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         .owner = THIS_MODULE,
 182 };
 183
 184 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
 185 {
 186         int ret;
 187         u8 masked_reg;
 188         struct i2c_client *client = data->client;
 189
 190         ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
 191         if (ret < 0)
 192                 goto exit_err;
 193
 194         if (mode)
 195                 masked_reg = ret | STK8BA50_MODE_POWERBIT;
 196         else
 197                 masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
 198
 199         ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
 200                                         masked_reg);
 201         if (ret < 0)
 202                 goto exit_err;
 203
 204         return ret;
 205
 206 exit_err:
 207         dev_err(&client->dev, "failed to change sensor mode\n");
 208         return ret;
 209 }
 210
 211 static int stk8ba50_read_raw(struct iio_dev *indio_dev,
 212                              struct iio_chan_spec const *chan,
 213                              int *val, int *val2, long mask)
 214 {
 215         struct stk8ba50_data *data = iio_priv(indio_dev);
 216         int ret;
 217
 218         switch (mask) {
 219         case IIO_CHAN_INFO_RAW:
 220                 if (iio_buffer_enabled(indio_dev))
 221                         return -EBUSY;
 222                 mutex_lock(&data->lock);
 223                 ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 224                 if (ret < 0) {
 225                         mutex_unlock(&data->lock);
 226                         return -EINVAL;
 227                 }
 228                 ret = stk8ba50_read_accel(data, chan->address);
 229                 if (ret < 0) {
 230                         stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 231                         mutex_unlock(&data->lock);
 232                         return -EINVAL;
 233                 }
 234                 *val = sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9);
 235                 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 236                 mutex_unlock(&data->lock);
 237                 return IIO_VAL_INT;
 238         case IIO_CHAN_INFO_SCALE:
 239                 *val = 0;
 240                 *val2 = stk8ba50_scale_table[data->range].scale_val;
 241                 return IIO_VAL_INT_PLUS_MICRO;
 242         case IIO_CHAN_INFO_SAMP_FREQ:
 243                 *val = stk8ba50_samp_freq_table
 244                                 [data->sample_rate_idx].samp_freq;
 245                 *val2 = 0;
 246                 return IIO_VAL_INT;
 247         }
 248
 249         return -EINVAL;
 250 }
 251
 252 static int stk8ba50_write_raw(struct iio_dev *indio_dev,
 253                               struct iio_chan_spec const *chan,
 254                               int val, int val2, long mask)
 255 {
 256         int ret;
 257         int i;
 258         int index = -1;
 259         struct stk8ba50_data *data = iio_priv(indio_dev);
 260
 261         switch (mask) {
 262         case IIO_CHAN_INFO_SCALE:
 263                 if (val != 0)
 264                         return -EINVAL;
 265
 266                 for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
 267                         if (val2 == stk8ba50_scale_table[i].scale_val) {
 268                                 index = i;
 269                                 break;
 270                         }
 271                 if (index < 0)
 272                         return -EINVAL;
 273
 274                 ret = i2c_smbus_write_byte_data(data->client,
 275                                 STK8BA50_REG_RANGE,
 276                                 stk8ba50_scale_table[index].reg_val);
 277                 if (ret < 0)
 278                         dev_err(&data->client->dev,
 279                                         "failed to set measurement range\n");
 280                 else
 281                         data->range = index;
 282
 283                 return ret;
 284         case IIO_CHAN_INFO_SAMP_FREQ:
 285                 for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
 286                         if (val == stk8ba50_samp_freq_table[i].samp_freq) {
 287                                 index = i;
 288                                 break;
 289                         }
 290                 if (index < 0)
 291                         return -EINVAL;
 292
 293                 ret = i2c_smbus_write_byte_data(data->client,
 294                                 STK8BA50_REG_BWSEL,
 295                                 stk8ba50_samp_freq_table[index].reg_val);
 296                 if (ret < 0)
 297                         dev_err(&data->client->dev,
 298                                         "failed to set sampling rate\n");
 299                 else
 300                         data->sample_rate_idx = index;
 301
 302                 return ret;
 303         }
 304
 305         return -EINVAL;
 306 }
 307
 308 static const struct iio_info stk8ba50_info = {
 309         .driver_module          = THIS_MODULE,
 310         .read_raw               = stk8ba50_read_raw,
 311         .write_raw              = stk8ba50_write_raw,
 312         .attrs                  = &stk8ba50_attribute_group,
 313 };
 314
 315 static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
 316 {
 317         struct iio_poll_func *pf = p;
 318         struct iio_dev *indio_dev = pf->indio_dev;
 319         struct stk8ba50_data *data = iio_priv(indio_dev);
 320         int bit, ret, i = 0;
 321
 322         mutex_lock(&data->lock);
 323         /*
 324          * Do a bulk read if all channels are requested,
 325          * from 0x02 (XOUT1) to 0x07 (ZOUT2)
 326          */
 327         if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
 328                 ret = i2c_smbus_read_i2c_block_data(data->client,
 329                                                     STK8BA50_REG_XOUT,
 330                                                     STK8BA50_ALL_CHANNEL_SIZE,
 331                                                     (u8 *)data->scan.chans);
 332                 if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
 333                         dev_err(&data->client->dev, "register read failed\n");
 334                         goto err;
 335                 }
 336         } else {
 337                 for_each_set_bit(bit, indio_dev->active_scan_mask,
 338                                  indio_dev->masklength) {
 339                         ret = stk8ba50_read_accel(data,
 340                                                   stk8ba50_channel_table[bit]);
 341                         if (ret < 0)
 342                                 goto err;
 343
 344                         data->scan.chans[i++] = ret;
 345                 }
 346         }
 347         iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 348                                            pf->timestamp);
 349 err:
 350         mutex_unlock(&data->lock);
 351         iio_trigger_notify_done(indio_dev->trig);
 352
 353         return IRQ_HANDLED;
 354 }
 355
 356 static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
 357 {
 358         struct iio_dev *indio_dev = private;
 359         struct stk8ba50_data *data = iio_priv(indio_dev);
 360
 361         if (data->dready_trigger_on)
 362                 iio_trigger_poll(data->dready_trig);
 363
 364         return IRQ_HANDLED;
 365 }
 366
 367 static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
 368 {
 369         struct stk8ba50_data *data = iio_priv(indio_dev);
 370
 371         return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 372 }
 373
 374 static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
 375 {
 376         struct stk8ba50_data *data = iio_priv(indio_dev);
 377
 378         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 379 }
 380
 381 static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
 382         .preenable   = stk8ba50_buffer_preenable,
 383         .postenable  = iio_triggered_buffer_postenable,
 384         .predisable  = iio_triggered_buffer_predisable,
 385         .postdisable = stk8ba50_buffer_postdisable,
 386 };
 387
 388 static int stk8ba50_probe(struct i2c_client *client,
 389                           const struct i2c_device_id *id)
 390 {
 391         int ret;
 392         struct iio_dev *indio_dev;
 393         struct stk8ba50_data *data;
 394
 395         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 396         if (!indio_dev) {
 397                 dev_err(&client->dev, "iio allocation failed!\n");
 398                 return -ENOMEM;
 399         }
 400
 401         data = iio_priv(indio_dev);
 402         data->client = client;
 403         i2c_set_clientdata(client, indio_dev);
 404         mutex_init(&data->lock);
 405
 406         indio_dev->dev.parent = &client->dev;
 407         indio_dev->info = &stk8ba50_info;
 408         indio_dev->name = STK8BA50_DRIVER_NAME;
 409         indio_dev->modes = INDIO_DIRECT_MODE;
 410         indio_dev->channels = stk8ba50_channels;
 411         indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
 412
 413         /* Reset all registers on startup */
 414         ret = i2c_smbus_write_byte_data(client,
 415                         STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
 416         if (ret < 0) {
 417                 dev_err(&client->dev, "failed to reset sensor\n");
 418                 goto err_power_off;
 419         }
 420
 421         /* The default range is +/-2g */
 422         data->range = 0;
 423
 424         /* The default sampling rate is 1792 Hz (maximum) */
 425         data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;
 426
 427         /* Set up interrupts */
 428         ret = i2c_smbus_write_byte_data(client,
 429                         STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
 430         if (ret < 0) {
 431                 dev_err(&client->dev, "failed to set up interrupts\n");
 432                 goto err_power_off;
 433         }
 434         ret = i2c_smbus_write_byte_data(client,
 435                         STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
 436         if (ret < 0) {
 437                 dev_err(&client->dev, "failed to set up interrupts\n");
 438                 goto err_power_off;
 439         }
 440
 441         if (client->irq > 0) {
 442                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 443                                                 stk8ba50_data_rdy_trig_poll,
 444                                                 NULL,
 445                                                 IRQF_TRIGGER_RISING |
 446                                                 IRQF_ONESHOT,
 447                                                 STK8BA50_IRQ_NAME,
 448                                                 indio_dev);
 449                 if (ret < 0) {
 450                         dev_err(&client->dev, "request irq %d failed\n",
 451                                 client->irq);
 452                         goto err_power_off;
 453                 }
 454
 455                 data->dready_trig = devm_iio_trigger_alloc(&client->dev,
 456                                                            "%s-dev%d",
 457                                                            indio_dev->name,
 458                                                            indio_dev->id);
 459                 if (!data->dready_trig) {
 460                         ret = -ENOMEM;
 461                         goto err_power_off;
 462                 }
 463
 464                 data->dready_trig->dev.parent = &client->dev;
 465                 data->dready_trig->ops = &stk8ba50_trigger_ops;
 466                 iio_trigger_set_drvdata(data->dready_trig, indio_dev);
 467                 ret = iio_trigger_register(data->dready_trig);
 468                 if (ret) {
 469                         dev_err(&client->dev, "iio trigger register failed\n");
 470                         goto err_power_off;
 471                 }
 472         }
 473
 474         ret = iio_triggered_buffer_setup(indio_dev,
 475                                          iio_pollfunc_store_time,
 476                                          stk8ba50_trigger_handler,
 477                                          &stk8ba50_buffer_setup_ops);
 478         if (ret < 0) {
 479                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 480                 goto err_trigger_unregister;
 481         }
 482
 483         ret = iio_device_register(indio_dev);
 484         if (ret < 0) {
 485                 dev_err(&client->dev, "device_register failed\n");
 486                 goto err_buffer_cleanup;
 487         }
 488
 489         return ret;
 490
 491 err_buffer_cleanup:
 492         iio_triggered_buffer_cleanup(indio_dev);
 493 err_trigger_unregister:
 494         if (data->dready_trig)
 495                 iio_trigger_unregister(data->dready_trig);
 496 err_power_off:
 497         stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 498         return ret;
 499 }
 500
 501 static int stk8ba50_remove(struct i2c_client *client)
 502 {
 503         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 504         struct stk8ba50_data *data = iio_priv(indio_dev);
 505
 506         iio_device_unregister(indio_dev);
 507         iio_triggered_buffer_cleanup(indio_dev);
 508
 509         if (data->dready_trig)
 510                 iio_trigger_unregister(data->dready_trig);
 511
 512         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 513 }
 514
 515 #ifdef CONFIG_PM_SLEEP
 516 static int stk8ba50_suspend(struct device *dev)
 517 {
 518         struct stk8ba50_data *data;
 519
 520         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 521
 522         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 523 }
 524
 525 static int stk8ba50_resume(struct device *dev)
 526 {
 527         struct stk8ba50_data *data;
 528
 529         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 530
 531         return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 532 }
 533
 534 static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume);
 535
 536 #define STK8BA50_PM_OPS (&stk8ba50_pm_ops)
 537 #else
 538 #define STK8BA50_PM_OPS NULL
 539 #endif
 540
 541 static const struct i2c_device_id stk8ba50_i2c_id[] = {
 542         {"stk8ba50", 0},
 543         {}
 544 };
 545 MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);
 546
 547 static const struct acpi_device_id stk8ba50_acpi_id[] = {
 548         {"STK8BA50", 0},
 549         {}
 550 };
 551
 552 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
 553
 554 static struct i2c_driver stk8ba50_driver = {
 555         .driver = {
 556                 .name = "stk8ba50",
 557                 .pm = STK8BA50_PM_OPS,
 558                 .acpi_match_table = ACPI_PTR(stk8ba50_acpi_id),
 559         },
 560         .probe =            stk8ba50_probe,
 561         .remove =           stk8ba50_remove,
 562         .id_table =         stk8ba50_i2c_id,
 563 };
 564
 565 module_i2c_driver(stk8ba50_driver);
 566
 567 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 568 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
 569 MODULE_LICENSE("GPL v2");