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_GPIO                           "stk8ba50_gpio"
  49 #define STK8BA50_IRQ_NAME                       "stk8ba50_event"
  50
  51 #define STK8BA50_SCALE_AVAIL                    "0.0384 0.0767 0.1534 0.3069"
  52
  53 /*
  54  * The accelerometer has four measurement ranges:
  55  * +/-2g; +/-4g; +/-8g; +/-16g
  56  *
  57  * Acceleration values are 10-bit, 2's complement.
  58  * Scales are calculated as following:
  59  *
  60  * scale1 = (2 + 2) * 9.81 / (2^10 - 1)   = 0.0384
  61  * scale2 = (4 + 4) * 9.81 / (2^10 - 1)   = 0.0767
  62  * etc.
  63  *
  64  * Scales are stored in this format:
  65  * { <register value>, <scale value> }
  66  *
  67  * Locally, the range is stored as a table index.
  68  */
  69 static const struct {
  70         u8 reg_val;
  71         u32 scale_val;
  72 } stk8ba50_scale_table[] = {
  73         {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
  74 };
  75
  76 /* Sample rates are stored as { <register value>, <Hz value> } */
  77 static const struct {
  78         u8 reg_val;
  79         u16 samp_freq;
  80 } stk8ba50_samp_freq_table[] = {
  81         {0x08, 14},  {0x09, 25},  {0x0A, 56},  {0x0B, 112},
  82         {0x0C, 224}, {0x0D, 448}, {0x0E, 896}, {0x0F, 1792}
  83 };
  84
  85 /* Used to map scan mask bits to their corresponding channel register. */
  86 static const int stk8ba50_channel_table[] = {
  87         STK8BA50_REG_XOUT,
  88         STK8BA50_REG_YOUT,
  89         STK8BA50_REG_ZOUT
  90 };
  91
  92 struct stk8ba50_data {
  93         struct i2c_client *client;
  94         struct mutex lock;
  95         int range;
  96         u8 sample_rate_idx;
  97         struct iio_trigger *dready_trig;
  98         bool dready_trigger_on;
  99         /*
 100          * 3 x 16-bit channels (10-bit data, 6-bit padding) +
 101          * 1 x 16 padding +
 102          * 4 x 16 64-bit timestamp
 103          */
 104         s16 buffer[8];
 105 };
 106
 107 #define STK8BA50_ACCEL_CHANNEL(index, reg, axis) {                      \
 108         .type = IIO_ACCEL,                                              \
 109         .address = reg,                                                 \
 110         .modified = 1,                                                  \
 111         .channel2 = IIO_MOD_##axis,                                     \
 112         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
 113         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),           \
 114                                     BIT(IIO_CHAN_INFO_SAMP_FREQ),       \
 115         .scan_index = index,                                            \
 116         .scan_type = {                                                  \
 117                 .sign = 's',                                            \
 118                 .realbits = 10,                                         \
 119                 .storagebits = 16,                                      \
 120                 .shift = STK8BA50_DATA_SHIFT,                           \
 121                 .endianness = IIO_CPU,                                  \
 122         },                                                              \
 123 }
 124
 125 static const struct iio_chan_spec stk8ba50_channels[] = {
 126         STK8BA50_ACCEL_CHANNEL(0, STK8BA50_REG_XOUT, X),
 127         STK8BA50_ACCEL_CHANNEL(1, STK8BA50_REG_YOUT, Y),
 128         STK8BA50_ACCEL_CHANNEL(2, STK8BA50_REG_ZOUT, Z),
 129         IIO_CHAN_SOFT_TIMESTAMP(3),
 130 };
 131
 132 static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
 133
 134 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");
 135
 136 static struct attribute *stk8ba50_attributes[] = {
 137         &iio_const_attr_in_accel_scale_available.dev_attr.attr,
 138         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 139         NULL,
 140 };
 141
 142 static const struct attribute_group stk8ba50_attribute_group = {
 143         .attrs = stk8ba50_attributes
 144 };
 145
 146 static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
 147 {
 148         int ret;
 149         struct i2c_client *client = data->client;
 150
 151         ret = i2c_smbus_read_word_data(client, reg);
 152         if (ret < 0) {
 153                 dev_err(&client->dev, "register read failed\n");
 154                 return ret;
 155         }
 156
 157         return ret;
 158 }
 159
 160 static int stk8ba50_data_rdy_trigger_set_state(struct iio_trigger *trig,
 161                                                bool state)
 162 {
 163         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 164         struct stk8ba50_data *data = iio_priv(indio_dev);
 165         int ret;
 166
 167         if (state)
 168                 ret = i2c_smbus_write_byte_data(data->client,
 169                         STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
 170         else
 171                 ret = i2c_smbus_write_byte_data(data->client,
 172                         STK8BA50_REG_INTEN2, 0x00);
 173
 174         if (ret < 0)
 175                 dev_err(&data->client->dev, "failed to set trigger state\n");
 176         else
 177                 data->dready_trigger_on = state;
 178
 179         return ret;
 180 }
 181
 182 static const struct iio_trigger_ops stk8ba50_trigger_ops = {
 183         .set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
 184         .owner = THIS_MODULE,
 185 };
 186
 187 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
 188 {
 189         int ret;
 190         u8 masked_reg;
 191         struct i2c_client *client = data->client;
 192
 193         ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
 194         if (ret < 0)
 195                 goto exit_err;
 196
 197         if (mode)
 198                 masked_reg = ret | STK8BA50_MODE_POWERBIT;
 199         else
 200                 masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
 201
 202         ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
 203                                         masked_reg);
 204         if (ret < 0)
 205                 goto exit_err;
 206
 207         return ret;
 208
 209 exit_err:
 210         dev_err(&client->dev, "failed to change sensor mode\n");
 211         return ret;
 212 }
 213
 214 static int stk8ba50_read_raw(struct iio_dev *indio_dev,
 215                              struct iio_chan_spec const *chan,
 216                              int *val, int *val2, long mask)
 217 {
 218         struct stk8ba50_data *data = iio_priv(indio_dev);
 219         int ret;
 220
 221         switch (mask) {
 222         case IIO_CHAN_INFO_RAW:
 223                 if (iio_buffer_enabled(indio_dev))
 224                         return -EBUSY;
 225                 mutex_lock(&data->lock);
 226                 ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 227                 if (ret < 0) {
 228                         mutex_unlock(&data->lock);
 229                         return -EINVAL;
 230                 }
 231                 ret = stk8ba50_read_accel(data, chan->address);
 232                 if (ret < 0) {
 233                         stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 234                         mutex_unlock(&data->lock);
 235                         return -EINVAL;
 236                 }
 237                 *val = sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9);
 238                 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 239                 mutex_unlock(&data->lock);
 240                 return IIO_VAL_INT;
 241         case IIO_CHAN_INFO_SCALE:
 242                 *val = 0;
 243                 *val2 = stk8ba50_scale_table[data->range].scale_val;
 244                 return IIO_VAL_INT_PLUS_MICRO;
 245         case IIO_CHAN_INFO_SAMP_FREQ:
 246                 *val = stk8ba50_samp_freq_table
 247                                 [data->sample_rate_idx].samp_freq;
 248                 *val2 = 0;
 249                 return IIO_VAL_INT;
 250         }
 251
 252         return -EINVAL;
 253 }
 254
 255 static int stk8ba50_write_raw(struct iio_dev *indio_dev,
 256                               struct iio_chan_spec const *chan,
 257                               int val, int val2, long mask)
 258 {
 259         int ret;
 260         int i;
 261         int index = -1;
 262         struct stk8ba50_data *data = iio_priv(indio_dev);
 263
 264         switch (mask) {
 265         case IIO_CHAN_INFO_SCALE:
 266                 if (val != 0)
 267                         return -EINVAL;
 268
 269                 for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
 270                         if (val2 == stk8ba50_scale_table[i].scale_val) {
 271                                 index = i;
 272                                 break;
 273                         }
 274                 if (index < 0)
 275                         return -EINVAL;
 276
 277                 ret = i2c_smbus_write_byte_data(data->client,
 278                                 STK8BA50_REG_RANGE,
 279                                 stk8ba50_scale_table[index].reg_val);
 280                 if (ret < 0)
 281                         dev_err(&data->client->dev,
 282                                         "failed to set measurement range\n");
 283                 else
 284                         data->range = index;
 285
 286                 return ret;
 287         case IIO_CHAN_INFO_SAMP_FREQ:
 288                 for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
 289                         if (val == stk8ba50_samp_freq_table[i].samp_freq) {
 290                                 index = i;
 291                                 break;
 292                         }
 293                 if (index < 0)
 294                         return -EINVAL;
 295
 296                 ret = i2c_smbus_write_byte_data(data->client,
 297                                 STK8BA50_REG_BWSEL,
 298                                 stk8ba50_samp_freq_table[index].reg_val);
 299                 if (ret < 0)
 300                         dev_err(&data->client->dev,
 301                                         "failed to set sampling rate\n");
 302                 else
 303                         data->sample_rate_idx = index;
 304
 305                 return ret;
 306         }
 307
 308         return -EINVAL;
 309 }
 310
 311 static const struct iio_info stk8ba50_info = {
 312         .driver_module          = THIS_MODULE,
 313         .read_raw               = stk8ba50_read_raw,
 314         .write_raw              = stk8ba50_write_raw,
 315         .attrs                  = &stk8ba50_attribute_group,
 316 };
 317
 318 static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
 319 {
 320         struct iio_poll_func *pf = p;
 321         struct iio_dev *indio_dev = pf->indio_dev;
 322         struct stk8ba50_data *data = iio_priv(indio_dev);
 323         int bit, ret, i = 0;
 324
 325         mutex_lock(&data->lock);
 326         /*
 327          * Do a bulk read if all channels are requested,
 328          * from 0x02 (XOUT1) to 0x07 (ZOUT2)
 329          */
 330         if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
 331                 ret = i2c_smbus_read_i2c_block_data(data->client,
 332                                                     STK8BA50_REG_XOUT,
 333                                                     STK8BA50_ALL_CHANNEL_SIZE,
 334                                                     (u8 *)data->buffer);
 335                 if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
 336                         dev_err(&data->client->dev, "register read failed\n");
 337                         goto err;
 338                 }
 339         } else {
 340                 for_each_set_bit(bit, indio_dev->active_scan_mask,
 341                                  indio_dev->masklength) {
 342                         ret = stk8ba50_read_accel(data,
 343                                                   stk8ba50_channel_table[bit]);
 344                         if (ret < 0)
 345                                 goto err;
 346
 347                         data->buffer[i++] = ret;
 348                 }
 349         }
 350         iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
 351                                            pf->timestamp);
 352 err:
 353         mutex_unlock(&data->lock);
 354         iio_trigger_notify_done(indio_dev->trig);
 355
 356         return IRQ_HANDLED;
 357 }
 358
 359 static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
 360 {
 361         struct iio_dev *indio_dev = private;
 362         struct stk8ba50_data *data = iio_priv(indio_dev);
 363
 364         if (data->dready_trigger_on)
 365                 iio_trigger_poll(data->dready_trig);
 366
 367         return IRQ_HANDLED;
 368 }
 369
 370 static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
 371 {
 372         struct stk8ba50_data *data = iio_priv(indio_dev);
 373
 374         return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 375 }
 376
 377 static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
 378 {
 379         struct stk8ba50_data *data = iio_priv(indio_dev);
 380
 381         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 382 }
 383
 384 static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
 385         .preenable   = stk8ba50_buffer_preenable,
 386         .postenable  = iio_triggered_buffer_postenable,
 387         .predisable  = iio_triggered_buffer_predisable,
 388         .postdisable = stk8ba50_buffer_postdisable,
 389 };
 390
 391 static int stk8ba50_gpio_probe(struct i2c_client *client)
 392 {
 393         struct device *dev;
 394         struct gpio_desc *gpio;
 395         int ret;
 396
 397         if (!client)
 398                 return -EINVAL;
 399
 400         dev = &client->dev;
 401
 402         /* data ready gpio interrupt pin */
 403         gpio = devm_gpiod_get_index(dev, STK8BA50_GPIO, 0, GPIOD_IN);
 404         if (IS_ERR(gpio)) {
 405                 dev_err(dev, "acpi gpio get index failed\n");
 406                 return PTR_ERR(gpio);
 407         }
 408
 409         ret = gpiod_to_irq(gpio);
 410         dev_dbg(dev, "GPIO resource, no:%d irq:%d\n", desc_to_gpio(gpio), ret);
 411
 412         return ret;
 413 }
 414
 415 static int stk8ba50_probe(struct i2c_client *client,
 416                           const struct i2c_device_id *id)
 417 {
 418         int ret;
 419         struct iio_dev *indio_dev;
 420         struct stk8ba50_data *data;
 421
 422         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 423         if (!indio_dev) {
 424                 dev_err(&client->dev, "iio allocation failed!\n");
 425                 return -ENOMEM;
 426         }
 427
 428         data = iio_priv(indio_dev);
 429         data->client = client;
 430         i2c_set_clientdata(client, indio_dev);
 431         mutex_init(&data->lock);
 432
 433         indio_dev->dev.parent = &client->dev;
 434         indio_dev->info = &stk8ba50_info;
 435         indio_dev->name = STK8BA50_DRIVER_NAME;
 436         indio_dev->modes = INDIO_DIRECT_MODE;
 437         indio_dev->channels = stk8ba50_channels;
 438         indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
 439
 440         /* Reset all registers on startup */
 441         ret = i2c_smbus_write_byte_data(client,
 442                         STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
 443         if (ret < 0) {
 444                 dev_err(&client->dev, "failed to reset sensor\n");
 445                 goto err_power_off;
 446         }
 447
 448         /* The default range is +/-2g */
 449         data->range = 0;
 450
 451         /* The default sampling rate is 1792 Hz (maximum) */
 452         data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;
 453
 454         /* Set up interrupts */
 455         ret = i2c_smbus_write_byte_data(client,
 456                         STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
 457         if (ret < 0) {
 458                 dev_err(&client->dev, "failed to set up interrupts\n");
 459                 goto err_power_off;
 460         }
 461         ret = i2c_smbus_write_byte_data(client,
 462                         STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
 463         if (ret < 0) {
 464                 dev_err(&client->dev, "failed to set up interrupts\n");
 465                 goto err_power_off;
 466         }
 467
 468         if (client->irq < 0)
 469                 client->irq = stk8ba50_gpio_probe(client);
 470
 471         if (client->irq >= 0) {
 472                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 473                                                 stk8ba50_data_rdy_trig_poll,
 474                                                 NULL,
 475                                                 IRQF_TRIGGER_RISING |
 476                                                 IRQF_ONESHOT,
 477                                                 STK8BA50_IRQ_NAME,
 478                                                 indio_dev);
 479                 if (ret < 0) {
 480                         dev_err(&client->dev, "request irq %d failed\n",
 481                                 client->irq);
 482                         goto err_power_off;
 483                 }
 484
 485                 data->dready_trig = devm_iio_trigger_alloc(&client->dev,
 486                                                            "%s-dev%d",
 487                                                            indio_dev->name,
 488                                                            indio_dev->id);
 489                 if (!data->dready_trig) {
 490                         ret = -ENOMEM;
 491                         goto err_power_off;
 492                 }
 493
 494                 data->dready_trig->dev.parent = &client->dev;
 495                 data->dready_trig->ops = &stk8ba50_trigger_ops;
 496                 iio_trigger_set_drvdata(data->dready_trig, indio_dev);
 497                 ret = iio_trigger_register(data->dready_trig);
 498                 if (ret) {
 499                         dev_err(&client->dev, "iio trigger register failed\n");
 500                         goto err_power_off;
 501                 }
 502         }
 503
 504         ret = iio_triggered_buffer_setup(indio_dev,
 505                                          iio_pollfunc_store_time,
 506                                          stk8ba50_trigger_handler,
 507                                          &stk8ba50_buffer_setup_ops);
 508         if (ret < 0) {
 509                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 510                 goto err_trigger_unregister;
 511         }
 512
 513         ret = iio_device_register(indio_dev);
 514         if (ret < 0) {
 515                 dev_err(&client->dev, "device_register failed\n");
 516                 goto err_buffer_cleanup;
 517         }
 518
 519         return ret;
 520
 521 err_buffer_cleanup:
 522         iio_triggered_buffer_cleanup(indio_dev);
 523 err_trigger_unregister:
 524         if (data->dready_trig)
 525                 iio_trigger_unregister(data->dready_trig);
 526 err_power_off:
 527         stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 528         return ret;
 529 }
 530
 531 static int stk8ba50_remove(struct i2c_client *client)
 532 {
 533         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 534         struct stk8ba50_data *data = iio_priv(indio_dev);
 535
 536         iio_device_unregister(indio_dev);
 537         iio_triggered_buffer_cleanup(indio_dev);
 538
 539         if (data->dready_trig)
 540                 iio_trigger_unregister(data->dready_trig);
 541
 542         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 543 }
 544
 545 #ifdef CONFIG_PM_SLEEP
 546 static int stk8ba50_suspend(struct device *dev)
 547 {
 548         struct stk8ba50_data *data;
 549
 550         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 551
 552         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 553 }
 554
 555 static int stk8ba50_resume(struct device *dev)
 556 {
 557         struct stk8ba50_data *data;
 558
 559         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 560
 561         return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 562 }
 563
 564 static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume);
 565
 566 #define STK8BA50_PM_OPS (&stk8ba50_pm_ops)
 567 #else
 568 #define STK8BA50_PM_OPS NULL
 569 #endif
 570
 571 static const struct i2c_device_id stk8ba50_i2c_id[] = {
 572         {"stk8ba50", 0},
 573         {}
 574 };
 575 MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);
 576
 577 static const struct acpi_device_id stk8ba50_acpi_id[] = {
 578         {"STK8BA50", 0},
 579         {}
 580 };
 581
 582 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
 583
 584 static struct i2c_driver stk8ba50_driver = {
 585         .driver = {
 586                 .name = "stk8ba50",
 587                 .pm = STK8BA50_PM_OPS,
 588                 .acpi_match_table = ACPI_PTR(stk8ba50_acpi_id),
 589         },
 590         .probe =            stk8ba50_probe,
 591         .remove =           stk8ba50_remove,
 592         .id_table =         stk8ba50_i2c_id,
 593 };
 594
 595 module_i2c_driver(stk8ba50_driver);
 596
 597 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 598 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
 599 MODULE_LICENSE("GPL v2");