drivers/iio/cdc/ad7746.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * AD7746 capacitive sensor driver supporting AD7745, AD7746 and AD7747
   4  *
   5  * Copyright 2011 Analog Devices Inc.
   6  */
   7
   8 #include <linux/bitfield.h>
   9 #include <linux/delay.h>
  10 #include <linux/device.h>
  11 #include <linux/i2c.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/stat.h>
  17 #include <linux/sysfs.h>
  18
  19 #include <asm/unaligned.h>
  20
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/sysfs.h>
  23
  24 /* AD7746 Register Definition */
  25
  26 #define AD7746_REG_STATUS               0
  27 #define AD7746_REG_CAP_DATA_HIGH        1
  28 #define AD7746_REG_VT_DATA_HIGH         4
  29 #define AD7746_REG_CAP_SETUP            7
  30 #define AD7746_REG_VT_SETUP             8
  31 #define AD7746_REG_EXC_SETUP            9
  32 #define AD7746_REG_CFG                  10
  33 #define AD7746_REG_CAPDACA              11
  34 #define AD7746_REG_CAPDACB              12
  35 #define AD7746_REG_CAP_OFFH             13
  36 #define AD7746_REG_CAP_GAINH            15
  37 #define AD7746_REG_VOLT_GAINH           17
  38
  39 /* Status Register Bit Designations (AD7746_REG_STATUS) */
  40 #define AD7746_STATUS_EXCERR            BIT(3)
  41 #define AD7746_STATUS_RDY               BIT(2)
  42 #define AD7746_STATUS_RDYVT             BIT(1)
  43 #define AD7746_STATUS_RDYCAP            BIT(0)
  44
  45 /* Capacitive Channel Setup Register Bit Designations (AD7746_REG_CAP_SETUP) */
  46 #define AD7746_CAPSETUP_CAPEN           BIT(7)
  47 #define AD7746_CAPSETUP_CIN2            BIT(6) /* AD7746 only */
  48 #define AD7746_CAPSETUP_CAPDIFF         BIT(5)
  49 #define AD7746_CAPSETUP_CACHOP          BIT(0)
  50
  51 /* Voltage/Temperature Setup Register Bit Designations (AD7746_REG_VT_SETUP) */
  52 #define AD7746_VTSETUP_VTEN             BIT(7)
  53 #define AD7746_VTSETUP_VTMD_MASK        GENMASK(6, 5)
  54 #define AD7746_VTSETUP_VTMD_INT_TEMP    0
  55 #define AD7746_VTSETUP_VTMD_EXT_TEMP    1
  56 #define AD7746_VTSETUP_VTMD_VDD_MON     2
  57 #define AD7746_VTSETUP_VTMD_EXT_VIN     3
  58 #define AD7746_VTSETUP_EXTREF           BIT(4)
  59 #define AD7746_VTSETUP_VTSHORT          BIT(1)
  60 #define AD7746_VTSETUP_VTCHOP           BIT(0)
  61
  62 /* Excitation Setup Register Bit Designations (AD7746_REG_EXC_SETUP) */
  63 #define AD7746_EXCSETUP_CLKCTRL         BIT(7)
  64 #define AD7746_EXCSETUP_EXCON           BIT(6)
  65 #define AD7746_EXCSETUP_EXCB            BIT(5)
  66 #define AD7746_EXCSETUP_NEXCB           BIT(4)
  67 #define AD7746_EXCSETUP_EXCA            BIT(3)
  68 #define AD7746_EXCSETUP_NEXCA           BIT(2)
  69 #define AD7746_EXCSETUP_EXCLVL_MASK     GENMASK(1, 0)
  70
  71 /* Config Register Bit Designations (AD7746_REG_CFG) */
  72 #define AD7746_CONF_VTFS_MASK           GENMASK(7, 6)
  73 #define AD7746_CONF_CAPFS_MASK          GENMASK(5, 3)
  74 #define AD7746_CONF_MODE_MASK           GENMASK(2, 0)
  75 #define AD7746_CONF_MODE_IDLE           0
  76 #define AD7746_CONF_MODE_CONT_CONV      1
  77 #define AD7746_CONF_MODE_SINGLE_CONV    2
  78 #define AD7746_CONF_MODE_PWRDN          3
  79 #define AD7746_CONF_MODE_OFFS_CAL       5
  80 #define AD7746_CONF_MODE_GAIN_CAL       6
  81
  82 /* CAPDAC Register Bit Designations (AD7746_REG_CAPDACx) */
  83 #define AD7746_CAPDAC_DACEN             BIT(7)
  84 #define AD7746_CAPDAC_DACP_MASK         GENMASK(6, 0)
  85
  86 struct ad7746_chip_info {
  87         struct i2c_client *client;
  88         struct mutex lock; /* protect sensor state */
  89         /*
  90          * Capacitive channel digital filter setup;
  91          * conversion time/update rate setup per channel
  92          */
  93         u8      config;
  94         u8      cap_setup;
  95         u8      vt_setup;
  96         u8      capdac[2][2];
  97         s8      capdac_set;
  98 };
  99
 100 enum ad7746_chan {
 101         VIN,
 102         VIN_VDD,
 103         TEMP_INT,
 104         TEMP_EXT,
 105         CIN1,
 106         CIN1_DIFF,
 107         CIN2,
 108         CIN2_DIFF,
 109 };
 110
 111 struct ad7746_chan_info {
 112         u8 addr;
 113         union {
 114                 u8 vtmd;
 115                 struct { /* CAP SETUP fields */
 116                         unsigned int cin2 : 1;
 117                         unsigned int capdiff : 1;
 118                 };
 119         };
 120 };
 121
 122 static const struct ad7746_chan_info ad7746_chan_info[] = {
 123         [VIN] = {
 124                 .addr = AD7746_REG_VT_DATA_HIGH,
 125                 .vtmd = AD7746_VTSETUP_VTMD_EXT_VIN,
 126         },
 127         [VIN_VDD] = {
 128                 .addr = AD7746_REG_VT_DATA_HIGH,
 129                 .vtmd = AD7746_VTSETUP_VTMD_VDD_MON,
 130         },
 131         [TEMP_INT] = {
 132                 .addr = AD7746_REG_VT_DATA_HIGH,
 133                 .vtmd = AD7746_VTSETUP_VTMD_INT_TEMP,
 134         },
 135         [TEMP_EXT] = {
 136                 .addr = AD7746_REG_VT_DATA_HIGH,
 137                 .vtmd = AD7746_VTSETUP_VTMD_EXT_TEMP,
 138         },
 139         [CIN1] = {
 140                 .addr = AD7746_REG_CAP_DATA_HIGH,
 141         },
 142         [CIN1_DIFF] = {
 143                 .addr =  AD7746_REG_CAP_DATA_HIGH,
 144                 .capdiff = 1,
 145         },
 146         [CIN2] = {
 147                 .addr = AD7746_REG_CAP_DATA_HIGH,
 148                 .cin2 = 1,
 149         },
 150         [CIN2_DIFF] = {
 151                 .addr = AD7746_REG_CAP_DATA_HIGH,
 152                 .cin2 = 1,
 153                 .capdiff = 1,
 154         },
 155 };
 156
 157 static const struct iio_chan_spec ad7746_channels[] = {
 158         [VIN] = {
 159                 .type = IIO_VOLTAGE,
 160                 .indexed = 1,
 161                 .channel = 0,
 162                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 163                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 164                 .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 165                 .address = VIN,
 166         },
 167         [VIN_VDD] = {
 168                 .type = IIO_VOLTAGE,
 169                 .indexed = 1,
 170                 .channel = 1,
 171                 .extend_name = "supply",
 172                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 173                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 174                 .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 175                 .address = VIN_VDD,
 176         },
 177         [TEMP_INT] = {
 178                 .type = IIO_TEMP,
 179                 .indexed = 1,
 180                 .channel = 0,
 181                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 182                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 183                 .address = TEMP_INT,
 184         },
 185         [TEMP_EXT] = {
 186                 .type = IIO_TEMP,
 187                 .indexed = 1,
 188                 .channel = 1,
 189                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 190                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 191                 .address = TEMP_EXT,
 192         },
 193         [CIN1] = {
 194                 .type = IIO_CAPACITANCE,
 195                 .indexed = 1,
 196                 .channel = 0,
 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) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
 201                 .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 202                 .address = CIN1,
 203         },
 204         [CIN1_DIFF] = {
 205                 .type = IIO_CAPACITANCE,
 206                 .differential = 1,
 207                 .indexed = 1,
 208                 .channel = 0,
 209                 .channel2 = 2,
 210                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 211                 BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_ZEROPOINT),
 212                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 213                 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
 214                 .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 215                 .address = CIN1_DIFF,
 216         },
 217         [CIN2] = {
 218                 .type = IIO_CAPACITANCE,
 219                 .indexed = 1,
 220                 .channel = 1,
 221                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 222                 BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_OFFSET),
 223                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 224                 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
 225                 .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 226                 .address = CIN2,
 227         },
 228         [CIN2_DIFF] = {
 229                 .type = IIO_CAPACITANCE,
 230                 .differential = 1,
 231                 .indexed = 1,
 232                 .channel = 1,
 233                 .channel2 = 3,
 234                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 235                 BIT(IIO_CHAN_INFO_CALIBSCALE) | BIT(IIO_CHAN_INFO_ZEROPOINT),
 236                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_CALIBBIAS) |
 237                 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_SAMP_FREQ),
 238                 .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 239                 .address = CIN2_DIFF,
 240         }
 241 };
 242
 243 /* Values are Update Rate (Hz), Conversion Time (ms) + 1*/
 244 static const unsigned char ad7746_vt_filter_rate_table[][2] = {
 245         { 50, 20 + 1 }, { 31, 32 + 1 }, { 16, 62 + 1 }, { 8, 122 + 1 },
 246 };
 247
 248 static const unsigned char ad7746_cap_filter_rate_table[][2] = {
 249         { 91, 11 + 1 }, { 84, 12 + 1 }, { 50, 20 + 1 }, { 26, 38 + 1 },
 250         { 16, 62 + 1 }, { 13, 77 + 1 }, { 11, 92 + 1 }, { 9, 110 + 1 },
 251 };
 252
 253 static int ad7746_set_capdac(struct ad7746_chip_info *chip, int channel)
 254 {
 255         int ret = i2c_smbus_write_byte_data(chip->client,
 256                                             AD7746_REG_CAPDACA,
 257                                             chip->capdac[channel][0]);
 258         if (ret < 0)
 259                 return ret;
 260
 261         return i2c_smbus_write_byte_data(chip->client,
 262                                           AD7746_REG_CAPDACB,
 263                                           chip->capdac[channel][1]);
 264 }
 265
 266 static int ad7746_select_channel(struct iio_dev *indio_dev,
 267                                  struct iio_chan_spec const *chan)
 268 {
 269         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 270         u8 vt_setup, cap_setup;
 271         int ret, delay, idx;
 272
 273         switch (chan->type) {
 274         case IIO_CAPACITANCE:
 275                 cap_setup = FIELD_PREP(AD7746_CAPSETUP_CIN2,
 276                                        ad7746_chan_info[chan->address].cin2) |
 277                         FIELD_PREP(AD7746_CAPSETUP_CAPDIFF,
 278                                    ad7746_chan_info[chan->address].capdiff) |
 279                         FIELD_PREP(AD7746_CAPSETUP_CAPEN, 1);
 280                 vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
 281                 idx = FIELD_GET(AD7746_CONF_CAPFS_MASK, chip->config);
 282                 delay = ad7746_cap_filter_rate_table[idx][1];
 283
 284                 ret = ad7746_set_capdac(chip, chan->channel);
 285                 if (ret < 0)
 286                         return ret;
 287
 288                 chip->capdac_set = chan->channel;
 289                 break;
 290         case IIO_VOLTAGE:
 291         case IIO_TEMP:
 292                 vt_setup = FIELD_PREP(AD7746_VTSETUP_VTMD_MASK,
 293                                       ad7746_chan_info[chan->address].vtmd) |
 294                         FIELD_PREP(AD7746_VTSETUP_VTEN, 1);
 295                 cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
 296                 idx = FIELD_GET(AD7746_CONF_VTFS_MASK, chip->config);
 297                 delay = ad7746_cap_filter_rate_table[idx][1];
 298                 break;
 299         default:
 300                 return -EINVAL;
 301         }
 302
 303         if (chip->cap_setup != cap_setup) {
 304                 ret = i2c_smbus_write_byte_data(chip->client,
 305                                                 AD7746_REG_CAP_SETUP,
 306                                                 cap_setup);
 307                 if (ret < 0)
 308                         return ret;
 309
 310                 chip->cap_setup = cap_setup;
 311         }
 312
 313         if (chip->vt_setup != vt_setup) {
 314                 ret = i2c_smbus_write_byte_data(chip->client,
 315                                                 AD7746_REG_VT_SETUP,
 316                                                 vt_setup);
 317                 if (ret < 0)
 318                         return ret;
 319
 320                 chip->vt_setup = vt_setup;
 321         }
 322
 323         return delay;
 324 }
 325
 326 static inline ssize_t ad7746_start_calib(struct device *dev,
 327                                          struct device_attribute *attr,
 328                                          const char *buf,
 329                                          size_t len,
 330                                          u8 regval)
 331 {
 332         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 333         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 334         int ret, timeout = 10;
 335         bool doit;
 336
 337         ret = kstrtobool(buf, &doit);
 338         if (ret < 0)
 339                 return ret;
 340
 341         if (!doit)
 342                 return 0;
 343
 344         mutex_lock(&chip->lock);
 345         regval |= chip->config;
 346         ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
 347         if (ret < 0)
 348                 goto unlock;
 349
 350         do {
 351                 msleep(20);
 352                 ret = i2c_smbus_read_byte_data(chip->client, AD7746_REG_CFG);
 353                 if (ret < 0)
 354                         goto unlock;
 355
 356         } while ((ret == regval) && timeout--);
 357
 358         mutex_unlock(&chip->lock);
 359
 360         return len;
 361
 362 unlock:
 363         mutex_unlock(&chip->lock);
 364         return ret;
 365 }
 366
 367 static ssize_t ad7746_start_offset_calib(struct device *dev,
 368                                          struct device_attribute *attr,
 369                                          const char *buf,
 370                                          size_t len)
 371 {
 372         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 373         int ret = ad7746_select_channel(indio_dev,
 374                               &ad7746_channels[to_iio_dev_attr(attr)->address]);
 375         if (ret < 0)
 376                 return ret;
 377
 378         return ad7746_start_calib(dev, attr, buf, len,
 379                                   FIELD_PREP(AD7746_CONF_MODE_MASK,
 380                                              AD7746_CONF_MODE_OFFS_CAL));
 381 }
 382
 383 static ssize_t ad7746_start_gain_calib(struct device *dev,
 384                                        struct device_attribute *attr,
 385                                        const char *buf,
 386                                        size_t len)
 387 {
 388         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 389         int ret = ad7746_select_channel(indio_dev,
 390                               &ad7746_channels[to_iio_dev_attr(attr)->address]);
 391         if (ret < 0)
 392                 return ret;
 393
 394         return ad7746_start_calib(dev, attr, buf, len,
 395                                   FIELD_PREP(AD7746_CONF_MODE_MASK,
 396                                              AD7746_CONF_MODE_GAIN_CAL));
 397 }
 398
 399 static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
 400                        0200, NULL, ad7746_start_offset_calib, CIN1);
 401 static IIO_DEVICE_ATTR(in_capacitance1_calibbias_calibration,
 402                        0200, NULL, ad7746_start_offset_calib, CIN2);
 403 static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
 404                        0200, NULL, ad7746_start_gain_calib, CIN1);
 405 static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
 406                        0200, NULL, ad7746_start_gain_calib, CIN2);
 407 static IIO_DEVICE_ATTR(in_voltage0_calibscale_calibration,
 408                        0200, NULL, ad7746_start_gain_calib, VIN);
 409
 410 static int ad7746_store_cap_filter_rate_setup(struct ad7746_chip_info *chip,
 411                                               int val)
 412 {
 413         int i;
 414
 415         for (i = 0; i < ARRAY_SIZE(ad7746_cap_filter_rate_table); i++)
 416                 if (val >= ad7746_cap_filter_rate_table[i][0])
 417                         break;
 418
 419         if (i >= ARRAY_SIZE(ad7746_cap_filter_rate_table))
 420                 i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
 421
 422         chip->config &= ~AD7746_CONF_CAPFS_MASK;
 423         chip->config |= FIELD_PREP(AD7746_CONF_CAPFS_MASK, i);
 424
 425         return 0;
 426 }
 427
 428 static int ad7746_store_vt_filter_rate_setup(struct ad7746_chip_info *chip,
 429                                              int val)
 430 {
 431         int i;
 432
 433         for (i = 0; i < ARRAY_SIZE(ad7746_vt_filter_rate_table); i++)
 434                 if (val >= ad7746_vt_filter_rate_table[i][0])
 435                         break;
 436
 437         if (i >= ARRAY_SIZE(ad7746_vt_filter_rate_table))
 438                 i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
 439
 440         chip->config &= ~AD7746_CONF_VTFS_MASK;
 441         chip->config |= FIELD_PREP(AD7746_CONF_VTFS_MASK, i);
 442
 443         return 0;
 444 }
 445
 446 static struct attribute *ad7746_attributes[] = {
 447         &iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
 448         &iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
 449         &iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
 450         &iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
 451         &iio_dev_attr_in_voltage0_calibscale_calibration.dev_attr.attr,
 452         NULL,
 453 };
 454
 455 static const struct attribute_group ad7746_attribute_group = {
 456         .attrs = ad7746_attributes,
 457 };
 458
 459 static int ad7746_write_raw(struct iio_dev *indio_dev,
 460                             struct iio_chan_spec const *chan,
 461                             int val,
 462                             int val2,
 463                             long mask)
 464 {
 465         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 466         int ret, reg;
 467
 468         switch (mask) {
 469         case IIO_CHAN_INFO_CALIBSCALE:
 470                 if (val != 1)
 471                         return -EINVAL;
 472
 473                 val = (val2 * 1024) / 15625;
 474
 475                 switch (chan->type) {
 476                 case IIO_CAPACITANCE:
 477                         reg = AD7746_REG_CAP_GAINH;
 478                         break;
 479                 case IIO_VOLTAGE:
 480                         reg = AD7746_REG_VOLT_GAINH;
 481                         break;
 482                 default:
 483                         return -EINVAL;
 484                 }
 485
 486                 mutex_lock(&chip->lock);
 487                 ret = i2c_smbus_write_word_swapped(chip->client, reg, val);
 488                 mutex_unlock(&chip->lock);
 489                 if (ret < 0)
 490                         return ret;
 491
 492                 return 0;
 493         case IIO_CHAN_INFO_CALIBBIAS:
 494                 if (val < 0 || val > 0xFFFF)
 495                         return -EINVAL;
 496
 497                 mutex_lock(&chip->lock);
 498                 ret = i2c_smbus_write_word_swapped(chip->client,
 499                                                    AD7746_REG_CAP_OFFH, val);
 500                 mutex_unlock(&chip->lock);
 501                 if (ret < 0)
 502                         return ret;
 503
 504                 return 0;
 505         case IIO_CHAN_INFO_OFFSET:
 506         case IIO_CHAN_INFO_ZEROPOINT:
 507                 if (val < 0 || val > 43008000) /* 21pF */
 508                         return -EINVAL;
 509
 510                 /*
 511                  * CAPDAC Scale = 21pF_typ / 127
 512                  * CIN Scale = 8.192pF / 2^24
 513                  * Offset Scale = CAPDAC Scale / CIN Scale = 338646
 514                  */
 515
 516                 val /= 338646;
 517                 mutex_lock(&chip->lock);
 518                 chip->capdac[chan->channel][chan->differential] = val > 0 ?
 519                         FIELD_PREP(AD7746_CAPDAC_DACP_MASK, val) | AD7746_CAPDAC_DACEN : 0;
 520
 521                 ret = ad7746_set_capdac(chip, chan->channel);
 522                 if (ret < 0) {
 523                         mutex_unlock(&chip->lock);
 524                         return ret;
 525                 }
 526
 527                 chip->capdac_set = chan->channel;
 528                 mutex_unlock(&chip->lock);
 529
 530                 return 0;
 531         case IIO_CHAN_INFO_SAMP_FREQ:
 532                 if (val2)
 533                         return -EINVAL;
 534
 535                 switch (chan->type) {
 536                 case IIO_CAPACITANCE:
 537                         mutex_lock(&chip->lock);
 538                         ret = ad7746_store_cap_filter_rate_setup(chip, val);
 539                         mutex_unlock(&chip->lock);
 540                         return ret;
 541                 case IIO_VOLTAGE:
 542                         mutex_lock(&chip->lock);
 543                         ret = ad7746_store_vt_filter_rate_setup(chip, val);
 544                         mutex_unlock(&chip->lock);
 545                         return ret;
 546                 default:
 547                         return -EINVAL;
 548                 }
 549         default:
 550                 return -EINVAL;
 551         }
 552 }
 553
 554 static const int ad7746_v_samp_freq[] = { 50, 31, 16, 8, };
 555 static const int ad7746_cap_samp_freq[] = { 91, 84, 50, 26, 16, 13, 11, 9, };
 556
 557 static int ad7746_read_avail(struct iio_dev *indio_dev,
 558                              struct iio_chan_spec const *chan, const int **vals,
 559                              int *type, int *length, long mask)
 560 {
 561         if (mask != IIO_CHAN_INFO_SAMP_FREQ)
 562                 return -EINVAL;
 563
 564         switch (chan->type) {
 565         case IIO_VOLTAGE:
 566                 *vals = ad7746_v_samp_freq;
 567                 *length = ARRAY_SIZE(ad7746_v_samp_freq);
 568                 break;
 569         case IIO_CAPACITANCE:
 570                 *vals = ad7746_cap_samp_freq;
 571                 *length = ARRAY_SIZE(ad7746_cap_samp_freq);
 572                 break;
 573         default:
 574                 return -EINVAL;
 575         }
 576         *type = IIO_VAL_INT;
 577         return IIO_AVAIL_LIST;
 578 }
 579
 580 static int ad7746_read_channel(struct iio_dev *indio_dev,
 581                                struct iio_chan_spec const *chan,
 582                                int *val)
 583 {
 584         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 585         int ret, delay;
 586         u8 data[3];
 587         u8 regval;
 588
 589         ret = ad7746_select_channel(indio_dev, chan);
 590         if (ret < 0)
 591                 return ret;
 592         delay = ret;
 593
 594         regval = chip->config | FIELD_PREP(AD7746_CONF_MODE_MASK,
 595                                            AD7746_CONF_MODE_SINGLE_CONV);
 596         ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
 597         if (ret < 0)
 598                 return ret;
 599
 600         msleep(delay);
 601         /* Now read the actual register */
 602         ret = i2c_smbus_read_i2c_block_data(chip->client,
 603                                             ad7746_chan_info[chan->address].addr,
 604                                             sizeof(data), data);
 605         if (ret < 0)
 606                 return ret;
 607
 608         /*
 609          * Offset applied internally becaue the _offset userspace interface is
 610          * needed for the CAP DACs which apply a controllable offset.
 611          */
 612         *val = get_unaligned_be24(data) - 0x800000;
 613
 614         return 0;
 615 }
 616
 617 static int ad7746_read_raw(struct iio_dev *indio_dev,
 618                            struct iio_chan_spec const *chan,
 619                            int *val, int *val2,
 620                            long mask)
 621 {
 622         struct ad7746_chip_info *chip = iio_priv(indio_dev);
 623         int ret, idx;
 624         u8 reg;
 625
 626         switch (mask) {
 627         case IIO_CHAN_INFO_RAW:
 628                 mutex_lock(&chip->lock);
 629                 ret = ad7746_read_channel(indio_dev, chan, val);
 630                 mutex_unlock(&chip->lock);
 631                 if (ret < 0)
 632                         return ret;
 633
 634                 return IIO_VAL_INT;
 635         case IIO_CHAN_INFO_CALIBSCALE:
 636                 switch (chan->type) {
 637                 case IIO_CAPACITANCE:
 638                         reg = AD7746_REG_CAP_GAINH;
 639                         break;
 640                 case IIO_VOLTAGE:
 641                         reg = AD7746_REG_VOLT_GAINH;
 642                         break;
 643                 default:
 644                         return -EINVAL;
 645                 }
 646
 647                 mutex_lock(&chip->lock);
 648                 ret = i2c_smbus_read_word_swapped(chip->client, reg);
 649                 mutex_unlock(&chip->lock);
 650                 if (ret < 0)
 651                         return ret;
 652                 /* 1 + gain_val / 2^16 */
 653                 *val = 1;
 654                 *val2 = (15625 * ret) / 1024;
 655
 656                 return IIO_VAL_INT_PLUS_MICRO;
 657         case IIO_CHAN_INFO_CALIBBIAS:
 658                 mutex_lock(&chip->lock);
 659                 ret = i2c_smbus_read_word_swapped(chip->client,
 660                                                   AD7746_REG_CAP_OFFH);
 661                 mutex_unlock(&chip->lock);
 662                 if (ret < 0)
 663                         return ret;
 664                 *val = ret;
 665
 666                 return IIO_VAL_INT;
 667         case IIO_CHAN_INFO_OFFSET:
 668         case IIO_CHAN_INFO_ZEROPOINT:
 669                 *val = FIELD_GET(AD7746_CAPDAC_DACP_MASK,
 670                                  chip->capdac[chan->channel][chan->differential]) * 338646;
 671
 672                 return IIO_VAL_INT;
 673         case IIO_CHAN_INFO_SCALE:
 674                 switch (chan->type) {
 675                 case IIO_CAPACITANCE:
 676                         /* 8.192pf / 2^24 */
 677                         *val =  0;
 678                         *val2 = 488;
 679                         return IIO_VAL_INT_PLUS_NANO;
 680                 case IIO_VOLTAGE:
 681                         /* 1170mV / 2^23 */
 682                         *val = 1170;
 683                         if (chan->channel == 1)
 684                                 *val *= 6;
 685                         *val2 = 23;
 686                         return IIO_VAL_FRACTIONAL_LOG2;
 687                 case IIO_TEMP:
 688                         *val = 125;
 689                         *val2 = 8;
 690                         return IIO_VAL_FRACTIONAL_LOG2;
 691                 default:
 692                         return -EINVAL;
 693                 }
 694         case IIO_CHAN_INFO_SAMP_FREQ:
 695                 switch (chan->type) {
 696                 case IIO_CAPACITANCE:
 697                         idx = FIELD_GET(AD7746_CONF_CAPFS_MASK, chip->config);
 698                         *val = ad7746_cap_filter_rate_table[idx][0];
 699                         return IIO_VAL_INT;
 700                 case IIO_VOLTAGE:
 701                         idx = FIELD_GET(AD7746_CONF_VTFS_MASK, chip->config);
 702                         *val = ad7746_vt_filter_rate_table[idx][0];
 703                         return IIO_VAL_INT;
 704                 default:
 705                         return -EINVAL;
 706                 }
 707         default:
 708                 return -EINVAL;
 709         }
 710 }
 711
 712 static const struct iio_info ad7746_info = {
 713         .attrs = &ad7746_attribute_group,
 714         .read_raw = ad7746_read_raw,
 715         .read_avail = ad7746_read_avail,
 716         .write_raw = ad7746_write_raw,
 717 };
 718
 719 static int ad7746_probe(struct i2c_client *client)
 720 {
 721         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 722         struct device *dev = &client->dev;
 723         struct ad7746_chip_info *chip;
 724         struct iio_dev *indio_dev;
 725         unsigned char regval = 0;
 726         unsigned int vdd_permille;
 727         int ret;
 728
 729         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
 730         if (!indio_dev)
 731                 return -ENOMEM;
 732
 733         chip = iio_priv(indio_dev);
 734         mutex_init(&chip->lock);
 735
 736         chip->client = client;
 737         chip->capdac_set = -1;
 738
 739         indio_dev->name = id->name;
 740         indio_dev->info = &ad7746_info;
 741         indio_dev->channels = ad7746_channels;
 742         if (id->driver_data == 7746)
 743                 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
 744         else
 745                 indio_dev->num_channels =  ARRAY_SIZE(ad7746_channels) - 2;
 746         indio_dev->modes = INDIO_DIRECT_MODE;
 747
 748         if (device_property_read_bool(dev, "adi,exca-output-en")) {
 749                 if (device_property_read_bool(dev, "adi,exca-output-invert"))
 750                         regval |= AD7746_EXCSETUP_NEXCA;
 751                 else
 752                         regval |= AD7746_EXCSETUP_EXCA;
 753         }
 754
 755         if (device_property_read_bool(dev, "adi,excb-output-en")) {
 756                 if (device_property_read_bool(dev, "adi,excb-output-invert"))
 757                         regval |= AD7746_EXCSETUP_NEXCB;
 758                 else
 759                         regval |= AD7746_EXCSETUP_EXCB;
 760         }
 761
 762         ret = device_property_read_u32(dev, "adi,excitation-vdd-permille",
 763                                        &vdd_permille);
 764         if (!ret) {
 765                 switch (vdd_permille) {
 766                 case 125:
 767                         regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 0);
 768                         break;
 769                 case 250:
 770                         regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 1);
 771                         break;
 772                 case 375:
 773                         regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 2);
 774                         break;
 775                 case 500:
 776                         regval |= FIELD_PREP(AD7746_EXCSETUP_EXCLVL_MASK, 3);
 777                         break;
 778                 default:
 779                         break;
 780                 }
 781         }
 782
 783         ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_EXC_SETUP,
 784                                         regval);
 785         if (ret < 0)
 786                 return ret;
 787
 788         return devm_iio_device_register(indio_dev->dev.parent, indio_dev);
 789 }
 790
 791 static const struct i2c_device_id ad7746_id[] = {
 792         { "ad7745", 7745 },
 793         { "ad7746", 7746 },
 794         { "ad7747", 7747 },
 795         {}
 796 };
 797 MODULE_DEVICE_TABLE(i2c, ad7746_id);
 798
 799 static const struct of_device_id ad7746_of_match[] = {
 800         { .compatible = "adi,ad7745" },
 801         { .compatible = "adi,ad7746" },
 802         { .compatible = "adi,ad7747" },
 803         { },
 804 };
 805 MODULE_DEVICE_TABLE(of, ad7746_of_match);
 806
 807 static struct i2c_driver ad7746_driver = {
 808         .driver = {
 809                 .name = KBUILD_MODNAME,
 810                 .of_match_table = ad7746_of_match,
 811         },
 812         .probe = ad7746_probe,
 813         .id_table = ad7746_id,
 814 };
 815 module_i2c_driver(ad7746_driver);
 816
 817 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 818 MODULE_DESCRIPTION("Analog Devices AD7746/5/7 capacitive sensor driver");
 819 MODULE_LICENSE("GPL v2");