linux/drivers/iio/adc/ad7266.c
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   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
  27struct 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
  49static 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
  55static 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
  61static 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
  77static 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
  83static 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
  90static 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
 109static 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
 132static 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
 143static 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
 156static 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 = IIO_CHAN_INFO_RAW_SEPARATE_BIT     \
 205                | IIO_CHAN_INFO_SCALE_SHARED_BIT        \
 206                | IIO_CHAN_INFO_OFFSET_SHARED_BIT,      \
 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) \
 218const 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) \
 235const 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
 241static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 242static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 243static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 244static 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 = IIO_CHAN_INFO_RAW_SEPARATE_BIT     \
 253                | IIO_CHAN_INFO_SCALE_SHARED_BIT        \
 254                | IIO_CHAN_INFO_OFFSET_SHARED_BIT,      \
 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) \
 267const 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
 277static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 278static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 279
 280#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 281const 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
 287static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 288static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 289
 290static 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
 296static unsigned long ad7266_available_scan_masks[] = {
 297        0x003,
 298        0x00c,
 299        0x030,
 300        0x0c0,
 301        0x300,
 302        0xc00,
 303        0x000,
 304};
 305
 306static unsigned long ad7266_available_scan_masks_diff[] = {
 307        0x003,
 308        0x00c,
 309        0x030,
 310        0x000,
 311};
 312
 313static unsigned long ad7266_available_scan_masks_fixed[] = {
 314        0x003,
 315        0x000,
 316};
 317
 318struct 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
 327static 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
 370static 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
 390static const char * const ad7266_gpio_labels[] = {
 391        "AD0", "AD1", "AD2",
 392};
 393
 394static 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 = iio_device_alloc(sizeof(*st));
 403        if (indio_dev == NULL)
 404                return -ENOMEM;
 405
 406        st = iio_priv(indio_dev);
 407
 408        st->reg = regulator_get(&spi->dev, "vref");
 409        if (!IS_ERR_OR_NULL(st->reg)) {
 410                ret = regulator_enable(st->reg);
 411                if (ret)
 412                        goto error_put_reg;
 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
 484error_buffer_cleanup:
 485        iio_triggered_buffer_cleanup(indio_dev);
 486error_free_gpios:
 487        if (!st->fixed_addr)
 488                gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 489error_disable_reg:
 490        if (!IS_ERR_OR_NULL(st->reg))
 491                regulator_disable(st->reg);
 492error_put_reg:
 493        if (!IS_ERR_OR_NULL(st->reg))
 494                regulator_put(st->reg);
 495
 496        iio_device_free(indio_dev);
 497
 498        return ret;
 499}
 500
 501static int ad7266_remove(struct spi_device *spi)
 502{
 503        struct iio_dev *indio_dev = spi_get_drvdata(spi);
 504        struct ad7266_state *st = iio_priv(indio_dev);
 505
 506        iio_device_unregister(indio_dev);
 507        iio_triggered_buffer_cleanup(indio_dev);
 508        if (!st->fixed_addr)
 509                gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
 510        if (!IS_ERR_OR_NULL(st->reg)) {
 511                regulator_disable(st->reg);
 512                regulator_put(st->reg);
 513        }
 514        iio_device_free(indio_dev);
 515
 516        return 0;
 517}
 518
 519static const struct spi_device_id ad7266_id[] = {
 520        {"ad7265", 0},
 521        {"ad7266", 0},
 522        { }
 523};
 524MODULE_DEVICE_TABLE(spi, ad7266_id);
 525
 526static struct spi_driver ad7266_driver = {
 527        .driver = {
 528                .name   = "ad7266",
 529                .owner  = THIS_MODULE,
 530        },
 531        .probe          = ad7266_probe,
 532        .remove         = ad7266_remove,
 533        .id_table       = ad7266_id,
 534};
 535module_spi_driver(ad7266_driver);
 536
 537MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 538MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 539MODULE_LICENSE("GPL v2");
 540