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