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