drivers/iio/adc/ad7476.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Analog Devices AD7466/7/8 AD7476/5/7/8 (A) SPI ADC driver
   4  * TI ADC081S/ADC101S/ADC121S 8/10/12-bit SPI ADC driver
   5  *
   6  * Copyright 2010 Analog Devices Inc.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/sysfs.h>
  13 #include <linux/spi/spi.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/gpio/consumer.h>
  16 #include <linux/err.h>
  17 #include <linux/module.h>
  18 #include <linux/bitops.h>
  19 #include <linux/delay.h>
  20
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/sysfs.h>
  23 #include <linux/iio/buffer.h>
  24 #include <linux/iio/trigger_consumer.h>
  25 #include <linux/iio/triggered_buffer.h>
  26
  27 struct ad7476_state;
  28
  29 struct ad7476_chip_info {
  30         unsigned int                    int_vref_uv;
  31         struct iio_chan_spec            channel[2];
  32         /* channels used when convst gpio is defined */
  33         struct iio_chan_spec            convst_channel[2];
  34         void (*reset)(struct ad7476_state *);
  35         bool                            has_vref;
  36         bool                            has_vdrive;
  37 };
  38
  39 struct ad7476_state {
  40         struct spi_device               *spi;
  41         const struct ad7476_chip_info   *chip_info;
  42         struct regulator                *ref_reg;
  43         struct gpio_desc                *convst_gpio;
  44         struct spi_transfer             xfer;
  45         struct spi_message              msg;
  46         /*
  47          * DMA (thus cache coherency maintenance) may require the
  48          * transfer buffers to live in their own cache lines.
  49          * Make the buffer large enough for one 16 bit sample and one 64 bit
  50          * aligned 64 bit timestamp.
  51          */
  52         unsigned char data[ALIGN(2, sizeof(s64)) + sizeof(s64)] __aligned(IIO_DMA_MINALIGN);
  53 };
  54
  55 enum ad7476_supported_device_ids {
  56         ID_AD7091,
  57         ID_AD7091R,
  58         ID_AD7273,
  59         ID_AD7274,
  60         ID_AD7276,
  61         ID_AD7277,
  62         ID_AD7278,
  63         ID_AD7466,
  64         ID_AD7467,
  65         ID_AD7468,
  66         ID_AD7475,
  67         ID_AD7495,
  68         ID_AD7940,
  69         ID_ADC081S,
  70         ID_ADC101S,
  71         ID_ADC121S,
  72         ID_ADS7866,
  73         ID_ADS7867,
  74         ID_ADS7868,
  75         ID_LTC2314_14,
  76 };
  77
  78 static void ad7091_convst(struct ad7476_state *st)
  79 {
  80         if (!st->convst_gpio)
  81                 return;
  82
  83         gpiod_set_value(st->convst_gpio, 0);
  84         udelay(1); /* CONVST pulse width: 10 ns min */
  85         gpiod_set_value(st->convst_gpio, 1);
  86         udelay(1); /* Conversion time: 650 ns max */
  87 }
  88
  89 static irqreturn_t ad7476_trigger_handler(int irq, void  *p)
  90 {
  91         struct iio_poll_func *pf = p;
  92         struct iio_dev *indio_dev = pf->indio_dev;
  93         struct ad7476_state *st = iio_priv(indio_dev);
  94         int b_sent;
  95
  96         ad7091_convst(st);
  97
  98         b_sent = spi_sync(st->spi, &st->msg);
  99         if (b_sent < 0)
 100                 goto done;
 101
 102         iio_push_to_buffers_with_timestamp(indio_dev, st->data,
 103                 iio_get_time_ns(indio_dev));
 104 done:
 105         iio_trigger_notify_done(indio_dev->trig);
 106
 107         return IRQ_HANDLED;
 108 }
 109
 110 static void ad7091_reset(struct ad7476_state *st)
 111 {
 112         /* Any transfers with 8 scl cycles will reset the device */
 113         spi_read(st->spi, st->data, 1);
 114 }
 115
 116 static int ad7476_scan_direct(struct ad7476_state *st)
 117 {
 118         int ret;
 119
 120         ad7091_convst(st);
 121
 122         ret = spi_sync(st->spi, &st->msg);
 123         if (ret)
 124                 return ret;
 125
 126         return be16_to_cpup((__be16 *)st->data);
 127 }
 128
 129 static int ad7476_read_raw(struct iio_dev *indio_dev,
 130                            struct iio_chan_spec const *chan,
 131                            int *val,
 132                            int *val2,
 133                            long m)
 134 {
 135         int ret;
 136         struct ad7476_state *st = iio_priv(indio_dev);
 137         int scale_uv;
 138
 139         switch (m) {
 140         case IIO_CHAN_INFO_RAW:
 141                 ret = iio_device_claim_direct_mode(indio_dev);
 142                 if (ret)
 143                         return ret;
 144                 ret = ad7476_scan_direct(st);
 145                 iio_device_release_direct_mode(indio_dev);
 146
 147                 if (ret < 0)
 148                         return ret;
 149                 *val = (ret >> st->chip_info->channel[0].scan_type.shift) &
 150                         GENMASK(st->chip_info->channel[0].scan_type.realbits - 1, 0);
 151                 return IIO_VAL_INT;
 152         case IIO_CHAN_INFO_SCALE:
 153                 if (st->ref_reg) {
 154                         scale_uv = regulator_get_voltage(st->ref_reg);
 155                         if (scale_uv < 0)
 156                                 return scale_uv;
 157                 } else {
 158                         scale_uv = st->chip_info->int_vref_uv;
 159                 }
 160                 *val = scale_uv / 1000;
 161                 *val2 = chan->scan_type.realbits;
 162                 return IIO_VAL_FRACTIONAL_LOG2;
 163         }
 164         return -EINVAL;
 165 }
 166
 167 #define _AD7476_CHAN(bits, _shift, _info_mask_sep)              \
 168         {                                                       \
 169         .type = IIO_VOLTAGE,                                    \
 170         .indexed = 1,                                           \
 171         .info_mask_separate = _info_mask_sep,                   \
 172         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 173         .scan_type = {                                          \
 174                 .sign = 'u',                                    \
 175                 .realbits = (bits),                             \
 176                 .storagebits = 16,                              \
 177                 .shift = (_shift),                              \
 178                 .endianness = IIO_BE,                           \
 179         },                                                      \
 180 }
 181
 182 #define ADC081S_CHAN(bits) _AD7476_CHAN((bits), 12 - (bits), \
 183                 BIT(IIO_CHAN_INFO_RAW))
 184 #define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \
 185                 BIT(IIO_CHAN_INFO_RAW))
 186 #define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \
 187                 BIT(IIO_CHAN_INFO_RAW))
 188 #define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0)
 189 #define AD7091R_CONVST_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), \
 190                 BIT(IIO_CHAN_INFO_RAW))
 191 #define ADS786X_CHAN(bits) _AD7476_CHAN((bits), 12 - (bits), \
 192                 BIT(IIO_CHAN_INFO_RAW))
 193
 194 static const struct ad7476_chip_info ad7476_chip_info_tbl[] = {
 195         [ID_AD7091] = {
 196                 .channel[0] = AD7091R_CHAN(12),
 197                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 198                 .convst_channel[0] = AD7091R_CONVST_CHAN(12),
 199                 .convst_channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 200                 .reset = ad7091_reset,
 201         },
 202         [ID_AD7091R] = {
 203                 .channel[0] = AD7091R_CHAN(12),
 204                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 205                 .convst_channel[0] = AD7091R_CONVST_CHAN(12),
 206                 .convst_channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 207                 .int_vref_uv = 2500000,
 208                 .has_vref = true,
 209                 .reset = ad7091_reset,
 210         },
 211         [ID_AD7273] = {
 212                 .channel[0] = AD7940_CHAN(10),
 213                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 214                 .has_vref = true,
 215         },
 216         [ID_AD7274] = {
 217                 .channel[0] = AD7940_CHAN(12),
 218                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 219                 .has_vref = true,
 220         },
 221         [ID_AD7276] = {
 222                 .channel[0] = AD7940_CHAN(12),
 223                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 224         },
 225         [ID_AD7277] = {
 226                 .channel[0] = AD7940_CHAN(10),
 227                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 228         },
 229         [ID_AD7278] = {
 230                 .channel[0] = AD7940_CHAN(8),
 231                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 232         },
 233         [ID_AD7466] = {
 234                 .channel[0] = AD7476_CHAN(12),
 235                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 236         },
 237         [ID_AD7467] = {
 238                 .channel[0] = AD7476_CHAN(10),
 239                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 240         },
 241         [ID_AD7468] = {
 242                 .channel[0] = AD7476_CHAN(8),
 243                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 244         },
 245         [ID_AD7475] = {
 246                 .channel[0] = AD7476_CHAN(12),
 247                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 248                 .has_vref = true,
 249                 .has_vdrive = true,
 250         },
 251         [ID_AD7495] = {
 252                 .channel[0] = AD7476_CHAN(12),
 253                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 254                 .int_vref_uv = 2500000,
 255                 .has_vdrive = true,
 256         },
 257         [ID_AD7940] = {
 258                 .channel[0] = AD7940_CHAN(14),
 259                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 260         },
 261         [ID_ADC081S] = {
 262                 .channel[0] = ADC081S_CHAN(8),
 263                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 264         },
 265         [ID_ADC101S] = {
 266                 .channel[0] = ADC081S_CHAN(10),
 267                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 268         },
 269         [ID_ADC121S] = {
 270                 .channel[0] = ADC081S_CHAN(12),
 271                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 272         },
 273         [ID_ADS7866] = {
 274                 .channel[0] = ADS786X_CHAN(12),
 275                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 276         },
 277         [ID_ADS7867] = {
 278                 .channel[0] = ADS786X_CHAN(10),
 279                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 280         },
 281         [ID_ADS7868] = {
 282                 .channel[0] = ADS786X_CHAN(8),
 283                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 284         },
 285         [ID_LTC2314_14] = {
 286                 .channel[0] = AD7940_CHAN(14),
 287                 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 288                 .has_vref = true,
 289         },
 290 };
 291
 292 static const struct iio_info ad7476_info = {
 293         .read_raw = &ad7476_read_raw,
 294 };
 295
 296 static void ad7476_reg_disable(void *data)
 297 {
 298         struct regulator *reg = data;
 299
 300         regulator_disable(reg);
 301 }
 302
 303 static int ad7476_probe(struct spi_device *spi)
 304 {
 305         struct ad7476_state *st;
 306         struct iio_dev *indio_dev;
 307         struct regulator *reg;
 308         int ret;
 309
 310         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 311         if (!indio_dev)
 312                 return -ENOMEM;
 313
 314         st = iio_priv(indio_dev);
 315         st->chip_info =
 316                 &ad7476_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 317
 318         reg = devm_regulator_get(&spi->dev, "vcc");
 319         if (IS_ERR(reg))
 320                 return PTR_ERR(reg);
 321
 322         ret = regulator_enable(reg);
 323         if (ret)
 324                 return ret;
 325
 326         ret = devm_add_action_or_reset(&spi->dev, ad7476_reg_disable, reg);
 327         if (ret)
 328                 return ret;
 329
 330         /* Either vcc or vref (below) as appropriate */
 331         if (!st->chip_info->int_vref_uv)
 332                 st->ref_reg = reg;
 333
 334         if (st->chip_info->has_vref) {
 335
 336                 /* If a device has an internal reference vref is optional */
 337                 if (st->chip_info->int_vref_uv) {
 338                         reg = devm_regulator_get_optional(&spi->dev, "vref");
 339                         if (IS_ERR(reg) && (PTR_ERR(reg) != -ENODEV))
 340                                 return PTR_ERR(reg);
 341                 } else {
 342                         reg = devm_regulator_get(&spi->dev, "vref");
 343                         if (IS_ERR(reg))
 344                                 return PTR_ERR(reg);
 345                 }
 346
 347                 if (!IS_ERR(reg)) {
 348                         ret = regulator_enable(reg);
 349                         if (ret)
 350                                 return ret;
 351
 352                         ret = devm_add_action_or_reset(&spi->dev,
 353                                                        ad7476_reg_disable,
 354                                                        reg);
 355                         if (ret)
 356                                 return ret;
 357                         st->ref_reg = reg;
 358                 } else {
 359                         /*
 360                          * Can only get here if device supports both internal
 361                          * and external reference, but the regulator connected
 362                          * to the external reference is not connected.
 363                          * Set the reference regulator pointer to NULL to
 364                          * indicate this.
 365                          */
 366                         st->ref_reg = NULL;
 367                 }
 368         }
 369
 370         if (st->chip_info->has_vdrive) {
 371                 ret = devm_regulator_get_enable(&spi->dev, "vdrive");
 372                 if (ret)
 373                         return ret;
 374         }
 375
 376         st->convst_gpio = devm_gpiod_get_optional(&spi->dev,
 377                                                   "adi,conversion-start",
 378                                                   GPIOD_OUT_LOW);
 379         if (IS_ERR(st->convst_gpio))
 380                 return PTR_ERR(st->convst_gpio);
 381
 382         st->spi = spi;
 383
 384         indio_dev->name = spi_get_device_id(spi)->name;
 385         indio_dev->modes = INDIO_DIRECT_MODE;
 386         indio_dev->channels = st->chip_info->channel;
 387         indio_dev->num_channels = 2;
 388         indio_dev->info = &ad7476_info;
 389
 390         if (st->convst_gpio)
 391                 indio_dev->channels = st->chip_info->convst_channel;
 392         /* Setup default message */
 393
 394         st->xfer.rx_buf = &st->data;
 395         st->xfer.len = st->chip_info->channel[0].scan_type.storagebits / 8;
 396
 397         spi_message_init(&st->msg);
 398         spi_message_add_tail(&st->xfer, &st->msg);
 399
 400         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
 401                                               &ad7476_trigger_handler, NULL);
 402         if (ret)
 403                 return ret;
 404
 405         if (st->chip_info->reset)
 406                 st->chip_info->reset(st);
 407
 408         return devm_iio_device_register(&spi->dev, indio_dev);
 409 }
 410
 411 static const struct spi_device_id ad7476_id[] = {
 412         {"ad7091", ID_AD7091},
 413         {"ad7091r", ID_AD7091R},
 414         {"ad7273", ID_AD7273},
 415         {"ad7274", ID_AD7274},
 416         {"ad7276", ID_AD7276},
 417         {"ad7277", ID_AD7277},
 418         {"ad7278", ID_AD7278},
 419         {"ad7466", ID_AD7466},
 420         {"ad7467", ID_AD7467},
 421         {"ad7468", ID_AD7468},
 422         {"ad7475", ID_AD7475},
 423         {"ad7476", ID_AD7466},
 424         {"ad7476a", ID_AD7466},
 425         {"ad7477", ID_AD7467},
 426         {"ad7477a", ID_AD7467},
 427         {"ad7478", ID_AD7468},
 428         {"ad7478a", ID_AD7468},
 429         {"ad7495", ID_AD7495},
 430         {"ad7910", ID_AD7467},
 431         {"ad7920", ID_AD7466},
 432         {"ad7940", ID_AD7940},
 433         {"adc081s", ID_ADC081S},
 434         {"adc101s", ID_ADC101S},
 435         {"adc121s", ID_ADC121S},
 436         {"ads7866", ID_ADS7866},
 437         {"ads7867", ID_ADS7867},
 438         {"ads7868", ID_ADS7868},
 439         {"ltc2314-14", ID_LTC2314_14},
 440         {}
 441 };
 442 MODULE_DEVICE_TABLE(spi, ad7476_id);
 443
 444 static struct spi_driver ad7476_driver = {
 445         .driver = {
 446                 .name   = "ad7476",
 447         },
 448         .probe          = ad7476_probe,
 449         .id_table       = ad7476_id,
 450 };
 451 module_spi_driver(ad7476_driver);
 452
 453 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 454 MODULE_DESCRIPTION("Analog Devices AD7476 and similar 1-channel ADCs");
 455 MODULE_LICENSE("GPL v2");