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_mv;
  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         return ad7266_wakeup(st);
  65 }
  66
  67 static int ad7266_postdisable(struct iio_dev *indio_dev)
  68 {
  69         struct ad7266_state *st = iio_priv(indio_dev);
  70         return ad7266_powerdown(st);
  71 }
  72
  73 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
  74         .preenable = &ad7266_preenable,
  75         .postenable = &iio_triggered_buffer_postenable,
  76         .predisable = &iio_triggered_buffer_predisable,
  77         .postdisable = &ad7266_postdisable,
  78 };
  79
  80 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
  81 {
  82         struct iio_poll_func *pf = p;
  83         struct iio_dev *indio_dev = pf->indio_dev;
  84         struct ad7266_state *st = iio_priv(indio_dev);
  85         int ret;
  86
  87         ret = spi_read(st->spi, st->data, 4);
  88         if (ret == 0) {
  89                 iio_push_to_buffers_with_timestamp(indio_dev, st->data,
  90                             pf->timestamp);
  91         }
  92
  93         iio_trigger_notify_done(indio_dev->trig);
  94
  95         return IRQ_HANDLED;
  96 }
  97
  98 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
  99 {
 100         unsigned int i;
 101
 102         if (st->fixed_addr)
 103                 return;
 104
 105         switch (st->mode) {
 106         case AD7266_MODE_SINGLE_ENDED:
 107                 nr >>= 1;
 108                 break;
 109         case AD7266_MODE_PSEUDO_DIFF:
 110                 nr |= 1;
 111                 break;
 112         case AD7266_MODE_DIFF:
 113                 nr &= ~1;
 114                 break;
 115         }
 116
 117         for (i = 0; i < 3; ++i)
 118                 gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));
 119 }
 120
 121 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
 122         const unsigned long *scan_mask)
 123 {
 124         struct ad7266_state *st = iio_priv(indio_dev);
 125         unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
 126
 127         ad7266_select_input(st, nr);
 128
 129         return 0;
 130 }
 131
 132 static int ad7266_read_single(struct ad7266_state *st, int *val,
 133         unsigned int address)
 134 {
 135         int ret;
 136
 137         ad7266_select_input(st, address);
 138
 139         ret = spi_sync(st->spi, &st->single_msg);
 140         *val = be16_to_cpu(st->data[address % 2]);
 141
 142         return ret;
 143 }
 144
 145 static int ad7266_read_raw(struct iio_dev *indio_dev,
 146         struct iio_chan_spec const *chan, int *val, int *val2, long m)
 147 {
 148         struct ad7266_state *st = iio_priv(indio_dev);
 149         unsigned long scale_mv;
 150         int ret;
 151
 152         switch (m) {
 153         case IIO_CHAN_INFO_RAW:
 154                 if (iio_buffer_enabled(indio_dev))
 155                         return -EBUSY;
 156
 157                 ret = ad7266_read_single(st, val, chan->address);
 158                 if (ret)
 159                         return ret;
 160
 161                 *val = (*val >> 2) & 0xfff;
 162                 if (chan->scan_type.sign == 's')
 163                         *val = sign_extend32(*val, 11);
 164
 165                 return IIO_VAL_INT;
 166         case IIO_CHAN_INFO_SCALE:
 167                 scale_mv = st->vref_mv;
 168                 if (st->mode == AD7266_MODE_DIFF)
 169                         scale_mv *= 2;
 170                 if (st->range == AD7266_RANGE_2VREF)
 171                         scale_mv *= 2;
 172
 173                 *val = scale_mv;
 174                 *val2 = chan->scan_type.realbits;
 175                 return IIO_VAL_FRACTIONAL_LOG2;
 176         case IIO_CHAN_INFO_OFFSET:
 177                 if (st->range == AD7266_RANGE_2VREF &&
 178                         st->mode != AD7266_MODE_DIFF)
 179                         *val = 2048;
 180                 else
 181                         *val = 0;
 182                 return IIO_VAL_INT;
 183         }
 184         return -EINVAL;
 185 }
 186
 187 #define AD7266_CHAN(_chan, _sign) {                     \
 188         .type = IIO_VOLTAGE,                            \
 189         .indexed = 1,                                   \
 190         .channel = (_chan),                             \
 191         .address = (_chan),                             \
 192         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 193         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 194                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 195         .scan_index = (_chan),                          \
 196         .scan_type = {                                  \
 197                 .sign = (_sign),                        \
 198                 .realbits = 12,                         \
 199                 .storagebits = 16,                      \
 200                 .shift = 2,                             \
 201                 .endianness = IIO_BE,                   \
 202         },                                              \
 203 }
 204
 205 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 206 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 207         AD7266_CHAN(0, (_sign)), \
 208         AD7266_CHAN(1, (_sign)), \
 209         AD7266_CHAN(2, (_sign)), \
 210         AD7266_CHAN(3, (_sign)), \
 211         AD7266_CHAN(4, (_sign)), \
 212         AD7266_CHAN(5, (_sign)), \
 213         AD7266_CHAN(6, (_sign)), \
 214         AD7266_CHAN(7, (_sign)), \
 215         AD7266_CHAN(8, (_sign)), \
 216         AD7266_CHAN(9, (_sign)), \
 217         AD7266_CHAN(10, (_sign)), \
 218         AD7266_CHAN(11, (_sign)), \
 219         IIO_CHAN_SOFT_TIMESTAMP(13), \
 220 }
 221
 222 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 223 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 224         AD7266_CHAN(0, (_sign)), \
 225         AD7266_CHAN(1, (_sign)), \
 226         IIO_CHAN_SOFT_TIMESTAMP(2), \
 227 }
 228
 229 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 230 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
 233
 234 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
 235         .type = IIO_VOLTAGE,                            \
 236         .indexed = 1,                                   \
 237         .channel = (_chan) * 2,                         \
 238         .channel2 = (_chan) * 2 + 1,                    \
 239         .address = (_chan),                             \
 240         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 241         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
 242                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 243         .scan_index = (_chan),                          \
 244         .scan_type = {                                  \
 245                 .sign = _sign,                  \
 246                 .realbits = 12,                         \
 247                 .storagebits = 16,                      \
 248                 .shift = 2,                             \
 249                 .endianness = IIO_BE,                   \
 250         },                                              \
 251         .differential = 1,                              \
 252 }
 253
 254 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 255 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 256         AD7266_CHAN_DIFF(0, (_sign)), \
 257         AD7266_CHAN_DIFF(1, (_sign)), \
 258         AD7266_CHAN_DIFF(2, (_sign)), \
 259         AD7266_CHAN_DIFF(3, (_sign)), \
 260         AD7266_CHAN_DIFF(4, (_sign)), \
 261         AD7266_CHAN_DIFF(5, (_sign)), \
 262         IIO_CHAN_SOFT_TIMESTAMP(6), \
 263 }
 264
 265 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 266 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 267
 268 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 269 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 270         AD7266_CHAN_DIFF(0, (_sign)), \
 271         AD7266_CHAN_DIFF(1, (_sign)), \
 272         IIO_CHAN_SOFT_TIMESTAMP(2), \
 273 }
 274
 275 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 276 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 277
 278 static const struct iio_info ad7266_info = {
 279         .read_raw = &ad7266_read_raw,
 280         .update_scan_mode = &ad7266_update_scan_mode,
 281         .driver_module = THIS_MODULE,
 282 };
 283
 284 static const unsigned long ad7266_available_scan_masks[] = {
 285         0x003,
 286         0x00c,
 287         0x030,
 288         0x0c0,
 289         0x300,
 290         0xc00,
 291         0x000,
 292 };
 293
 294 static const unsigned long ad7266_available_scan_masks_diff[] = {
 295         0x003,
 296         0x00c,
 297         0x030,
 298         0x000,
 299 };
 300
 301 static const unsigned long ad7266_available_scan_masks_fixed[] = {
 302         0x003,
 303         0x000,
 304 };
 305
 306 struct ad7266_chan_info {
 307         const struct iio_chan_spec *channels;
 308         unsigned int num_channels;
 309         const unsigned long *scan_masks;
 310 };
 311
 312 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 313         (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
 314
 315 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 316         [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 317                 .channels = ad7266_channels_u,
 318                 .num_channels = ARRAY_SIZE(ad7266_channels_u),
 319                 .scan_masks = ad7266_available_scan_masks,
 320         },
 321         [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 322                 .channels = ad7266_channels_u_fixed,
 323                 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 324                 .scan_masks = ad7266_available_scan_masks_fixed,
 325         },
 326         [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 327                 .channels = ad7266_channels_s,
 328                 .num_channels = ARRAY_SIZE(ad7266_channels_s),
 329                 .scan_masks = ad7266_available_scan_masks,
 330         },
 331         [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 332                 .channels = ad7266_channels_s_fixed,
 333                 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 334                 .scan_masks = ad7266_available_scan_masks_fixed,
 335         },
 336         [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 337                 .channels = ad7266_channels_diff_u,
 338                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 339                 .scan_masks = ad7266_available_scan_masks_diff,
 340         },
 341         [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 342                 .channels = ad7266_channels_diff_fixed_u,
 343                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 344                 .scan_masks = ad7266_available_scan_masks_fixed,
 345         },
 346         [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 347                 .channels = ad7266_channels_diff_s,
 348                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 349                 .scan_masks = ad7266_available_scan_masks_diff,
 350         },
 351         [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 352                 .channels = ad7266_channels_diff_fixed_s,
 353                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 354                 .scan_masks = ad7266_available_scan_masks_fixed,
 355         },
 356 };
 357
 358 static void ad7266_init_channels(struct iio_dev *indio_dev)
 359 {
 360         struct ad7266_state *st = iio_priv(indio_dev);
 361         bool is_differential, is_signed;
 362         const struct ad7266_chan_info *chan_info;
 363         int i;
 364
 365         is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 366         is_signed = (st->range == AD7266_RANGE_2VREF) |
 367                     (st->mode == AD7266_MODE_DIFF);
 368
 369         i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 370         chan_info = &ad7266_chan_infos[i];
 371
 372         indio_dev->channels = chan_info->channels;
 373         indio_dev->num_channels = chan_info->num_channels;
 374         indio_dev->available_scan_masks = chan_info->scan_masks;
 375         indio_dev->masklength = chan_info->num_channels - 1;
 376 }
 377
 378 static const char * const ad7266_gpio_labels[] = {
 379         "AD0", "AD1", "AD2",
 380 };
 381
 382 static int ad7266_probe(struct spi_device *spi)
 383 {
 384         struct ad7266_platform_data *pdata = spi->dev.platform_data;
 385         struct iio_dev *indio_dev;
 386         struct ad7266_state *st;
 387         unsigned int i;
 388         int ret;
 389
 390         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 391         if (indio_dev == NULL)
 392                 return -ENOMEM;
 393
 394         st = iio_priv(indio_dev);
 395
 396         st->reg = devm_regulator_get(&spi->dev, "vref");
 397         if (!IS_ERR_OR_NULL(st->reg)) {
 398                 ret = regulator_enable(st->reg);
 399                 if (ret)
 400                         return ret;
 401
 402                 ret = regulator_get_voltage(st->reg);
 403                 if (ret < 0)
 404                         goto error_disable_reg;
 405
 406                 st->vref_mv = ret / 1000;
 407         } else {
 408                 /* Use internal reference */
 409                 st->vref_mv = 2500;
 410         }
 411
 412         if (pdata) {
 413                 st->fixed_addr = pdata->fixed_addr;
 414                 st->mode = pdata->mode;
 415                 st->range = pdata->range;
 416
 417                 if (!st->fixed_addr) {
 418                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 419                                 st->gpios[i].gpio = pdata->addr_gpios[i];
 420                                 st->gpios[i].flags = GPIOF_OUT_INIT_LOW;
 421                                 st->gpios[i].label = ad7266_gpio_labels[i];
 422                         }
 423                         ret = gpio_request_array(st->gpios,
 424                                 ARRAY_SIZE(st->gpios));
 425                         if (ret)
 426                                 goto error_disable_reg;
 427                 }
 428         } else {
 429                 st->fixed_addr = true;
 430                 st->range = AD7266_RANGE_VREF;
 431                 st->mode = AD7266_MODE_DIFF;
 432         }
 433
 434         spi_set_drvdata(spi, indio_dev);
 435         st->spi = spi;
 436
 437         indio_dev->dev.parent = &spi->dev;
 438         indio_dev->name = spi_get_device_id(spi)->name;
 439         indio_dev->modes = INDIO_DIRECT_MODE;
 440         indio_dev->info = &ad7266_info;
 441
 442         ad7266_init_channels(indio_dev);
 443
 444         /* wakeup */
 445         st->single_xfer[0].rx_buf = &st->data;
 446         st->single_xfer[0].len = 2;
 447         st->single_xfer[0].cs_change = 1;
 448         /* conversion */
 449         st->single_xfer[1].rx_buf = &st->data;
 450         st->single_xfer[1].len = 4;
 451         st->single_xfer[1].cs_change = 1;
 452         /* powerdown */
 453         st->single_xfer[2].tx_buf = &st->data;
 454         st->single_xfer[2].len = 1;
 455
 456         spi_message_init(&st->single_msg);
 457         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 458         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 459         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
 460
 461         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 462                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 463         if (ret)
 464                 goto error_free_gpios;
 465
 466         ret = iio_device_register(indio_dev);
 467         if (ret)
 468                 goto error_buffer_cleanup;
 469
 470         return 0;
 471
 472 error_buffer_cleanup:
 473         iio_triggered_buffer_cleanup(indio_dev);
 474 error_free_gpios:
 475         if (!st->fixed_addr)
 476                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 477 error_disable_reg:
 478         if (!IS_ERR_OR_NULL(st->reg))
 479                 regulator_disable(st->reg);
 480
 481         return ret;
 482 }
 483
 484 static int ad7266_remove(struct spi_device *spi)
 485 {
 486         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 487         struct ad7266_state *st = iio_priv(indio_dev);
 488
 489         iio_device_unregister(indio_dev);
 490         iio_triggered_buffer_cleanup(indio_dev);
 491         if (!st->fixed_addr)
 492                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 493         if (!IS_ERR_OR_NULL(st->reg))
 494                 regulator_disable(st->reg);
 495
 496         return 0;
 497 }
 498
 499 static const struct spi_device_id ad7266_id[] = {
 500         {"ad7265", 0},
 501         {"ad7266", 0},
 502         { }
 503 };
 504 MODULE_DEVICE_TABLE(spi, ad7266_id);
 505
 506 static struct spi_driver ad7266_driver = {
 507         .driver = {
 508                 .name   = "ad7266",
 509                 .owner  = THIS_MODULE,
 510         },
 511         .probe          = ad7266_probe,
 512         .remove         = ad7266_remove,
 513         .id_table       = ad7266_id,
 514 };
 515 module_spi_driver(ad7266_driver);
 516
 517 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 518 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 519 MODULE_LICENSE("GPL v2");