drivers/iio/adc/ad7791.c

   1 /*
   2  * AD7787/AD7788/AD7789/AD7790/AD7791 SPI ADC driver
   3  *
   4  * Copyright 2012 Analog Devices Inc.
   5  *  Author: Lars-Peter Clausen <lars@metafoo.de>
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/device.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysfs.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/regulator/consumer.h>
  17 #include <linux/err.h>
  18 #include <linux/sched.h>
  19 #include <linux/delay.h>
  20 #include <linux/module.h>
  21
  22 #include <linux/iio/iio.h>
  23 #include <linux/iio/sysfs.h>
  24 #include <linux/iio/buffer.h>
  25 #include <linux/iio/trigger.h>
  26 #include <linux/iio/trigger_consumer.h>
  27 #include <linux/iio/triggered_buffer.h>
  28 #include <linux/iio/adc/ad_sigma_delta.h>
  29
  30 #include <linux/platform_data/ad7791.h>
  31
  32 #define AD7791_REG_COMM                 0x0 /* For writes */
  33 #define AD7791_REG_STATUS               0x0 /* For reads */
  34 #define AD7791_REG_MODE                 0x1
  35 #define AD7791_REG_FILTER               0x2
  36 #define AD7791_REG_DATA                 0x3
  37
  38 #define AD7791_MODE_CONTINUOUS          0x00
  39 #define AD7791_MODE_SINGLE              0x02
  40 #define AD7791_MODE_POWERDOWN           0x03
  41
  42 #define AD7791_CH_AIN1P_AIN1N           0x00
  43 #define AD7791_CH_AIN2                  0x01
  44 #define AD7791_CH_AIN1N_AIN1N           0x02
  45 #define AD7791_CH_AVDD_MONITOR          0x03
  46
  47 #define AD7791_FILTER_CLK_DIV_1         (0x0 << 4)
  48 #define AD7791_FILTER_CLK_DIV_2         (0x1 << 4)
  49 #define AD7791_FILTER_CLK_DIV_4         (0x2 << 4)
  50 #define AD7791_FILTER_CLK_DIV_8         (0x3 << 4)
  51 #define AD7791_FILTER_CLK_MASK          (0x3 << 4)
  52 #define AD7791_FILTER_RATE_120          0x0
  53 #define AD7791_FILTER_RATE_100          0x1
  54 #define AD7791_FILTER_RATE_33_3         0x2
  55 #define AD7791_FILTER_RATE_20           0x3
  56 #define AD7791_FILTER_RATE_16_6         0x4
  57 #define AD7791_FILTER_RATE_16_7         0x5
  58 #define AD7791_FILTER_RATE_13_3         0x6
  59 #define AD7791_FILTER_RATE_9_5          0x7
  60 #define AD7791_FILTER_RATE_MASK         0x7
  61
  62 #define AD7791_MODE_BUFFER              BIT(1)
  63 #define AD7791_MODE_UNIPOLAR            BIT(2)
  64 #define AD7791_MODE_BURNOUT             BIT(3)
  65 #define AD7791_MODE_SEL_MASK            (0x3 << 6)
  66 #define AD7791_MODE_SEL(x)              ((x) << 6)
  67
  68 #define DECLARE_AD7787_CHANNELS(name, bits, storagebits) \
  69 const struct iio_chan_spec name[] = { \
  70         AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
  71                 (bits), (storagebits), 0), \
  72         AD_SD_CHANNEL(1, 1, AD7791_CH_AIN2, (bits), (storagebits), 0), \
  73         AD_SD_SHORTED_CHANNEL(2, 0, AD7791_CH_AIN1N_AIN1N, \
  74                 (bits), (storagebits), 0), \
  75         AD_SD_SUPPLY_CHANNEL(3, 2, AD7791_CH_AVDD_MONITOR,  \
  76                 (bits), (storagebits), 0), \
  77         IIO_CHAN_SOFT_TIMESTAMP(4), \
  78 }
  79
  80 #define DECLARE_AD7791_CHANNELS(name, bits, storagebits) \
  81 const struct iio_chan_spec name[] = { \
  82         AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
  83                 (bits), (storagebits), 0), \
  84         AD_SD_SHORTED_CHANNEL(1, 0, AD7791_CH_AIN1N_AIN1N, \
  85                 (bits), (storagebits), 0), \
  86         AD_SD_SUPPLY_CHANNEL(2, 1, AD7791_CH_AVDD_MONITOR, \
  87                 (bits), (storagebits), 0), \
  88         IIO_CHAN_SOFT_TIMESTAMP(3), \
  89 }
  90
  91 static DECLARE_AD7787_CHANNELS(ad7787_channels, 24, 32);
  92 static DECLARE_AD7791_CHANNELS(ad7790_channels, 16, 16);
  93 static DECLARE_AD7791_CHANNELS(ad7791_channels, 24, 32);
  94
  95 enum {
  96         AD7787,
  97         AD7788,
  98         AD7789,
  99         AD7790,
 100         AD7791,
 101 };
 102
 103 enum ad7791_chip_info_flags {
 104         AD7791_FLAG_HAS_FILTER          = (1 << 0),
 105         AD7791_FLAG_HAS_BUFFER          = (1 << 1),
 106         AD7791_FLAG_HAS_UNIPOLAR        = (1 << 2),
 107         AD7791_FLAG_HAS_BURNOUT         = (1 << 3),
 108 };
 109
 110 struct ad7791_chip_info {
 111         const struct iio_chan_spec *channels;
 112         unsigned int num_channels;
 113         enum ad7791_chip_info_flags flags;
 114 };
 115
 116 static const struct ad7791_chip_info ad7791_chip_infos[] = {
 117         [AD7787] = {
 118                 .channels = ad7787_channels,
 119                 .num_channels = ARRAY_SIZE(ad7787_channels),
 120                 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
 121                         AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
 122         },
 123         [AD7788] = {
 124                 .channels = ad7790_channels,
 125                 .num_channels = ARRAY_SIZE(ad7790_channels),
 126                 .flags = AD7791_FLAG_HAS_UNIPOLAR,
 127         },
 128         [AD7789] = {
 129                 .channels = ad7791_channels,
 130                 .num_channels = ARRAY_SIZE(ad7791_channels),
 131                 .flags = AD7791_FLAG_HAS_UNIPOLAR,
 132         },
 133         [AD7790] = {
 134                 .channels = ad7790_channels,
 135                 .num_channels = ARRAY_SIZE(ad7790_channels),
 136                 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
 137                         AD7791_FLAG_HAS_BURNOUT,
 138         },
 139         [AD7791] = {
 140                 .channels = ad7791_channels,
 141                 .num_channels = ARRAY_SIZE(ad7791_channels),
 142                 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
 143                         AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
 144         },
 145 };
 146
 147 struct ad7791_state {
 148         struct ad_sigma_delta sd;
 149         uint8_t mode;
 150         uint8_t filter;
 151
 152         struct regulator *reg;
 153         const struct ad7791_chip_info *info;
 154 };
 155
 156 static const int ad7791_sample_freq_avail[8][2] = {
 157         [AD7791_FILTER_RATE_120] =  { 120, 0 },
 158         [AD7791_FILTER_RATE_100] =  { 100, 0 },
 159         [AD7791_FILTER_RATE_33_3] = { 33,  300000 },
 160         [AD7791_FILTER_RATE_20] =   { 20,  0 },
 161         [AD7791_FILTER_RATE_16_6] = { 16,  600000 },
 162         [AD7791_FILTER_RATE_16_7] = { 16,  700000 },
 163         [AD7791_FILTER_RATE_13_3] = { 13,  300000 },
 164         [AD7791_FILTER_RATE_9_5] =  { 9,   500000 },
 165 };
 166
 167 static struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd)
 168 {
 169         return container_of(sd, struct ad7791_state, sd);
 170 }
 171
 172 static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
 173 {
 174         ad_sd_set_comm(sd, channel);
 175
 176         return 0;
 177 }
 178
 179 static int ad7791_set_mode(struct ad_sigma_delta *sd,
 180         enum ad_sigma_delta_mode mode)
 181 {
 182         struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd);
 183
 184         switch (mode) {
 185         case AD_SD_MODE_CONTINUOUS:
 186                 mode = AD7791_MODE_CONTINUOUS;
 187                 break;
 188         case AD_SD_MODE_SINGLE:
 189                 mode = AD7791_MODE_SINGLE;
 190                 break;
 191         case AD_SD_MODE_IDLE:
 192         case AD_SD_MODE_POWERDOWN:
 193                 mode = AD7791_MODE_POWERDOWN;
 194                 break;
 195         }
 196
 197         st->mode &= ~AD7791_MODE_SEL_MASK;
 198         st->mode |= AD7791_MODE_SEL(mode);
 199
 200         return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode);
 201 }
 202
 203 static const struct ad_sigma_delta_info ad7791_sigma_delta_info = {
 204         .set_channel = ad7791_set_channel,
 205         .set_mode = ad7791_set_mode,
 206         .has_registers = true,
 207         .addr_shift = 4,
 208         .read_mask = BIT(3),
 209 };
 210
 211 static int ad7791_read_raw(struct iio_dev *indio_dev,
 212         const struct iio_chan_spec *chan, int *val, int *val2, long info)
 213 {
 214         struct ad7791_state *st = iio_priv(indio_dev);
 215         bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR);
 216         unsigned int rate;
 217
 218         switch (info) {
 219         case IIO_CHAN_INFO_RAW:
 220                 return ad_sigma_delta_single_conversion(indio_dev, chan, val);
 221         case IIO_CHAN_INFO_OFFSET:
 222                 /**
 223                  * Unipolar: 0 to VREF
 224                  * Bipolar -VREF to VREF
 225                  **/
 226                 if (unipolar)
 227                         *val = 0;
 228                 else
 229                         *val = -(1 << (chan->scan_type.realbits - 1));
 230                 return IIO_VAL_INT;
 231         case IIO_CHAN_INFO_SCALE:
 232                 /* The monitor channel uses an internal reference. */
 233                 if (chan->address == AD7791_CH_AVDD_MONITOR) {
 234                         /*
 235                          * The signal is attenuated by a factor of 5 and
 236                          * compared against a 1.17V internal reference.
 237                          */
 238                         *val = 1170 * 5;
 239                 } else {
 240                         int voltage_uv;
 241
 242                         voltage_uv = regulator_get_voltage(st->reg);
 243                         if (voltage_uv < 0)
 244                                 return voltage_uv;
 245
 246                         *val = voltage_uv / 1000;
 247                 }
 248                 if (unipolar)
 249                         *val2 = chan->scan_type.realbits;
 250                 else
 251                         *val2 = chan->scan_type.realbits - 1;
 252
 253                 return IIO_VAL_FRACTIONAL_LOG2;
 254         case IIO_CHAN_INFO_SAMP_FREQ:
 255                 rate = st->filter & AD7791_FILTER_RATE_MASK;
 256                 *val = ad7791_sample_freq_avail[rate][0];
 257                 *val2 = ad7791_sample_freq_avail[rate][1];
 258                 return IIO_VAL_INT_PLUS_MICRO;
 259         }
 260
 261         return -EINVAL;
 262 }
 263
 264 static int ad7791_write_raw(struct iio_dev *indio_dev,
 265         struct iio_chan_spec const *chan, int val, int val2, long mask)
 266 {
 267         struct ad7791_state *st = iio_priv(indio_dev);
 268         int ret, i;
 269
 270         ret = iio_device_claim_direct_mode(indio_dev);
 271         if (ret)
 272                 return ret;
 273
 274         switch (mask) {
 275         case IIO_CHAN_INFO_SAMP_FREQ:
 276                 for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
 277                         if (ad7791_sample_freq_avail[i][0] == val &&
 278                             ad7791_sample_freq_avail[i][1] == val2)
 279                                 break;
 280                 }
 281
 282                 if (i == ARRAY_SIZE(ad7791_sample_freq_avail)) {
 283                         ret = -EINVAL;
 284                         break;
 285                 }
 286
 287                 st->filter &= ~AD7791_FILTER_RATE_MASK;
 288                 st->filter |= i;
 289                 ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
 290                                 sizeof(st->filter),
 291                                 st->filter);
 292                 break;
 293         default:
 294                 ret = -EINVAL;
 295         }
 296
 297         iio_device_release_direct_mode(indio_dev);
 298         return ret;
 299 }
 300
 301 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5");
 302
 303 static struct attribute *ad7791_attributes[] = {
 304         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 305         NULL
 306 };
 307
 308 static const struct attribute_group ad7791_attribute_group = {
 309         .attrs = ad7791_attributes,
 310 };
 311
 312 static const struct iio_info ad7791_info = {
 313         .read_raw = &ad7791_read_raw,
 314         .write_raw = &ad7791_write_raw,
 315         .attrs = &ad7791_attribute_group,
 316         .validate_trigger = ad_sd_validate_trigger,
 317 };
 318
 319 static const struct iio_info ad7791_no_filter_info = {
 320         .read_raw = &ad7791_read_raw,
 321         .write_raw = &ad7791_write_raw,
 322         .validate_trigger = ad_sd_validate_trigger,
 323 };
 324
 325 static int ad7791_setup(struct ad7791_state *st,
 326                         struct ad7791_platform_data *pdata)
 327 {
 328         /* Set to poweron-reset default values */
 329         st->mode = AD7791_MODE_BUFFER;
 330         st->filter = AD7791_FILTER_RATE_16_6;
 331
 332         if (!pdata)
 333                 return 0;
 334
 335         if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered)
 336                 st->mode &= ~AD7791_MODE_BUFFER;
 337
 338         if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) &&
 339                 pdata->burnout_current)
 340                 st->mode |= AD7791_MODE_BURNOUT;
 341
 342         if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar)
 343                 st->mode |= AD7791_MODE_UNIPOLAR;
 344
 345         return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode),
 346                 st->mode);
 347 }
 348
 349 static int ad7791_probe(struct spi_device *spi)
 350 {
 351         struct ad7791_platform_data *pdata = spi->dev.platform_data;
 352         struct iio_dev *indio_dev;
 353         struct ad7791_state *st;
 354         int ret;
 355
 356         if (!spi->irq) {
 357                 dev_err(&spi->dev, "Missing IRQ.\n");
 358                 return -ENXIO;
 359         }
 360
 361         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 362         if (!indio_dev)
 363                 return -ENOMEM;
 364
 365         st = iio_priv(indio_dev);
 366
 367         st->reg = devm_regulator_get(&spi->dev, "refin");
 368         if (IS_ERR(st->reg))
 369                 return PTR_ERR(st->reg);
 370
 371         ret = regulator_enable(st->reg);
 372         if (ret)
 373                 return ret;
 374
 375         st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data];
 376         ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info);
 377
 378         spi_set_drvdata(spi, indio_dev);
 379
 380         indio_dev->dev.parent = &spi->dev;
 381         indio_dev->dev.of_node = spi->dev.of_node;
 382         indio_dev->name = spi_get_device_id(spi)->name;
 383         indio_dev->modes = INDIO_DIRECT_MODE;
 384         indio_dev->channels = st->info->channels;
 385         indio_dev->num_channels = st->info->num_channels;
 386         if (st->info->flags & AD7791_FLAG_HAS_FILTER)
 387                 indio_dev->info = &ad7791_info;
 388         else
 389                 indio_dev->info = &ad7791_no_filter_info;
 390
 391         ret = ad_sd_setup_buffer_and_trigger(indio_dev);
 392         if (ret)
 393                 goto error_disable_reg;
 394
 395         ret = ad7791_setup(st, pdata);
 396         if (ret)
 397                 goto error_remove_trigger;
 398
 399         ret = iio_device_register(indio_dev);
 400         if (ret)
 401                 goto error_remove_trigger;
 402
 403         return 0;
 404
 405 error_remove_trigger:
 406         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 407 error_disable_reg:
 408         regulator_disable(st->reg);
 409
 410         return ret;
 411 }
 412
 413 static int ad7791_remove(struct spi_device *spi)
 414 {
 415         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 416         struct ad7791_state *st = iio_priv(indio_dev);
 417
 418         iio_device_unregister(indio_dev);
 419         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 420
 421         regulator_disable(st->reg);
 422
 423         return 0;
 424 }
 425
 426 static const struct spi_device_id ad7791_spi_ids[] = {
 427         { "ad7787", AD7787 },
 428         { "ad7788", AD7788 },
 429         { "ad7789", AD7789 },
 430         { "ad7790", AD7790 },
 431         { "ad7791", AD7791 },
 432         {}
 433 };
 434 MODULE_DEVICE_TABLE(spi, ad7791_spi_ids);
 435
 436 static struct spi_driver ad7791_driver = {
 437         .driver = {
 438                 .name   = "ad7791",
 439         },
 440         .probe          = ad7791_probe,
 441         .remove         = ad7791_remove,
 442         .id_table       = ad7791_spi_ids,
 443 };
 444 module_spi_driver(ad7791_driver);
 445
 446 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 447 MODULE_DESCRIPTION("Analog Device AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver");
 448 MODULE_LICENSE("GPL v2");