drivers/iio/adc/at91_adc.c

   1 /*
   2  * Driver for the ADC present in the Atmel AT91 evaluation boards.
   3  *
   4  * Copyright 2011 Free Electrons
   5  *
   6  * Licensed under the GPLv2 or later.
   7  */
   8
   9 #include <linux/bitmap.h>
  10 #include <linux/bitops.h>
  11 #include <linux/clk.h>
  12 #include <linux/err.h>
  13 #include <linux/io.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/of_device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <linux/wait.h>
  24
  25 #include <linux/platform_data/at91_adc.h>
  26
  27 #include <linux/iio/iio.h>
  28 #include <linux/iio/buffer.h>
  29 #include <linux/iio/trigger.h>
  30 #include <linux/iio/trigger_consumer.h>
  31 #include <linux/iio/triggered_buffer.h>
  32
  33 #include <mach/at91_adc.h>
  34
  35 #define AT91_ADC_CHAN(st, ch) \
  36         (st->registers->channel_base + (ch * 4))
  37 #define at91_adc_readl(st, reg) \
  38         (readl_relaxed(st->reg_base + reg))
  39 #define at91_adc_writel(st, reg, val) \
  40         (writel_relaxed(val, st->reg_base + reg))
  41
  42 struct at91_adc_state {
  43         struct clk              *adc_clk;
  44         u16                     *buffer;
  45         unsigned long           channels_mask;
  46         struct clk              *clk;
  47         bool                    done;
  48         int                     irq;
  49         u16                     last_value;
  50         struct mutex            lock;
  51         u8                      num_channels;
  52         void __iomem            *reg_base;
  53         struct at91_adc_reg_desc *registers;
  54         u8                      startup_time;
  55         struct iio_trigger      **trig;
  56         struct at91_adc_trigger *trigger_list;
  57         u32                     trigger_number;
  58         bool                    use_external;
  59         u32                     vref_mv;
  60         wait_queue_head_t       wq_data_avail;
  61 };
  62
  63 static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
  64 {
  65         struct iio_poll_func *pf = p;
  66         struct iio_dev *idev = pf->indio_dev;
  67         struct at91_adc_state *st = iio_priv(idev);
  68         int i, j = 0;
  69
  70         for (i = 0; i < idev->masklength; i++) {
  71                 if (!test_bit(i, idev->active_scan_mask))
  72                         continue;
  73                 st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
  74                 j++;
  75         }
  76
  77         if (idev->scan_timestamp) {
  78                 s64 *timestamp = (s64 *)((u8 *)st->buffer +
  79                                         ALIGN(j, sizeof(s64)));
  80                 *timestamp = pf->timestamp;
  81         }
  82
  83         iio_push_to_buffers(idev, (u8 *)st->buffer);
  84
  85         iio_trigger_notify_done(idev->trig);
  86
  87         /* Needed to ACK the DRDY interruption */
  88         at91_adc_readl(st, AT91_ADC_LCDR);
  89
  90         enable_irq(st->irq);
  91
  92         return IRQ_HANDLED;
  93 }
  94
  95 static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
  96 {
  97         struct iio_dev *idev = private;
  98         struct at91_adc_state *st = iio_priv(idev);
  99         u32 status = at91_adc_readl(st, st->registers->status_register);
 100
 101         if (!(status & st->registers->drdy_mask))
 102                 return IRQ_HANDLED;
 103
 104         if (iio_buffer_enabled(idev)) {
 105                 disable_irq_nosync(irq);
 106                 iio_trigger_poll(idev->trig, iio_get_time_ns());
 107         } else {
 108                 st->last_value = at91_adc_readl(st, AT91_ADC_LCDR);
 109                 st->done = true;
 110                 wake_up_interruptible(&st->wq_data_avail);
 111         }
 112
 113         return IRQ_HANDLED;
 114 }
 115
 116 static int at91_adc_channel_init(struct iio_dev *idev)
 117 {
 118         struct at91_adc_state *st = iio_priv(idev);
 119         struct iio_chan_spec *chan_array, *timestamp;
 120         int bit, idx = 0;
 121
 122         idev->num_channels = bitmap_weight(&st->channels_mask,
 123                                            st->num_channels) + 1;
 124
 125         chan_array = devm_kzalloc(&idev->dev,
 126                                   ((idev->num_channels + 1) *
 127                                         sizeof(struct iio_chan_spec)),
 128                                   GFP_KERNEL);
 129
 130         if (!chan_array)
 131                 return -ENOMEM;
 132
 133         for_each_set_bit(bit, &st->channels_mask, st->num_channels) {
 134                 struct iio_chan_spec *chan = chan_array + idx;
 135
 136                 chan->type = IIO_VOLTAGE;
 137                 chan->indexed = 1;
 138                 chan->channel = bit;
 139                 chan->scan_index = idx;
 140                 chan->scan_type.sign = 'u';
 141                 chan->scan_type.realbits = 10;
 142                 chan->scan_type.storagebits = 16;
 143                 chan->info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT |
 144                         IIO_CHAN_INFO_RAW_SEPARATE_BIT;
 145                 idx++;
 146         }
 147         timestamp = chan_array + idx;
 148
 149         timestamp->type = IIO_TIMESTAMP;
 150         timestamp->channel = -1;
 151         timestamp->scan_index = idx;
 152         timestamp->scan_type.sign = 's';
 153         timestamp->scan_type.realbits = 64;
 154         timestamp->scan_type.storagebits = 64;
 155
 156         idev->channels = chan_array;
 157         return idev->num_channels;
 158 }
 159
 160 static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
 161                                              struct at91_adc_trigger *triggers,
 162                                              const char *trigger_name)
 163 {
 164         struct at91_adc_state *st = iio_priv(idev);
 165         u8 value = 0;
 166         int i;
 167
 168         for (i = 0; i < st->trigger_number; i++) {
 169                 char *name = kasprintf(GFP_KERNEL,
 170                                 "%s-dev%d-%s",
 171                                 idev->name,
 172                                 idev->id,
 173                                 triggers[i].name);
 174                 if (!name)
 175                         return -ENOMEM;
 176
 177                 if (strcmp(trigger_name, name) == 0) {
 178                         value = triggers[i].value;
 179                         kfree(name);
 180                         break;
 181                 }
 182
 183                 kfree(name);
 184         }
 185
 186         return value;
 187 }
 188
 189 static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
 190 {
 191         struct iio_dev *idev = trig->private_data;
 192         struct at91_adc_state *st = iio_priv(idev);
 193         struct iio_buffer *buffer = idev->buffer;
 194         struct at91_adc_reg_desc *reg = st->registers;
 195         u32 status = at91_adc_readl(st, reg->trigger_register);
 196         u8 value;
 197         u8 bit;
 198
 199         value = at91_adc_get_trigger_value_by_name(idev,
 200                                                    st->trigger_list,
 201                                                    idev->trig->name);
 202         if (value == 0)
 203                 return -EINVAL;
 204
 205         if (state) {
 206                 st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);
 207                 if (st->buffer == NULL)
 208                         return -ENOMEM;
 209
 210                 at91_adc_writel(st, reg->trigger_register,
 211                                 status | value);
 212
 213                 for_each_set_bit(bit, buffer->scan_mask,
 214                                  st->num_channels) {
 215                         struct iio_chan_spec const *chan = idev->channels + bit;
 216                         at91_adc_writel(st, AT91_ADC_CHER,
 217                                         AT91_ADC_CH(chan->channel));
 218                 }
 219
 220                 at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask);
 221
 222         } else {
 223                 at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask);
 224
 225                 at91_adc_writel(st, reg->trigger_register,
 226                                 status & ~value);
 227
 228                 for_each_set_bit(bit, buffer->scan_mask,
 229                                  st->num_channels) {
 230                         struct iio_chan_spec const *chan = idev->channels + bit;
 231                         at91_adc_writel(st, AT91_ADC_CHDR,
 232                                         AT91_ADC_CH(chan->channel));
 233                 }
 234                 kfree(st->buffer);
 235         }
 236
 237         return 0;
 238 }
 239
 240 static const struct iio_trigger_ops at91_adc_trigger_ops = {
 241         .owner = THIS_MODULE,
 242         .set_trigger_state = &at91_adc_configure_trigger,
 243 };
 244
 245 static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev,
 246                                                      struct at91_adc_trigger *trigger)
 247 {
 248         struct iio_trigger *trig;
 249         int ret;
 250
 251         trig = iio_trigger_alloc("%s-dev%d-%s", idev->name,
 252                                  idev->id, trigger->name);
 253         if (trig == NULL)
 254                 return NULL;
 255
 256         trig->dev.parent = idev->dev.parent;
 257         trig->private_data = idev;
 258         trig->ops = &at91_adc_trigger_ops;
 259
 260         ret = iio_trigger_register(trig);
 261         if (ret)
 262                 return NULL;
 263
 264         return trig;
 265 }
 266
 267 static int at91_adc_trigger_init(struct iio_dev *idev)
 268 {
 269         struct at91_adc_state *st = iio_priv(idev);
 270         int i, ret;
 271
 272         st->trig = devm_kzalloc(&idev->dev,
 273                                 st->trigger_number * sizeof(st->trig),
 274                                 GFP_KERNEL);
 275
 276         if (st->trig == NULL) {
 277                 ret = -ENOMEM;
 278                 goto error_ret;
 279         }
 280
 281         for (i = 0; i < st->trigger_number; i++) {
 282                 if (st->trigger_list[i].is_external && !(st->use_external))
 283                         continue;
 284
 285                 st->trig[i] = at91_adc_allocate_trigger(idev,
 286                                                         st->trigger_list + i);
 287                 if (st->trig[i] == NULL) {
 288                         dev_err(&idev->dev,
 289                                 "Could not allocate trigger %d\n", i);
 290                         ret = -ENOMEM;
 291                         goto error_trigger;
 292                 }
 293         }
 294
 295         return 0;
 296
 297 error_trigger:
 298         for (i--; i >= 0; i--) {
 299                 iio_trigger_unregister(st->trig[i]);
 300                 iio_trigger_free(st->trig[i]);
 301         }
 302 error_ret:
 303         return ret;
 304 }
 305
 306 static void at91_adc_trigger_remove(struct iio_dev *idev)
 307 {
 308         struct at91_adc_state *st = iio_priv(idev);
 309         int i;
 310
 311         for (i = 0; i < st->trigger_number; i++) {
 312                 iio_trigger_unregister(st->trig[i]);
 313                 iio_trigger_free(st->trig[i]);
 314         }
 315 }
 316
 317 static int at91_adc_buffer_init(struct iio_dev *idev)
 318 {
 319         return iio_triggered_buffer_setup(idev, &iio_pollfunc_store_time,
 320                 &at91_adc_trigger_handler, NULL);
 321 }
 322
 323 static void at91_adc_buffer_remove(struct iio_dev *idev)
 324 {
 325         iio_triggered_buffer_cleanup(idev);
 326 }
 327
 328 static int at91_adc_read_raw(struct iio_dev *idev,
 329                              struct iio_chan_spec const *chan,
 330                              int *val, int *val2, long mask)
 331 {
 332         struct at91_adc_state *st = iio_priv(idev);
 333         int ret;
 334
 335         switch (mask) {
 336         case IIO_CHAN_INFO_RAW:
 337                 mutex_lock(&st->lock);
 338
 339                 at91_adc_writel(st, AT91_ADC_CHER,
 340                                 AT91_ADC_CH(chan->channel));
 341                 at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask);
 342                 at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START);
 343
 344                 ret = wait_event_interruptible_timeout(st->wq_data_avail,
 345                                                        st->done,
 346                                                        msecs_to_jiffies(1000));
 347                 if (ret == 0)
 348                         ret = -ETIMEDOUT;
 349                 if (ret < 0) {
 350                         mutex_unlock(&st->lock);
 351                         return ret;
 352                 }
 353
 354                 *val = st->last_value;
 355
 356                 at91_adc_writel(st, AT91_ADC_CHDR,
 357                                 AT91_ADC_CH(chan->channel));
 358                 at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask);
 359
 360                 st->last_value = 0;
 361                 st->done = false;
 362                 mutex_unlock(&st->lock);
 363                 return IIO_VAL_INT;
 364
 365         case IIO_CHAN_INFO_SCALE:
 366                 *val = (st->vref_mv * 1000) >> chan->scan_type.realbits;
 367                 *val2 = 0;
 368                 return IIO_VAL_INT_PLUS_MICRO;
 369         default:
 370                 break;
 371         }
 372         return -EINVAL;
 373 }
 374
 375 static int at91_adc_probe_dt(struct at91_adc_state *st,
 376                              struct platform_device *pdev)
 377 {
 378         struct iio_dev *idev = iio_priv_to_dev(st);
 379         struct device_node *node = pdev->dev.of_node;
 380         struct device_node *trig_node;
 381         int i = 0, ret;
 382         u32 prop;
 383
 384         if (!node)
 385                 return -EINVAL;
 386
 387         st->use_external = of_property_read_bool(node, "atmel,adc-use-external-triggers");
 388
 389         if (of_property_read_u32(node, "atmel,adc-channels-used", &prop)) {
 390                 dev_err(&idev->dev, "Missing adc-channels-used property in the DT.\n");
 391                 ret = -EINVAL;
 392                 goto error_ret;
 393         }
 394         st->channels_mask = prop;
 395
 396         if (of_property_read_u32(node, "atmel,adc-num-channels", &prop)) {
 397                 dev_err(&idev->dev, "Missing adc-num-channels property in the DT.\n");
 398                 ret = -EINVAL;
 399                 goto error_ret;
 400         }
 401         st->num_channels = prop;
 402
 403         if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
 404                 dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n");
 405                 ret = -EINVAL;
 406                 goto error_ret;
 407         }
 408         st->startup_time = prop;
 409
 410
 411         if (of_property_read_u32(node, "atmel,adc-vref", &prop)) {
 412                 dev_err(&idev->dev, "Missing adc-vref property in the DT.\n");
 413                 ret = -EINVAL;
 414                 goto error_ret;
 415         }
 416         st->vref_mv = prop;
 417
 418         st->registers = devm_kzalloc(&idev->dev,
 419                                      sizeof(struct at91_adc_reg_desc),
 420                                      GFP_KERNEL);
 421         if (!st->registers) {
 422                 dev_err(&idev->dev, "Could not allocate register memory.\n");
 423                 ret = -ENOMEM;
 424                 goto error_ret;
 425         }
 426
 427         if (of_property_read_u32(node, "atmel,adc-channel-base", &prop)) {
 428                 dev_err(&idev->dev, "Missing adc-channel-base property in the DT.\n");
 429                 ret = -EINVAL;
 430                 goto error_ret;
 431         }
 432         st->registers->channel_base = prop;
 433
 434         if (of_property_read_u32(node, "atmel,adc-drdy-mask", &prop)) {
 435                 dev_err(&idev->dev, "Missing adc-drdy-mask property in the DT.\n");
 436                 ret = -EINVAL;
 437                 goto error_ret;
 438         }
 439         st->registers->drdy_mask = prop;
 440
 441         if (of_property_read_u32(node, "atmel,adc-status-register", &prop)) {
 442                 dev_err(&idev->dev, "Missing adc-status-register property in the DT.\n");
 443                 ret = -EINVAL;
 444                 goto error_ret;
 445         }
 446         st->registers->status_register = prop;
 447
 448         if (of_property_read_u32(node, "atmel,adc-trigger-register", &prop)) {
 449                 dev_err(&idev->dev, "Missing adc-trigger-register property in the DT.\n");
 450                 ret = -EINVAL;
 451                 goto error_ret;
 452         }
 453         st->registers->trigger_register = prop;
 454
 455         st->trigger_number = of_get_child_count(node);
 456         st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
 457                                         sizeof(struct at91_adc_trigger),
 458                                         GFP_KERNEL);
 459         if (!st->trigger_list) {
 460                 dev_err(&idev->dev, "Could not allocate trigger list memory.\n");
 461                 ret = -ENOMEM;
 462                 goto error_ret;
 463         }
 464
 465         for_each_child_of_node(node, trig_node) {
 466                 struct at91_adc_trigger *trig = st->trigger_list + i;
 467                 const char *name;
 468
 469                 if (of_property_read_string(trig_node, "trigger-name", &name)) {
 470                         dev_err(&idev->dev, "Missing trigger-name property in the DT.\n");
 471                         ret = -EINVAL;
 472                         goto error_ret;
 473                 }
 474                 trig->name = name;
 475
 476                 if (of_property_read_u32(trig_node, "trigger-value", &prop)) {
 477                         dev_err(&idev->dev, "Missing trigger-value property in the DT.\n");
 478                         ret = -EINVAL;
 479                         goto error_ret;
 480                 }
 481                 trig->value = prop;
 482                 trig->is_external = of_property_read_bool(trig_node, "trigger-external");
 483                 i++;
 484         }
 485
 486         return 0;
 487
 488 error_ret:
 489         return ret;
 490 }
 491
 492 static int at91_adc_probe_pdata(struct at91_adc_state *st,
 493                                 struct platform_device *pdev)
 494 {
 495         struct at91_adc_data *pdata = pdev->dev.platform_data;
 496
 497         if (!pdata)
 498                 return -EINVAL;
 499
 500         st->use_external = pdata->use_external_triggers;
 501         st->vref_mv = pdata->vref;
 502         st->channels_mask = pdata->channels_used;
 503         st->num_channels = pdata->num_channels;
 504         st->startup_time = pdata->startup_time;
 505         st->trigger_number = pdata->trigger_number;
 506         st->trigger_list = pdata->trigger_list;
 507         st->registers = pdata->registers;
 508
 509         return 0;
 510 }
 511
 512 static const struct iio_info at91_adc_info = {
 513         .driver_module = THIS_MODULE,
 514         .read_raw = &at91_adc_read_raw,
 515 };
 516
 517 static int at91_adc_probe(struct platform_device *pdev)
 518 {
 519         unsigned int prsc, mstrclk, ticks, adc_clk;
 520         int ret;
 521         struct iio_dev *idev;
 522         struct at91_adc_state *st;
 523         struct resource *res;
 524
 525         idev = iio_device_alloc(sizeof(struct at91_adc_state));
 526         if (idev == NULL) {
 527                 ret = -ENOMEM;
 528                 goto error_ret;
 529         }
 530
 531         st = iio_priv(idev);
 532
 533         if (pdev->dev.of_node)
 534                 ret = at91_adc_probe_dt(st, pdev);
 535         else
 536                 ret = at91_adc_probe_pdata(st, pdev);
 537
 538         if (ret) {
 539                 dev_err(&pdev->dev, "No platform data available.\n");
 540                 ret = -EINVAL;
 541                 goto error_free_device;
 542         }
 543
 544         platform_set_drvdata(pdev, idev);
 545
 546         idev->dev.parent = &pdev->dev;
 547         idev->name = dev_name(&pdev->dev);
 548         idev->modes = INDIO_DIRECT_MODE;
 549         idev->info = &at91_adc_info;
 550
 551         st->irq = platform_get_irq(pdev, 0);
 552         if (st->irq < 0) {
 553                 dev_err(&pdev->dev, "No IRQ ID is designated\n");
 554                 ret = -ENODEV;
 555                 goto error_free_device;
 556         }
 557
 558         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 559
 560         st->reg_base = devm_request_and_ioremap(&pdev->dev, res);
 561         if (!st->reg_base) {
 562                 ret = -ENOMEM;
 563                 goto error_free_device;
 564         }
 565
 566         /*
 567          * Disable all IRQs before setting up the handler
 568          */
 569         at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
 570         at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
 571         ret = request_irq(st->irq,
 572                           at91_adc_eoc_trigger,
 573                           0,
 574                           pdev->dev.driver->name,
 575                           idev);
 576         if (ret) {
 577                 dev_err(&pdev->dev, "Failed to allocate IRQ.\n");
 578                 goto error_free_device;
 579         }
 580
 581         st->clk = devm_clk_get(&pdev->dev, "adc_clk");
 582         if (IS_ERR(st->clk)) {
 583                 dev_err(&pdev->dev, "Failed to get the clock.\n");
 584                 ret = PTR_ERR(st->clk);
 585                 goto error_free_irq;
 586         }
 587
 588         ret = clk_prepare_enable(st->clk);
 589         if (ret) {
 590                 dev_err(&pdev->dev,
 591                         "Could not prepare or enable the clock.\n");
 592                 goto error_free_irq;
 593         }
 594
 595         st->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
 596         if (IS_ERR(st->adc_clk)) {
 597                 dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
 598                 ret = PTR_ERR(st->adc_clk);
 599                 goto error_disable_clk;
 600         }
 601
 602         ret = clk_prepare_enable(st->adc_clk);
 603         if (ret) {
 604                 dev_err(&pdev->dev,
 605                         "Could not prepare or enable the ADC clock.\n");
 606                 goto error_disable_clk;
 607         }
 608
 609         /*
 610          * Prescaler rate computation using the formula from the Atmel's
 611          * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
 612          * specified by the electrical characteristics of the board.
 613          */
 614         mstrclk = clk_get_rate(st->clk);
 615         adc_clk = clk_get_rate(st->adc_clk);
 616         prsc = (mstrclk / (2 * adc_clk)) - 1;
 617
 618         if (!st->startup_time) {
 619                 dev_err(&pdev->dev, "No startup time available.\n");
 620                 ret = -EINVAL;
 621                 goto error_disable_adc_clk;
 622         }
 623
 624         /*
 625          * Number of ticks needed to cover the startup time of the ADC as
 626          * defined in the electrical characteristics of the board, divided by 8.
 627          * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
 628          */
 629         ticks = round_up((st->startup_time * adc_clk /
 630                           1000000) - 1, 8) / 8;
 631         at91_adc_writel(st, AT91_ADC_MR,
 632                         (AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) |
 633                         (AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP));
 634
 635         /* Setup the ADC channels available on the board */
 636         ret = at91_adc_channel_init(idev);
 637         if (ret < 0) {
 638                 dev_err(&pdev->dev, "Couldn't initialize the channels.\n");
 639                 goto error_disable_adc_clk;
 640         }
 641
 642         init_waitqueue_head(&st->wq_data_avail);
 643         mutex_init(&st->lock);
 644
 645         ret = at91_adc_buffer_init(idev);
 646         if (ret < 0) {
 647                 dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
 648                 goto error_disable_adc_clk;
 649         }
 650
 651         ret = at91_adc_trigger_init(idev);
 652         if (ret < 0) {
 653                 dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
 654                 goto error_unregister_buffer;
 655         }
 656
 657         ret = iio_device_register(idev);
 658         if (ret < 0) {
 659                 dev_err(&pdev->dev, "Couldn't register the device.\n");
 660                 goto error_remove_triggers;
 661         }
 662
 663         return 0;
 664
 665 error_remove_triggers:
 666         at91_adc_trigger_remove(idev);
 667 error_unregister_buffer:
 668         at91_adc_buffer_remove(idev);
 669 error_disable_adc_clk:
 670         clk_disable_unprepare(st->adc_clk);
 671 error_disable_clk:
 672         clk_disable_unprepare(st->clk);
 673 error_free_irq:
 674         free_irq(st->irq, idev);
 675 error_free_device:
 676         iio_device_free(idev);
 677 error_ret:
 678         return ret;
 679 }
 680
 681 static int at91_adc_remove(struct platform_device *pdev)
 682 {
 683         struct iio_dev *idev = platform_get_drvdata(pdev);
 684         struct at91_adc_state *st = iio_priv(idev);
 685
 686         iio_device_unregister(idev);
 687         at91_adc_trigger_remove(idev);
 688         at91_adc_buffer_remove(idev);
 689         clk_disable_unprepare(st->adc_clk);
 690         clk_disable_unprepare(st->clk);
 691         free_irq(st->irq, idev);
 692         iio_device_free(idev);
 693
 694         return 0;
 695 }
 696
 697 static const struct of_device_id at91_adc_dt_ids[] = {
 698         { .compatible = "atmel,at91sam9260-adc" },
 699         {},
 700 };
 701 MODULE_DEVICE_TABLE(of, at91_adc_dt_ids);
 702
 703 static struct platform_driver at91_adc_driver = {
 704         .probe = at91_adc_probe,
 705         .remove = at91_adc_remove,
 706         .driver = {
 707                    .name = "at91_adc",
 708                    .of_match_table = of_match_ptr(at91_adc_dt_ids),
 709         },
 710 };
 711
 712 module_platform_driver(at91_adc_driver);
 713
 714 MODULE_LICENSE("GPL");
 715 MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
 716 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");