drivers/iio/adc/ad7266.c

   1 /*
   2  * AD7266/65 SPI ADC driver
   3  *
   4  * Copyright 2012 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/spi/spi.h>
  13 #include <linux/regulator/consumer.h>
  14 #include <linux/err.h>
  15 #include <linux/gpio.h>
  16 #include <linux/module.h>
  17
  18 #include <linux/interrupt.h>
  19
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/buffer.h>
  22 #include <linux/iio/trigger_consumer.h>
  23 #include <linux/iio/triggered_buffer.h>
  24
  25 #include <linux/platform_data/ad7266.h>
  26
  27 struct ad7266_state {
  28         struct spi_device       *spi;
  29         struct regulator        *reg;
  30         unsigned long           vref_uv;
  31
  32         struct spi_transfer     single_xfer[3];
  33         struct spi_message      single_msg;
  34
  35         enum ad7266_range       range;
  36         enum ad7266_mode        mode;
  37         bool                    fixed_addr;
  38         struct gpio             gpios[3];
  39
  40         /*
  41          * DMA (thus cache coherency maintenance) requires the
  42          * transfer buffers to live in their own cache lines.
  43          * The buffer needs to be large enough to hold two samples (4 bytes) and
  44          * the naturally aligned timestamp (8 bytes).
  45          */
  46         uint8_t data[ALIGN(4, sizeof(s64)) + sizeof(s64)] ____cacheline_aligned;
  47 };
  48
  49 static int ad7266_wakeup(struct ad7266_state *st)
  50 {
  51         /* Any read with >= 2 bytes will wake the device */
  52         return spi_read(st->spi, st->data, 2);
  53 }
  54
  55 static int ad7266_powerdown(struct ad7266_state *st)
  56 {
  57         /* Any read with < 2 bytes will powerdown the device */
  58         return spi_read(st->spi, st->data, 1);
  59 }
  60
  61 static int ad7266_preenable(struct iio_dev *indio_dev)
  62 {
  63         struct ad7266_state *st = iio_priv(indio_dev);
  64         int ret;
  65
  66         ret = ad7266_wakeup(st);
  67         if (ret)
  68                 return ret;
  69
  70         ret = iio_sw_buffer_preenable(indio_dev);
  71         if (ret)
  72                 ad7266_powerdown(st);
  73
  74         return ret;
  75 }
  76
  77 static int ad7266_postdisable(struct iio_dev *indio_dev)
  78 {
  79         struct ad7266_state *st = iio_priv(indio_dev);
  80         return ad7266_powerdown(st);
  81 }
  82
  83 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
  84         .preenable = &ad7266_preenable,
  85         .postenable = &iio_triggered_buffer_postenable,
  86         .predisable = &iio_triggered_buffer_predisable,
  87         .postdisable = &ad7266_postdisable,
  88 };
  89
  90 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
  91 {
  92         struct iio_poll_func *pf = p;
  93         struct iio_dev *indio_dev = pf->indio_dev;
  94         struct ad7266_state *st = iio_priv(indio_dev);
  95         int ret;
  96
  97         ret = spi_read(st->spi, st->data, 4);
  98         if (ret == 0) {
  99                 if (indio_dev->scan_timestamp)
 100                         ((s64 *)st->data)[1] = pf->timestamp;
 101                 iio_push_to_buffers(indio_dev, (u8 *)st->data);
 102         }
 103
 104         iio_trigger_notify_done(indio_dev->trig);
 105
 106         return IRQ_HANDLED;
 107 }
 108
 109 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
 110 {
 111         unsigned int i;
 112
 113         if (st->fixed_addr)
 114                 return;
 115
 116         switch (st->mode) {
 117         case AD7266_MODE_SINGLE_ENDED:
 118                 nr >>= 1;
 119                 break;
 120         case AD7266_MODE_PSEUDO_DIFF:
 121                 nr |= 1;
 122                 break;
 123         case AD7266_MODE_DIFF:
 124                 nr &= ~1;
 125                 break;
 126         }
 127
 128         for (i = 0; i < 3; ++i)
 129                 gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));
 130 }
 131
 132 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
 133         const unsigned long *scan_mask)
 134 {
 135         struct ad7266_state *st = iio_priv(indio_dev);
 136         unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
 137
 138         ad7266_select_input(st, nr);
 139
 140         return 0;
 141 }
 142
 143 static int ad7266_read_single(struct ad7266_state *st, int *val,
 144         unsigned int address)
 145 {
 146         int ret;
 147
 148         ad7266_select_input(st, address);
 149
 150         ret = spi_sync(st->spi, &st->single_msg);
 151         *val = be16_to_cpu(st->data[address % 2]);
 152
 153         return ret;
 154 }
 155
 156 static int ad7266_read_raw(struct iio_dev *indio_dev,
 157         struct iio_chan_spec const *chan, int *val, int *val2, long m)
 158 {
 159         struct ad7266_state *st = iio_priv(indio_dev);
 160         unsigned long scale_uv;
 161         int ret;
 162
 163         switch (m) {
 164         case IIO_CHAN_INFO_RAW:
 165                 if (iio_buffer_enabled(indio_dev))
 166                         return -EBUSY;
 167
 168                 ret = ad7266_read_single(st, val, chan->address);
 169                 if (ret)
 170                         return ret;
 171
 172                 *val = (*val >> 2) & 0xfff;
 173                 if (chan->scan_type.sign == 's')
 174                         *val = sign_extend32(*val, 11);
 175
 176                 return IIO_VAL_INT;
 177         case IIO_CHAN_INFO_SCALE:
 178                 scale_uv = (st->vref_uv * 100);
 179                 if (st->mode == AD7266_MODE_DIFF)
 180                         scale_uv *= 2;
 181                 if (st->range == AD7266_RANGE_2VREF)
 182                         scale_uv *= 2;
 183
 184                 scale_uv >>= chan->scan_type.realbits;
 185                 *val =  scale_uv / 100000;
 186                 *val2 = (scale_uv % 100000) * 10;
 187                 return IIO_VAL_INT_PLUS_MICRO;
 188         case IIO_CHAN_INFO_OFFSET:
 189                 if (st->range == AD7266_RANGE_2VREF &&
 190                         st->mode != AD7266_MODE_DIFF)
 191                         *val = 2048;
 192                 else
 193                         *val = 0;
 194                 return IIO_VAL_INT;
 195         }
 196         return -EINVAL;
 197 }
 198
 199 #define AD7266_CHAN(_chan, _sign) {                     \
 200         .type = IIO_VOLTAGE,                            \
 201         .indexed = 1,                                   \
 202         .channel = (_chan),                             \
 203         .address = (_chan),                             \
 204         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 205         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 206                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 207         .scan_index = (_chan),                          \
 208         .scan_type = {                                  \
 209                 .sign = (_sign),                        \
 210                 .realbits = 12,                         \
 211                 .storagebits = 16,                      \
 212                 .shift = 2,                             \
 213                 .endianness = IIO_BE,                   \
 214         },                                              \
 215 }
 216
 217 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 218 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 219         AD7266_CHAN(0, (_sign)), \
 220         AD7266_CHAN(1, (_sign)), \
 221         AD7266_CHAN(2, (_sign)), \
 222         AD7266_CHAN(3, (_sign)), \
 223         AD7266_CHAN(4, (_sign)), \
 224         AD7266_CHAN(5, (_sign)), \
 225         AD7266_CHAN(6, (_sign)), \
 226         AD7266_CHAN(7, (_sign)), \
 227         AD7266_CHAN(8, (_sign)), \
 228         AD7266_CHAN(9, (_sign)), \
 229         AD7266_CHAN(10, (_sign)), \
 230         AD7266_CHAN(11, (_sign)), \
 231         IIO_CHAN_SOFT_TIMESTAMP(13), \
 232 }
 233
 234 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 235 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 236         AD7266_CHAN(0, (_sign)), \
 237         AD7266_CHAN(1, (_sign)), \
 238         IIO_CHAN_SOFT_TIMESTAMP(2), \
 239 }
 240
 241 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 242 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 243 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 244 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
 245
 246 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
 247         .type = IIO_VOLTAGE,                            \
 248         .indexed = 1,                                   \
 249         .channel = (_chan) * 2,                         \
 250         .channel2 = (_chan) * 2 + 1,                    \
 251         .address = (_chan),                             \
 252         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 253         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
 254                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 255         .scan_index = (_chan),                          \
 256         .scan_type = {                                  \
 257                 .sign = _sign,                  \
 258                 .realbits = 12,                         \
 259                 .storagebits = 16,                      \
 260                 .shift = 2,                             \
 261                 .endianness = IIO_BE,                   \
 262         },                                              \
 263         .differential = 1,                              \
 264 }
 265
 266 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 267 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 268         AD7266_CHAN_DIFF(0, (_sign)), \
 269         AD7266_CHAN_DIFF(1, (_sign)), \
 270         AD7266_CHAN_DIFF(2, (_sign)), \
 271         AD7266_CHAN_DIFF(3, (_sign)), \
 272         AD7266_CHAN_DIFF(4, (_sign)), \
 273         AD7266_CHAN_DIFF(5, (_sign)), \
 274         IIO_CHAN_SOFT_TIMESTAMP(6), \
 275 }
 276
 277 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 278 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 279
 280 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 281 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 282         AD7266_CHAN_DIFF(0, (_sign)), \
 283         AD7266_CHAN_DIFF(1, (_sign)), \
 284         IIO_CHAN_SOFT_TIMESTAMP(2), \
 285 }
 286
 287 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 288 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 289
 290 static const struct iio_info ad7266_info = {
 291         .read_raw = &ad7266_read_raw,
 292         .update_scan_mode = &ad7266_update_scan_mode,
 293         .driver_module = THIS_MODULE,
 294 };
 295
 296 static unsigned long ad7266_available_scan_masks[] = {
 297         0x003,
 298         0x00c,
 299         0x030,
 300         0x0c0,
 301         0x300,
 302         0xc00,
 303         0x000,
 304 };
 305
 306 static unsigned long ad7266_available_scan_masks_diff[] = {
 307         0x003,
 308         0x00c,
 309         0x030,
 310         0x000,
 311 };
 312
 313 static unsigned long ad7266_available_scan_masks_fixed[] = {
 314         0x003,
 315         0x000,
 316 };
 317
 318 struct ad7266_chan_info {
 319         const struct iio_chan_spec *channels;
 320         unsigned int num_channels;
 321         unsigned long *scan_masks;
 322 };
 323
 324 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 325         (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
 326
 327 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 328         [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 329                 .channels = ad7266_channels_u,
 330                 .num_channels = ARRAY_SIZE(ad7266_channels_u),
 331                 .scan_masks = ad7266_available_scan_masks,
 332         },
 333         [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 334                 .channels = ad7266_channels_u_fixed,
 335                 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 336                 .scan_masks = ad7266_available_scan_masks_fixed,
 337         },
 338         [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 339                 .channels = ad7266_channels_s,
 340                 .num_channels = ARRAY_SIZE(ad7266_channels_s),
 341                 .scan_masks = ad7266_available_scan_masks,
 342         },
 343         [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 344                 .channels = ad7266_channels_s_fixed,
 345                 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 346                 .scan_masks = ad7266_available_scan_masks_fixed,
 347         },
 348         [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 349                 .channels = ad7266_channels_diff_u,
 350                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 351                 .scan_masks = ad7266_available_scan_masks_diff,
 352         },
 353         [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 354                 .channels = ad7266_channels_diff_fixed_u,
 355                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 356                 .scan_masks = ad7266_available_scan_masks_fixed,
 357         },
 358         [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 359                 .channels = ad7266_channels_diff_s,
 360                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 361                 .scan_masks = ad7266_available_scan_masks_diff,
 362         },
 363         [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 364                 .channels = ad7266_channels_diff_fixed_s,
 365                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 366                 .scan_masks = ad7266_available_scan_masks_fixed,
 367         },
 368 };
 369
 370 static void ad7266_init_channels(struct iio_dev *indio_dev)
 371 {
 372         struct ad7266_state *st = iio_priv(indio_dev);
 373         bool is_differential, is_signed;
 374         const struct ad7266_chan_info *chan_info;
 375         int i;
 376
 377         is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 378         is_signed = (st->range == AD7266_RANGE_2VREF) |
 379                     (st->mode == AD7266_MODE_DIFF);
 380
 381         i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 382         chan_info = &ad7266_chan_infos[i];
 383
 384         indio_dev->channels = chan_info->channels;
 385         indio_dev->num_channels = chan_info->num_channels;
 386         indio_dev->available_scan_masks = chan_info->scan_masks;
 387         indio_dev->masklength = chan_info->num_channels - 1;
 388 }
 389
 390 static const char * const ad7266_gpio_labels[] = {
 391         "AD0", "AD1", "AD2",
 392 };
 393
 394 static int ad7266_probe(struct spi_device *spi)
 395 {
 396         struct ad7266_platform_data *pdata = spi->dev.platform_data;
 397         struct iio_dev *indio_dev;
 398         struct ad7266_state *st;
 399         unsigned int i;
 400         int ret;
 401
 402         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 403         if (indio_dev == NULL)
 404                 return -ENOMEM;
 405
 406         st = iio_priv(indio_dev);
 407
 408         st->reg = devm_regulator_get(&spi->dev, "vref");
 409         if (!IS_ERR_OR_NULL(st->reg)) {
 410                 ret = regulator_enable(st->reg);
 411                 if (ret)
 412                         return ret;
 413
 414                 ret = regulator_get_voltage(st->reg);
 415                 if (ret < 0)
 416                         goto error_disable_reg;
 417
 418                 st->vref_uv = ret;
 419         } else {
 420                 /* Use internal reference */
 421                 st->vref_uv = 2500000;
 422         }
 423
 424         if (pdata) {
 425                 st->fixed_addr = pdata->fixed_addr;
 426                 st->mode = pdata->mode;
 427                 st->range = pdata->range;
 428
 429                 if (!st->fixed_addr) {
 430                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 431                                 st->gpios[i].gpio = pdata->addr_gpios[i];
 432                                 st->gpios[i].flags = GPIOF_OUT_INIT_LOW;
 433                                 st->gpios[i].label = ad7266_gpio_labels[i];
 434                         }
 435                         ret = gpio_request_array(st->gpios,
 436                                 ARRAY_SIZE(st->gpios));
 437                         if (ret)
 438                                 goto error_disable_reg;
 439                 }
 440         } else {
 441                 st->fixed_addr = true;
 442                 st->range = AD7266_RANGE_VREF;
 443                 st->mode = AD7266_MODE_DIFF;
 444         }
 445
 446         spi_set_drvdata(spi, indio_dev);
 447         st->spi = spi;
 448
 449         indio_dev->dev.parent = &spi->dev;
 450         indio_dev->name = spi_get_device_id(spi)->name;
 451         indio_dev->modes = INDIO_DIRECT_MODE;
 452         indio_dev->info = &ad7266_info;
 453
 454         ad7266_init_channels(indio_dev);
 455
 456         /* wakeup */
 457         st->single_xfer[0].rx_buf = &st->data;
 458         st->single_xfer[0].len = 2;
 459         st->single_xfer[0].cs_change = 1;
 460         /* conversion */
 461         st->single_xfer[1].rx_buf = &st->data;
 462         st->single_xfer[1].len = 4;
 463         st->single_xfer[1].cs_change = 1;
 464         /* powerdown */
 465         st->single_xfer[2].tx_buf = &st->data;
 466         st->single_xfer[2].len = 1;
 467
 468         spi_message_init(&st->single_msg);
 469         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 470         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 471         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
 472
 473         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 474                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 475         if (ret)
 476                 goto error_free_gpios;
 477
 478         ret = iio_device_register(indio_dev);
 479         if (ret)
 480                 goto error_buffer_cleanup;
 481
 482         return 0;
 483
 484 error_buffer_cleanup:
 485         iio_triggered_buffer_cleanup(indio_dev);
 486 error_free_gpios:
 487         if (!st->fixed_addr)
 488                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 489 error_disable_reg:
 490         if (!IS_ERR_OR_NULL(st->reg))
 491                 regulator_disable(st->reg);
 492
 493         return ret;
 494 }
 495
 496 static int ad7266_remove(struct spi_device *spi)
 497 {
 498         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 499         struct ad7266_state *st = iio_priv(indio_dev);
 500
 501         iio_device_unregister(indio_dev);
 502         iio_triggered_buffer_cleanup(indio_dev);
 503         if (!st->fixed_addr)
 504                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 505         if (!IS_ERR_OR_NULL(st->reg))
 506                 regulator_disable(st->reg);
 507
 508         return 0;
 509 }
 510
 511 static const struct spi_device_id ad7266_id[] = {
 512         {"ad7265", 0},
 513         {"ad7266", 0},
 514         { }
 515 };
 516 MODULE_DEVICE_TABLE(spi, ad7266_id);
 517
 518 static struct spi_driver ad7266_driver = {
 519         .driver = {
 520                 .name   = "ad7266",
 521                 .owner  = THIS_MODULE,
 522         },
 523         .probe          = ad7266_probe,
 524         .remove         = ad7266_remove,
 525         .id_table       = ad7266_id,
 526 };
 527 module_spi_driver(ad7266_driver);
 528
 529 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 530 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 531 MODULE_LICENSE("GPL v2");