drivers/staging/iio/cdc/ad7746.c

   1 /*
   2  * AD7746 capacitive sensor driver supporting AD7745, AD7746 and AD7747
   3  *
   4  * Copyright 2011 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/i2c.h>
  15 #include <linux/delay.h>
  16 #include <linux/module.h>
  17 #include <linux/stat.h>
  18
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/sysfs.h>
  21
  22 #include "ad7746.h"
  23
  24 /*
  25  * AD7746 Register Definition
  26  */
  27
  28 #define AD7746_REG_STATUS               0
  29 #define AD7746_REG_CAP_DATA_HIGH        1
  30 #define AD7746_REG_CAP_DATA_MID         2
  31 #define AD7746_REG_CAP_DATA_LOW         3
  32 #define AD7746_REG_VT_DATA_HIGH         4
  33 #define AD7746_REG_VT_DATA_MID          5
  34 #define AD7746_REG_VT_DATA_LOW          6
  35 #define AD7746_REG_CAP_SETUP            7
  36 #define AD7746_REG_VT_SETUP             8
  37 #define AD7746_REG_EXC_SETUP            9
  38 #define AD7746_REG_CFG                  10
  39 #define AD7746_REG_CAPDACA              11
  40 #define AD7746_REG_CAPDACB              12
  41 #define AD7746_REG_CAP_OFFH             13
  42 #define AD7746_REG_CAP_OFFL             14
  43 #define AD7746_REG_CAP_GAINH            15
  44 #define AD7746_REG_CAP_GAINL            16
  45 #define AD7746_REG_VOLT_GAINH           17
  46 #define AD7746_REG_VOLT_GAINL           18
  47
  48 /* Status Register Bit Designations (AD7746_REG_STATUS) */
  49 #define AD7746_STATUS_EXCERR            (1 << 3)
  50 #define AD7746_STATUS_RDY               (1 << 2)
  51 #define AD7746_STATUS_RDYVT             (1 << 1)
  52 #define AD7746_STATUS_RDYCAP            (1 << 0)
  53
  54 /* Capacitive Channel Setup Register Bit Designations (AD7746_REG_CAP_SETUP) */
  55 #define AD7746_CAPSETUP_CAPEN           (1 << 7)
  56 #define AD7746_CAPSETUP_CIN2            (1 << 6) /* AD7746 only */
  57 #define AD7746_CAPSETUP_CAPDIFF         (1 << 5)
  58 #define AD7746_CAPSETUP_CACHOP          (1 << 0)
  59
  60 /* Voltage/Temperature Setup Register Bit Designations (AD7746_REG_VT_SETUP) */
  61 #define AD7746_VTSETUP_VTEN             (1 << 7)
  62 #define AD7746_VTSETUP_VTMD_INT_TEMP    (0 << 5)
  63 #define AD7746_VTSETUP_VTMD_EXT_TEMP    (1 << 5)
  64 #define AD7746_VTSETUP_VTMD_VDD_MON     (2 << 5)
  65 #define AD7746_VTSETUP_VTMD_EXT_VIN     (3 << 5)
  66 #define AD7746_VTSETUP_EXTREF           (1 << 4)
  67 #define AD7746_VTSETUP_VTSHORT          (1 << 1)
  68 #define AD7746_VTSETUP_VTCHOP           (1 << 0)
  69
  70 /* Excitation Setup Register Bit Designations (AD7746_REG_EXC_SETUP) */
  71 #define AD7746_EXCSETUP_CLKCTRL         (1 << 7)
  72 #define AD7746_EXCSETUP_EXCON           (1 << 6)
  73 #define AD7746_EXCSETUP_EXCB            (1 << 5)
  74 #define AD7746_EXCSETUP_NEXCB           (1 << 4)
  75 #define AD7746_EXCSETUP_EXCA            (1 << 3)
  76 #define AD7746_EXCSETUP_NEXCA           (1 << 2)
  77 #define AD7746_EXCSETUP_EXCLVL(x)       (((x) & 0x3) << 0)
  78
  79 /* Config Register Bit Designations (AD7746_REG_CFG) */
  80 #define AD7746_CONF_VTFS(x)             ((x) << 6)
  81 #define AD7746_CONF_CAPFS(x)            ((x) << 3)
  82 #define AD7746_CONF_MODE_IDLE           (0 << 0)
  83 #define AD7746_CONF_MODE_CONT_CONV      (1 << 0)
  84 #define AD7746_CONF_MODE_SINGLE_CONV    (2 << 0)
  85 #define AD7746_CONF_MODE_PWRDN          (3 << 0)
  86 #define AD7746_CONF_MODE_OFFS_CAL       (5 << 0)
  87 #define AD7746_CONF_MODE_GAIN_CAL       (6 << 0)
  88
  89 /* CAPDAC Register Bit Designations (AD7746_REG_CAPDACx) */
  90 #define AD7746_CAPDAC_DACEN             (1 << 7)
  91 #define AD7746_CAPDAC_DACP(x)           ((x) & 0x7F)
  92
  93 /*
  94  * struct ad7746_chip_info - chip specifc information
  95  */
  96
  97 struct ad7746_chip_info {
  98         struct i2c_client *client;
  99         /*
 100          * Capacitive channel digital filter setup;
 101          * conversion time/update rate setup per channel
 102          */
 103         u8      config;
 104         u8      cap_setup;
 105         u8      vt_setup;
 106         u8      capdac[2][2];
 107         s8      capdac_set;
 108 };
 109
 110 enum ad7746_chan {
 111         VIN,
 112         VIN_VDD,
 113         TEMP_INT,
 114         TEMP_EXT,
 115         CIN1,
 116         CIN1_DIFF,
 117         CIN2,
 118         CIN2_DIFF,
 119 };
 120
 121 static const struct iio_chan_spec ad7746_channels[] = {
 122         [VIN] = {
 123                 .type = IIO_VOLTAGE,
 124                 .indexed = 1,
 125                 .channel = 0,
 126                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 127                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 128                 .address = AD7746_REG_VT_DATA_HIGH << 8 |
 129                         AD7746_VTSETUP_VTMD_EXT_VIN,
 130         },
 131         [VIN_VDD] = {
 132                 .type = IIO_VOLTAGE,
 133                 .indexed = 1,
 134                 .channel = 1,
 135                 .extend_name = "supply",
 136                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 137                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 138                 .address = AD7746_REG_VT_DATA_HIGH << 8 |
 139                         AD7746_VTSETUP_VTMD_VDD_MON,
 140         },
 141         [TEMP_INT] = {
 142                 .type = IIO_TEMP,
 143                 .indexed = 1,
 144                 .channel = 0,
 145                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 146                 .address = AD7746_REG_VT_DATA_HIGH << 8 |
 147                         AD7746_VTSETUP_VTMD_INT_TEMP,
 148         },
 149         [TEMP_EXT] = {
 150                 .type = IIO_TEMP,
 151                 .indexed = 1,
 152                 .channel = 1,
 153                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
 154                 .address = AD7746_REG_VT_DATA_HIGH << 8 |
 155                         AD7746_VTSETUP_VTMD_EXT_TEMP,
 156         },
 157         [CIN1] = {
 158                 .type = IIO_CAPACITANCE,
 159                 .indexed = 1,
 160                 .channel = 0,
 161                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 162                 BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 163                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 164                 BIT(IIO_CHAN_INFO_SCALE),
 165                 .address = AD7746_REG_CAP_DATA_HIGH << 8,
 166         },
 167         [CIN1_DIFF] = {
 168                 .type = IIO_CAPACITANCE,
 169                 .differential = 1,
 170                 .indexed = 1,
 171                 .channel = 0,
 172                 .channel2 = 2,
 173                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 174                 BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 175                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 176                 BIT(IIO_CHAN_INFO_SCALE),
 177                 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
 178                         AD7746_CAPSETUP_CAPDIFF
 179         },
 180         [CIN2] = {
 181                 .type = IIO_CAPACITANCE,
 182                 .indexed = 1,
 183                 .channel = 1,
 184                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 185                 BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 186                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 187                 BIT(IIO_CHAN_INFO_SCALE),
 188                 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
 189                         AD7746_CAPSETUP_CIN2,
 190         },
 191         [CIN2_DIFF] = {
 192                 .type = IIO_CAPACITANCE,
 193                 .differential = 1,
 194                 .indexed = 1,
 195                 .channel = 1,
 196                 .channel2 = 3,
 197                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 198                 BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 199                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 200                 BIT(IIO_CHAN_INFO_SCALE),
 201                 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
 202                         AD7746_CAPSETUP_CAPDIFF | AD7746_CAPSETUP_CIN2,
 203         }
 204 };
 205
 206 /* Values are Update Rate (Hz), Conversion Time (ms) + 1*/
 207 static const unsigned char ad7746_vt_filter_rate_table[][2] = {
 208         {50, 20 + 1}, {31, 32 + 1}, {16, 62 + 1}, {8, 122 + 1},
 209 };
 210
 211 static const unsigned char ad7746_cap_filter_rate_table[][2] = {
 212         {91, 11 + 1}, {84, 12 + 1}, {50, 20 + 1}, {26, 38 + 1},
 213         {16, 62 + 1}, {13, 77 + 1}, {11, 92 + 1}, {9, 110 + 1},
 214 };
 215
 216 static int ad7746_select_channel(struct iio_dev *indio_dev,
 217                             struct iio_chan_spec const *chan)
 218 {
 219         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 220         int ret, delay;
 221         u8 vt_setup, cap_setup;
 222
 223         switch (chan->type) {
 224         case IIO_CAPACITANCE:
 225                 cap_setup = (chan->address & 0xFF) | AD7746_CAPSETUP_CAPEN;
 226                 vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
 227                 delay = ad7746_cap_filter_rate_table[(chip->config >> 3) &
 228                         0x7][1];
 229
 230                 if (chip->capdac_set != chan->channel) {
 231                         ret = i2c_smbus_write_byte_data(chip->client,
 232                                 AD7746_REG_CAPDACA,
 233                                 chip->capdac[chan->channel][0]);
 234                         if (ret < 0)
 235                                 return ret;
 236                         ret = i2c_smbus_write_byte_data(chip->client,
 237                                 AD7746_REG_CAPDACB,
 238                                 chip->capdac[chan->channel][1]);
 239                         if (ret < 0)
 240                                 return ret;
 241
 242                         chip->capdac_set = chan->channel;
 243                 }
 244                 break;
 245         case IIO_VOLTAGE:
 246         case IIO_TEMP:
 247                 vt_setup = (chan->address & 0xFF) | AD7746_VTSETUP_VTEN;
 248                 cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
 249                 delay = ad7746_cap_filter_rate_table[(chip->config >> 6) &
 250                         0x3][1];
 251                 break;
 252         default:
 253                 return -EINVAL;
 254         }
 255
 256         if (chip->cap_setup != cap_setup) {
 257                 ret = i2c_smbus_write_byte_data(chip->client,
 258                                                 AD7746_REG_CAP_SETUP,
 259                                                 cap_setup);
 260                 if (ret < 0)
 261                         return ret;
 262
 263                 chip->cap_setup = cap_setup;
 264         }
 265
 266         if (chip->vt_setup != vt_setup) {
 267                 ret = i2c_smbus_write_byte_data(chip->client,
 268                                                 AD7746_REG_VT_SETUP,
 269                                                 vt_setup);
 270                 if (ret < 0)
 271                         return ret;
 272
 273                 chip->vt_setup = vt_setup;
 274         }
 275
 276         return delay;
 277 }
 278
 279 static inline ssize_t ad7746_start_calib(struct device *dev,
 280                                          struct device_attribute *attr,
 281                                          const char *buf,
 282                                          size_t len,
 283                                          u8 regval)
 284 {
 285         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 286         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 287         bool doit;
 288         int ret, timeout = 10;
 289
 290         ret = strtobool(buf, &doit);
 291         if (ret < 0)
 292                 return ret;
 293
 294         if (!doit)
 295                 return 0;
 296
 297         mutex_lock(&indio_dev->mlock);
 298         regval |= chip->config;
 299         ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
 300         if (ret < 0) {
 301                 mutex_unlock(&indio_dev->mlock);
 302                 return ret;
 303         }
 304
 305         do {
 306                 msleep(20);
 307                 ret = i2c_smbus_read_byte_data(chip->client, AD7746_REG_CFG);
 308                 if (ret < 0) {
 309                         mutex_unlock(&indio_dev->mlock);
 310                         return ret;
 311                 }
 312         } while ((ret == regval) && timeout--);
 313
 314         mutex_unlock(&indio_dev->mlock);
 315
 316         return len;
 317 }
 318
 319 static ssize_t ad7746_start_offset_calib(struct device *dev,
 320                                          struct device_attribute *attr,
 321                                          const char *buf,
 322                                          size_t len)
 323 {
 324         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 325         int ret = ad7746_select_channel(indio_dev,
 326                               &ad7746_channels[to_iio_dev_attr(attr)->address]);
 327         if (ret < 0)
 328                 return ret;
 329
 330         return ad7746_start_calib(dev, attr, buf, len,
 331                                   AD7746_CONF_MODE_OFFS_CAL);
 332 }
 333
 334 static ssize_t ad7746_start_gain_calib(struct device *dev,
 335                                        struct device_attribute *attr,
 336                                        const char *buf,
 337                                        size_t len)
 338 {
 339         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 340         int ret = ad7746_select_channel(indio_dev,
 341                               &ad7746_channels[to_iio_dev_attr(attr)->address]);
 342         if (ret < 0)
 343                 return ret;
 344
 345         return ad7746_start_calib(dev, attr, buf, len,
 346                                   AD7746_CONF_MODE_GAIN_CAL);
 347 }
 348
 349 static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
 350                        S_IWUSR, NULL, ad7746_start_offset_calib, CIN1);
 351 static IIO_DEVICE_ATTR(in_capacitance1_calibbias_calibration,
 352                        S_IWUSR, NULL, ad7746_start_offset_calib, CIN2);
 353 static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
 354                        S_IWUSR, NULL, ad7746_start_gain_calib, CIN1);
 355 static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
 356                        S_IWUSR, NULL, ad7746_start_gain_calib, CIN2);
 357 static IIO_DEVICE_ATTR(in_voltage0_calibscale_calibration,
 358                        S_IWUSR, NULL, ad7746_start_gain_calib, VIN);
 359
 360 static ssize_t ad7746_show_cap_filter_rate_setup(struct device *dev,
 361                 struct device_attribute *attr,
 362                 char *buf)
 363 {
 364         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 365         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 366
 367         return sprintf(buf, "%d\n", ad7746_cap_filter_rate_table[
 368                         (chip->config >> 3) & 0x7][0]);
 369 }
 370
 371 static ssize_t ad7746_store_cap_filter_rate_setup(struct device *dev,
 372                 struct device_attribute *attr,
 373                 const char *buf,
 374                 size_t len)
 375 {
 376         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 377         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 378         u8 data;
 379         int ret, i;
 380
 381         ret = kstrtou8(buf, 10, &data);
 382         if (ret < 0)
 383                 return ret;
 384
 385         for (i = 0; i < ARRAY_SIZE(ad7746_cap_filter_rate_table); i++)
 386                 if (data >= ad7746_cap_filter_rate_table[i][0])
 387                         break;
 388
 389         if (i >= ARRAY_SIZE(ad7746_cap_filter_rate_table))
 390                 i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
 391
 392         mutex_lock(&indio_dev->mlock);
 393         chip->config &= ~AD7746_CONF_CAPFS(0x7);
 394         chip->config |= AD7746_CONF_CAPFS(i);
 395         mutex_unlock(&indio_dev->mlock);
 396
 397         return len;
 398 }
 399
 400 static ssize_t ad7746_show_vt_filter_rate_setup(struct device *dev,
 401                 struct device_attribute *attr,
 402                 char *buf)
 403 {
 404         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 405         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 406
 407         return sprintf(buf, "%d\n", ad7746_vt_filter_rate_table[
 408                         (chip->config >> 6) & 0x3][0]);
 409 }
 410
 411 static ssize_t ad7746_store_vt_filter_rate_setup(struct device *dev,
 412                 struct device_attribute *attr,
 413                 const char *buf,
 414                 size_t len)
 415 {
 416         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 417         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 418         u8 data;
 419         int ret, i;
 420
 421         ret = kstrtou8(buf, 10, &data);
 422         if (ret < 0)
 423                 return ret;
 424
 425         for (i = 0; i < ARRAY_SIZE(ad7746_vt_filter_rate_table); i++)
 426                 if (data >= ad7746_vt_filter_rate_table[i][0])
 427                         break;
 428
 429         if (i >= ARRAY_SIZE(ad7746_vt_filter_rate_table))
 430                 i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
 431
 432         mutex_lock(&indio_dev->mlock);
 433         chip->config &= ~AD7746_CONF_VTFS(0x3);
 434         chip->config |= AD7746_CONF_VTFS(i);
 435         mutex_unlock(&indio_dev->mlock);
 436
 437         return len;
 438 }
 439
 440 static IIO_DEVICE_ATTR(in_capacitance_sampling_frequency,
 441                        S_IRUGO | S_IWUSR, ad7746_show_cap_filter_rate_setup,
 442                         ad7746_store_cap_filter_rate_setup, 0);
 443
 444 static IIO_DEVICE_ATTR(in_voltage_sampling_frequency,
 445                        S_IRUGO | S_IWUSR, ad7746_show_vt_filter_rate_setup,
 446                        ad7746_store_vt_filter_rate_setup, 0);
 447
 448 static IIO_CONST_ATTR(in_voltage_sampling_frequency_available, "50 31 16 8");
 449 static IIO_CONST_ATTR(in_capacitance_sampling_frequency_available,
 450                        "91 84 50 26 16 13 11 9");
 451
 452 static struct attribute *ad7746_attributes[] = {
 453         &iio_dev_attr_in_capacitance_sampling_frequency.dev_attr.attr,
 454         &iio_dev_attr_in_voltage_sampling_frequency.dev_attr.attr,
 455         &iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
 456         &iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
 457         &iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
 458         &iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
 459         &iio_dev_attr_in_voltage0_calibscale_calibration.dev_attr.attr,
 460         &iio_const_attr_in_voltage_sampling_frequency_available.dev_attr.attr,
 461         &iio_const_attr_in_capacitance_sampling_frequency_available.
 462         dev_attr.attr,
 463         NULL,
 464 };
 465
 466 static const struct attribute_group ad7746_attribute_group = {
 467         .attrs = ad7746_attributes,
 468 };
 469
 470 static int ad7746_write_raw(struct iio_dev *indio_dev,
 471                             struct iio_chan_spec const *chan,
 472                             int val,
 473                             int val2,
 474                             long mask)
 475 {
 476         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 477         int ret, reg;
 478
 479         mutex_lock(&indio_dev->mlock);
 480
 481         switch (mask) {
 482         case IIO_CHAN_INFO_CALIBSCALE:
 483                 if (val != 1) {
 484                         ret = -EINVAL;
 485                         goto out;
 486                 }
 487
 488                 val = (val2 * 1024) / 15625;
 489
 490                 switch (chan->type) {
 491                 case IIO_CAPACITANCE:
 492                         reg = AD7746_REG_CAP_GAINH;
 493                         break;
 494                 case IIO_VOLTAGE:
 495                         reg = AD7746_REG_VOLT_GAINH;
 496                         break;
 497                 default:
 498                         ret = -EINVAL;
 499                         goto out;
 500                 }
 501
 502                 ret = i2c_smbus_write_word_data(chip->client, reg, swab16(val));
 503                 if (ret < 0)
 504                         goto out;
 505
 506                 ret = 0;
 507                 break;
 508         case IIO_CHAN_INFO_CALIBBIAS:
 509                 if ((val < 0) | (val > 0xFFFF)) {
 510                         ret = -EINVAL;
 511                         goto out;
 512                 }
 513                 ret = i2c_smbus_write_word_data(chip->client,
 514                                 AD7746_REG_CAP_OFFH, swab16(val));
 515                 if (ret < 0)
 516                         goto out;
 517
 518                 ret = 0;
 519                 break;
 520         case IIO_CHAN_INFO_OFFSET:
 521                 if ((val < 0) | (val > 43008000)) { /* 21pF */
 522                         ret = -EINVAL;
 523                         goto out;
 524                 }
 525
 526                 /* CAPDAC Scale = 21pF_typ / 127
 527                  * CIN Scale = 8.192pF / 2^24
 528                  * Offset Scale = CAPDAC Scale / CIN Scale = 338646
 529                  * */
 530
 531                 val /= 338646;
 532
 533                 chip->capdac[chan->channel][chan->differential] = (val > 0 ?
 534                         AD7746_CAPDAC_DACP(val) | AD7746_CAPDAC_DACEN : 0);
 535
 536                 ret = i2c_smbus_write_byte_data(chip->client,
 537                         AD7746_REG_CAPDACA,
 538                         chip->capdac[chan->channel][0]);
 539                 if (ret < 0)
 540                         goto out;
 541                 ret = i2c_smbus_write_byte_data(chip->client,
 542                         AD7746_REG_CAPDACB,
 543                         chip->capdac[chan->channel][1]);
 544                 if (ret < 0)
 545                         goto out;
 546
 547                 chip->capdac_set = chan->channel;
 548
 549                 ret = 0;
 550                 break;
 551         default:
 552                 ret = -EINVAL;
 553         }
 554
 555 out:
 556         mutex_unlock(&indio_dev->mlock);
 557         return ret;
 558 }
 559
 560 static int ad7746_read_raw(struct iio_dev *indio_dev,
 561                            struct iio_chan_spec const *chan,
 562                            int *val, int *val2,
 563                            long mask)
 564 {
 565         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 566         int ret, delay;
 567         u8 regval, reg;
 568
 569         union {
 570                 u32 d32;
 571                 u8 d8[4];
 572         } data;
 573
 574         mutex_lock(&indio_dev->mlock);
 575
 576         switch (mask) {
 577         case IIO_CHAN_INFO_RAW:
 578         case IIO_CHAN_INFO_PROCESSED:
 579                 ret = ad7746_select_channel(indio_dev, chan);
 580                 if (ret < 0)
 581                         goto out;
 582                 delay = ret;
 583
 584                 regval = chip->config | AD7746_CONF_MODE_SINGLE_CONV;
 585                 ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG,
 586                                 regval);
 587                 if (ret < 0)
 588                         goto out;
 589
 590                 msleep(delay);
 591                 /* Now read the actual register */
 592
 593                 ret = i2c_smbus_read_i2c_block_data(chip->client,
 594                         chan->address >> 8, 3, &data.d8[1]);
 595
 596                 if (ret < 0)
 597                         goto out;
 598
 599                 *val = (be32_to_cpu(data.d32) & 0xFFFFFF) - 0x800000;
 600
 601                 switch (chan->type) {
 602                 case IIO_TEMP:
 603                 /* temperature in milli degrees Celsius
 604                  * T = ((*val / 2048) - 4096) * 1000
 605                  */
 606                         *val = (*val * 125) / 256;
 607                         break;
 608                 case IIO_VOLTAGE:
 609                         if (chan->channel == 1) /* supply_raw*/
 610                                 *val = *val * 6;
 611                         break;
 612                 default:
 613                         break;
 614                 }
 615
 616                 ret = IIO_VAL_INT;
 617                 break;
 618         case IIO_CHAN_INFO_CALIBSCALE:
 619                 switch (chan->type) {
 620                 case IIO_CAPACITANCE:
 621                         reg = AD7746_REG_CAP_GAINH;
 622                         break;
 623                 case IIO_VOLTAGE:
 624                         reg = AD7746_REG_VOLT_GAINH;
 625                         break;
 626                 default:
 627                         ret = -EINVAL;
 628                         goto out;
 629                 }
 630
 631                 ret = i2c_smbus_read_word_data(chip->client, reg);
 632                 if (ret < 0)
 633                         goto out;
 634                 /* 1 + gain_val / 2^16 */
 635                 *val = 1;
 636                 *val2 = (15625 * swab16(ret)) / 1024;
 637
 638                 ret = IIO_VAL_INT_PLUS_MICRO;
 639                 break;
 640         case IIO_CHAN_INFO_CALIBBIAS:
 641                 ret = i2c_smbus_read_word_data(chip->client,
 642                                                AD7746_REG_CAP_OFFH);
 643                 if (ret < 0)
 644                         goto out;
 645                 *val = swab16(ret);
 646
 647                 ret = IIO_VAL_INT;
 648                 break;
 649         case IIO_CHAN_INFO_OFFSET:
 650                 *val = AD7746_CAPDAC_DACP(chip->capdac[chan->channel]
 651                         [chan->differential]) * 338646;
 652
 653                 ret = IIO_VAL_INT;
 654                 break;
 655         case IIO_CHAN_INFO_SCALE:
 656                 switch (chan->type) {
 657                 case IIO_CAPACITANCE:
 658                         /* 8.192pf / 2^24 */
 659                         *val2 = 488;
 660                         *val =  0;
 661                         break;
 662                 case IIO_VOLTAGE:
 663                         /* 1170mV / 2^23 */
 664                         *val2 = 139475;
 665                         *val =  0;
 666                         break;
 667                 default:
 668                         ret =  -EINVAL;
 669                         goto out;
 670                 }
 671
 672                 ret = IIO_VAL_INT_PLUS_NANO;
 673                 break;
 674         default:
 675                 ret = -EINVAL;
 676         }
 677 out:
 678         mutex_unlock(&indio_dev->mlock);
 679         return ret;
 680 }
 681
 682 static const struct iio_info ad7746_info = {
 683         .attrs = &ad7746_attribute_group,
 684         .read_raw = &ad7746_read_raw,
 685         .write_raw = &ad7746_write_raw,
 686         .driver_module = THIS_MODULE,
 687 };
 688
 689 /*
 690  * device probe and remove
 691  */
 692
 693 static int ad7746_probe(struct i2c_client *client,
 694                 const struct i2c_device_id *id)
 695 {
 696         struct ad7746_platform_data *pdata = client->dev.platform_data;
 697         struct ad7746_chip_info *chip;
 698         struct iio_dev *indio_dev;
 699         int ret = 0;
 700         unsigned char regval = 0;
 701
 702         indio_dev = iio_device_alloc(sizeof(*chip));
 703         if (indio_dev == NULL) {
 704                 ret = -ENOMEM;
 705                 goto error_ret;
 706         }
 707         chip = iio_priv(indio_dev);
 708         /* this is only used for device removal purposes */
 709         i2c_set_clientdata(client, indio_dev);
 710
 711         chip->client = client;
 712         chip->capdac_set = -1;
 713
 714         /* Establish that the iio_dev is a child of the i2c device */
 715         indio_dev->name = id->name;
 716         indio_dev->dev.parent = &client->dev;
 717         indio_dev->info = &ad7746_info;
 718         indio_dev->channels = ad7746_channels;
 719         if (id->driver_data == 7746)
 720                 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
 721         else
 722                 indio_dev->num_channels =  ARRAY_SIZE(ad7746_channels) - 2;
 723         indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
 724         indio_dev->modes = INDIO_DIRECT_MODE;
 725
 726         if (pdata) {
 727                 if (pdata->exca_en) {
 728                         if (pdata->exca_inv_en)
 729                                 regval |= AD7746_EXCSETUP_NEXCA;
 730                         else
 731                                 regval |= AD7746_EXCSETUP_EXCA;
 732                 }
 733
 734                 if (pdata->excb_en) {
 735                         if (pdata->excb_inv_en)
 736                                 regval |= AD7746_EXCSETUP_NEXCB;
 737                         else
 738                                 regval |= AD7746_EXCSETUP_EXCB;
 739                 }
 740
 741                 regval |= AD7746_EXCSETUP_EXCLVL(pdata->exclvl);
 742         } else {
 743                 dev_warn(&client->dev, "No platform data? using default\n");
 744                 regval = AD7746_EXCSETUP_EXCA | AD7746_EXCSETUP_EXCB |
 745                         AD7746_EXCSETUP_EXCLVL(3);
 746         }
 747
 748         ret = i2c_smbus_write_byte_data(chip->client,
 749                                         AD7746_REG_EXC_SETUP, regval);
 750         if (ret < 0)
 751                 goto error_free_dev;
 752
 753         ret = iio_device_register(indio_dev);
 754         if (ret)
 755                 goto error_free_dev;
 756
 757         dev_info(&client->dev, "%s capacitive sensor registered\n", id->name);
 758
 759         return 0;
 760
 761 error_free_dev:
 762         iio_device_free(indio_dev);
 763 error_ret:
 764         return ret;
 765 }
 766
 767 static int ad7746_remove(struct i2c_client *client)
 768 {
 769         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 770
 771         iio_device_unregister(indio_dev);
 772         iio_device_free(indio_dev);
 773
 774         return 0;
 775 }
 776
 777 static const struct i2c_device_id ad7746_id[] = {
 778         { "ad7745", 7745 },
 779         { "ad7746", 7746 },
 780         { "ad7747", 7747 },
 781         {}
 782 };
 783
 784 MODULE_DEVICE_TABLE(i2c, ad7746_id);
 785
 786 static struct i2c_driver ad7746_driver = {
 787         .driver = {
 788                 .name = KBUILD_MODNAME,
 789         },
 790         .probe = ad7746_probe,
 791         .remove = ad7746_remove,
 792         .id_table = ad7746_id,
 793 };
 794 module_i2c_driver(ad7746_driver);
 795
 796 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 797 MODULE_DESCRIPTION("Analog Devices AD7746/5/7 capacitive sensor driver");
 798 MODULE_LICENSE("GPL v2");