drivers/staging/iio/iio_simple_dummy.c

   1 /**
   2  * Copyright (c) 2011 Jonathan Cameron
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * A reference industrial I/O driver to illustrate the functionality available.
   9  *
  10  * There are numerous real drivers to illustrate the finer points.
  11  * The purpose of this driver is to provide a driver with far more comments
  12  * and explanatory notes than any 'real' driver would have.
  13  * Anyone starting out writing an IIO driver should first make sure they
  14  * understand all of this driver except those bits specifically marked
  15  * as being present to allow us to 'fake' the presence of hardware.
  16  */
  17 #include <linux/kernel.h>
  18 #include <linux/slab.h>
  19 #include <linux/module.h>
  20
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/sysfs.h>
  23 #include <linux/iio/events.h>
  24 #include <linux/iio/buffer.h>
  25 #include "iio_simple_dummy.h"
  26
  27 /*
  28  * A few elements needed to fake a bus for this driver
  29  * Note instances parameter controls how many of these
  30  * dummy devices are registered.
  31  */
  32 static unsigned instances = 1;
  33 module_param(instances, uint, 0);
  34
  35 /* Pointer array used to fake bus elements */
  36 static struct iio_dev **iio_dummy_devs;
  37
  38 /* Fake a name for the part number, usually obtained from the id table */
  39 static const char *iio_dummy_part_number = "iio_dummy_part_no";
  40
  41 /**
  42  * struct iio_dummy_accel_calibscale - realworld to register mapping
  43  * @val: first value in read_raw - here integer part.
  44  * @val2: second value in read_raw etc - here micro part.
  45  * @regval: register value - magic device specific numbers.
  46  */
  47 struct iio_dummy_accel_calibscale {
  48         int val;
  49         int val2;
  50         int regval; /* what would be written to hardware */
  51 };
  52
  53 static const struct iio_dummy_accel_calibscale dummy_scales[] = {
  54         { 0, 100, 0x8 }, /* 0.000100 */
  55         { 0, 133, 0x7 }, /* 0.000133 */
  56         { 733, 13, 0x9 }, /* 733.000013 */
  57 };
  58
  59 #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
  60
  61 /*
  62  * simple event - triggered when value rises above
  63  * a threshold
  64  */
  65 static const struct iio_event_spec iio_dummy_event = {
  66         .type = IIO_EV_TYPE_THRESH,
  67         .dir = IIO_EV_DIR_RISING,
  68         .mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
  69 };
  70
  71 /*
  72  * simple step detect event - triggered when a step is detected
  73  */
  74 static const struct iio_event_spec step_detect_event = {
  75         .type = IIO_EV_TYPE_CHANGE,
  76         .dir = IIO_EV_DIR_NONE,
  77         .mask_separate = BIT(IIO_EV_INFO_ENABLE),
  78 };
  79
  80 /*
  81  * simple transition event - triggered when the reported running confidence
  82  * value rises above a threshold value
  83  */
  84 static const struct iio_event_spec iio_running_event = {
  85         .type = IIO_EV_TYPE_THRESH,
  86         .dir = IIO_EV_DIR_RISING,
  87         .mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
  88 };
  89
  90 /*
  91  * simple transition event - triggered when the reported walking confidence
  92  * value falls under a threshold value
  93  */
  94 static const struct iio_event_spec iio_walking_event = {
  95         .type = IIO_EV_TYPE_THRESH,
  96         .dir = IIO_EV_DIR_FALLING,
  97         .mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
  98 };
  99 #endif
 100
 101 /*
 102  * iio_dummy_channels - Description of available channels
 103  *
 104  * This array of structures tells the IIO core about what the device
 105  * actually provides for a given channel.
 106  */
 107 static const struct iio_chan_spec iio_dummy_channels[] = {
 108         /* indexed ADC channel in_voltage0_raw etc */
 109         {
 110                 .type = IIO_VOLTAGE,
 111                 /* Channel has a numeric index of 0 */
 112                 .indexed = 1,
 113                 .channel = 0,
 114                 /* What other information is available? */
 115                 .info_mask_separate =
 116                 /*
 117                  * in_voltage0_raw
 118                  * Raw (unscaled no bias removal etc) measurement
 119                  * from the device.
 120                  */
 121                 BIT(IIO_CHAN_INFO_RAW) |
 122                 /*
 123                  * in_voltage0_offset
 124                  * Offset for userspace to apply prior to scale
 125                  * when converting to standard units (microvolts)
 126                  */
 127                 BIT(IIO_CHAN_INFO_OFFSET) |
 128                 /*
 129                  * in_voltage0_scale
 130                  * Multipler for userspace to apply post offset
 131                  * when converting to standard units (microvolts)
 132                  */
 133                 BIT(IIO_CHAN_INFO_SCALE),
 134                 /*
 135                  * sampling_frequency
 136                  * The frequency in Hz at which the channels are sampled
 137                  */
 138                 .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 139                 /* The ordering of elements in the buffer via an enum */
 140                 .scan_index = voltage0,
 141                 .scan_type = { /* Description of storage in buffer */
 142                         .sign = 'u', /* unsigned */
 143                         .realbits = 13, /* 13 bits */
 144                         .storagebits = 16, /* 16 bits used for storage */
 145                         .shift = 0, /* zero shift */
 146                 },
 147 #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
 148                 .event_spec = &iio_dummy_event,
 149                 .num_event_specs = 1,
 150 #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
 151         },
 152         /* Differential ADC channel in_voltage1-voltage2_raw etc*/
 153         {
 154                 .type = IIO_VOLTAGE,
 155                 .differential = 1,
 156                 /*
 157                  * Indexing for differential channels uses channel
 158                  * for the positive part, channel2 for the negative.
 159                  */
 160                 .indexed = 1,
 161                 .channel = 1,
 162                 .channel2 = 2,
 163                 /*
 164                  * in_voltage1-voltage2_raw
 165                  * Raw (unscaled no bias removal etc) measurement
 166                  * from the device.
 167                  */
 168                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 169                 /*
 170                  * in_voltage-voltage_scale
 171                  * Shared version of scale - shared by differential
 172                  * input channels of type IIO_VOLTAGE.
 173                  */
 174                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 175                 /*
 176                  * sampling_frequency
 177                  * The frequency in Hz at which the channels are sampled
 178                  */
 179                 .scan_index = diffvoltage1m2,
 180                 .scan_type = { /* Description of storage in buffer */
 181                         .sign = 's', /* signed */
 182                         .realbits = 12, /* 12 bits */
 183                         .storagebits = 16, /* 16 bits used for storage */
 184                         .shift = 0, /* zero shift */
 185                 },
 186         },
 187         /* Differential ADC channel in_voltage3-voltage4_raw etc*/
 188         {
 189                 .type = IIO_VOLTAGE,
 190                 .differential = 1,
 191                 .indexed = 1,
 192                 .channel = 3,
 193                 .channel2 = 4,
 194                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 195                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 196                 .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 197                 .scan_index = diffvoltage3m4,
 198                 .scan_type = {
 199                         .sign = 's',
 200                         .realbits = 11,
 201                         .storagebits = 16,
 202                         .shift = 0,
 203                 },
 204         },
 205         /*
 206          * 'modified' (i.e. axis specified) acceleration channel
 207          * in_accel_z_raw
 208          */
 209         {
 210                 .type = IIO_ACCEL,
 211                 .modified = 1,
 212                 /* Channel 2 is use for modifiers */
 213                 .channel2 = IIO_MOD_X,
 214                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 215                 /*
 216                  * Internal bias and gain correction values. Applied
 217                  * by the hardware or driver prior to userspace
 218                  * seeing the readings. Typically part of hardware
 219                  * calibration.
 220                  */
 221                 BIT(IIO_CHAN_INFO_CALIBSCALE) |
 222                 BIT(IIO_CHAN_INFO_CALIBBIAS),
 223                 .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 224                 .scan_index = accelx,
 225                 .scan_type = { /* Description of storage in buffer */
 226                         .sign = 's', /* signed */
 227                         .realbits = 16, /* 16 bits */
 228                         .storagebits = 16, /* 16 bits used for storage */
 229                         .shift = 0, /* zero shift */
 230                 },
 231         },
 232         /*
 233          * Convenience macro for timestamps. 4 is the index in
 234          * the buffer.
 235          */
 236         IIO_CHAN_SOFT_TIMESTAMP(4),
 237         /* DAC channel out_voltage0_raw */
 238         {
 239                 .type = IIO_VOLTAGE,
 240                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 241                 .scan_index = -1, /* No buffer support */
 242                 .output = 1,
 243                 .indexed = 1,
 244                 .channel = 0,
 245         },
 246         {
 247                 .type = IIO_STEPS,
 248                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_ENABLE) |
 249                         BIT(IIO_CHAN_INFO_CALIBHEIGHT),
 250                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 251                 .scan_index = -1, /* No buffer support */
 252 #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
 253                 .event_spec = &step_detect_event,
 254                 .num_event_specs = 1,
 255 #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
 256         },
 257         {
 258                 .type = IIO_ACTIVITY,
 259                 .modified = 1,
 260                 .channel2 = IIO_MOD_RUNNING,
 261                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 262                 .scan_index = -1, /* No buffer support */
 263 #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
 264                 .event_spec = &iio_running_event,
 265                 .num_event_specs = 1,
 266 #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
 267         },
 268         {
 269                 .type = IIO_ACTIVITY,
 270                 .modified = 1,
 271                 .channel2 = IIO_MOD_WALKING,
 272                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 273                 .scan_index = -1, /* No buffer support */
 274 #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
 275                 .event_spec = &iio_walking_event,
 276                 .num_event_specs = 1,
 277 #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
 278         },
 279 };
 280
 281 /**
 282  * iio_dummy_read_raw() - data read function.
 283  * @indio_dev:  the struct iio_dev associated with this device instance
 284  * @chan:       the channel whose data is to be read
 285  * @val:        first element of returned value (typically INT)
 286  * @val2:       second element of returned value (typically MICRO)
 287  * @mask:       what we actually want to read as per the info_mask_*
 288  *              in iio_chan_spec.
 289  */
 290 static int iio_dummy_read_raw(struct iio_dev *indio_dev,
 291                               struct iio_chan_spec const *chan,
 292                               int *val,
 293                               int *val2,
 294                               long mask)
 295 {
 296         struct iio_dummy_state *st = iio_priv(indio_dev);
 297         int ret = -EINVAL;
 298
 299         mutex_lock(&st->lock);
 300         switch (mask) {
 301         case IIO_CHAN_INFO_RAW: /* magic value - channel value read */
 302                 switch (chan->type) {
 303                 case IIO_VOLTAGE:
 304                         if (chan->output) {
 305                                 /* Set integer part to cached value */
 306                                 *val = st->dac_val;
 307                                 ret = IIO_VAL_INT;
 308                         } else if (chan->differential) {
 309                                 if (chan->channel == 1)
 310                                         *val = st->differential_adc_val[0];
 311                                 else
 312                                         *val = st->differential_adc_val[1];
 313                                 ret = IIO_VAL_INT;
 314                         } else {
 315                                 *val = st->single_ended_adc_val;
 316                                 ret = IIO_VAL_INT;
 317                         }
 318                         break;
 319                 case IIO_ACCEL:
 320                         *val = st->accel_val;
 321                         ret = IIO_VAL_INT;
 322                         break;
 323                 default:
 324                         break;
 325                 }
 326                 break;
 327         case IIO_CHAN_INFO_PROCESSED:
 328                 switch (chan->type) {
 329                 case IIO_STEPS:
 330                         *val = st->steps;
 331                         ret = IIO_VAL_INT;
 332                         break;
 333                 case IIO_ACTIVITY:
 334                         switch (chan->channel2) {
 335                         case IIO_MOD_RUNNING:
 336                                 *val = st->activity_running;
 337                                 ret = IIO_VAL_INT;
 338                                 break;
 339                         case IIO_MOD_WALKING:
 340                                 *val = st->activity_walking;
 341                                 ret = IIO_VAL_INT;
 342                                 break;
 343                         default:
 344                                 break;
 345                         }
 346                         break;
 347                 default:
 348                         break;
 349                 }
 350                 break;
 351         case IIO_CHAN_INFO_OFFSET:
 352                 /* only single ended adc -> 7 */
 353                 *val = 7;
 354                 ret = IIO_VAL_INT;
 355                 break;
 356         case IIO_CHAN_INFO_SCALE:
 357                 switch (chan->type) {
 358                 case IIO_VOLTAGE:
 359                         switch (chan->differential) {
 360                         case 0:
 361                                 /* only single ended adc -> 0.001333 */
 362                                 *val = 0;
 363                                 *val2 = 1333;
 364                                 ret = IIO_VAL_INT_PLUS_MICRO;
 365                                 break;
 366                         case 1:
 367                                 /* all differential adc channels ->
 368                                  * 0.000001344 */
 369                                 *val = 0;
 370                                 *val2 = 1344;
 371                                 ret = IIO_VAL_INT_PLUS_NANO;
 372                         }
 373                         break;
 374                 default:
 375                         break;
 376                 }
 377                 break;
 378         case IIO_CHAN_INFO_CALIBBIAS:
 379                 /* only the acceleration axis - read from cache */
 380                 *val = st->accel_calibbias;
 381                 ret = IIO_VAL_INT;
 382                 break;
 383         case IIO_CHAN_INFO_CALIBSCALE:
 384                 *val = st->accel_calibscale->val;
 385                 *val2 = st->accel_calibscale->val2;
 386                 ret = IIO_VAL_INT_PLUS_MICRO;
 387                 break;
 388         case IIO_CHAN_INFO_SAMP_FREQ:
 389                 *val = 3;
 390                 *val2 = 33;
 391                 ret = IIO_VAL_INT_PLUS_NANO;
 392                 break;
 393         case IIO_CHAN_INFO_ENABLE:
 394                 switch (chan->type) {
 395                 case IIO_STEPS:
 396                         *val = st->steps_enabled;
 397                         ret = IIO_VAL_INT;
 398                         break;
 399                 default:
 400                         break;
 401                 }
 402                 break;
 403         case IIO_CHAN_INFO_CALIBHEIGHT:
 404                 switch (chan->type) {
 405                 case IIO_STEPS:
 406                         *val = st->height;
 407                         ret = IIO_VAL_INT;
 408                         break;
 409                 default:
 410                         break;
 411                 }
 412                 break;
 413
 414         default:
 415                 break;
 416         }
 417         mutex_unlock(&st->lock);
 418         return ret;
 419 }
 420
 421 /**
 422  * iio_dummy_write_raw() - data write function.
 423  * @indio_dev:  the struct iio_dev associated with this device instance
 424  * @chan:       the channel whose data is to be written
 425  * @val:        first element of value to set (typically INT)
 426  * @val2:       second element of value to set (typically MICRO)
 427  * @mask:       what we actually want to write as per the info_mask_*
 428  *              in iio_chan_spec.
 429  *
 430  * Note that all raw writes are assumed IIO_VAL_INT and info mask elements
 431  * are assumed to be IIO_INT_PLUS_MICRO unless the callback write_raw_get_fmt
 432  * in struct iio_info is provided by the driver.
 433  */
 434 static int iio_dummy_write_raw(struct iio_dev *indio_dev,
 435                                struct iio_chan_spec const *chan,
 436                                int val,
 437                                int val2,
 438                                long mask)
 439 {
 440         int i;
 441         int ret = 0;
 442         struct iio_dummy_state *st = iio_priv(indio_dev);
 443
 444         switch (mask) {
 445         case IIO_CHAN_INFO_RAW:
 446                 switch (chan->type) {
 447                 case IIO_VOLTAGE:
 448                         if (chan->output == 0)
 449                                 return -EINVAL;
 450
 451                         /* Locking not required as writing single value */
 452                         mutex_lock(&st->lock);
 453                         st->dac_val = val;
 454                         mutex_unlock(&st->lock);
 455                         return 0;
 456                 default:
 457                         return -EINVAL;
 458                 }
 459         case IIO_CHAN_INFO_PROCESSED:
 460                 switch (chan->type) {
 461                 case IIO_STEPS:
 462                         mutex_lock(&st->lock);
 463                         st->steps = val;
 464                         mutex_unlock(&st->lock);
 465                         return 0;
 466                 case IIO_ACTIVITY:
 467                         if (val < 0)
 468                                 val = 0;
 469                         if (val > 100)
 470                                 val = 100;
 471                         switch (chan->channel2) {
 472                         case IIO_MOD_RUNNING:
 473                                 st->activity_running = val;
 474                                 return 0;
 475                         case IIO_MOD_WALKING:
 476                                 st->activity_walking = val;
 477                                 return 0;
 478                         default:
 479                                 return -EINVAL;
 480                         }
 481                         break;
 482                 default:
 483                         return -EINVAL;
 484                 }
 485         case IIO_CHAN_INFO_CALIBSCALE:
 486                 mutex_lock(&st->lock);
 487                 /* Compare against table - hard matching here */
 488                 for (i = 0; i < ARRAY_SIZE(dummy_scales); i++)
 489                         if (val == dummy_scales[i].val &&
 490                             val2 == dummy_scales[i].val2)
 491                                 break;
 492                 if (i == ARRAY_SIZE(dummy_scales))
 493                         ret = -EINVAL;
 494                 else
 495                         st->accel_calibscale = &dummy_scales[i];
 496                 mutex_unlock(&st->lock);
 497                 return ret;
 498         case IIO_CHAN_INFO_CALIBBIAS:
 499                 mutex_lock(&st->lock);
 500                 st->accel_calibbias = val;
 501                 mutex_unlock(&st->lock);
 502                 return 0;
 503         case IIO_CHAN_INFO_ENABLE:
 504                 switch (chan->type) {
 505                 case IIO_STEPS:
 506                         mutex_lock(&st->lock);
 507                         st->steps_enabled = val;
 508                         mutex_unlock(&st->lock);
 509                         return 0;
 510                 default:
 511                         return -EINVAL;
 512                 }
 513         case IIO_CHAN_INFO_CALIBHEIGHT:
 514                 switch (chan->type) {
 515                 case IIO_STEPS:
 516                         st->height = val;
 517                         return 0;
 518                 default:
 519                         return -EINVAL;
 520                 }
 521
 522         default:
 523                 return -EINVAL;
 524         }
 525 }
 526
 527 /*
 528  * Device type specific information.
 529  */
 530 static const struct iio_info iio_dummy_info = {
 531         .driver_module = THIS_MODULE,
 532         .read_raw = &iio_dummy_read_raw,
 533         .write_raw = &iio_dummy_write_raw,
 534 #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
 535         .read_event_config = &iio_simple_dummy_read_event_config,
 536         .write_event_config = &iio_simple_dummy_write_event_config,
 537         .read_event_value = &iio_simple_dummy_read_event_value,
 538         .write_event_value = &iio_simple_dummy_write_event_value,
 539 #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
 540 };
 541
 542 /**
 543  * iio_dummy_init_device() - device instance specific init
 544  * @indio_dev: the iio device structure
 545  *
 546  * Most drivers have one of these to set up default values,
 547  * reset the device to known state etc.
 548  */
 549 static int iio_dummy_init_device(struct iio_dev *indio_dev)
 550 {
 551         struct iio_dummy_state *st = iio_priv(indio_dev);
 552
 553         st->dac_val = 0;
 554         st->single_ended_adc_val = 73;
 555         st->differential_adc_val[0] = 33;
 556         st->differential_adc_val[1] = -34;
 557         st->accel_val = 34;
 558         st->accel_calibbias = -7;
 559         st->accel_calibscale = &dummy_scales[0];
 560         st->steps = 47;
 561         st->activity_running = 98;
 562         st->activity_walking = 4;
 563
 564         return 0;
 565 }
 566
 567 /**
 568  * iio_dummy_probe() - device instance probe
 569  * @index: an id number for this instance.
 570  *
 571  * Arguments are bus type specific.
 572  * I2C: iio_dummy_probe(struct i2c_client *client,
 573  *                      const struct i2c_device_id *id)
 574  * SPI: iio_dummy_probe(struct spi_device *spi)
 575  */
 576 static int iio_dummy_probe(int index)
 577 {
 578         int ret;
 579         struct iio_dev *indio_dev;
 580         struct iio_dummy_state *st;
 581
 582         /*
 583          * Allocate an IIO device.
 584          *
 585          * This structure contains all generic state
 586          * information about the device instance.
 587          * It also has a region (accessed by iio_priv()
 588          * for chip specific state information.
 589          */
 590         indio_dev = iio_device_alloc(sizeof(*st));
 591         if (!indio_dev) {
 592                 ret = -ENOMEM;
 593                 goto error_ret;
 594         }
 595
 596         st = iio_priv(indio_dev);
 597         mutex_init(&st->lock);
 598
 599         iio_dummy_init_device(indio_dev);
 600         /*
 601          * With hardware: Set the parent device.
 602          * indio_dev->dev.parent = &spi->dev;
 603          * indio_dev->dev.parent = &client->dev;
 604          */
 605
 606          /*
 607          * Make the iio_dev struct available to remove function.
 608          * Bus equivalents
 609          * i2c_set_clientdata(client, indio_dev);
 610          * spi_set_drvdata(spi, indio_dev);
 611          */
 612         iio_dummy_devs[index] = indio_dev;
 613
 614         /*
 615          * Set the device name.
 616          *
 617          * This is typically a part number and obtained from the module
 618          * id table.
 619          * e.g. for i2c and spi:
 620          *    indio_dev->name = id->name;
 621          *    indio_dev->name = spi_get_device_id(spi)->name;
 622          */
 623         indio_dev->name = iio_dummy_part_number;
 624
 625         /* Provide description of available channels */
 626         indio_dev->channels = iio_dummy_channels;
 627         indio_dev->num_channels = ARRAY_SIZE(iio_dummy_channels);
 628
 629         /*
 630          * Provide device type specific interface functions and
 631          * constant data.
 632          */
 633         indio_dev->info = &iio_dummy_info;
 634
 635         /* Specify that device provides sysfs type interfaces */
 636         indio_dev->modes = INDIO_DIRECT_MODE;
 637
 638         ret = iio_simple_dummy_events_register(indio_dev);
 639         if (ret < 0)
 640                 goto error_free_device;
 641
 642         ret = iio_simple_dummy_configure_buffer(indio_dev);
 643         if (ret < 0)
 644                 goto error_unregister_events;
 645
 646         ret = iio_device_register(indio_dev);
 647         if (ret < 0)
 648                 goto error_unconfigure_buffer;
 649
 650         return 0;
 651 error_unconfigure_buffer:
 652         iio_simple_dummy_unconfigure_buffer(indio_dev);
 653 error_unregister_events:
 654         iio_simple_dummy_events_unregister(indio_dev);
 655 error_free_device:
 656         iio_device_free(indio_dev);
 657 error_ret:
 658         return ret;
 659 }
 660
 661 /**
 662  * iio_dummy_remove() - device instance removal function
 663  * @index: device index.
 664  *
 665  * Parameters follow those of iio_dummy_probe for buses.
 666  */
 667 static void iio_dummy_remove(int index)
 668 {
 669         /*
 670          * Get a pointer to the device instance iio_dev structure
 671          * from the bus subsystem. E.g.
 672          * struct iio_dev *indio_dev = i2c_get_clientdata(client);
 673          * struct iio_dev *indio_dev = spi_get_drvdata(spi);
 674          */
 675         struct iio_dev *indio_dev = iio_dummy_devs[index];
 676
 677         /* Unregister the device */
 678         iio_device_unregister(indio_dev);
 679
 680         /* Device specific code to power down etc */
 681
 682         /* Buffered capture related cleanup */
 683         iio_simple_dummy_unconfigure_buffer(indio_dev);
 684
 685         iio_simple_dummy_events_unregister(indio_dev);
 686
 687         /* Free all structures */
 688         iio_device_free(indio_dev);
 689 }
 690
 691 /**
 692  * iio_dummy_init() -  device driver registration
 693  *
 694  * Varies depending on bus type of the device. As there is no device
 695  * here, call probe directly. For information on device registration
 696  * i2c:
 697  * Documentation/i2c/writing-clients
 698  * spi:
 699  * Documentation/spi/spi-summary
 700  */
 701 static __init int iio_dummy_init(void)
 702 {
 703         int i, ret;
 704
 705         if (instances > 10) {
 706                 instances = 1;
 707                 return -EINVAL;
 708         }
 709
 710         /* Fake a bus */
 711         iio_dummy_devs = kcalloc(instances, sizeof(*iio_dummy_devs),
 712                                  GFP_KERNEL);
 713         /* Here we have no actual device so call probe */
 714         for (i = 0; i < instances; i++) {
 715                 ret = iio_dummy_probe(i);
 716                 if (ret < 0)
 717                         goto error_remove_devs;
 718         }
 719         return 0;
 720
 721 error_remove_devs:
 722         while (i--)
 723                 iio_dummy_remove(i);
 724
 725         kfree(iio_dummy_devs);
 726         return ret;
 727 }
 728 module_init(iio_dummy_init);
 729
 730 /**
 731  * iio_dummy_exit() - device driver removal
 732  *
 733  * Varies depending on bus type of the device.
 734  * As there is no device here, call remove directly.
 735  */
 736 static __exit void iio_dummy_exit(void)
 737 {
 738         int i;
 739
 740         for (i = 0; i < instances; i++)
 741                 iio_dummy_remove(i);
 742         kfree(iio_dummy_devs);
 743 }
 744 module_exit(iio_dummy_exit);
 745
 746 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
 747 MODULE_DESCRIPTION("IIO dummy driver");
 748 MODULE_LICENSE("GPL v2");