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 iio_buffer *buffer = indio_dev->buffer;
  95         struct ad7266_state *st = iio_priv(indio_dev);
  96         int ret;
  97
  98         ret = spi_read(st->spi, st->data, 4);
  99         if (ret == 0) {
 100                 if (indio_dev->scan_timestamp)
 101                         ((s64 *)st->data)[1] = pf->timestamp;
 102                 iio_push_to_buffer(buffer, (u8 *)st->data, pf->timestamp);
 103         }
 104
 105         iio_trigger_notify_done(indio_dev->trig);
 106
 107         return IRQ_HANDLED;
 108 }
 109
 110 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
 111 {
 112         unsigned int i;
 113
 114         if (st->fixed_addr)
 115                 return;
 116
 117         switch (st->mode) {
 118         case AD7266_MODE_SINGLE_ENDED:
 119                 nr >>= 1;
 120                 break;
 121         case AD7266_MODE_PSEUDO_DIFF:
 122                 nr |= 1;
 123                 break;
 124         case AD7266_MODE_DIFF:
 125                 nr &= ~1;
 126                 break;
 127         }
 128
 129         for (i = 0; i < 3; ++i)
 130                 gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));
 131 }
 132
 133 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
 134         const unsigned long *scan_mask)
 135 {
 136         struct ad7266_state *st = iio_priv(indio_dev);
 137         unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
 138
 139         ad7266_select_input(st, nr);
 140
 141         return 0;
 142 }
 143
 144 static int ad7266_read_single(struct ad7266_state *st, int *val,
 145         unsigned int address)
 146 {
 147         int ret;
 148
 149         ad7266_select_input(st, address);
 150
 151         ret = spi_sync(st->spi, &st->single_msg);
 152         *val = be16_to_cpu(st->data[address % 2]);
 153
 154         return ret;
 155 }
 156
 157 static int ad7266_read_raw(struct iio_dev *indio_dev,
 158         struct iio_chan_spec const *chan, int *val, int *val2, long m)
 159 {
 160         struct ad7266_state *st = iio_priv(indio_dev);
 161         unsigned long scale_uv;
 162         int ret;
 163
 164         switch (m) {
 165         case IIO_CHAN_INFO_RAW:
 166                 if (iio_buffer_enabled(indio_dev))
 167                         return -EBUSY;
 168
 169                 ret = ad7266_read_single(st, val, chan->address);
 170                 if (ret)
 171                         return ret;
 172
 173                 *val = (*val >> 2) & 0xfff;
 174                 if (chan->scan_type.sign == 's')
 175                         *val = sign_extend32(*val, 11);
 176
 177                 return IIO_VAL_INT;
 178         case IIO_CHAN_INFO_SCALE:
 179                 scale_uv = (st->vref_uv * 100);
 180                 if (st->mode == AD7266_MODE_DIFF)
 181                         scale_uv *= 2;
 182                 if (st->range == AD7266_RANGE_2VREF)
 183                         scale_uv *= 2;
 184
 185                 scale_uv >>= chan->scan_type.realbits;
 186                 *val =  scale_uv / 100000;
 187                 *val2 = (scale_uv % 100000) * 10;
 188                 return IIO_VAL_INT_PLUS_MICRO;
 189         case IIO_CHAN_INFO_OFFSET:
 190                 if (st->range == AD7266_RANGE_2VREF &&
 191                         st->mode != AD7266_MODE_DIFF)
 192                         *val = 2048;
 193                 else
 194                         *val = 0;
 195                 return IIO_VAL_INT;
 196         }
 197         return -EINVAL;
 198 }
 199
 200 #define AD7266_CHAN(_chan, _sign) {                     \
 201         .type = IIO_VOLTAGE,                            \
 202         .indexed = 1,                                   \
 203         .channel = (_chan),                             \
 204         .address = (_chan),                             \
 205         .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT     \
 206                 | IIO_CHAN_INFO_SCALE_SHARED_BIT        \
 207                 | IIO_CHAN_INFO_OFFSET_SHARED_BIT,      \
 208         .scan_index = (_chan),                          \
 209         .scan_type = {                                  \
 210                 .sign = (_sign),                        \
 211                 .realbits = 12,                         \
 212                 .storagebits = 16,                      \
 213                 .shift = 2,                             \
 214                 .endianness = IIO_BE,                   \
 215         },                                              \
 216 }
 217
 218 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 219 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 220         AD7266_CHAN(0, (_sign)), \
 221         AD7266_CHAN(1, (_sign)), \
 222         AD7266_CHAN(2, (_sign)), \
 223         AD7266_CHAN(3, (_sign)), \
 224         AD7266_CHAN(4, (_sign)), \
 225         AD7266_CHAN(5, (_sign)), \
 226         AD7266_CHAN(6, (_sign)), \
 227         AD7266_CHAN(7, (_sign)), \
 228         AD7266_CHAN(8, (_sign)), \
 229         AD7266_CHAN(9, (_sign)), \
 230         AD7266_CHAN(10, (_sign)), \
 231         AD7266_CHAN(11, (_sign)), \
 232         IIO_CHAN_SOFT_TIMESTAMP(13), \
 233 }
 234
 235 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 236 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 237         AD7266_CHAN(0, (_sign)), \
 238         AD7266_CHAN(1, (_sign)), \
 239         IIO_CHAN_SOFT_TIMESTAMP(2), \
 240 }
 241
 242 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 243 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 244 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 245 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
 246
 247 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
 248         .type = IIO_VOLTAGE,                            \
 249         .indexed = 1,                                   \
 250         .channel = (_chan) * 2,                         \
 251         .channel2 = (_chan) * 2 + 1,                    \
 252         .address = (_chan),                             \
 253         .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT     \
 254                 | IIO_CHAN_INFO_SCALE_SHARED_BIT        \
 255                 | IIO_CHAN_INFO_OFFSET_SHARED_BIT,      \
 256         .scan_index = (_chan),                          \
 257         .scan_type = {                                  \
 258                 .sign = _sign,                  \
 259                 .realbits = 12,                         \
 260                 .storagebits = 16,                      \
 261                 .shift = 2,                             \
 262                 .endianness = IIO_BE,                   \
 263         },                                              \
 264         .differential = 1,                              \
 265 }
 266
 267 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 268 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 269         AD7266_CHAN_DIFF(0, (_sign)), \
 270         AD7266_CHAN_DIFF(1, (_sign)), \
 271         AD7266_CHAN_DIFF(2, (_sign)), \
 272         AD7266_CHAN_DIFF(3, (_sign)), \
 273         AD7266_CHAN_DIFF(4, (_sign)), \
 274         AD7266_CHAN_DIFF(5, (_sign)), \
 275         IIO_CHAN_SOFT_TIMESTAMP(6), \
 276 }
 277
 278 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 279 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 280
 281 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 282 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 283         AD7266_CHAN_DIFF(0, (_sign)), \
 284         AD7266_CHAN_DIFF(1, (_sign)), \
 285         IIO_CHAN_SOFT_TIMESTAMP(2), \
 286 }
 287
 288 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 289 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 290
 291 static const struct iio_info ad7266_info = {
 292         .read_raw = &ad7266_read_raw,
 293         .update_scan_mode = &ad7266_update_scan_mode,
 294         .driver_module = THIS_MODULE,
 295 };
 296
 297 static unsigned long ad7266_available_scan_masks[] = {
 298         0x003,
 299         0x00c,
 300         0x030,
 301         0x0c0,
 302         0x300,
 303         0xc00,
 304         0x000,
 305 };
 306
 307 static unsigned long ad7266_available_scan_masks_diff[] = {
 308         0x003,
 309         0x00c,
 310         0x030,
 311         0x000,
 312 };
 313
 314 static unsigned long ad7266_available_scan_masks_fixed[] = {
 315         0x003,
 316         0x000,
 317 };
 318
 319 struct ad7266_chan_info {
 320         const struct iio_chan_spec *channels;
 321         unsigned int num_channels;
 322         unsigned long *scan_masks;
 323 };
 324
 325 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 326         (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
 327
 328 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 329         [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 330                 .channels = ad7266_channels_u,
 331                 .num_channels = ARRAY_SIZE(ad7266_channels_u),
 332                 .scan_masks = ad7266_available_scan_masks,
 333         },
 334         [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 335                 .channels = ad7266_channels_u_fixed,
 336                 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 337                 .scan_masks = ad7266_available_scan_masks_fixed,
 338         },
 339         [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 340                 .channels = ad7266_channels_s,
 341                 .num_channels = ARRAY_SIZE(ad7266_channels_s),
 342                 .scan_masks = ad7266_available_scan_masks,
 343         },
 344         [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 345                 .channels = ad7266_channels_s_fixed,
 346                 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 347                 .scan_masks = ad7266_available_scan_masks_fixed,
 348         },
 349         [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 350                 .channels = ad7266_channels_diff_u,
 351                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 352                 .scan_masks = ad7266_available_scan_masks_diff,
 353         },
 354         [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 355                 .channels = ad7266_channels_diff_fixed_u,
 356                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 357                 .scan_masks = ad7266_available_scan_masks_fixed,
 358         },
 359         [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 360                 .channels = ad7266_channels_diff_s,
 361                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 362                 .scan_masks = ad7266_available_scan_masks_diff,
 363         },
 364         [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 365                 .channels = ad7266_channels_diff_fixed_s,
 366                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 367                 .scan_masks = ad7266_available_scan_masks_fixed,
 368         },
 369 };
 370
 371 static void __devinit ad7266_init_channels(struct iio_dev *indio_dev)
 372 {
 373         struct ad7266_state *st = iio_priv(indio_dev);
 374         bool is_differential, is_signed;
 375         const struct ad7266_chan_info *chan_info;
 376         int i;
 377
 378         is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 379         is_signed = (st->range == AD7266_RANGE_2VREF) |
 380                     (st->mode == AD7266_MODE_DIFF);
 381
 382         i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 383         chan_info = &ad7266_chan_infos[i];
 384
 385         indio_dev->channels = chan_info->channels;
 386         indio_dev->num_channels = chan_info->num_channels;
 387         indio_dev->available_scan_masks = chan_info->scan_masks;
 388         indio_dev->masklength = chan_info->num_channels - 1;
 389 }
 390
 391 static const char * const ad7266_gpio_labels[] = {
 392         "AD0", "AD1", "AD2",
 393 };
 394
 395 static int __devinit ad7266_probe(struct spi_device *spi)
 396 {
 397         struct ad7266_platform_data *pdata = spi->dev.platform_data;
 398         struct iio_dev *indio_dev;
 399         struct ad7266_state *st;
 400         unsigned int i;
 401         int ret;
 402
 403         indio_dev = iio_device_alloc(sizeof(*st));
 404         if (indio_dev == NULL)
 405                 return -ENOMEM;
 406
 407         st = iio_priv(indio_dev);
 408
 409         st->reg = regulator_get(&spi->dev, "vref");
 410         if (!IS_ERR_OR_NULL(st->reg)) {
 411                 ret = regulator_enable(st->reg);
 412                 if (ret)
 413                         goto error_put_reg;
 414
 415                 st->vref_uv = regulator_get_voltage(st->reg);
 416         } else {
 417                 /* Use internal reference */
 418                 st->vref_uv = 2500000;
 419         }
 420
 421         if (pdata) {
 422                 st->fixed_addr = pdata->fixed_addr;
 423                 st->mode = pdata->mode;
 424                 st->range = pdata->range;
 425
 426                 if (!st->fixed_addr) {
 427                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 428                                 st->gpios[i].gpio = pdata->addr_gpios[i];
 429                                 st->gpios[i].flags = GPIOF_OUT_INIT_LOW;
 430                                 st->gpios[i].label = ad7266_gpio_labels[i];
 431                         }
 432                         ret = gpio_request_array(st->gpios,
 433                                 ARRAY_SIZE(st->gpios));
 434                         if (ret)
 435                                 goto error_disable_reg;
 436                 }
 437         } else {
 438                 st->fixed_addr = true;
 439                 st->range = AD7266_RANGE_VREF;
 440                 st->mode = AD7266_MODE_DIFF;
 441         }
 442
 443         spi_set_drvdata(spi, indio_dev);
 444         st->spi = spi;
 445
 446         indio_dev->dev.parent = &spi->dev;
 447         indio_dev->name = spi_get_device_id(spi)->name;
 448         indio_dev->modes = INDIO_DIRECT_MODE;
 449         indio_dev->info = &ad7266_info;
 450
 451         ad7266_init_channels(indio_dev);
 452
 453         /* wakeup */
 454         st->single_xfer[0].rx_buf = &st->data;
 455         st->single_xfer[0].len = 2;
 456         st->single_xfer[0].cs_change = 1;
 457         /* conversion */
 458         st->single_xfer[1].rx_buf = &st->data;
 459         st->single_xfer[1].len = 4;
 460         st->single_xfer[1].cs_change = 1;
 461         /* powerdown */
 462         st->single_xfer[2].tx_buf = &st->data;
 463         st->single_xfer[2].len = 1;
 464
 465         spi_message_init(&st->single_msg);
 466         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 467         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 468         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
 469
 470         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 471                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 472         if (ret)
 473                 goto error_free_gpios;
 474
 475         ret = iio_device_register(indio_dev);
 476         if (ret)
 477                 goto error_buffer_cleanup;
 478
 479         return 0;
 480
 481 error_buffer_cleanup:
 482         iio_triggered_buffer_cleanup(indio_dev);
 483 error_free_gpios:
 484         if (!st->fixed_addr)
 485                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 486 error_disable_reg:
 487         if (!IS_ERR_OR_NULL(st->reg))
 488                 regulator_disable(st->reg);
 489 error_put_reg:
 490         if (!IS_ERR_OR_NULL(st->reg))
 491                 regulator_put(st->reg);
 492
 493         iio_device_free(indio_dev);
 494
 495         return ret;
 496 }
 497
 498 static int __devexit ad7266_remove(struct spi_device *spi)
 499 {
 500         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 501         struct ad7266_state *st = iio_priv(indio_dev);
 502
 503         iio_device_unregister(indio_dev);
 504         iio_triggered_buffer_cleanup(indio_dev);
 505         if (!st->fixed_addr)
 506                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 507         if (!IS_ERR_OR_NULL(st->reg)) {
 508                 regulator_disable(st->reg);
 509                 regulator_put(st->reg);
 510         }
 511         iio_device_free(indio_dev);
 512
 513         return 0;
 514 }
 515
 516 static const struct spi_device_id ad7266_id[] = {
 517         {"ad7265", 0},
 518         {"ad7266", 0},
 519         { }
 520 };
 521 MODULE_DEVICE_TABLE(spi, ad7266_id);
 522
 523 static struct spi_driver ad7266_driver = {
 524         .driver = {
 525                 .name   = "ad7266",
 526                 .owner  = THIS_MODULE,
 527         },
 528         .probe          = ad7266_probe,
 529         .remove         = __devexit_p(ad7266_remove),
 530         .id_table       = ad7266_id,
 531 };
 532 module_spi_driver(ad7266_driver);
 533
 534 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 535 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 536 MODULE_LICENSE("GPL v2");