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 struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd)
 157 {
 158         return container_of(sd, struct ad7791_state, sd);
 159 }
 160
 161 static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
 162 {
 163         ad_sd_set_comm(sd, channel);
 164
 165         return 0;
 166 }
 167
 168 static int ad7791_set_mode(struct ad_sigma_delta *sd,
 169         enum ad_sigma_delta_mode mode)
 170 {
 171         struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd);
 172
 173         switch (mode) {
 174         case AD_SD_MODE_CONTINUOUS:
 175                 mode = AD7791_MODE_CONTINUOUS;
 176                 break;
 177         case AD_SD_MODE_SINGLE:
 178                 mode = AD7791_MODE_SINGLE;
 179                 break;
 180         case AD_SD_MODE_IDLE:
 181         case AD_SD_MODE_POWERDOWN:
 182                 mode = AD7791_MODE_POWERDOWN;
 183                 break;
 184         }
 185
 186         st->mode &= ~AD7791_MODE_SEL_MASK;
 187         st->mode |= AD7791_MODE_SEL(mode);
 188
 189         return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode);
 190 }
 191
 192 static const struct ad_sigma_delta_info ad7791_sigma_delta_info = {
 193         .set_channel = ad7791_set_channel,
 194         .set_mode = ad7791_set_mode,
 195         .has_registers = true,
 196         .addr_shift = 4,
 197         .read_mask = BIT(3),
 198 };
 199
 200 static int ad7791_read_raw(struct iio_dev *indio_dev,
 201         const struct iio_chan_spec *chan, int *val, int *val2, long info)
 202 {
 203         struct ad7791_state *st = iio_priv(indio_dev);
 204         bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR);
 205
 206         switch (info) {
 207         case IIO_CHAN_INFO_RAW:
 208                 return ad_sigma_delta_single_conversion(indio_dev, chan, val);
 209         case IIO_CHAN_INFO_OFFSET:
 210                 /**
 211                  * Unipolar: 0 to VREF
 212                  * Bipolar -VREF to VREF
 213                  **/
 214                 if (unipolar)
 215                         *val = 0;
 216                 else
 217                         *val = -(1 << (chan->scan_type.realbits - 1));
 218                 return IIO_VAL_INT;
 219         case IIO_CHAN_INFO_SCALE:
 220                 /* The monitor channel uses an internal reference. */
 221                 if (chan->address == AD7791_CH_AVDD_MONITOR) {
 222                         /*
 223                          * The signal is attenuated by a factor of 5 and
 224                          * compared against a 1.17V internal reference.
 225                          */
 226                         *val = 1170 * 5;
 227                 } else {
 228                         int voltage_uv;
 229
 230                         voltage_uv = regulator_get_voltage(st->reg);
 231                         if (voltage_uv < 0)
 232                                 return voltage_uv;
 233
 234                         *val = voltage_uv / 1000;
 235                 }
 236                 if (unipolar)
 237                         *val2 = chan->scan_type.realbits;
 238                 else
 239                         *val2 = chan->scan_type.realbits - 1;
 240
 241                 return IIO_VAL_FRACTIONAL_LOG2;
 242         }
 243
 244         return -EINVAL;
 245 }
 246
 247 static const char * const ad7791_sample_freq_avail[] = {
 248         [AD7791_FILTER_RATE_120] = "120",
 249         [AD7791_FILTER_RATE_100] = "100",
 250         [AD7791_FILTER_RATE_33_3] = "33.3",
 251         [AD7791_FILTER_RATE_20] = "20",
 252         [AD7791_FILTER_RATE_16_6] = "16.6",
 253         [AD7791_FILTER_RATE_16_7] = "16.7",
 254         [AD7791_FILTER_RATE_13_3] = "13.3",
 255         [AD7791_FILTER_RATE_9_5] = "9.5",
 256 };
 257
 258 static ssize_t ad7791_read_frequency(struct device *dev,
 259         struct device_attribute *attr, char *buf)
 260 {
 261         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 262         struct ad7791_state *st = iio_priv(indio_dev);
 263         unsigned int rate = st->filter & AD7791_FILTER_RATE_MASK;
 264
 265         return sprintf(buf, "%s\n", ad7791_sample_freq_avail[rate]);
 266 }
 267
 268 static ssize_t ad7791_write_frequency(struct device *dev,
 269         struct device_attribute *attr, const char *buf, size_t len)
 270 {
 271         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 272         struct ad7791_state *st = iio_priv(indio_dev);
 273         int i, ret;
 274
 275         mutex_lock(&indio_dev->mlock);
 276         if (iio_buffer_enabled(indio_dev)) {
 277                 mutex_unlock(&indio_dev->mlock);
 278                 return -EBUSY;
 279         }
 280         mutex_unlock(&indio_dev->mlock);
 281
 282         ret = -EINVAL;
 283
 284         for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
 285                 if (sysfs_streq(ad7791_sample_freq_avail[i], buf)) {
 286
 287                         mutex_lock(&indio_dev->mlock);
 288                         st->filter &= ~AD7791_FILTER_RATE_MASK;
 289                         st->filter |= i;
 290                         ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
 291                                          sizeof(st->filter), st->filter);
 292                         mutex_unlock(&indio_dev->mlock);
 293                         ret = 0;
 294                         break;
 295                 }
 296         }
 297
 298         return ret ? ret : len;
 299 }
 300
 301 static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
 302                 ad7791_read_frequency,
 303                 ad7791_write_frequency);
 304
 305 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5");
 306
 307 static struct attribute *ad7791_attributes[] = {
 308         &iio_dev_attr_sampling_frequency.dev_attr.attr,
 309         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 310         NULL
 311 };
 312
 313 static const struct attribute_group ad7791_attribute_group = {
 314         .attrs = ad7791_attributes,
 315 };
 316
 317 static const struct iio_info ad7791_info = {
 318         .read_raw = &ad7791_read_raw,
 319         .attrs = &ad7791_attribute_group,
 320         .validate_trigger = ad_sd_validate_trigger,
 321         .driver_module = THIS_MODULE,
 322 };
 323
 324 static const struct iio_info ad7791_no_filter_info = {
 325         .read_raw = &ad7791_read_raw,
 326         .validate_trigger = ad_sd_validate_trigger,
 327         .driver_module = THIS_MODULE,
 328 };
 329
 330 static int ad7791_setup(struct ad7791_state *st,
 331                         struct ad7791_platform_data *pdata)
 332 {
 333         /* Set to poweron-reset default values */
 334         st->mode = AD7791_MODE_BUFFER;
 335         st->filter = AD7791_FILTER_RATE_16_6;
 336
 337         if (!pdata)
 338                 return 0;
 339
 340         if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered)
 341                 st->mode &= ~AD7791_MODE_BUFFER;
 342
 343         if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) &&
 344                 pdata->burnout_current)
 345                 st->mode |= AD7791_MODE_BURNOUT;
 346
 347         if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar)
 348                 st->mode |= AD7791_MODE_UNIPOLAR;
 349
 350         return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode),
 351                 st->mode);
 352 }
 353
 354 static int ad7791_probe(struct spi_device *spi)
 355 {
 356         struct ad7791_platform_data *pdata = spi->dev.platform_data;
 357         struct iio_dev *indio_dev;
 358         struct ad7791_state *st;
 359         int ret;
 360
 361         if (!spi->irq) {
 362                 dev_err(&spi->dev, "Missing IRQ.\n");
 363                 return -ENXIO;
 364         }
 365
 366         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 367         if (!indio_dev)
 368                 return -ENOMEM;
 369
 370         st = iio_priv(indio_dev);
 371
 372         st->reg = devm_regulator_get(&spi->dev, "refin");
 373         if (IS_ERR(st->reg))
 374                 return PTR_ERR(st->reg);
 375
 376         ret = regulator_enable(st->reg);
 377         if (ret)
 378                 return ret;
 379
 380         st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data];
 381         ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info);
 382
 383         spi_set_drvdata(spi, indio_dev);
 384
 385         indio_dev->dev.parent = &spi->dev;
 386         indio_dev->name = spi_get_device_id(spi)->name;
 387         indio_dev->modes = INDIO_DIRECT_MODE;
 388         indio_dev->channels = st->info->channels;
 389         indio_dev->num_channels = st->info->num_channels;
 390         if (st->info->flags & AD7791_FLAG_HAS_FILTER)
 391                 indio_dev->info = &ad7791_info;
 392         else
 393                 indio_dev->info = &ad7791_no_filter_info;
 394
 395         ret = ad_sd_setup_buffer_and_trigger(indio_dev);
 396         if (ret)
 397                 goto error_disable_reg;
 398
 399         ret = ad7791_setup(st, pdata);
 400         if (ret)
 401                 goto error_remove_trigger;
 402
 403         ret = iio_device_register(indio_dev);
 404         if (ret)
 405                 goto error_remove_trigger;
 406
 407         return 0;
 408
 409 error_remove_trigger:
 410         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 411 error_disable_reg:
 412         regulator_disable(st->reg);
 413
 414         return ret;
 415 }
 416
 417 static int ad7791_remove(struct spi_device *spi)
 418 {
 419         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 420         struct ad7791_state *st = iio_priv(indio_dev);
 421
 422         iio_device_unregister(indio_dev);
 423         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 424
 425         regulator_disable(st->reg);
 426
 427         return 0;
 428 }
 429
 430 static const struct spi_device_id ad7791_spi_ids[] = {
 431         { "ad7787", AD7787 },
 432         { "ad7788", AD7788 },
 433         { "ad7789", AD7789 },
 434         { "ad7790", AD7790 },
 435         { "ad7791", AD7791 },
 436         {}
 437 };
 438 MODULE_DEVICE_TABLE(spi, ad7791_spi_ids);
 439
 440 static struct spi_driver ad7791_driver = {
 441         .driver = {
 442                 .name   = "ad7791",
 443         },
 444         .probe          = ad7791_probe,
 445         .remove         = ad7791_remove,
 446         .id_table       = ad7791_spi_ids,
 447 };
 448 module_spi_driver(ad7791_driver);
 449
 450 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 451 MODULE_DESCRIPTION("Analog Device AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver");
 452 MODULE_LICENSE("GPL v2");