drivers/iio/adc/ad7266.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AD7266/65 SPI ADC driver
   4  *
   5  * Copyright 2012 Analog Devices Inc.
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/regulator/consumer.h>
  13 #include <linux/err.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/module.h>
  16
  17 #include <linux/interrupt.h>
  18
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/buffer.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23
  24 #include <linux/platform_data/ad7266.h>
  25
  26 #define AD7266_INTERNAL_REF_MV  2500
  27
  28 struct ad7266_state {
  29         struct spi_device       *spi;
  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_desc        *gpios[3];
  39
  40         /*
  41          * DMA (thus cache coherency maintenance) may require 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         struct {
  47                 __be16 sample[2];
  48                 s64 timestamp;
  49         } data __aligned(IIO_DMA_MINALIGN);
  50 };
  51
  52 static int ad7266_wakeup(struct ad7266_state *st)
  53 {
  54         /* Any read with >= 2 bytes will wake the device */
  55         return spi_read(st->spi, &st->data.sample[0], 2);
  56 }
  57
  58 static int ad7266_powerdown(struct ad7266_state *st)
  59 {
  60         /* Any read with < 2 bytes will powerdown the device */
  61         return spi_read(st->spi, &st->data.sample[0], 1);
  62 }
  63
  64 static int ad7266_preenable(struct iio_dev *indio_dev)
  65 {
  66         struct ad7266_state *st = iio_priv(indio_dev);
  67         return ad7266_wakeup(st);
  68 }
  69
  70 static int ad7266_postdisable(struct iio_dev *indio_dev)
  71 {
  72         struct ad7266_state *st = iio_priv(indio_dev);
  73         return ad7266_powerdown(st);
  74 }
  75
  76 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
  77         .preenable = &ad7266_preenable,
  78         .postdisable = &ad7266_postdisable,
  79 };
  80
  81 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
  82 {
  83         struct iio_poll_func *pf = p;
  84         struct iio_dev *indio_dev = pf->indio_dev;
  85         struct ad7266_state *st = iio_priv(indio_dev);
  86         int ret;
  87
  88         ret = spi_read(st->spi, st->data.sample, 4);
  89         if (ret == 0) {
  90                 iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
  91                             pf->timestamp);
  92         }
  93
  94         iio_trigger_notify_done(indio_dev->trig);
  95
  96         return IRQ_HANDLED;
  97 }
  98
  99 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
 100 {
 101         unsigned int i;
 102
 103         if (st->fixed_addr)
 104                 return;
 105
 106         switch (st->mode) {
 107         case AD7266_MODE_SINGLE_ENDED:
 108                 nr >>= 1;
 109                 break;
 110         case AD7266_MODE_PSEUDO_DIFF:
 111                 nr |= 1;
 112                 break;
 113         case AD7266_MODE_DIFF:
 114                 nr &= ~1;
 115                 break;
 116         }
 117
 118         for (i = 0; i < 3; ++i)
 119                 gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i)));
 120 }
 121
 122 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
 123         const unsigned long *scan_mask)
 124 {
 125         struct ad7266_state *st = iio_priv(indio_dev);
 126         unsigned int nr = find_first_bit(scan_mask,
 127                                          iio_get_masklength(indio_dev));
 128
 129         ad7266_select_input(st, nr);
 130
 131         return 0;
 132 }
 133
 134 static int ad7266_read_single(struct ad7266_state *st, int *val,
 135         unsigned int address)
 136 {
 137         int ret;
 138
 139         ad7266_select_input(st, address);
 140
 141         ret = spi_sync(st->spi, &st->single_msg);
 142         *val = be16_to_cpu(st->data.sample[address % 2]);
 143
 144         return ret;
 145 }
 146
 147 static int ad7266_read_raw(struct iio_dev *indio_dev,
 148         struct iio_chan_spec const *chan, int *val, int *val2, long m)
 149 {
 150         struct ad7266_state *st = iio_priv(indio_dev);
 151         unsigned long scale_mv;
 152         int ret;
 153
 154         switch (m) {
 155         case IIO_CHAN_INFO_RAW:
 156                 ret = iio_device_claim_direct_mode(indio_dev);
 157                 if (ret)
 158                         return ret;
 159                 ret = ad7266_read_single(st, val, chan->address);
 160                 iio_device_release_direct_mode(indio_dev);
 161
 162                 if (ret < 0)
 163                         return ret;
 164                 *val = (*val >> 2) & 0xfff;
 165                 if (chan->scan_type.sign == 's')
 166                         *val = sign_extend32(*val,
 167                                              chan->scan_type.realbits - 1);
 168
 169                 return IIO_VAL_INT;
 170         case IIO_CHAN_INFO_SCALE:
 171                 scale_mv = st->vref_mv;
 172                 if (st->mode == AD7266_MODE_DIFF)
 173                         scale_mv *= 2;
 174                 if (st->range == AD7266_RANGE_2VREF)
 175                         scale_mv *= 2;
 176
 177                 *val = scale_mv;
 178                 *val2 = chan->scan_type.realbits;
 179                 return IIO_VAL_FRACTIONAL_LOG2;
 180         case IIO_CHAN_INFO_OFFSET:
 181                 if (st->range == AD7266_RANGE_2VREF &&
 182                         st->mode != AD7266_MODE_DIFF)
 183                         *val = 2048;
 184                 else
 185                         *val = 0;
 186                 return IIO_VAL_INT;
 187         }
 188         return -EINVAL;
 189 }
 190
 191 #define AD7266_CHAN(_chan, _sign) {                     \
 192         .type = IIO_VOLTAGE,                            \
 193         .indexed = 1,                                   \
 194         .channel = (_chan),                             \
 195         .address = (_chan),                             \
 196         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 197         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 198                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 199         .scan_index = (_chan),                          \
 200         .scan_type = {                                  \
 201                 .sign = (_sign),                        \
 202                 .realbits = 12,                         \
 203                 .storagebits = 16,                      \
 204                 .shift = 2,                             \
 205                 .endianness = IIO_BE,                   \
 206         },                                              \
 207 }
 208
 209 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 210 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 211         AD7266_CHAN(0, (_sign)), \
 212         AD7266_CHAN(1, (_sign)), \
 213         AD7266_CHAN(2, (_sign)), \
 214         AD7266_CHAN(3, (_sign)), \
 215         AD7266_CHAN(4, (_sign)), \
 216         AD7266_CHAN(5, (_sign)), \
 217         AD7266_CHAN(6, (_sign)), \
 218         AD7266_CHAN(7, (_sign)), \
 219         AD7266_CHAN(8, (_sign)), \
 220         AD7266_CHAN(9, (_sign)), \
 221         AD7266_CHAN(10, (_sign)), \
 222         AD7266_CHAN(11, (_sign)), \
 223         IIO_CHAN_SOFT_TIMESTAMP(13), \
 224 }
 225
 226 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 227 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 228         AD7266_CHAN(0, (_sign)), \
 229         AD7266_CHAN(1, (_sign)), \
 230         IIO_CHAN_SOFT_TIMESTAMP(2), \
 231 }
 232
 233 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 234 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 235 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 236 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
 237
 238 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
 239         .type = IIO_VOLTAGE,                            \
 240         .indexed = 1,                                   \
 241         .channel = (_chan) * 2,                         \
 242         .channel2 = (_chan) * 2 + 1,                    \
 243         .address = (_chan),                             \
 244         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 245         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
 246                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 247         .scan_index = (_chan),                          \
 248         .scan_type = {                                  \
 249                 .sign = _sign,                  \
 250                 .realbits = 12,                         \
 251                 .storagebits = 16,                      \
 252                 .shift = 2,                             \
 253                 .endianness = IIO_BE,                   \
 254         },                                              \
 255         .differential = 1,                              \
 256 }
 257
 258 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 259 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 260         AD7266_CHAN_DIFF(0, (_sign)), \
 261         AD7266_CHAN_DIFF(1, (_sign)), \
 262         AD7266_CHAN_DIFF(2, (_sign)), \
 263         AD7266_CHAN_DIFF(3, (_sign)), \
 264         AD7266_CHAN_DIFF(4, (_sign)), \
 265         AD7266_CHAN_DIFF(5, (_sign)), \
 266         IIO_CHAN_SOFT_TIMESTAMP(6), \
 267 }
 268
 269 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 270 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 271
 272 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 273 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 274         AD7266_CHAN_DIFF(0, (_sign)), \
 275         AD7266_CHAN_DIFF(1, (_sign)), \
 276         IIO_CHAN_SOFT_TIMESTAMP(2), \
 277 }
 278
 279 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 280 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 281
 282 static const struct iio_info ad7266_info = {
 283         .read_raw = &ad7266_read_raw,
 284         .update_scan_mode = &ad7266_update_scan_mode,
 285 };
 286
 287 static const unsigned long ad7266_available_scan_masks[] = {
 288         0x003,
 289         0x00c,
 290         0x030,
 291         0x0c0,
 292         0x300,
 293         0xc00,
 294         0x000,
 295 };
 296
 297 static const unsigned long ad7266_available_scan_masks_diff[] = {
 298         0x003,
 299         0x00c,
 300         0x030,
 301         0x000,
 302 };
 303
 304 static const unsigned long ad7266_available_scan_masks_fixed[] = {
 305         0x003,
 306         0x000,
 307 };
 308
 309 struct ad7266_chan_info {
 310         const struct iio_chan_spec *channels;
 311         unsigned int num_channels;
 312         const unsigned long *scan_masks;
 313 };
 314
 315 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 316         (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
 317
 318 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 319         [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 320                 .channels = ad7266_channels_u,
 321                 .num_channels = ARRAY_SIZE(ad7266_channels_u),
 322                 .scan_masks = ad7266_available_scan_masks,
 323         },
 324         [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 325                 .channels = ad7266_channels_u_fixed,
 326                 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 327                 .scan_masks = ad7266_available_scan_masks_fixed,
 328         },
 329         [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 330                 .channels = ad7266_channels_s,
 331                 .num_channels = ARRAY_SIZE(ad7266_channels_s),
 332                 .scan_masks = ad7266_available_scan_masks,
 333         },
 334         [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 335                 .channels = ad7266_channels_s_fixed,
 336                 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 337                 .scan_masks = ad7266_available_scan_masks_fixed,
 338         },
 339         [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 340                 .channels = ad7266_channels_diff_u,
 341                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 342                 .scan_masks = ad7266_available_scan_masks_diff,
 343         },
 344         [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 345                 .channels = ad7266_channels_diff_fixed_u,
 346                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 347                 .scan_masks = ad7266_available_scan_masks_fixed,
 348         },
 349         [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 350                 .channels = ad7266_channels_diff_s,
 351                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 352                 .scan_masks = ad7266_available_scan_masks_diff,
 353         },
 354         [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 355                 .channels = ad7266_channels_diff_fixed_s,
 356                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 357                 .scan_masks = ad7266_available_scan_masks_fixed,
 358         },
 359 };
 360
 361 static void ad7266_init_channels(struct iio_dev *indio_dev)
 362 {
 363         struct ad7266_state *st = iio_priv(indio_dev);
 364         bool is_differential, is_signed;
 365         const struct ad7266_chan_info *chan_info;
 366         int i;
 367
 368         is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 369         is_signed = (st->range == AD7266_RANGE_2VREF) |
 370                     (st->mode == AD7266_MODE_DIFF);
 371
 372         i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 373         chan_info = &ad7266_chan_infos[i];
 374
 375         indio_dev->channels = chan_info->channels;
 376         indio_dev->num_channels = chan_info->num_channels;
 377         indio_dev->available_scan_masks = chan_info->scan_masks;
 378 }
 379
 380 static const char * const ad7266_gpio_labels[] = {
 381         "ad0", "ad1", "ad2",
 382 };
 383
 384 static int ad7266_probe(struct spi_device *spi)
 385 {
 386         const struct ad7266_platform_data *pdata = dev_get_platdata(&spi->dev);
 387         struct iio_dev *indio_dev;
 388         struct ad7266_state *st;
 389         unsigned int i;
 390         int ret;
 391
 392         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 393         if (indio_dev == NULL)
 394                 return -ENOMEM;
 395
 396         st = iio_priv(indio_dev);
 397
 398         ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
 399         if (ret < 0 && ret != -ENODEV)
 400                 return ret;
 401
 402         st->vref_mv = ret == -ENODEV ? AD7266_INTERNAL_REF_MV : ret / 1000;
 403
 404         if (pdata) {
 405                 st->fixed_addr = pdata->fixed_addr;
 406                 st->mode = pdata->mode;
 407                 st->range = pdata->range;
 408
 409                 if (!st->fixed_addr) {
 410                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 411                                 st->gpios[i] = devm_gpiod_get(&spi->dev,
 412                                                       ad7266_gpio_labels[i],
 413                                                       GPIOD_OUT_LOW);
 414                                 if (IS_ERR(st->gpios[i])) {
 415                                         ret = PTR_ERR(st->gpios[i]);
 416                                         return ret;
 417                                 }
 418                         }
 419                 }
 420         } else {
 421                 st->fixed_addr = true;
 422                 st->range = AD7266_RANGE_VREF;
 423                 st->mode = AD7266_MODE_DIFF;
 424         }
 425
 426         st->spi = spi;
 427
 428         indio_dev->name = spi_get_device_id(spi)->name;
 429         indio_dev->modes = INDIO_DIRECT_MODE;
 430         indio_dev->info = &ad7266_info;
 431
 432         ad7266_init_channels(indio_dev);
 433
 434         /* wakeup */
 435         st->single_xfer[0].rx_buf = &st->data.sample[0];
 436         st->single_xfer[0].len = 2;
 437         st->single_xfer[0].cs_change = 1;
 438         /* conversion */
 439         st->single_xfer[1].rx_buf = st->data.sample;
 440         st->single_xfer[1].len = 4;
 441         st->single_xfer[1].cs_change = 1;
 442         /* powerdown */
 443         st->single_xfer[2].tx_buf = &st->data.sample[0];
 444         st->single_xfer[2].len = 1;
 445
 446         spi_message_init(&st->single_msg);
 447         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 448         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 449         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
 450
 451         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, &iio_pollfunc_store_time,
 452                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 453         if (ret)
 454                 return ret;
 455
 456         return devm_iio_device_register(&spi->dev, indio_dev);
 457 }
 458
 459 static const struct spi_device_id ad7266_id[] = {
 460         { "ad7265", 0 },
 461         { "ad7266", 0 },
 462         { }
 463 };
 464 MODULE_DEVICE_TABLE(spi, ad7266_id);
 465
 466 static struct spi_driver ad7266_driver = {
 467         .driver = {
 468                 .name   = "ad7266",
 469         },
 470         .probe          = ad7266_probe,
 471         .id_table       = ad7266_id,
 472 };
 473 module_spi_driver(ad7266_driver);
 474
 475 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 476 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 477 MODULE_LICENSE("GPL v2");