drivers/iio/accel/stk8ba50.c

   1 /**
   2  * Sensortek STK8BA50 3-Axis Accelerometer
   3  *
   4  * Copyright (c) 2015, Intel Corporation.
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License. See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * STK8BA50 7-bit I2C address: 0x18.
  11  */
  12
  13 #include <linux/acpi.h>
  14 #include <linux/i2c.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/iio/buffer.h>
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/sysfs.h>
  21 #include <linux/iio/trigger.h>
  22 #include <linux/iio/triggered_buffer.h>
  23 #include <linux/iio/trigger_consumer.h>
  24
  25 #define STK8BA50_REG_XOUT                       0x02
  26 #define STK8BA50_REG_YOUT                       0x04
  27 #define STK8BA50_REG_ZOUT                       0x06
  28 #define STK8BA50_REG_RANGE                      0x0F
  29 #define STK8BA50_REG_BWSEL                      0x10
  30 #define STK8BA50_REG_POWMODE                    0x11
  31 #define STK8BA50_REG_SWRST                      0x14
  32 #define STK8BA50_REG_INTEN2                     0x17
  33 #define STK8BA50_REG_INTMAP2                    0x1A
  34
  35 #define STK8BA50_MODE_NORMAL                    0
  36 #define STK8BA50_MODE_SUSPEND                   1
  37 #define STK8BA50_MODE_POWERBIT                  BIT(7)
  38 #define STK8BA50_DATA_SHIFT                     6
  39 #define STK8BA50_RESET_CMD                      0xB6
  40 #define STK8BA50_SR_1792HZ_IDX                  7
  41 #define STK8BA50_DREADY_INT_MASK                0x10
  42 #define STK8BA50_DREADY_INT_MAP                 0x81
  43 #define STK8BA50_ALL_CHANNEL_MASK               7
  44 #define STK8BA50_ALL_CHANNEL_SIZE               6
  45
  46 #define STK8BA50_DRIVER_NAME                    "stk8ba50"
  47 #define STK8BA50_IRQ_NAME                       "stk8ba50_event"
  48
  49 #define STK8BA50_SCALE_AVAIL                    "0.0384 0.0767 0.1534 0.3069"
  50
  51 /*
  52  * The accelerometer has four measurement ranges:
  53  * +/-2g; +/-4g; +/-8g; +/-16g
  54  *
  55  * Acceleration values are 10-bit, 2's complement.
  56  * Scales are calculated as following:
  57  *
  58  * scale1 = (2 + 2) * 9.81 / (2^10 - 1)   = 0.0384
  59  * scale2 = (4 + 4) * 9.81 / (2^10 - 1)   = 0.0767
  60  * etc.
  61  *
  62  * Scales are stored in this format:
  63  * { <register value>, <scale value> }
  64  *
  65  * Locally, the range is stored as a table index.
  66  */
  67 static const struct {
  68         u8 reg_val;
  69         u32 scale_val;
  70 } stk8ba50_scale_table[] = {
  71         {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
  72 };
  73
  74 /* Sample rates are stored as { <register value>, <Hz value> } */
  75 static const struct {
  76         u8 reg_val;
  77         u16 samp_freq;
  78 } stk8ba50_samp_freq_table[] = {
  79         {0x08, 14},  {0x09, 25},  {0x0A, 56},  {0x0B, 112},
  80         {0x0C, 224}, {0x0D, 448}, {0x0E, 896}, {0x0F, 1792}
  81 };
  82
  83 /* Used to map scan mask bits to their corresponding channel register. */
  84 static const int stk8ba50_channel_table[] = {
  85         STK8BA50_REG_XOUT,
  86         STK8BA50_REG_YOUT,
  87         STK8BA50_REG_ZOUT
  88 };
  89
  90 struct stk8ba50_data {
  91         struct i2c_client *client;
  92         struct mutex lock;
  93         int range;
  94         u8 sample_rate_idx;
  95         struct iio_trigger *dready_trig;
  96         bool dready_trigger_on;
  97         /* Ensure timestamp is naturally aligned */
  98         struct {
  99                 s16 chans[3];
 100                 s64 timetamp __aligned(8);
 101         } scan;
 102 };
 103
 104 #define STK8BA50_ACCEL_CHANNEL(index, reg, axis) {                      \
 105         .type = IIO_ACCEL,                                              \
 106         .address = reg,                                                 \
 107         .modified = 1,                                                  \
 108         .channel2 = IIO_MOD_##axis,                                     \
 109         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
 110         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),           \
 111                                     BIT(IIO_CHAN_INFO_SAMP_FREQ),       \
 112         .scan_index = index,                                            \
 113         .scan_type = {                                                  \
 114                 .sign = 's',                                            \
 115                 .realbits = 10,                                         \
 116                 .storagebits = 16,                                      \
 117                 .shift = STK8BA50_DATA_SHIFT,                           \
 118                 .endianness = IIO_CPU,                                  \
 119         },                                                              \
 120 }
 121
 122 static const struct iio_chan_spec stk8ba50_channels[] = {
 123         STK8BA50_ACCEL_CHANNEL(0, STK8BA50_REG_XOUT, X),
 124         STK8BA50_ACCEL_CHANNEL(1, STK8BA50_REG_YOUT, Y),
 125         STK8BA50_ACCEL_CHANNEL(2, STK8BA50_REG_ZOUT, Z),
 126         IIO_CHAN_SOFT_TIMESTAMP(3),
 127 };
 128
 129 static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
 130
 131 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");
 132
 133 static struct attribute *stk8ba50_attributes[] = {
 134         &iio_const_attr_in_accel_scale_available.dev_attr.attr,
 135         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 136         NULL,
 137 };
 138
 139 static const struct attribute_group stk8ba50_attribute_group = {
 140         .attrs = stk8ba50_attributes
 141 };
 142
 143 static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
 144 {
 145         int ret;
 146         struct i2c_client *client = data->client;
 147
 148         ret = i2c_smbus_read_word_data(client, reg);
 149         if (ret < 0) {
 150                 dev_err(&client->dev, "register read failed\n");
 151                 return ret;
 152         }
 153
 154         return ret;
 155 }
 156
 157 static int stk8ba50_data_rdy_trigger_set_state(struct iio_trigger *trig,
 158                                                bool state)
 159 {
 160         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 161         struct stk8ba50_data *data = iio_priv(indio_dev);
 162         int ret;
 163
 164         if (state)
 165                 ret = i2c_smbus_write_byte_data(data->client,
 166                         STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
 167         else
 168                 ret = i2c_smbus_write_byte_data(data->client,
 169                         STK8BA50_REG_INTEN2, 0x00);
 170
 171         if (ret < 0)
 172                 dev_err(&data->client->dev, "failed to set trigger state\n");
 173         else
 174                 data->dready_trigger_on = state;
 175
 176         return ret;
 177 }
 178
 179 static const struct iio_trigger_ops stk8ba50_trigger_ops = {
 180         .set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
 181 };
 182
 183 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
 184 {
 185         int ret;
 186         u8 masked_reg;
 187         struct i2c_client *client = data->client;
 188
 189         ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
 190         if (ret < 0)
 191                 goto exit_err;
 192
 193         if (mode)
 194                 masked_reg = ret | STK8BA50_MODE_POWERBIT;
 195         else
 196                 masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
 197
 198         ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
 199                                         masked_reg);
 200         if (ret < 0)
 201                 goto exit_err;
 202
 203         return ret;
 204
 205 exit_err:
 206         dev_err(&client->dev, "failed to change sensor mode\n");
 207         return ret;
 208 }
 209
 210 static int stk8ba50_read_raw(struct iio_dev *indio_dev,
 211                              struct iio_chan_spec const *chan,
 212                              int *val, int *val2, long mask)
 213 {
 214         struct stk8ba50_data *data = iio_priv(indio_dev);
 215         int ret;
 216
 217         switch (mask) {
 218         case IIO_CHAN_INFO_RAW:
 219                 if (iio_buffer_enabled(indio_dev))
 220                         return -EBUSY;
 221                 mutex_lock(&data->lock);
 222                 ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 223                 if (ret < 0) {
 224                         mutex_unlock(&data->lock);
 225                         return -EINVAL;
 226                 }
 227                 ret = stk8ba50_read_accel(data, chan->address);
 228                 if (ret < 0) {
 229                         stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 230                         mutex_unlock(&data->lock);
 231                         return -EINVAL;
 232                 }
 233                 *val = sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9);
 234                 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 235                 mutex_unlock(&data->lock);
 236                 return IIO_VAL_INT;
 237         case IIO_CHAN_INFO_SCALE:
 238                 *val = 0;
 239                 *val2 = stk8ba50_scale_table[data->range].scale_val;
 240                 return IIO_VAL_INT_PLUS_MICRO;
 241         case IIO_CHAN_INFO_SAMP_FREQ:
 242                 *val = stk8ba50_samp_freq_table
 243                                 [data->sample_rate_idx].samp_freq;
 244                 *val2 = 0;
 245                 return IIO_VAL_INT;
 246         }
 247
 248         return -EINVAL;
 249 }
 250
 251 static int stk8ba50_write_raw(struct iio_dev *indio_dev,
 252                               struct iio_chan_spec const *chan,
 253                               int val, int val2, long mask)
 254 {
 255         int ret;
 256         int i;
 257         int index = -1;
 258         struct stk8ba50_data *data = iio_priv(indio_dev);
 259
 260         switch (mask) {
 261         case IIO_CHAN_INFO_SCALE:
 262                 if (val != 0)
 263                         return -EINVAL;
 264
 265                 for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
 266                         if (val2 == stk8ba50_scale_table[i].scale_val) {
 267                                 index = i;
 268                                 break;
 269                         }
 270                 if (index < 0)
 271                         return -EINVAL;
 272
 273                 ret = i2c_smbus_write_byte_data(data->client,
 274                                 STK8BA50_REG_RANGE,
 275                                 stk8ba50_scale_table[index].reg_val);
 276                 if (ret < 0)
 277                         dev_err(&data->client->dev,
 278                                         "failed to set measurement range\n");
 279                 else
 280                         data->range = index;
 281
 282                 return ret;
 283         case IIO_CHAN_INFO_SAMP_FREQ:
 284                 for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
 285                         if (val == stk8ba50_samp_freq_table[i].samp_freq) {
 286                                 index = i;
 287                                 break;
 288                         }
 289                 if (index < 0)
 290                         return -EINVAL;
 291
 292                 ret = i2c_smbus_write_byte_data(data->client,
 293                                 STK8BA50_REG_BWSEL,
 294                                 stk8ba50_samp_freq_table[index].reg_val);
 295                 if (ret < 0)
 296                         dev_err(&data->client->dev,
 297                                         "failed to set sampling rate\n");
 298                 else
 299                         data->sample_rate_idx = index;
 300
 301                 return ret;
 302         }
 303
 304         return -EINVAL;
 305 }
 306
 307 static const struct iio_info stk8ba50_info = {
 308         .read_raw               = stk8ba50_read_raw,
 309         .write_raw              = stk8ba50_write_raw,
 310         .attrs                  = &stk8ba50_attribute_group,
 311 };
 312
 313 static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
 314 {
 315         struct iio_poll_func *pf = p;
 316         struct iio_dev *indio_dev = pf->indio_dev;
 317         struct stk8ba50_data *data = iio_priv(indio_dev);
 318         int bit, ret, i = 0;
 319
 320         mutex_lock(&data->lock);
 321         /*
 322          * Do a bulk read if all channels are requested,
 323          * from 0x02 (XOUT1) to 0x07 (ZOUT2)
 324          */
 325         if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
 326                 ret = i2c_smbus_read_i2c_block_data(data->client,
 327                                                     STK8BA50_REG_XOUT,
 328                                                     STK8BA50_ALL_CHANNEL_SIZE,
 329                                                     (u8 *)data->scan.chans);
 330                 if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
 331                         dev_err(&data->client->dev, "register read failed\n");
 332                         goto err;
 333                 }
 334         } else {
 335                 for_each_set_bit(bit, indio_dev->active_scan_mask,
 336                                  indio_dev->masklength) {
 337                         ret = stk8ba50_read_accel(data,
 338                                                   stk8ba50_channel_table[bit]);
 339                         if (ret < 0)
 340                                 goto err;
 341
 342                         data->scan.chans[i++] = ret;
 343                 }
 344         }
 345         iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 346                                            pf->timestamp);
 347 err:
 348         mutex_unlock(&data->lock);
 349         iio_trigger_notify_done(indio_dev->trig);
 350
 351         return IRQ_HANDLED;
 352 }
 353
 354 static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
 355 {
 356         struct iio_dev *indio_dev = private;
 357         struct stk8ba50_data *data = iio_priv(indio_dev);
 358
 359         if (data->dready_trigger_on)
 360                 iio_trigger_poll(data->dready_trig);
 361
 362         return IRQ_HANDLED;
 363 }
 364
 365 static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
 366 {
 367         struct stk8ba50_data *data = iio_priv(indio_dev);
 368
 369         return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 370 }
 371
 372 static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
 373 {
 374         struct stk8ba50_data *data = iio_priv(indio_dev);
 375
 376         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 377 }
 378
 379 static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
 380         .preenable   = stk8ba50_buffer_preenable,
 381         .postenable  = iio_triggered_buffer_postenable,
 382         .predisable  = iio_triggered_buffer_predisable,
 383         .postdisable = stk8ba50_buffer_postdisable,
 384 };
 385
 386 static int stk8ba50_probe(struct i2c_client *client,
 387                           const struct i2c_device_id *id)
 388 {
 389         int ret;
 390         struct iio_dev *indio_dev;
 391         struct stk8ba50_data *data;
 392
 393         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 394         if (!indio_dev) {
 395                 dev_err(&client->dev, "iio allocation failed!\n");
 396                 return -ENOMEM;
 397         }
 398
 399         data = iio_priv(indio_dev);
 400         data->client = client;
 401         i2c_set_clientdata(client, indio_dev);
 402         mutex_init(&data->lock);
 403
 404         indio_dev->dev.parent = &client->dev;
 405         indio_dev->info = &stk8ba50_info;
 406         indio_dev->name = STK8BA50_DRIVER_NAME;
 407         indio_dev->modes = INDIO_DIRECT_MODE;
 408         indio_dev->channels = stk8ba50_channels;
 409         indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
 410
 411         /* Reset all registers on startup */
 412         ret = i2c_smbus_write_byte_data(client,
 413                         STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
 414         if (ret < 0) {
 415                 dev_err(&client->dev, "failed to reset sensor\n");
 416                 goto err_power_off;
 417         }
 418
 419         /* The default range is +/-2g */
 420         data->range = 0;
 421
 422         /* The default sampling rate is 1792 Hz (maximum) */
 423         data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;
 424
 425         /* Set up interrupts */
 426         ret = i2c_smbus_write_byte_data(client,
 427                         STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
 428         if (ret < 0) {
 429                 dev_err(&client->dev, "failed to set up interrupts\n");
 430                 goto err_power_off;
 431         }
 432         ret = i2c_smbus_write_byte_data(client,
 433                         STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
 434         if (ret < 0) {
 435                 dev_err(&client->dev, "failed to set up interrupts\n");
 436                 goto err_power_off;
 437         }
 438
 439         if (client->irq > 0) {
 440                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 441                                                 stk8ba50_data_rdy_trig_poll,
 442                                                 NULL,
 443                                                 IRQF_TRIGGER_RISING |
 444                                                 IRQF_ONESHOT,
 445                                                 STK8BA50_IRQ_NAME,
 446                                                 indio_dev);
 447                 if (ret < 0) {
 448                         dev_err(&client->dev, "request irq %d failed\n",
 449                                 client->irq);
 450                         goto err_power_off;
 451                 }
 452
 453                 data->dready_trig = devm_iio_trigger_alloc(&client->dev,
 454                                                            "%s-dev%d",
 455                                                            indio_dev->name,
 456                                                            indio_dev->id);
 457                 if (!data->dready_trig) {
 458                         ret = -ENOMEM;
 459                         goto err_power_off;
 460                 }
 461
 462                 data->dready_trig->dev.parent = &client->dev;
 463                 data->dready_trig->ops = &stk8ba50_trigger_ops;
 464                 iio_trigger_set_drvdata(data->dready_trig, indio_dev);
 465                 ret = iio_trigger_register(data->dready_trig);
 466                 if (ret) {
 467                         dev_err(&client->dev, "iio trigger register failed\n");
 468                         goto err_power_off;
 469                 }
 470         }
 471
 472         ret = iio_triggered_buffer_setup(indio_dev,
 473                                          iio_pollfunc_store_time,
 474                                          stk8ba50_trigger_handler,
 475                                          &stk8ba50_buffer_setup_ops);
 476         if (ret < 0) {
 477                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 478                 goto err_trigger_unregister;
 479         }
 480
 481         ret = iio_device_register(indio_dev);
 482         if (ret < 0) {
 483                 dev_err(&client->dev, "device_register failed\n");
 484                 goto err_buffer_cleanup;
 485         }
 486
 487         return ret;
 488
 489 err_buffer_cleanup:
 490         iio_triggered_buffer_cleanup(indio_dev);
 491 err_trigger_unregister:
 492         if (data->dready_trig)
 493                 iio_trigger_unregister(data->dready_trig);
 494 err_power_off:
 495         stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 496         return ret;
 497 }
 498
 499 static int stk8ba50_remove(struct i2c_client *client)
 500 {
 501         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 502         struct stk8ba50_data *data = iio_priv(indio_dev);
 503
 504         iio_device_unregister(indio_dev);
 505         iio_triggered_buffer_cleanup(indio_dev);
 506
 507         if (data->dready_trig)
 508                 iio_trigger_unregister(data->dready_trig);
 509
 510         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 511 }
 512
 513 #ifdef CONFIG_PM_SLEEP
 514 static int stk8ba50_suspend(struct device *dev)
 515 {
 516         struct stk8ba50_data *data;
 517
 518         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 519
 520         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 521 }
 522
 523 static int stk8ba50_resume(struct device *dev)
 524 {
 525         struct stk8ba50_data *data;
 526
 527         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 528
 529         return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 530 }
 531
 532 static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume);
 533
 534 #define STK8BA50_PM_OPS (&stk8ba50_pm_ops)
 535 #else
 536 #define STK8BA50_PM_OPS NULL
 537 #endif
 538
 539 static const struct i2c_device_id stk8ba50_i2c_id[] = {
 540         {"stk8ba50", 0},
 541         {}
 542 };
 543 MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);
 544
 545 static const struct acpi_device_id stk8ba50_acpi_id[] = {
 546         {"STK8BA50", 0},
 547         {}
 548 };
 549
 550 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
 551
 552 static struct i2c_driver stk8ba50_driver = {
 553         .driver = {
 554                 .name = "stk8ba50",
 555                 .pm = STK8BA50_PM_OPS,
 556                 .acpi_match_table = ACPI_PTR(stk8ba50_acpi_id),
 557         },
 558         .probe =            stk8ba50_probe,
 559         .remove =           stk8ba50_remove,
 560         .id_table =         stk8ba50_i2c_id,
 561 };
 562
 563 module_i2c_driver(stk8ba50_driver);
 564
 565 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 566 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
 567 MODULE_LICENSE("GPL v2");