
 407                 data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
 408                                                          "%s-dev%d",
 409                                                          indio_dev->name,
 410                                                          indio_dev->id);
 411                 if (!data->drdy_trig) {
 412                         ret = -ENOMEM;
 413                         goto err_poweroff;
 414                 }
 415
 416                 data->drdy_trig->dev.parent = &client->dev;
 417                 data->drdy_trig->ops = &ccs811_trigger_ops;
 418                 iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
 419                 indio_dev->trig = data->drdy_trig;
 420                 iio_trigger_get(indio_dev->trig);
 421                 ret = iio_trigger_register(data->drdy_trig);
 422                 if (ret)
 423                         goto err_poweroff;
 424         }
 425
 426         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 427                                          ccs811_trigger_handler, NULL);
 428
 429         if (ret < 0) {
 430                 dev_err(&client->dev, "triggered buffer setup failed\n");
 431                 goto err_trigger_unregister;
 432         }
 433
 434         ret = iio_device_register(indio_dev);
 435         if (ret < 0) {
 436                 dev_err(&client->dev, "unable to register iio device\n");
 437                 goto err_buffer_cleanup;
 438         }
 439         return 0;
 440
 441 err_buffer_cleanup:
 442         iio_triggered_buffer_cleanup(indio_dev);
 443 err_trigger_unregister:
 444         if (data->drdy_trig)
 445                 iio_trigger_unregister(data->drdy_trig);
 446 err_poweroff:
 447         i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);
 448
 449         return ret;
 450 }
 451
 452 static int ccs811_remove(struct i2c_client *client)
 453 {
 454         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 455         struct ccs811_data *data = iio_priv(indio_dev);
 456
 457         iio_device_unregister(indio_dev);
 458         iio_triggered_buffer_cleanup(indio_dev);
 459         if (data->drdy_trig)
 460                 iio_trigger_unregister(data->drdy_trig);
 461
 462         return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
 463                                          CCS811_MODE_IDLE);
 464 }
 465
 466 static const struct i2c_device_id ccs811_id[] = {
 467         {"ccs811", 0},
 468         {       }
 469 };
 470 MODULE_DEVICE_TABLE(i2c, ccs811_id);
 471
 472 static struct i2c_driver ccs811_driver = {
 473         .driver = {
 474                 .name = "ccs811",
 475         },
 476         .probe = ccs811_probe,
 477         .remove = ccs811_remove,
 478         .id_table = ccs811_id,
 479 };
 480 module_i2c_driver(ccs811_driver);
 481
 482 MODULE_AUTHOR("Narcisa Vasile <narcisaanamaria12@gmail.com>");
 483 MODULE_DESCRIPTION("CCS811 volatile organic compounds sensor");
 484 MODULE_LICENSE("GPL v2");