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 CCS881_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 resistance;
  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_APP_VALID_MASK) !=
 137             CCS811_STATUS_APP_VALID_LOADED)
 138                 return -EIO;
 139
 140         ret = i2c_smbus_write_byte(client, CCS811_APP_START);
 141         if (ret < 0)
 142                 return ret;
 143
 144         ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
 145         if (ret < 0)
 146                 return ret;
 147
 148         if ((ret & CCS811_STATUS_FW_MODE_MASK) !=
 149             CCS811_STATUS_FW_MODE_APPLICATION) {
 150                 dev_err(&client->dev, "Application failed to start. Sensor is still in boot mode.\n");
 151                 return -EIO;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int ccs811_setup(struct i2c_client *client)
 158 {
 159         int ret;
 160
 161         ret = ccs811_start_sensor_application(client);
 162         if (ret < 0)
 163                 return ret;
 164
 165         return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
 166                                          CCS811_MODE_IAQ_1SEC);
 167 }
 168
 169 static int ccs811_get_measurement(struct ccs811_data *data)
 170 {
 171         int ret, tries = 11;
 172
 173         /* Maximum waiting time: 1s, as measurements are made every second */
 174         while (tries-- > 0) {
 175                 ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS);
 176                 if (ret < 0)
 177                         return ret;
 178
 179                 if ((ret & CCS811_STATUS_DATA_READY) || tries == 0)
 180                         break;
 181                 msleep(100);
 182         }
 183         if (!(ret & CCS811_STATUS_DATA_READY))
 184                 return -EIO;
 185
 186         return i2c_smbus_read_i2c_block_data(data->client,
 187                                             CCS811_ALG_RESULT_DATA, 8,
 188                                             (char *)&data->buffer);
 189 }
 190
 191 static int ccs811_read_raw(struct iio_dev *indio_dev,
 192                            struct iio_chan_spec const *chan,
 193                            int *val, int *val2, long mask)
 194 {
 195         struct ccs811_data *data = iio_priv(indio_dev);
 196         int ret;
 197
 198         switch (mask) {
 199         case IIO_CHAN_INFO_RAW:
 200                 ret = iio_device_claim_direct_mode(indio_dev);
 201                 if (ret)
 202                         return ret;
 203                 mutex_lock(&data->lock);
 204                 ret = ccs811_get_measurement(data);
 205                 if (ret < 0) {
 206                         mutex_unlock(&data->lock);
 207                         iio_device_release_direct_mode(indio_dev);
 208                         return ret;
 209                 }
 210
 211                 switch (chan->type) {
 212                 case IIO_VOLTAGE:
 213                         *val = be16_to_cpu(data->buffer.resistance) &
 214                                            CCS811_VOLTAGE_MASK;
 215                         ret = IIO_VAL_INT;
 216                         break;
 217                 case IIO_CURRENT:
 218                         *val = be16_to_cpu(data->buffer.resistance) >> 10;
 219                         ret = IIO_VAL_INT;
 220                         break;
 221                 case IIO_CONCENTRATION:
 222                         switch (chan->channel2) {
 223                         case IIO_MOD_CO2:
 224                                 *val = be16_to_cpu(data->buffer.co2);
 225                                 ret =  IIO_VAL_INT;
 226                                 break;
 227                         case IIO_MOD_VOC:
 228                                 *val = be16_to_cpu(data->buffer.voc);
 229                                 ret = IIO_VAL_INT;
 230                                 break;
 231                         default:
 232                                 ret = -EINVAL;
 233                         }
 234                         break;
 235                 default:
 236                         ret = -EINVAL;
 237                 }
 238                 mutex_unlock(&data->lock);
 239                 iio_device_release_direct_mode(indio_dev);
 240
 241                 return ret;
 242
 243         case IIO_CHAN_INFO_SCALE:
 244                 switch (chan->type) {
 245                 case IIO_VOLTAGE:
 246                         *val = 1;
 247                         *val2 = 612903;
 248                         return IIO_VAL_INT_PLUS_MICRO;
 249                 case IIO_CURRENT:
 250                         *val = 0;
 251                         *val2 = 1000;
 252                         return IIO_VAL_INT_PLUS_MICRO;
 253                 case IIO_CONCENTRATION:
 254                         switch (chan->channel2) {
 255                         case IIO_MOD_CO2:
 256                                 *val = 0;
 257                                 *val2 = 100;
 258                                 return IIO_VAL_INT_PLUS_MICRO;
 259                         case IIO_MOD_VOC:
 260                                 *val = 0;
 261                                 *val2 = 100;
 262                                 return IIO_VAL_INT_PLUS_NANO;
 263                         default:
 264                                 return -EINVAL;
 265                         }
 266                 default:
 267                         return -EINVAL;
 268                 }
 269         default:
 270                 return -EINVAL;
 271         }
 272 }
 273
 274 static const struct iio_info ccs811_info = {
 275         .read_raw = ccs811_read_raw,
 276 };
 277
 278 static int ccs811_set_trigger_state(struct iio_trigger *trig,
 279                                     bool state)
 280 {
 281         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 282         struct ccs811_data *data = iio_priv(indio_dev);
 283         int ret;
 284
 285         ret = i2c_smbus_read_byte_data(data->client, CCS811_MEAS_MODE);
 286         if (ret < 0)
 287                 return ret;
 288
 289         if (state)
 290                 ret |= CCS811_MEAS_MODE_INTERRUPT;
 291         else
 292                 ret &= ~CCS811_MEAS_MODE_INTERRUPT;
 293
 294         data->drdy_trig_on = state;
 295
 296         return i2c_smbus_write_byte_data(data->client, CCS811_MEAS_MODE, ret);
 297 }
 298
 299 static const struct iio_trigger_ops ccs811_trigger_ops = {
 300         .set_trigger_state = ccs811_set_trigger_state,
 301 };
 302
 303 static irqreturn_t ccs811_trigger_handler(int irq, void *p)
 304 {
 305         struct iio_poll_func *pf = p;
 306         struct iio_dev *indio_dev = pf->indio_dev;
 307         struct ccs811_data *data = iio_priv(indio_dev);
 308         struct i2c_client *client = data->client;
 309         s16 buf[8]; /* s16 eCO2 + s16 TVOC + padding + 8 byte timestamp */
 310         int ret;
 311
 312         ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, 4,
 313                                             (u8 *)&buf);
 314         if (ret != 4) {
 315                 dev_err(&client->dev, "cannot read sensor data\n");
 316                 goto err;
 317         }
 318
 319         iio_push_to_buffers_with_timestamp(indio_dev, buf,
 320                                            iio_get_time_ns(indio_dev));
 321
 322 err:
 323         iio_trigger_notify_done(indio_dev->trig);
 324
 325         return IRQ_HANDLED;
 326 }
 327
 328 static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private)
 329 {
 330         struct iio_dev *indio_dev = private;
 331         struct ccs811_data *data = iio_priv(indio_dev);
 332
 333         if (data->drdy_trig_on)
 334                 iio_trigger_poll(data->drdy_trig);
 335
 336         return IRQ_HANDLED;
 337 }
 338
 339 static int ccs811_probe(struct i2c_client *client,
 340                         const struct i2c_device_id *id)
 341 {
 342         struct iio_dev *indio_dev;
 343         struct ccs811_data *data;
 344         int ret;
 345
 346         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE
 347                                      | I2C_FUNC_SMBUS_BYTE_DATA
 348                                      | I2C_FUNC_SMBUS_READ_I2C_BLOCK))
 349                 return -EOPNOTSUPP;
 350
 351         /* Check hardware id (should be 0x81 for this family of devices) */
 352         ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
 353         if (ret < 0)
 354                 return ret;
 355
 356         if (ret != CCS881_HW_ID_VALUE) {
 357                 dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
 358                 return -ENODEV;
 359         }
 360
 361         ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
 362         if (ret < 0)
 363                 return ret;
 364
 365         if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
 366                 dev_err(&client->dev, "no CCS811 sensor\n");
 367                 return -ENODEV;
 368         }
 369
 370         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 371         if (!indio_dev)
 372                 return -ENOMEM;
 373
 374         ret = ccs811_setup(client);
 375         if (ret < 0)
 376                 return ret;
 377
 378         data = iio_priv(indio_dev);
 379         i2c_set_clientdata(client, indio_dev);
 380         data->client = client;
 381
 382         mutex_init(&data->lock);
 383
 384         indio_dev->dev.parent = &client->dev;
 385         indio_dev->name = id->name;
 386         indio_dev->info = &ccs811_info;
 387         indio_dev->modes = INDIO_DIRECT_MODE;
 388
 389         indio_dev->channels = ccs811_channels;
 390         indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);
 391
 392         if (client->irq > 0) {
 393                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 394                                                 ccs811_data_rdy_trigger_poll,
 395                                                 NULL,
 396                                                 IRQF_TRIGGER_FALLING |
 397                                                 IRQF_ONESHOT,
 398                                                 "ccs811_irq", indio_dev);
 399                 if (ret) {
 400                         dev_err(&client->dev, "irq request error %d\n", -ret);
 401                         goto err_poweroff;
 402                 }
 403
 404                 data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
 405                                                          "%s-dev%d",
 406                                                          indio_dev->name,
 407                                                          indio_dev->id);
 408                 if (!data->drdy_trig) {
 409                         ret = -ENOMEM;
 410                         goto err_poweroff;
 411                 }
 412
 413                 data->drdy_trig->dev.parent = &client->dev;
 414                 data->drdy_trig->ops = &ccs811_trigger_ops;
 415                 iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
 416                 indio_dev->trig = data->drdy_trig;
 417                 iio_trigger_get(indio_dev->trig);
 418                 ret = iio_trigger_register(data->drdy_trig);
 419                 if (ret)
 420                         goto err_poweroff;
 421         }
 422
 423         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 424                                          ccs811_trigger_handler, NULL);
 425
 426         if (ret < 0) {
 427                 dev_err(&client->dev, "triggered buffer setup failed\n");
 428                 goto err_trigger_unregister;
 429         }
 430
 431         ret = iio_device_register(indio_dev);
 432         if (ret < 0) {
 433                 dev_err(&client->dev, "unable to register iio device\n");
 434                 goto err_buffer_cleanup;
 435         }
 436         return 0;
 437
 438 err_buffer_cleanup:
 439         iio_triggered_buffer_cleanup(indio_dev);
 440 err_trigger_unregister:
 441         if (data->drdy_trig)
 442                 iio_trigger_unregister(data->drdy_trig);
 443 err_poweroff:
 444         i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);
 445
 446         return ret;
 447 }
 448
 449 static int ccs811_remove(struct i2c_client *client)
 450 {
 451         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 452         struct ccs811_data *data = iio_priv(indio_dev);
 453
 454         iio_device_unregister(indio_dev);
 455         iio_triggered_buffer_cleanup(indio_dev);
 456         if (data->drdy_trig)
 457                 iio_trigger_unregister(data->drdy_trig);
 458
 459         return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
 460                                          CCS811_MODE_IDLE);
 461 }
 462
 463 static const struct i2c_device_id ccs811_id[] = {
 464         {"ccs811", 0},
 465         {       }
 466 };
 467 MODULE_DEVICE_TABLE(i2c, ccs811_id);
 468
 469 static struct i2c_driver ccs811_driver = {
 470         .driver = {
 471                 .name = "ccs811",
 472         },
 473         .probe = ccs811_probe,
 474         .remove = ccs811_remove,
 475         .id_table = ccs811_id,
 476 };
 477 module_i2c_driver(ccs811_driver);
 478
 479 MODULE_AUTHOR("Narcisa Vasile <narcisaanamaria12@gmail.com>");
 480 MODULE_DESCRIPTION("CCS811 volatile organic compounds sensor");
 481 MODULE_LICENSE("GPL v2");