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