drivers/iio/adc/sc27xx_adc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 Spreadtrum Communications Inc.
   3
   4 #include <linux/hwspinlock.h>
   5 #include <linux/iio/iio.h>
   6 #include <linux/interrupt.h>
   7 #include <linux/module.h>
   8 #include <linux/nvmem-consumer.h>
   9 #include <linux/of.h>
  10 #include <linux/of_device.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/regmap.h>
  13 #include <linux/slab.h>
  14
  15 /* PMIC global registers definition */
  16 #define SC27XX_MODULE_EN                0xc08
  17 #define SC27XX_MODULE_ADC_EN            BIT(5)
  18 #define SC27XX_ARM_CLK_EN               0xc10
  19 #define SC27XX_CLK_ADC_EN               BIT(5)
  20 #define SC27XX_CLK_ADC_CLK_EN           BIT(6)
  21
  22 /* ADC controller registers definition */
  23 #define SC27XX_ADC_CTL                  0x0
  24 #define SC27XX_ADC_CH_CFG               0x4
  25 #define SC27XX_ADC_DATA                 0x4c
  26 #define SC27XX_ADC_INT_EN               0x50
  27 #define SC27XX_ADC_INT_CLR              0x54
  28 #define SC27XX_ADC_INT_STS              0x58
  29 #define SC27XX_ADC_INT_RAW              0x5c
  30
  31 /* Bits and mask definition for SC27XX_ADC_CTL register */
  32 #define SC27XX_ADC_EN                   BIT(0)
  33 #define SC27XX_ADC_CHN_RUN              BIT(1)
  34 #define SC27XX_ADC_12BIT_MODE           BIT(2)
  35 #define SC27XX_ADC_RUN_NUM_MASK         GENMASK(7, 4)
  36 #define SC27XX_ADC_RUN_NUM_SHIFT        4
  37
  38 /* Bits and mask definition for SC27XX_ADC_CH_CFG register */
  39 #define SC27XX_ADC_CHN_ID_MASK          GENMASK(4, 0)
  40 #define SC27XX_ADC_SCALE_MASK           GENMASK(10, 8)
  41 #define SC27XX_ADC_SCALE_SHIFT          8
  42
  43 /* Bits definitions for SC27XX_ADC_INT_EN registers */
  44 #define SC27XX_ADC_IRQ_EN               BIT(0)
  45
  46 /* Bits definitions for SC27XX_ADC_INT_CLR registers */
  47 #define SC27XX_ADC_IRQ_CLR              BIT(0)
  48
  49 /* Mask definition for SC27XX_ADC_DATA register */
  50 #define SC27XX_ADC_DATA_MASK            GENMASK(11, 0)
  51
  52 /* Timeout (ms) for the trylock of hardware spinlocks */
  53 #define SC27XX_ADC_HWLOCK_TIMEOUT       5000
  54
  55 /* Maximum ADC channel number */
  56 #define SC27XX_ADC_CHANNEL_MAX          32
  57
  58 /* ADC voltage ratio definition */
  59 #define SC27XX_VOLT_RATIO(n, d)         \
  60         (((n) << SC27XX_RATIO_NUMERATOR_OFFSET) | (d))
  61 #define SC27XX_RATIO_NUMERATOR_OFFSET   16
  62 #define SC27XX_RATIO_DENOMINATOR_MASK   GENMASK(15, 0)
  63
  64 struct sc27xx_adc_data {
  65         struct device *dev;
  66         struct regmap *regmap;
  67         /*
  68          * One hardware spinlock to synchronize between the multiple
  69          * subsystems which will access the unique ADC controller.
  70          */
  71         struct hwspinlock *hwlock;
  72         struct completion completion;
  73         int channel_scale[SC27XX_ADC_CHANNEL_MAX];
  74         u32 base;
  75         int value;
  76         int irq;
  77 };
  78
  79 struct sc27xx_adc_linear_graph {
  80         int volt0;
  81         int adc0;
  82         int volt1;
  83         int adc1;
  84 };
  85
  86 /*
  87  * According to the datasheet, we can convert one ADC value to one voltage value
  88  * through 2 points in the linear graph. If the voltage is less than 1.2v, we
  89  * should use the small-scale graph, and if more than 1.2v, we should use the
  90  * big-scale graph.
  91  */
  92 static struct sc27xx_adc_linear_graph big_scale_graph = {
  93         4200, 3310,
  94         3600, 2832,
  95 };
  96
  97 static struct sc27xx_adc_linear_graph small_scale_graph = {
  98         1000, 3413,
  99         100, 341,
 100 };
 101
 102 static const struct sc27xx_adc_linear_graph big_scale_graph_calib = {
 103         4200, 856,
 104         3600, 733,
 105 };
 106
 107 static const struct sc27xx_adc_linear_graph small_scale_graph_calib = {
 108         1000, 833,
 109         100, 80,
 110 };
 111
 112 static int sc27xx_adc_get_calib_data(u32 calib_data, int calib_adc)
 113 {
 114         return ((calib_data & 0xff) + calib_adc - 128) * 4;
 115 }
 116
 117 static int sc27xx_adc_scale_calibration(struct sc27xx_adc_data *data,
 118                                         bool big_scale)
 119 {
 120         const struct sc27xx_adc_linear_graph *calib_graph;
 121         struct sc27xx_adc_linear_graph *graph;
 122         struct nvmem_cell *cell;
 123         const char *cell_name;
 124         u32 calib_data = 0;
 125         void *buf;
 126         size_t len;
 127
 128         if (big_scale) {
 129                 calib_graph = &big_scale_graph_calib;
 130                 graph = &big_scale_graph;
 131                 cell_name = "big_scale_calib";
 132         } else {
 133                 calib_graph = &small_scale_graph_calib;
 134                 graph = &small_scale_graph;
 135                 cell_name = "small_scale_calib";
 136         }
 137
 138         cell = nvmem_cell_get(data->dev, cell_name);
 139         if (IS_ERR(cell))
 140                 return PTR_ERR(cell);
 141
 142         buf = nvmem_cell_read(cell, &len);
 143         nvmem_cell_put(cell);
 144
 145         if (IS_ERR(buf))
 146                 return PTR_ERR(buf);
 147
 148         memcpy(&calib_data, buf, min(len, sizeof(u32)));
 149
 150         /* Only need to calibrate the adc values in the linear graph. */
 151         graph->adc0 = sc27xx_adc_get_calib_data(calib_data, calib_graph->adc0);
 152         graph->adc1 = sc27xx_adc_get_calib_data(calib_data >> 8,
 153                                                 calib_graph->adc1);
 154
 155         kfree(buf);
 156         return 0;
 157 }
 158
 159 static int sc27xx_adc_get_ratio(int channel, int scale)
 160 {
 161         switch (channel) {
 162         case 1:
 163         case 2:
 164         case 3:
 165         case 4:
 166                 return scale ? SC27XX_VOLT_RATIO(400, 1025) :
 167                         SC27XX_VOLT_RATIO(1, 1);
 168         case 5:
 169                 return SC27XX_VOLT_RATIO(7, 29);
 170         case 6:
 171                 return SC27XX_VOLT_RATIO(375, 9000);
 172         case 7:
 173         case 8:
 174                 return scale ? SC27XX_VOLT_RATIO(100, 125) :
 175                         SC27XX_VOLT_RATIO(1, 1);
 176         case 19:
 177                 return SC27XX_VOLT_RATIO(1, 3);
 178         default:
 179                 return SC27XX_VOLT_RATIO(1, 1);
 180         }
 181         return SC27XX_VOLT_RATIO(1, 1);
 182 }
 183
 184 static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel,
 185                            int scale, int *val)
 186 {
 187         int ret;
 188         u32 tmp;
 189
 190         reinit_completion(&data->completion);
 191
 192         ret = hwspin_lock_timeout_raw(data->hwlock, SC27XX_ADC_HWLOCK_TIMEOUT);
 193         if (ret) {
 194                 dev_err(data->dev, "timeout to get the hwspinlock\n");
 195                 return ret;
 196         }
 197
 198         ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
 199                                  SC27XX_ADC_EN, SC27XX_ADC_EN);
 200         if (ret)
 201                 goto unlock_adc;
 202
 203         /* Configure the channel id and scale */
 204         tmp = (scale << SC27XX_ADC_SCALE_SHIFT) & SC27XX_ADC_SCALE_MASK;
 205         tmp |= channel & SC27XX_ADC_CHN_ID_MASK;
 206         ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CH_CFG,
 207                                  SC27XX_ADC_CHN_ID_MASK | SC27XX_ADC_SCALE_MASK,
 208                                  tmp);
 209         if (ret)
 210                 goto disable_adc;
 211
 212         /* Select 12bit conversion mode, and only sample 1 time */
 213         tmp = SC27XX_ADC_12BIT_MODE;
 214         tmp |= (0 << SC27XX_ADC_RUN_NUM_SHIFT) & SC27XX_ADC_RUN_NUM_MASK;
 215         ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
 216                                  SC27XX_ADC_RUN_NUM_MASK | SC27XX_ADC_12BIT_MODE,
 217                                  tmp);
 218         if (ret)
 219                 goto disable_adc;
 220
 221         ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
 222                                  SC27XX_ADC_CHN_RUN, SC27XX_ADC_CHN_RUN);
 223         if (ret)
 224                 goto disable_adc;
 225
 226         wait_for_completion(&data->completion);
 227
 228 disable_adc:
 229         regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
 230                            SC27XX_ADC_EN, 0);
 231 unlock_adc:
 232         hwspin_unlock_raw(data->hwlock);
 233
 234         if (!ret)
 235                 *val = data->value;
 236
 237         return ret;
 238 }
 239
 240 static irqreturn_t sc27xx_adc_isr(int irq, void *dev_id)
 241 {
 242         struct sc27xx_adc_data *data = dev_id;
 243         int ret;
 244
 245         ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_CLR,
 246                                  SC27XX_ADC_IRQ_CLR, SC27XX_ADC_IRQ_CLR);
 247         if (ret)
 248                 return IRQ_RETVAL(ret);
 249
 250         ret = regmap_read(data->regmap, data->base + SC27XX_ADC_DATA,
 251                           &data->value);
 252         if (ret)
 253                 return IRQ_RETVAL(ret);
 254
 255         data->value &= SC27XX_ADC_DATA_MASK;
 256         complete(&data->completion);
 257
 258         return IRQ_HANDLED;
 259 }
 260
 261 static void sc27xx_adc_volt_ratio(struct sc27xx_adc_data *data,
 262                                   int channel, int scale,
 263                                   u32 *div_numerator, u32 *div_denominator)
 264 {
 265         u32 ratio = sc27xx_adc_get_ratio(channel, scale);
 266
 267         *div_numerator = ratio >> SC27XX_RATIO_NUMERATOR_OFFSET;
 268         *div_denominator = ratio & SC27XX_RATIO_DENOMINATOR_MASK;
 269 }
 270
 271 static int sc27xx_adc_to_volt(struct sc27xx_adc_linear_graph *graph,
 272                               int raw_adc)
 273 {
 274         int tmp;
 275
 276         tmp = (graph->volt0 - graph->volt1) * (raw_adc - graph->adc1);
 277         tmp /= (graph->adc0 - graph->adc1);
 278         tmp += graph->volt1;
 279
 280         return tmp < 0 ? 0 : tmp;
 281 }
 282
 283 static int sc27xx_adc_convert_volt(struct sc27xx_adc_data *data, int channel,
 284                                    int scale, int raw_adc)
 285 {
 286         u32 numerator, denominator;
 287         u32 volt;
 288
 289         /*
 290          * Convert ADC values to voltage values according to the linear graph,
 291          * and channel 5 and channel 1 has been calibrated, so we can just
 292          * return the voltage values calculated by the linear graph. But other
 293          * channels need be calculated to the real voltage values with the
 294          * voltage ratio.
 295          */
 296         switch (channel) {
 297         case 5:
 298                 return sc27xx_adc_to_volt(&big_scale_graph, raw_adc);
 299
 300         case 1:
 301                 return sc27xx_adc_to_volt(&small_scale_graph, raw_adc);
 302
 303         default:
 304                 volt = sc27xx_adc_to_volt(&small_scale_graph, raw_adc);
 305                 break;
 306         }
 307
 308         sc27xx_adc_volt_ratio(data, channel, scale, &numerator, &denominator);
 309
 310         return (volt * denominator + numerator / 2) / numerator;
 311 }
 312
 313 static int sc27xx_adc_read_processed(struct sc27xx_adc_data *data,
 314                                      int channel, int scale, int *val)
 315 {
 316         int ret, raw_adc;
 317
 318         ret = sc27xx_adc_read(data, channel, scale, &raw_adc);
 319         if (ret)
 320                 return ret;
 321
 322         *val = sc27xx_adc_convert_volt(data, channel, scale, raw_adc);
 323         return 0;
 324 }
 325
 326 static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,
 327                                struct iio_chan_spec const *chan,
 328                                int *val, int *val2, long mask)
 329 {
 330         struct sc27xx_adc_data *data = iio_priv(indio_dev);
 331         int scale = data->channel_scale[chan->channel];
 332         int ret, tmp;
 333
 334         switch (mask) {
 335         case IIO_CHAN_INFO_RAW:
 336                 mutex_lock(&indio_dev->mlock);
 337                 ret = sc27xx_adc_read(data, chan->channel, scale, &tmp);
 338                 mutex_unlock(&indio_dev->mlock);
 339
 340                 if (ret)
 341                         return ret;
 342
 343                 *val = tmp;
 344                 return IIO_VAL_INT;
 345
 346         case IIO_CHAN_INFO_PROCESSED:
 347                 mutex_lock(&indio_dev->mlock);
 348                 ret = sc27xx_adc_read_processed(data, chan->channel, scale,
 349                                                 &tmp);
 350                 mutex_unlock(&indio_dev->mlock);
 351
 352                 if (ret)
 353                         return ret;
 354
 355                 *val = tmp;
 356                 return IIO_VAL_INT;
 357
 358         case IIO_CHAN_INFO_SCALE:
 359                 *val = scale;
 360                 return IIO_VAL_INT;
 361
 362         default:
 363                 return -EINVAL;
 364         }
 365 }
 366
 367 static int sc27xx_adc_write_raw(struct iio_dev *indio_dev,
 368                                 struct iio_chan_spec const *chan,
 369                                 int val, int val2, long mask)
 370 {
 371         struct sc27xx_adc_data *data = iio_priv(indio_dev);
 372
 373         switch (mask) {
 374         case IIO_CHAN_INFO_SCALE:
 375                 data->channel_scale[chan->channel] = val;
 376                 return IIO_VAL_INT;
 377
 378         default:
 379                 return -EINVAL;
 380         }
 381 }
 382
 383 static const struct iio_info sc27xx_info = {
 384         .read_raw = &sc27xx_adc_read_raw,
 385         .write_raw = &sc27xx_adc_write_raw,
 386 };
 387
 388 #define SC27XX_ADC_CHANNEL(index, mask) {                       \
 389         .type = IIO_VOLTAGE,                                    \
 390         .channel = index,                                       \
 391         .info_mask_separate = mask | BIT(IIO_CHAN_INFO_SCALE),  \
 392         .datasheet_name = "CH##index",                          \
 393         .indexed = 1,                                           \
 394 }
 395
 396 static const struct iio_chan_spec sc27xx_channels[] = {
 397         SC27XX_ADC_CHANNEL(0, BIT(IIO_CHAN_INFO_PROCESSED)),
 398         SC27XX_ADC_CHANNEL(1, BIT(IIO_CHAN_INFO_PROCESSED)),
 399         SC27XX_ADC_CHANNEL(2, BIT(IIO_CHAN_INFO_PROCESSED)),
 400         SC27XX_ADC_CHANNEL(3, BIT(IIO_CHAN_INFO_PROCESSED)),
 401         SC27XX_ADC_CHANNEL(4, BIT(IIO_CHAN_INFO_PROCESSED)),
 402         SC27XX_ADC_CHANNEL(5, BIT(IIO_CHAN_INFO_PROCESSED)),
 403         SC27XX_ADC_CHANNEL(6, BIT(IIO_CHAN_INFO_PROCESSED)),
 404         SC27XX_ADC_CHANNEL(7, BIT(IIO_CHAN_INFO_PROCESSED)),
 405         SC27XX_ADC_CHANNEL(8, BIT(IIO_CHAN_INFO_PROCESSED)),
 406         SC27XX_ADC_CHANNEL(9, BIT(IIO_CHAN_INFO_PROCESSED)),
 407         SC27XX_ADC_CHANNEL(10, BIT(IIO_CHAN_INFO_PROCESSED)),
 408         SC27XX_ADC_CHANNEL(11, BIT(IIO_CHAN_INFO_PROCESSED)),
 409         SC27XX_ADC_CHANNEL(12, BIT(IIO_CHAN_INFO_PROCESSED)),
 410         SC27XX_ADC_CHANNEL(13, BIT(IIO_CHAN_INFO_PROCESSED)),
 411         SC27XX_ADC_CHANNEL(14, BIT(IIO_CHAN_INFO_PROCESSED)),
 412         SC27XX_ADC_CHANNEL(15, BIT(IIO_CHAN_INFO_PROCESSED)),
 413         SC27XX_ADC_CHANNEL(16, BIT(IIO_CHAN_INFO_PROCESSED)),
 414         SC27XX_ADC_CHANNEL(17, BIT(IIO_CHAN_INFO_PROCESSED)),
 415         SC27XX_ADC_CHANNEL(18, BIT(IIO_CHAN_INFO_PROCESSED)),
 416         SC27XX_ADC_CHANNEL(19, BIT(IIO_CHAN_INFO_PROCESSED)),
 417         SC27XX_ADC_CHANNEL(20, BIT(IIO_CHAN_INFO_RAW)),
 418         SC27XX_ADC_CHANNEL(21, BIT(IIO_CHAN_INFO_PROCESSED)),
 419         SC27XX_ADC_CHANNEL(22, BIT(IIO_CHAN_INFO_PROCESSED)),
 420         SC27XX_ADC_CHANNEL(23, BIT(IIO_CHAN_INFO_PROCESSED)),
 421         SC27XX_ADC_CHANNEL(24, BIT(IIO_CHAN_INFO_PROCESSED)),
 422         SC27XX_ADC_CHANNEL(25, BIT(IIO_CHAN_INFO_PROCESSED)),
 423         SC27XX_ADC_CHANNEL(26, BIT(IIO_CHAN_INFO_PROCESSED)),
 424         SC27XX_ADC_CHANNEL(27, BIT(IIO_CHAN_INFO_PROCESSED)),
 425         SC27XX_ADC_CHANNEL(28, BIT(IIO_CHAN_INFO_PROCESSED)),
 426         SC27XX_ADC_CHANNEL(29, BIT(IIO_CHAN_INFO_PROCESSED)),
 427         SC27XX_ADC_CHANNEL(30, BIT(IIO_CHAN_INFO_PROCESSED)),
 428         SC27XX_ADC_CHANNEL(31, BIT(IIO_CHAN_INFO_PROCESSED)),
 429 };
 430
 431 static int sc27xx_adc_enable(struct sc27xx_adc_data *data)
 432 {
 433         int ret;
 434
 435         ret = regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
 436                                  SC27XX_MODULE_ADC_EN, SC27XX_MODULE_ADC_EN);
 437         if (ret)
 438                 return ret;
 439
 440         /* Enable ADC work clock and controller clock */
 441         ret = regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
 442                                  SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN,
 443                                  SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN);
 444         if (ret)
 445                 goto disable_adc;
 446
 447         ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN,
 448                                  SC27XX_ADC_IRQ_EN, SC27XX_ADC_IRQ_EN);
 449         if (ret)
 450                 goto disable_clk;
 451
 452         /* ADC channel scales' calibration from nvmem device */
 453         ret = sc27xx_adc_scale_calibration(data, true);
 454         if (ret)
 455                 goto disable_clk;
 456
 457         ret = sc27xx_adc_scale_calibration(data, false);
 458         if (ret)
 459                 goto disable_clk;
 460
 461         return 0;
 462
 463 disable_clk:
 464         regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
 465                            SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, 0);
 466 disable_adc:
 467         regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
 468                            SC27XX_MODULE_ADC_EN, 0);
 469
 470         return ret;
 471 }
 472
 473 static void sc27xx_adc_disable(void *_data)
 474 {
 475         struct sc27xx_adc_data *data = _data;
 476
 477         regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN,
 478                            SC27XX_ADC_IRQ_EN, 0);
 479
 480         /* Disable ADC work clock and controller clock */
 481         regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
 482                            SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, 0);
 483
 484         regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
 485                            SC27XX_MODULE_ADC_EN, 0);
 486 }
 487
 488 static void sc27xx_adc_free_hwlock(void *_data)
 489 {
 490         struct hwspinlock *hwlock = _data;
 491
 492         hwspin_lock_free(hwlock);
 493 }
 494
 495 static int sc27xx_adc_probe(struct platform_device *pdev)
 496 {
 497         struct device_node *np = pdev->dev.of_node;
 498         struct sc27xx_adc_data *sc27xx_data;
 499         struct iio_dev *indio_dev;
 500         int ret;
 501
 502         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*sc27xx_data));
 503         if (!indio_dev)
 504                 return -ENOMEM;
 505
 506         sc27xx_data = iio_priv(indio_dev);
 507
 508         sc27xx_data->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 509         if (!sc27xx_data->regmap) {
 510                 dev_err(&pdev->dev, "failed to get ADC regmap\n");
 511                 return -ENODEV;
 512         }
 513
 514         ret = of_property_read_u32(np, "reg", &sc27xx_data->base);
 515         if (ret) {
 516                 dev_err(&pdev->dev, "failed to get ADC base address\n");
 517                 return ret;
 518         }
 519
 520         sc27xx_data->irq = platform_get_irq(pdev, 0);
 521         if (sc27xx_data->irq < 0) {
 522                 dev_err(&pdev->dev, "failed to get ADC irq number\n");
 523                 return sc27xx_data->irq;
 524         }
 525
 526         ret = of_hwspin_lock_get_id(np, 0);
 527         if (ret < 0) {
 528                 dev_err(&pdev->dev, "failed to get hwspinlock id\n");
 529                 return ret;
 530         }
 531
 532         sc27xx_data->hwlock = hwspin_lock_request_specific(ret);
 533         if (!sc27xx_data->hwlock) {
 534                 dev_err(&pdev->dev, "failed to request hwspinlock\n");
 535                 return -ENXIO;
 536         }
 537
 538         ret = devm_add_action(&pdev->dev, sc27xx_adc_free_hwlock,
 539                               sc27xx_data->hwlock);
 540         if (ret) {
 541                 sc27xx_adc_free_hwlock(sc27xx_data->hwlock);
 542                 dev_err(&pdev->dev, "failed to add hwspinlock action\n");
 543                 return ret;
 544         }
 545
 546         init_completion(&sc27xx_data->completion);
 547         sc27xx_data->dev = &pdev->dev;
 548
 549         ret = sc27xx_adc_enable(sc27xx_data);
 550         if (ret) {
 551                 dev_err(&pdev->dev, "failed to enable ADC module\n");
 552                 return ret;
 553         }
 554
 555         ret = devm_add_action(&pdev->dev, sc27xx_adc_disable, sc27xx_data);
 556         if (ret) {
 557                 sc27xx_adc_disable(sc27xx_data);
 558                 dev_err(&pdev->dev, "failed to add ADC disable action\n");
 559                 return ret;
 560         }
 561
 562         ret = devm_request_threaded_irq(&pdev->dev, sc27xx_data->irq, NULL,
 563                                         sc27xx_adc_isr, IRQF_ONESHOT,
 564                                         pdev->name, sc27xx_data);
 565         if (ret) {
 566                 dev_err(&pdev->dev, "failed to request ADC irq\n");
 567                 return ret;
 568         }
 569
 570         indio_dev->dev.parent = &pdev->dev;
 571         indio_dev->name = dev_name(&pdev->dev);
 572         indio_dev->modes = INDIO_DIRECT_MODE;
 573         indio_dev->info = &sc27xx_info;
 574         indio_dev->channels = sc27xx_channels;
 575         indio_dev->num_channels = ARRAY_SIZE(sc27xx_channels);
 576         ret = devm_iio_device_register(&pdev->dev, indio_dev);
 577         if (ret)
 578                 dev_err(&pdev->dev, "could not register iio (ADC)");
 579
 580         return ret;
 581 }
 582
 583 static const struct of_device_id sc27xx_adc_of_match[] = {
 584         { .compatible = "sprd,sc2731-adc", },
 585         { }
 586 };
 587
 588 static struct platform_driver sc27xx_adc_driver = {
 589         .probe = sc27xx_adc_probe,
 590         .driver = {
 591                 .name = "sc27xx-adc",
 592                 .of_match_table = sc27xx_adc_of_match,
 593         },
 594 };
 595
 596 module_platform_driver(sc27xx_adc_driver);
 597
 598 MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>");
 599 MODULE_DESCRIPTION("Spreadtrum SC27XX ADC Driver");
 600 MODULE_LICENSE("GPL v2");