drivers/iio/adc/ad7923.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AD7904/AD7914/AD7923/AD7924/AD7908/AD7918/AD7928 SPI ADC driver
   4  *
   5  * Copyright 2011 Analog Devices Inc (from AD7923 Driver)
   6  * Copyright 2012 CS Systemes d'Information
   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/err.h>
  16 #include <linux/delay.h>
  17 #include <linux/module.h>
  18 #include <linux/interrupt.h>
  19
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/sysfs.h>
  22 #include <linux/iio/buffer.h>
  23 #include <linux/iio/trigger_consumer.h>
  24 #include <linux/iio/triggered_buffer.h>
  25
  26 #define AD7923_WRITE_CR         BIT(11)         /* write control register */
  27 #define AD7923_RANGE            BIT(1)          /* range to REFin */
  28 #define AD7923_CODING           BIT(0)          /* coding is straight binary */
  29 #define AD7923_PM_MODE_AS       (1)             /* auto shutdown */
  30 #define AD7923_PM_MODE_FS       (2)             /* full shutdown */
  31 #define AD7923_PM_MODE_OPS      (3)             /* normal operation */
  32 #define AD7923_SEQUENCE_OFF     (0)             /* no sequence fonction */
  33 #define AD7923_SEQUENCE_PROTECT (2)             /* no interrupt write cycle */
  34 #define AD7923_SEQUENCE_ON      (3)             /* continuous sequence */
  35
  36
  37 #define AD7923_PM_MODE_WRITE(mode)      ((mode) << 4)    /* write mode */
  38 #define AD7923_CHANNEL_WRITE(channel)   ((channel) << 6) /* write channel */
  39 #define AD7923_SEQUENCE_WRITE(sequence) ((((sequence) & 1) << 3) \
  40                                         + (((sequence) & 2) << 9))
  41                                                 /* write sequence fonction */
  42 /* left shift for CR : bit 11 transmit in first */
  43 #define AD7923_SHIFT_REGISTER   4
  44
  45 /* val = value, dec = left shift, bits = number of bits of the mask */
  46 #define EXTRACT(val, dec, bits)         (((val) >> (dec)) & ((1 << (bits)) - 1))
  47
  48 struct ad7923_state {
  49         struct spi_device               *spi;
  50         struct spi_transfer             ring_xfer[5];
  51         struct spi_transfer             scan_single_xfer[2];
  52         struct spi_message              ring_msg;
  53         struct spi_message              scan_single_msg;
  54
  55         struct regulator                *reg;
  56
  57         unsigned int                    settings;
  58
  59         /*
  60          * DMA (thus cache coherency maintenance) requires the
  61          * transfer buffers to live in their own cache lines.
  62          */
  63         __be16                          rx_buf[4] ____cacheline_aligned;
  64         __be16                          tx_buf[4];
  65 };
  66
  67 struct ad7923_chip_info {
  68         const struct iio_chan_spec *channels;
  69         unsigned int num_channels;
  70 };
  71
  72 enum ad7923_id {
  73         AD7904,
  74         AD7914,
  75         AD7924,
  76         AD7908,
  77         AD7918,
  78         AD7928
  79 };
  80
  81 #define AD7923_V_CHAN(index, bits)                                      \
  82         {                                                               \
  83                 .type = IIO_VOLTAGE,                                    \
  84                 .indexed = 1,                                           \
  85                 .channel = index,                                       \
  86                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  87                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  88                 .address = index,                                       \
  89                 .scan_index = index,                                    \
  90                 .scan_type = {                                          \
  91                         .sign = 'u',                                    \
  92                         .realbits = (bits),                             \
  93                         .storagebits = 16,                              \
  94                         .endianness = IIO_BE,                           \
  95                 },                                                      \
  96         }
  97
  98 #define DECLARE_AD7923_CHANNELS(name, bits) \
  99 const struct iio_chan_spec name ## _channels[] = { \
 100         AD7923_V_CHAN(0, bits), \
 101         AD7923_V_CHAN(1, bits), \
 102         AD7923_V_CHAN(2, bits), \
 103         AD7923_V_CHAN(3, bits), \
 104         IIO_CHAN_SOFT_TIMESTAMP(4), \
 105 }
 106
 107 #define DECLARE_AD7908_CHANNELS(name, bits) \
 108 const struct iio_chan_spec name ## _channels[] = { \
 109         AD7923_V_CHAN(0, bits), \
 110         AD7923_V_CHAN(1, bits), \
 111         AD7923_V_CHAN(2, bits), \
 112         AD7923_V_CHAN(3, bits), \
 113         AD7923_V_CHAN(4, bits), \
 114         AD7923_V_CHAN(5, bits), \
 115         AD7923_V_CHAN(6, bits), \
 116         AD7923_V_CHAN(7, bits), \
 117         IIO_CHAN_SOFT_TIMESTAMP(8), \
 118 }
 119
 120 static DECLARE_AD7923_CHANNELS(ad7904, 8);
 121 static DECLARE_AD7923_CHANNELS(ad7914, 10);
 122 static DECLARE_AD7923_CHANNELS(ad7924, 12);
 123 static DECLARE_AD7908_CHANNELS(ad7908, 8);
 124 static DECLARE_AD7908_CHANNELS(ad7918, 10);
 125 static DECLARE_AD7908_CHANNELS(ad7928, 12);
 126
 127 static const struct ad7923_chip_info ad7923_chip_info[] = {
 128         [AD7904] = {
 129                 .channels = ad7904_channels,
 130                 .num_channels = ARRAY_SIZE(ad7904_channels),
 131         },
 132         [AD7914] = {
 133                 .channels = ad7914_channels,
 134                 .num_channels = ARRAY_SIZE(ad7914_channels),
 135         },
 136         [AD7924] = {
 137                 .channels = ad7924_channels,
 138                 .num_channels = ARRAY_SIZE(ad7924_channels),
 139         },
 140         [AD7908] = {
 141                 .channels = ad7908_channels,
 142                 .num_channels = ARRAY_SIZE(ad7908_channels),
 143         },
 144         [AD7918] = {
 145                 .channels = ad7918_channels,
 146                 .num_channels = ARRAY_SIZE(ad7918_channels),
 147         },
 148         [AD7928] = {
 149                 .channels = ad7928_channels,
 150                 .num_channels = ARRAY_SIZE(ad7928_channels),
 151         },
 152 };
 153
 154 /**
 155  * ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask
 156  **/
 157 static int ad7923_update_scan_mode(struct iio_dev *indio_dev,
 158                                    const unsigned long *active_scan_mask)
 159 {
 160         struct ad7923_state *st = iio_priv(indio_dev);
 161         int i, cmd, len;
 162
 163         len = 0;
 164         /*
 165          * For this driver the last channel is always the software timestamp so
 166          * skip that one.
 167          */
 168         for_each_set_bit(i, active_scan_mask, indio_dev->num_channels - 1) {
 169                 cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(i) |
 170                         AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 171                         st->settings;
 172                 cmd <<= AD7923_SHIFT_REGISTER;
 173                 st->tx_buf[len++] = cpu_to_be16(cmd);
 174         }
 175         /* build spi ring message */
 176         st->ring_xfer[0].tx_buf = &st->tx_buf[0];
 177         st->ring_xfer[0].len = len;
 178         st->ring_xfer[0].cs_change = 1;
 179
 180         spi_message_init(&st->ring_msg);
 181         spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
 182
 183         for (i = 0; i < len; i++) {
 184                 st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i];
 185                 st->ring_xfer[i + 1].len = 2;
 186                 st->ring_xfer[i + 1].cs_change = 1;
 187                 spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg);
 188         }
 189         /* make sure last transfer cs_change is not set */
 190         st->ring_xfer[i + 1].cs_change = 0;
 191
 192         return 0;
 193 }
 194
 195 /**
 196  * ad7923_trigger_handler() bh of trigger launched polling to ring buffer
 197  *
 198  * Currently there is no option in this driver to disable the saving of
 199  * timestamps within the ring.
 200  **/
 201 static irqreturn_t ad7923_trigger_handler(int irq, void *p)
 202 {
 203         struct iio_poll_func *pf = p;
 204         struct iio_dev *indio_dev = pf->indio_dev;
 205         struct ad7923_state *st = iio_priv(indio_dev);
 206         int b_sent;
 207
 208         b_sent = spi_sync(st->spi, &st->ring_msg);
 209         if (b_sent)
 210                 goto done;
 211
 212         iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
 213                                            iio_get_time_ns(indio_dev));
 214
 215 done:
 216         iio_trigger_notify_done(indio_dev->trig);
 217
 218         return IRQ_HANDLED;
 219 }
 220
 221 static int ad7923_scan_direct(struct ad7923_state *st, unsigned int ch)
 222 {
 223         int ret, cmd;
 224
 225         cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(ch) |
 226                 AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 227                 st->settings;
 228         cmd <<= AD7923_SHIFT_REGISTER;
 229         st->tx_buf[0] = cpu_to_be16(cmd);
 230
 231         ret = spi_sync(st->spi, &st->scan_single_msg);
 232         if (ret)
 233                 return ret;
 234
 235         return be16_to_cpu(st->rx_buf[0]);
 236 }
 237
 238 static int ad7923_get_range(struct ad7923_state *st)
 239 {
 240         int vref;
 241
 242         vref = regulator_get_voltage(st->reg);
 243         if (vref < 0)
 244                 return vref;
 245
 246         vref /= 1000;
 247
 248         if (!(st->settings & AD7923_RANGE))
 249                 vref *= 2;
 250
 251         return vref;
 252 }
 253
 254 static int ad7923_read_raw(struct iio_dev *indio_dev,
 255                            struct iio_chan_spec const *chan,
 256                            int *val,
 257                            int *val2,
 258                            long m)
 259 {
 260         int ret;
 261         struct ad7923_state *st = iio_priv(indio_dev);
 262
 263         switch (m) {
 264         case IIO_CHAN_INFO_RAW:
 265                 ret = iio_device_claim_direct_mode(indio_dev);
 266                 if (ret)
 267                         return ret;
 268                 ret = ad7923_scan_direct(st, chan->address);
 269                 iio_device_release_direct_mode(indio_dev);
 270
 271                 if (ret < 0)
 272                         return ret;
 273
 274                 if (chan->address == EXTRACT(ret, 12, 4))
 275                         *val = EXTRACT(ret, 0, 12);
 276                 else
 277                         return -EIO;
 278
 279                 return IIO_VAL_INT;
 280         case IIO_CHAN_INFO_SCALE:
 281                 ret = ad7923_get_range(st);
 282                 if (ret < 0)
 283                         return ret;
 284                 *val = ret;
 285                 *val2 = chan->scan_type.realbits;
 286                 return IIO_VAL_FRACTIONAL_LOG2;
 287         }
 288         return -EINVAL;
 289 }
 290
 291 static const struct iio_info ad7923_info = {
 292         .read_raw = &ad7923_read_raw,
 293         .update_scan_mode = ad7923_update_scan_mode,
 294 };
 295
 296 static int ad7923_probe(struct spi_device *spi)
 297 {
 298         struct ad7923_state *st;
 299         struct iio_dev *indio_dev;
 300         const struct ad7923_chip_info *info;
 301         int ret;
 302
 303         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 304         if (!indio_dev)
 305                 return -ENOMEM;
 306
 307         st = iio_priv(indio_dev);
 308
 309         spi_set_drvdata(spi, indio_dev);
 310
 311         st->spi = spi;
 312         st->settings = AD7923_CODING | AD7923_RANGE |
 313                         AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS);
 314
 315         info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data];
 316
 317         indio_dev->name = spi_get_device_id(spi)->name;
 318         indio_dev->dev.parent = &spi->dev;
 319         indio_dev->dev.of_node = spi->dev.of_node;
 320         indio_dev->modes = INDIO_DIRECT_MODE;
 321         indio_dev->channels = info->channels;
 322         indio_dev->num_channels = info->num_channels;
 323         indio_dev->info = &ad7923_info;
 324
 325         /* Setup default message */
 326
 327         st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
 328         st->scan_single_xfer[0].len = 2;
 329         st->scan_single_xfer[0].cs_change = 1;
 330         st->scan_single_xfer[1].rx_buf = &st->rx_buf[0];
 331         st->scan_single_xfer[1].len = 2;
 332
 333         spi_message_init(&st->scan_single_msg);
 334         spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
 335         spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
 336
 337         st->reg = devm_regulator_get(&spi->dev, "refin");
 338         if (IS_ERR(st->reg))
 339                 return PTR_ERR(st->reg);
 340
 341         ret = regulator_enable(st->reg);
 342         if (ret)
 343                 return ret;
 344
 345         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 346                                          &ad7923_trigger_handler, NULL);
 347         if (ret)
 348                 goto error_disable_reg;
 349
 350         ret = iio_device_register(indio_dev);
 351         if (ret)
 352                 goto error_cleanup_ring;
 353
 354         return 0;
 355
 356 error_cleanup_ring:
 357         iio_triggered_buffer_cleanup(indio_dev);
 358 error_disable_reg:
 359         regulator_disable(st->reg);
 360
 361         return ret;
 362 }
 363
 364 static int ad7923_remove(struct spi_device *spi)
 365 {
 366         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 367         struct ad7923_state *st = iio_priv(indio_dev);
 368
 369         iio_device_unregister(indio_dev);
 370         iio_triggered_buffer_cleanup(indio_dev);
 371         regulator_disable(st->reg);
 372
 373         return 0;
 374 }
 375
 376 static const struct spi_device_id ad7923_id[] = {
 377         {"ad7904", AD7904},
 378         {"ad7914", AD7914},
 379         {"ad7923", AD7924},
 380         {"ad7924", AD7924},
 381         {"ad7908", AD7908},
 382         {"ad7918", AD7918},
 383         {"ad7928", AD7928},
 384         {}
 385 };
 386 MODULE_DEVICE_TABLE(spi, ad7923_id);
 387
 388 static const struct of_device_id ad7923_of_match[] = {
 389         { .compatible = "adi,ad7904", },
 390         { .compatible = "adi,ad7914", },
 391         { .compatible = "adi,ad7923", },
 392         { .compatible = "adi,ad7924", },
 393         { .compatible = "adi,ad7908", },
 394         { .compatible = "adi,ad7918", },
 395         { .compatible = "adi,ad7928", },
 396         { },
 397 };
 398 MODULE_DEVICE_TABLE(of, ad7923_of_match);
 399
 400 static struct spi_driver ad7923_driver = {
 401         .driver = {
 402                 .name   = "ad7923",
 403                 .of_match_table = ad7923_of_match,
 404         },
 405         .probe          = ad7923_probe,
 406         .remove         = ad7923_remove,
 407         .id_table       = ad7923_id,
 408 };
 409 module_spi_driver(ad7923_driver);
 410
 411 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 412 MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>");
 413 MODULE_DESCRIPTION("Analog Devices AD7923 and similar ADC");
 414 MODULE_LICENSE("GPL v2");