drivers/iio/light/opt3001.c

   1 /**
   2  * opt3001.c - Texas Instruments OPT3001 Light Sensor
   3  *
   4  * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
   5  *
   6  * Author: Andreas Dannenberg <dannenberg@ti.com>
   7  * Based on previous work from: Felipe Balbi <balbi@ti.com>
   8  *
   9  * This program is free software: you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License version 2 of the License
  11  * as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16  * more details.
  17  */
  18
  19 #include <linux/bitops.h>
  20 #include <linux/delay.h>
  21 #include <linux/device.h>
  22 #include <linux/i2c.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/irq.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/mutex.h>
  28 #include <linux/slab.h>
  29 #include <linux/types.h>
  30
  31 #include <linux/iio/events.h>
  32 #include <linux/iio/iio.h>
  33 #include <linux/iio/sysfs.h>
  34
  35 #define OPT3001_RESULT          0x00
  36 #define OPT3001_CONFIGURATION   0x01
  37 #define OPT3001_LOW_LIMIT       0x02
  38 #define OPT3001_HIGH_LIMIT      0x03
  39 #define OPT3001_MANUFACTURER_ID 0x7e
  40 #define OPT3001_DEVICE_ID       0x7f
  41
  42 #define OPT3001_CONFIGURATION_RN_MASK   (0xf << 12)
  43 #define OPT3001_CONFIGURATION_RN_AUTO   (0xc << 12)
  44
  45 #define OPT3001_CONFIGURATION_CT        BIT(11)
  46
  47 #define OPT3001_CONFIGURATION_M_MASK    (3 << 9)
  48 #define OPT3001_CONFIGURATION_M_SHUTDOWN (0 << 9)
  49 #define OPT3001_CONFIGURATION_M_SINGLE  (1 << 9)
  50 #define OPT3001_CONFIGURATION_M_CONTINUOUS (2 << 9) /* also 3 << 9 */
  51
  52 #define OPT3001_CONFIGURATION_OVF       BIT(8)
  53 #define OPT3001_CONFIGURATION_CRF       BIT(7)
  54 #define OPT3001_CONFIGURATION_FH        BIT(6)
  55 #define OPT3001_CONFIGURATION_FL        BIT(5)
  56 #define OPT3001_CONFIGURATION_L         BIT(4)
  57 #define OPT3001_CONFIGURATION_POL       BIT(3)
  58 #define OPT3001_CONFIGURATION_ME        BIT(2)
  59
  60 #define OPT3001_CONFIGURATION_FC_MASK   (3 << 0)
  61
  62 /* The end-of-conversion enable is located in the low-limit register */
  63 #define OPT3001_LOW_LIMIT_EOC_ENABLE    0xc000
  64
  65 #define OPT3001_REG_EXPONENT(n)         ((n) >> 12)
  66 #define OPT3001_REG_MANTISSA(n)         ((n) & 0xfff)
  67
  68 #define OPT3001_INT_TIME_LONG           800000
  69 #define OPT3001_INT_TIME_SHORT          100000
  70
  71 /*
  72  * Time to wait for conversion result to be ready. The device datasheet
  73  * sect. 6.5 states results are ready after total integration time plus 3ms.
  74  * This results in worst-case max values of 113ms or 883ms, respectively.
  75  * Add some slack to be on the safe side.
  76  */
  77 #define OPT3001_RESULT_READY_SHORT      150
  78 #define OPT3001_RESULT_READY_LONG       1000
  79
  80 struct opt3001 {
  81         struct i2c_client       *client;
  82         struct device           *dev;
  83
  84         struct mutex            lock;
  85         bool                    ok_to_ignore_lock;
  86         bool                    result_ready;
  87         wait_queue_head_t       result_ready_queue;
  88         u16                     result;
  89
  90         u32                     int_time;
  91         u32                     mode;
  92
  93         u16                     high_thresh_mantissa;
  94         u16                     low_thresh_mantissa;
  95
  96         u8                      high_thresh_exp;
  97         u8                      low_thresh_exp;
  98
  99         bool                    use_irq;
 100 };
 101
 102 struct opt3001_scale {
 103         int     val;
 104         int     val2;
 105 };
 106
 107 static const struct opt3001_scale opt3001_scales[] = {
 108         {
 109                 .val = 40,
 110                 .val2 = 950000,
 111         },
 112         {
 113                 .val = 81,
 114                 .val2 = 900000,
 115         },
 116         {
 117                 .val = 163,
 118                 .val2 = 800000,
 119         },
 120         {
 121                 .val = 327,
 122                 .val2 = 600000,
 123         },
 124         {
 125                 .val = 655,
 126                 .val2 = 200000,
 127         },
 128         {
 129                 .val = 1310,
 130                 .val2 = 400000,
 131         },
 132         {
 133                 .val = 2620,
 134                 .val2 = 800000,
 135         },
 136         {
 137                 .val = 5241,
 138                 .val2 = 600000,
 139         },
 140         {
 141                 .val = 10483,
 142                 .val2 = 200000,
 143         },
 144         {
 145                 .val = 20966,
 146                 .val2 = 400000,
 147         },
 148         {
 149                 .val = 83865,
 150                 .val2 = 600000,
 151         },
 152 };
 153
 154 static int opt3001_find_scale(const struct opt3001 *opt, int val,
 155                 int val2, u8 *exponent)
 156 {
 157         int i;
 158
 159         for (i = 0; i < ARRAY_SIZE(opt3001_scales); i++) {
 160                 const struct opt3001_scale *scale = &opt3001_scales[i];
 161
 162                 /*
 163                  * Combine the integer and micro parts for comparison
 164                  * purposes. Use milli lux precision to avoid 32-bit integer
 165                  * overflows.
 166                  */
 167                 if ((val * 1000 + val2 / 1000) <=
 168                                 (scale->val * 1000 + scale->val2 / 1000)) {
 169                         *exponent = i;
 170                         return 0;
 171                 }
 172         }
 173
 174         return -EINVAL;
 175 }
 176
 177 static void opt3001_to_iio_ret(struct opt3001 *opt, u8 exponent,
 178                 u16 mantissa, int *val, int *val2)
 179 {
 180         int lux;
 181
 182         lux = 10 * (mantissa << exponent);
 183         *val = lux / 1000;
 184         *val2 = (lux - (*val * 1000)) * 1000;
 185 }
 186
 187 static void opt3001_set_mode(struct opt3001 *opt, u16 *reg, u16 mode)
 188 {
 189         *reg &= ~OPT3001_CONFIGURATION_M_MASK;
 190         *reg |= mode;
 191         opt->mode = mode;
 192 }
 193
 194 static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.8");
 195
 196 static struct attribute *opt3001_attributes[] = {
 197         &iio_const_attr_integration_time_available.dev_attr.attr,
 198         NULL
 199 };
 200
 201 static const struct attribute_group opt3001_attribute_group = {
 202         .attrs = opt3001_attributes,
 203 };
 204
 205 static const struct iio_event_spec opt3001_event_spec[] = {
 206         {
 207                 .type = IIO_EV_TYPE_THRESH,
 208                 .dir = IIO_EV_DIR_RISING,
 209                 .mask_separate = BIT(IIO_EV_INFO_VALUE) |
 210                         BIT(IIO_EV_INFO_ENABLE),
 211         },
 212         {
 213                 .type = IIO_EV_TYPE_THRESH,
 214                 .dir = IIO_EV_DIR_FALLING,
 215                 .mask_separate = BIT(IIO_EV_INFO_VALUE) |
 216                         BIT(IIO_EV_INFO_ENABLE),
 217         },
 218 };
 219
 220 static const struct iio_chan_spec opt3001_channels[] = {
 221         {
 222                 .type = IIO_LIGHT,
 223                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 224                                 BIT(IIO_CHAN_INFO_INT_TIME),
 225                 .event_spec = opt3001_event_spec,
 226                 .num_event_specs = ARRAY_SIZE(opt3001_event_spec),
 227         },
 228         IIO_CHAN_SOFT_TIMESTAMP(1),
 229 };
 230
 231 static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2)
 232 {
 233         int ret;
 234         u16 mantissa;
 235         u16 reg;
 236         u8 exponent;
 237         u16 value;
 238         long timeout;
 239
 240         if (opt->use_irq) {
 241                 /*
 242                  * Enable the end-of-conversion interrupt mechanism. Note that
 243                  * doing so will overwrite the low-level limit value however we
 244                  * will restore this value later on.
 245                  */
 246                 ret = i2c_smbus_write_word_swapped(opt->client,
 247                                         OPT3001_LOW_LIMIT,
 248                                         OPT3001_LOW_LIMIT_EOC_ENABLE);
 249                 if (ret < 0) {
 250                         dev_err(opt->dev, "failed to write register %02x\n",
 251                                         OPT3001_LOW_LIMIT);
 252                         return ret;
 253                 }
 254
 255                 /* Allow IRQ to access the device despite lock being set */
 256                 opt->ok_to_ignore_lock = true;
 257         }
 258
 259         /* Reset data-ready indicator flag */
 260         opt->result_ready = false;
 261
 262         /* Configure for single-conversion mode and start a new conversion */
 263         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
 264         if (ret < 0) {
 265                 dev_err(opt->dev, "failed to read register %02x\n",
 266                                 OPT3001_CONFIGURATION);
 267                 goto err;
 268         }
 269
 270         reg = ret;
 271         opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SINGLE);
 272
 273         ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
 274                         reg);
 275         if (ret < 0) {
 276                 dev_err(opt->dev, "failed to write register %02x\n",
 277                                 OPT3001_CONFIGURATION);
 278                 goto err;
 279         }
 280
 281         if (opt->use_irq) {
 282                 /* Wait for the IRQ to indicate the conversion is complete */
 283                 ret = wait_event_timeout(opt->result_ready_queue,
 284                                 opt->result_ready,
 285                                 msecs_to_jiffies(OPT3001_RESULT_READY_LONG));
 286         } else {
 287                 /* Sleep for result ready time */
 288                 timeout = (opt->int_time == OPT3001_INT_TIME_SHORT) ?
 289                         OPT3001_RESULT_READY_SHORT : OPT3001_RESULT_READY_LONG;
 290                 msleep(timeout);
 291
 292                 /* Check result ready flag */
 293                 ret = i2c_smbus_read_word_swapped(opt->client,
 294                                                   OPT3001_CONFIGURATION);
 295                 if (ret < 0) {
 296                         dev_err(opt->dev, "failed to read register %02x\n",
 297                                 OPT3001_CONFIGURATION);
 298                         goto err;
 299                 }
 300
 301                 if (!(ret & OPT3001_CONFIGURATION_CRF)) {
 302                         ret = -ETIMEDOUT;
 303                         goto err;
 304                 }
 305
 306                 /* Obtain value */
 307                 ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
 308                 if (ret < 0) {
 309                         dev_err(opt->dev, "failed to read register %02x\n",
 310                                 OPT3001_RESULT);
 311                         goto err;
 312                 }
 313                 opt->result = ret;
 314                 opt->result_ready = true;
 315         }
 316
 317 err:
 318         if (opt->use_irq)
 319                 /* Disallow IRQ to access the device while lock is active */
 320                 opt->ok_to_ignore_lock = false;
 321
 322         if (ret == 0)
 323                 return -ETIMEDOUT;
 324         else if (ret < 0)
 325                 return ret;
 326
 327         if (opt->use_irq) {
 328                 /*
 329                  * Disable the end-of-conversion interrupt mechanism by
 330                  * restoring the low-level limit value (clearing
 331                  * OPT3001_LOW_LIMIT_EOC_ENABLE). Note that selectively clearing
 332                  * those enable bits would affect the actual limit value due to
 333                  * bit-overlap and therefore can't be done.
 334                  */
 335                 value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa;
 336                 ret = i2c_smbus_write_word_swapped(opt->client,
 337                                                    OPT3001_LOW_LIMIT,
 338                                                    value);
 339                 if (ret < 0) {
 340                         dev_err(opt->dev, "failed to write register %02x\n",
 341                                         OPT3001_LOW_LIMIT);
 342                         return ret;
 343                 }
 344         }
 345
 346         exponent = OPT3001_REG_EXPONENT(opt->result);
 347         mantissa = OPT3001_REG_MANTISSA(opt->result);
 348
 349         opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);
 350
 351         return IIO_VAL_INT_PLUS_MICRO;
 352 }
 353
 354 static int opt3001_get_int_time(struct opt3001 *opt, int *val, int *val2)
 355 {
 356         *val = 0;
 357         *val2 = opt->int_time;
 358
 359         return IIO_VAL_INT_PLUS_MICRO;
 360 }
 361
 362 static int opt3001_set_int_time(struct opt3001 *opt, int time)
 363 {
 364         int ret;
 365         u16 reg;
 366
 367         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
 368         if (ret < 0) {
 369                 dev_err(opt->dev, "failed to read register %02x\n",
 370                                 OPT3001_CONFIGURATION);
 371                 return ret;
 372         }
 373
 374         reg = ret;
 375
 376         switch (time) {
 377         case OPT3001_INT_TIME_SHORT:
 378                 reg &= ~OPT3001_CONFIGURATION_CT;
 379                 opt->int_time = OPT3001_INT_TIME_SHORT;
 380                 break;
 381         case OPT3001_INT_TIME_LONG:
 382                 reg |= OPT3001_CONFIGURATION_CT;
 383                 opt->int_time = OPT3001_INT_TIME_LONG;
 384                 break;
 385         default:
 386                 return -EINVAL;
 387         }
 388
 389         return i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
 390                         reg);
 391 }
 392
 393 static int opt3001_read_raw(struct iio_dev *iio,
 394                 struct iio_chan_spec const *chan, int *val, int *val2,
 395                 long mask)
 396 {
 397         struct opt3001 *opt = iio_priv(iio);
 398         int ret;
 399
 400         if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
 401                 return -EBUSY;
 402
 403         if (chan->type != IIO_LIGHT)
 404                 return -EINVAL;
 405
 406         mutex_lock(&opt->lock);
 407
 408         switch (mask) {
 409         case IIO_CHAN_INFO_PROCESSED:
 410                 ret = opt3001_get_lux(opt, val, val2);
 411                 break;
 412         case IIO_CHAN_INFO_INT_TIME:
 413                 ret = opt3001_get_int_time(opt, val, val2);
 414                 break;
 415         default:
 416                 ret = -EINVAL;
 417         }
 418
 419         mutex_unlock(&opt->lock);
 420
 421         return ret;
 422 }
 423
 424 static int opt3001_write_raw(struct iio_dev *iio,
 425                 struct iio_chan_spec const *chan, int val, int val2,
 426                 long mask)
 427 {
 428         struct opt3001 *opt = iio_priv(iio);
 429         int ret;
 430
 431         if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
 432                 return -EBUSY;
 433
 434         if (chan->type != IIO_LIGHT)
 435                 return -EINVAL;
 436
 437         if (mask != IIO_CHAN_INFO_INT_TIME)
 438                 return -EINVAL;
 439
 440         if (val != 0)
 441                 return -EINVAL;
 442
 443         mutex_lock(&opt->lock);
 444         ret = opt3001_set_int_time(opt, val2);
 445         mutex_unlock(&opt->lock);
 446
 447         return ret;
 448 }
 449
 450 static int opt3001_read_event_value(struct iio_dev *iio,
 451                 const struct iio_chan_spec *chan, enum iio_event_type type,
 452                 enum iio_event_direction dir, enum iio_event_info info,
 453                 int *val, int *val2)
 454 {
 455         struct opt3001 *opt = iio_priv(iio);
 456         int ret = IIO_VAL_INT_PLUS_MICRO;
 457
 458         mutex_lock(&opt->lock);
 459
 460         switch (dir) {
 461         case IIO_EV_DIR_RISING:
 462                 opt3001_to_iio_ret(opt, opt->high_thresh_exp,
 463                                 opt->high_thresh_mantissa, val, val2);
 464                 break;
 465         case IIO_EV_DIR_FALLING:
 466                 opt3001_to_iio_ret(opt, opt->low_thresh_exp,
 467                                 opt->low_thresh_mantissa, val, val2);
 468                 break;
 469         default:
 470                 ret = -EINVAL;
 471         }
 472
 473         mutex_unlock(&opt->lock);
 474
 475         return ret;
 476 }
 477
 478 static int opt3001_write_event_value(struct iio_dev *iio,
 479                 const struct iio_chan_spec *chan, enum iio_event_type type,
 480                 enum iio_event_direction dir, enum iio_event_info info,
 481                 int val, int val2)
 482 {
 483         struct opt3001 *opt = iio_priv(iio);
 484         int ret;
 485
 486         u16 mantissa;
 487         u16 value;
 488         u16 reg;
 489
 490         u8 exponent;
 491
 492         if (val < 0)
 493                 return -EINVAL;
 494
 495         mutex_lock(&opt->lock);
 496
 497         ret = opt3001_find_scale(opt, val, val2, &exponent);
 498         if (ret < 0) {
 499                 dev_err(opt->dev, "can't find scale for %d.%06u\n", val, val2);
 500                 goto err;
 501         }
 502
 503         mantissa = (((val * 1000) + (val2 / 1000)) / 10) >> exponent;
 504         value = (exponent << 12) | mantissa;
 505
 506         switch (dir) {
 507         case IIO_EV_DIR_RISING:
 508                 reg = OPT3001_HIGH_LIMIT;
 509                 opt->high_thresh_mantissa = mantissa;
 510                 opt->high_thresh_exp = exponent;
 511                 break;
 512         case IIO_EV_DIR_FALLING:
 513                 reg = OPT3001_LOW_LIMIT;
 514                 opt->low_thresh_mantissa = mantissa;
 515                 opt->low_thresh_exp = exponent;
 516                 break;
 517         default:
 518                 ret = -EINVAL;
 519                 goto err;
 520         }
 521
 522         ret = i2c_smbus_write_word_swapped(opt->client, reg, value);
 523         if (ret < 0) {
 524                 dev_err(opt->dev, "failed to write register %02x\n", reg);
 525                 goto err;
 526         }
 527
 528 err:
 529         mutex_unlock(&opt->lock);
 530
 531         return ret;
 532 }
 533
 534 static int opt3001_read_event_config(struct iio_dev *iio,
 535                 const struct iio_chan_spec *chan, enum iio_event_type type,
 536                 enum iio_event_direction dir)
 537 {
 538         struct opt3001 *opt = iio_priv(iio);
 539
 540         return opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS;
 541 }
 542
 543 static int opt3001_write_event_config(struct iio_dev *iio,
 544                 const struct iio_chan_spec *chan, enum iio_event_type type,
 545                 enum iio_event_direction dir, int state)
 546 {
 547         struct opt3001 *opt = iio_priv(iio);
 548         int ret;
 549         u16 mode;
 550         u16 reg;
 551
 552         if (state && opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
 553                 return 0;
 554
 555         if (!state && opt->mode == OPT3001_CONFIGURATION_M_SHUTDOWN)
 556                 return 0;
 557
 558         mutex_lock(&opt->lock);
 559
 560         mode = state ? OPT3001_CONFIGURATION_M_CONTINUOUS
 561                 : OPT3001_CONFIGURATION_M_SHUTDOWN;
 562
 563         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
 564         if (ret < 0) {
 565                 dev_err(opt->dev, "failed to read register %02x\n",
 566                                 OPT3001_CONFIGURATION);
 567                 goto err;
 568         }
 569
 570         reg = ret;
 571         opt3001_set_mode(opt, &reg, mode);
 572
 573         ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
 574                         reg);
 575         if (ret < 0) {
 576                 dev_err(opt->dev, "failed to write register %02x\n",
 577                                 OPT3001_CONFIGURATION);
 578                 goto err;
 579         }
 580
 581 err:
 582         mutex_unlock(&opt->lock);
 583
 584         return ret;
 585 }
 586
 587 static const struct iio_info opt3001_info = {
 588         .driver_module = THIS_MODULE,
 589         .attrs = &opt3001_attribute_group,
 590         .read_raw = opt3001_read_raw,
 591         .write_raw = opt3001_write_raw,
 592         .read_event_value = opt3001_read_event_value,
 593         .write_event_value = opt3001_write_event_value,
 594         .read_event_config = opt3001_read_event_config,
 595         .write_event_config = opt3001_write_event_config,
 596 };
 597
 598 static int opt3001_read_id(struct opt3001 *opt)
 599 {
 600         char manufacturer[2];
 601         u16 device_id;
 602         int ret;
 603
 604         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_MANUFACTURER_ID);
 605         if (ret < 0) {
 606                 dev_err(opt->dev, "failed to read register %02x\n",
 607                                 OPT3001_MANUFACTURER_ID);
 608                 return ret;
 609         }
 610
 611         manufacturer[0] = ret >> 8;
 612         manufacturer[1] = ret & 0xff;
 613
 614         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_DEVICE_ID);
 615         if (ret < 0) {
 616                 dev_err(opt->dev, "failed to read register %02x\n",
 617                                 OPT3001_DEVICE_ID);
 618                 return ret;
 619         }
 620
 621         device_id = ret;
 622
 623         dev_info(opt->dev, "Found %c%c OPT%04x\n", manufacturer[0],
 624                         manufacturer[1], device_id);
 625
 626         return 0;
 627 }
 628
 629 static int opt3001_configure(struct opt3001 *opt)
 630 {
 631         int ret;
 632         u16 reg;
 633
 634         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
 635         if (ret < 0) {
 636                 dev_err(opt->dev, "failed to read register %02x\n",
 637                                 OPT3001_CONFIGURATION);
 638                 return ret;
 639         }
 640
 641         reg = ret;
 642
 643         /* Enable automatic full-scale setting mode */
 644         reg &= ~OPT3001_CONFIGURATION_RN_MASK;
 645         reg |= OPT3001_CONFIGURATION_RN_AUTO;
 646
 647         /* Reflect status of the device's integration time setting */
 648         if (reg & OPT3001_CONFIGURATION_CT)
 649                 opt->int_time = OPT3001_INT_TIME_LONG;
 650         else
 651                 opt->int_time = OPT3001_INT_TIME_SHORT;
 652
 653         /* Ensure device is in shutdown initially */
 654         opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
 655
 656         /* Configure for latched window-style comparison operation */
 657         reg |= OPT3001_CONFIGURATION_L;
 658         reg &= ~OPT3001_CONFIGURATION_POL;
 659         reg &= ~OPT3001_CONFIGURATION_ME;
 660         reg &= ~OPT3001_CONFIGURATION_FC_MASK;
 661
 662         ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
 663                         reg);
 664         if (ret < 0) {
 665                 dev_err(opt->dev, "failed to write register %02x\n",
 666                                 OPT3001_CONFIGURATION);
 667                 return ret;
 668         }
 669
 670         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_LOW_LIMIT);
 671         if (ret < 0) {
 672                 dev_err(opt->dev, "failed to read register %02x\n",
 673                                 OPT3001_LOW_LIMIT);
 674                 return ret;
 675         }
 676
 677         opt->low_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
 678         opt->low_thresh_exp = OPT3001_REG_EXPONENT(ret);
 679
 680         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_HIGH_LIMIT);
 681         if (ret < 0) {
 682                 dev_err(opt->dev, "failed to read register %02x\n",
 683                                 OPT3001_HIGH_LIMIT);
 684                 return ret;
 685         }
 686
 687         opt->high_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
 688         opt->high_thresh_exp = OPT3001_REG_EXPONENT(ret);
 689
 690         return 0;
 691 }
 692
 693 static irqreturn_t opt3001_irq(int irq, void *_iio)
 694 {
 695         struct iio_dev *iio = _iio;
 696         struct opt3001 *opt = iio_priv(iio);
 697         int ret;
 698
 699         if (!opt->ok_to_ignore_lock)
 700                 mutex_lock(&opt->lock);
 701
 702         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
 703         if (ret < 0) {
 704                 dev_err(opt->dev, "failed to read register %02x\n",
 705                                 OPT3001_CONFIGURATION);
 706                 goto out;
 707         }
 708
 709         if ((ret & OPT3001_CONFIGURATION_M_MASK) ==
 710                         OPT3001_CONFIGURATION_M_CONTINUOUS) {
 711                 if (ret & OPT3001_CONFIGURATION_FH)
 712                         iio_push_event(iio,
 713                                         IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
 714                                                         IIO_EV_TYPE_THRESH,
 715                                                         IIO_EV_DIR_RISING),
 716                                         iio_get_time_ns(iio));
 717                 if (ret & OPT3001_CONFIGURATION_FL)
 718                         iio_push_event(iio,
 719                                         IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
 720                                                         IIO_EV_TYPE_THRESH,
 721                                                         IIO_EV_DIR_FALLING),
 722                                         iio_get_time_ns(iio));
 723         } else if (ret & OPT3001_CONFIGURATION_CRF) {
 724                 ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
 725                 if (ret < 0) {
 726                         dev_err(opt->dev, "failed to read register %02x\n",
 727                                         OPT3001_RESULT);
 728                         goto out;
 729                 }
 730                 opt->result = ret;
 731                 opt->result_ready = true;
 732                 wake_up(&opt->result_ready_queue);
 733         }
 734
 735 out:
 736         if (!opt->ok_to_ignore_lock)
 737                 mutex_unlock(&opt->lock);
 738
 739         return IRQ_HANDLED;
 740 }
 741
 742 static int opt3001_probe(struct i2c_client *client,
 743                 const struct i2c_device_id *id)
 744 {
 745         struct device *dev = &client->dev;
 746
 747         struct iio_dev *iio;
 748         struct opt3001 *opt;
 749         int irq = client->irq;
 750         int ret;
 751
 752         iio = devm_iio_device_alloc(dev, sizeof(*opt));
 753         if (!iio)
 754                 return -ENOMEM;
 755
 756         opt = iio_priv(iio);
 757         opt->client = client;
 758         opt->dev = dev;
 759
 760         mutex_init(&opt->lock);
 761         init_waitqueue_head(&opt->result_ready_queue);
 762         i2c_set_clientdata(client, iio);
 763
 764         ret = opt3001_read_id(opt);
 765         if (ret)
 766                 return ret;
 767
 768         ret = opt3001_configure(opt);
 769         if (ret)
 770                 return ret;
 771
 772         iio->name = client->name;
 773         iio->channels = opt3001_channels;
 774         iio->num_channels = ARRAY_SIZE(opt3001_channels);
 775         iio->dev.parent = dev;
 776         iio->modes = INDIO_DIRECT_MODE;
 777         iio->info = &opt3001_info;
 778
 779         ret = devm_iio_device_register(dev, iio);
 780         if (ret) {
 781                 dev_err(dev, "failed to register IIO device\n");
 782                 return ret;
 783         }
 784
 785         /* Make use of INT pin only if valid IRQ no. is given */
 786         if (irq > 0) {
 787                 ret = request_threaded_irq(irq, NULL, opt3001_irq,
 788                                 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 789                                 "opt3001", iio);
 790                 if (ret) {
 791                         dev_err(dev, "failed to request IRQ #%d\n", irq);
 792                         return ret;
 793                 }
 794                 opt->use_irq = true;
 795         } else {
 796                 dev_dbg(opt->dev, "enabling interrupt-less operation\n");
 797         }
 798
 799         return 0;
 800 }
 801
 802 static int opt3001_remove(struct i2c_client *client)
 803 {
 804         struct iio_dev *iio = i2c_get_clientdata(client);
 805         struct opt3001 *opt = iio_priv(iio);
 806         int ret;
 807         u16 reg;
 808
 809         if (opt->use_irq)
 810                 free_irq(client->irq, iio);
 811
 812         ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
 813         if (ret < 0) {
 814                 dev_err(opt->dev, "failed to read register %02x\n",
 815                                 OPT3001_CONFIGURATION);
 816                 return ret;
 817         }
 818
 819         reg = ret;
 820         opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
 821
 822         ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
 823                         reg);
 824         if (ret < 0) {
 825                 dev_err(opt->dev, "failed to write register %02x\n",
 826                                 OPT3001_CONFIGURATION);
 827                 return ret;
 828         }
 829
 830         return 0;
 831 }
 832
 833 static const struct i2c_device_id opt3001_id[] = {
 834         { "opt3001", 0 },
 835         { } /* Terminating Entry */
 836 };
 837 MODULE_DEVICE_TABLE(i2c, opt3001_id);
 838
 839 static const struct of_device_id opt3001_of_match[] = {
 840         { .compatible = "ti,opt3001" },
 841         { }
 842 };
 843 MODULE_DEVICE_TABLE(of, opt3001_of_match);
 844
 845 static struct i2c_driver opt3001_driver = {
 846         .probe = opt3001_probe,
 847         .remove = opt3001_remove,
 848         .id_table = opt3001_id,
 849
 850         .driver = {
 851                 .name = "opt3001",
 852                 .of_match_table = of_match_ptr(opt3001_of_match),
 853         },
 854 };
 855
 856 module_i2c_driver(opt3001_driver);
 857
 858 MODULE_LICENSE("GPL v2");
 859 MODULE_AUTHOR("Andreas Dannenberg <dannenberg@ti.com>");
 860 MODULE_DESCRIPTION("Texas Instruments OPT3001 Light Sensor Driver");