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/property.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/err.h>
  17 #include <linux/delay.h>
  18 #include <linux/module.h>
  19 #include <linux/interrupt.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 #define AD7923_WRITE_CR         BIT(11)         /* write control register */
  28 #define AD7923_RANGE            BIT(1)          /* range to REFin */
  29 #define AD7923_CODING           BIT(0)          /* coding is straight binary */
  30 #define AD7923_PM_MODE_AS       (1)             /* auto shutdown */
  31 #define AD7923_PM_MODE_FS       (2)             /* full shutdown */
  32 #define AD7923_PM_MODE_OPS      (3)             /* normal operation */
  33 #define AD7923_SEQUENCE_OFF     (0)             /* no sequence fonction */
  34 #define AD7923_SEQUENCE_PROTECT (2)             /* no interrupt write cycle */
  35 #define AD7923_SEQUENCE_ON      (3)             /* continuous sequence */
  36
  37
  38 #define AD7923_PM_MODE_WRITE(mode)      ((mode) << 4)    /* write mode */
  39 #define AD7923_CHANNEL_WRITE(channel)   ((channel) << 6) /* write channel */
  40 #define AD7923_SEQUENCE_WRITE(sequence) ((((sequence) & 1) << 3) \
  41                                         + (((sequence) & 2) << 9))
  42                                                 /* write sequence fonction */
  43 /* left shift for CR : bit 11 transmit in first */
  44 #define AD7923_SHIFT_REGISTER   4
  45
  46 /* val = value, dec = left shift, bits = number of bits of the mask */
  47 #define EXTRACT(val, dec, bits)         (((val) >> (dec)) & ((1 << (bits)) - 1))
  48
  49 struct ad7923_state {
  50         struct spi_device               *spi;
  51         struct spi_transfer             ring_xfer[5];
  52         struct spi_transfer             scan_single_xfer[2];
  53         struct spi_message              ring_msg;
  54         struct spi_message              scan_single_msg;
  55
  56         struct regulator                *reg;
  57
  58         unsigned int                    settings;
  59
  60         /*
  61          * DMA (thus cache coherency maintenance) may require the
  62          * transfer buffers to live in their own cache lines.
  63          * Ensure rx_buf can be directly used in iio_push_to_buffers_with_timetamp
  64          * Length = 8 channels + 4 extra for 8 byte timestamp
  65          */
  66         __be16                          rx_buf[12] __aligned(IIO_DMA_MINALIGN);
  67         __be16                          tx_buf[4];
  68 };
  69
  70 struct ad7923_chip_info {
  71         const struct iio_chan_spec *channels;
  72         unsigned int num_channels;
  73 };
  74
  75 enum ad7923_id {
  76         AD7904,
  77         AD7914,
  78         AD7924,
  79         AD7908,
  80         AD7918,
  81         AD7928
  82 };
  83
  84 #define AD7923_V_CHAN(index, bits)                                      \
  85         {                                                               \
  86                 .type = IIO_VOLTAGE,                                    \
  87                 .indexed = 1,                                           \
  88                 .channel = index,                                       \
  89                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  90                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  91                 .address = index,                                       \
  92                 .scan_index = index,                                    \
  93                 .scan_type = {                                          \
  94                         .sign = 'u',                                    \
  95                         .realbits = (bits),                             \
  96                         .storagebits = 16,                              \
  97                         .shift = 12 - (bits),                           \
  98                         .endianness = IIO_BE,                           \
  99                 },                                                      \
 100         }
 101
 102 #define DECLARE_AD7923_CHANNELS(name, bits) \
 103 const struct iio_chan_spec name ## _channels[] = { \
 104         AD7923_V_CHAN(0, bits), \
 105         AD7923_V_CHAN(1, bits), \
 106         AD7923_V_CHAN(2, bits), \
 107         AD7923_V_CHAN(3, bits), \
 108         IIO_CHAN_SOFT_TIMESTAMP(4), \
 109 }
 110
 111 #define DECLARE_AD7908_CHANNELS(name, bits) \
 112 const struct iio_chan_spec name ## _channels[] = { \
 113         AD7923_V_CHAN(0, bits), \
 114         AD7923_V_CHAN(1, bits), \
 115         AD7923_V_CHAN(2, bits), \
 116         AD7923_V_CHAN(3, bits), \
 117         AD7923_V_CHAN(4, bits), \
 118         AD7923_V_CHAN(5, bits), \
 119         AD7923_V_CHAN(6, bits), \
 120         AD7923_V_CHAN(7, bits), \
 121         IIO_CHAN_SOFT_TIMESTAMP(8), \
 122 }
 123
 124 static DECLARE_AD7923_CHANNELS(ad7904, 8);
 125 static DECLARE_AD7923_CHANNELS(ad7914, 10);
 126 static DECLARE_AD7923_CHANNELS(ad7924, 12);
 127 static DECLARE_AD7908_CHANNELS(ad7908, 8);
 128 static DECLARE_AD7908_CHANNELS(ad7918, 10);
 129 static DECLARE_AD7908_CHANNELS(ad7928, 12);
 130
 131 static const struct ad7923_chip_info ad7923_chip_info[] = {
 132         [AD7904] = {
 133                 .channels = ad7904_channels,
 134                 .num_channels = ARRAY_SIZE(ad7904_channels),
 135         },
 136         [AD7914] = {
 137                 .channels = ad7914_channels,
 138                 .num_channels = ARRAY_SIZE(ad7914_channels),
 139         },
 140         [AD7924] = {
 141                 .channels = ad7924_channels,
 142                 .num_channels = ARRAY_SIZE(ad7924_channels),
 143         },
 144         [AD7908] = {
 145                 .channels = ad7908_channels,
 146                 .num_channels = ARRAY_SIZE(ad7908_channels),
 147         },
 148         [AD7918] = {
 149                 .channels = ad7918_channels,
 150                 .num_channels = ARRAY_SIZE(ad7918_channels),
 151         },
 152         [AD7928] = {
 153                 .channels = ad7928_channels,
 154                 .num_channels = ARRAY_SIZE(ad7928_channels),
 155         },
 156 };
 157
 158 /*
 159  * ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask
 160  */
 161 static int ad7923_update_scan_mode(struct iio_dev *indio_dev,
 162                                    const unsigned long *active_scan_mask)
 163 {
 164         struct ad7923_state *st = iio_priv(indio_dev);
 165         int i, cmd, len;
 166
 167         len = 0;
 168         /*
 169          * For this driver the last channel is always the software timestamp so
 170          * skip that one.
 171          */
 172         for_each_set_bit(i, active_scan_mask, indio_dev->num_channels - 1) {
 173                 cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(i) |
 174                         AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 175                         st->settings;
 176                 cmd <<= AD7923_SHIFT_REGISTER;
 177                 st->tx_buf[len++] = cpu_to_be16(cmd);
 178         }
 179         /* build spi ring message */
 180         st->ring_xfer[0].tx_buf = &st->tx_buf[0];
 181         st->ring_xfer[0].len = len;
 182         st->ring_xfer[0].cs_change = 1;
 183
 184         spi_message_init(&st->ring_msg);
 185         spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
 186
 187         for (i = 0; i < len; i++) {
 188                 st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i];
 189                 st->ring_xfer[i + 1].len = 2;
 190                 st->ring_xfer[i + 1].cs_change = 1;
 191                 spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg);
 192         }
 193         /* make sure last transfer cs_change is not set */
 194         st->ring_xfer[i + 1].cs_change = 0;
 195
 196         return 0;
 197 }
 198
 199 static irqreturn_t ad7923_trigger_handler(int irq, void *p)
 200 {
 201         struct iio_poll_func *pf = p;
 202         struct iio_dev *indio_dev = pf->indio_dev;
 203         struct ad7923_state *st = iio_priv(indio_dev);
 204         int b_sent;
 205
 206         b_sent = spi_sync(st->spi, &st->ring_msg);
 207         if (b_sent)
 208                 goto done;
 209
 210         iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
 211                                            iio_get_time_ns(indio_dev));
 212
 213 done:
 214         iio_trigger_notify_done(indio_dev->trig);
 215
 216         return IRQ_HANDLED;
 217 }
 218
 219 static int ad7923_scan_direct(struct ad7923_state *st, unsigned int ch)
 220 {
 221         int ret, cmd;
 222
 223         cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(ch) |
 224                 AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) |
 225                 st->settings;
 226         cmd <<= AD7923_SHIFT_REGISTER;
 227         st->tx_buf[0] = cpu_to_be16(cmd);
 228
 229         ret = spi_sync(st->spi, &st->scan_single_msg);
 230         if (ret)
 231                 return ret;
 232
 233         return be16_to_cpu(st->rx_buf[0]);
 234 }
 235
 236 static int ad7923_get_range(struct ad7923_state *st)
 237 {
 238         int vref;
 239
 240         vref = regulator_get_voltage(st->reg);
 241         if (vref < 0)
 242                 return vref;
 243
 244         vref /= 1000;
 245
 246         if (!(st->settings & AD7923_RANGE))
 247                 vref *= 2;
 248
 249         return vref;
 250 }
 251
 252 static int ad7923_read_raw(struct iio_dev *indio_dev,
 253                            struct iio_chan_spec const *chan,
 254                            int *val,
 255                            int *val2,
 256                            long m)
 257 {
 258         int ret;
 259         struct ad7923_state *st = iio_priv(indio_dev);
 260
 261         switch (m) {
 262         case IIO_CHAN_INFO_RAW:
 263                 ret = iio_device_claim_direct_mode(indio_dev);
 264                 if (ret)
 265                         return ret;
 266                 ret = ad7923_scan_direct(st, chan->address);
 267                 iio_device_release_direct_mode(indio_dev);
 268
 269                 if (ret < 0)
 270                         return ret;
 271
 272                 if (chan->address == EXTRACT(ret, 12, 4))
 273                         *val = EXTRACT(ret, chan->scan_type.shift,
 274                                        chan->scan_type.realbits);
 275                 else
 276                         return -EIO;
 277
 278                 return IIO_VAL_INT;
 279         case IIO_CHAN_INFO_SCALE:
 280                 ret = ad7923_get_range(st);
 281                 if (ret < 0)
 282                         return ret;
 283                 *val = ret;
 284                 *val2 = chan->scan_type.realbits;
 285                 return IIO_VAL_FRACTIONAL_LOG2;
 286         }
 287         return -EINVAL;
 288 }
 289
 290 static const struct iio_info ad7923_info = {
 291         .read_raw = &ad7923_read_raw,
 292         .update_scan_mode = ad7923_update_scan_mode,
 293 };
 294
 295 static void ad7923_regulator_disable(void *data)
 296 {
 297         struct ad7923_state *st = data;
 298
 299         regulator_disable(st->reg);
 300 }
 301
 302 static int ad7923_probe(struct spi_device *spi)
 303 {
 304         u32 ad7923_range = AD7923_RANGE;
 305         struct ad7923_state *st;
 306         struct iio_dev *indio_dev;
 307         const struct ad7923_chip_info *info;
 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
 316         if (device_property_read_bool(&spi->dev, "adi,range-double"))
 317                 ad7923_range = 0;
 318
 319         st->spi = spi;
 320         st->settings = AD7923_CODING | ad7923_range |
 321                         AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS);
 322
 323         info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data];
 324
 325         indio_dev->name = spi_get_device_id(spi)->name;
 326         indio_dev->modes = INDIO_DIRECT_MODE;
 327         indio_dev->channels = info->channels;
 328         indio_dev->num_channels = info->num_channels;
 329         indio_dev->info = &ad7923_info;
 330
 331         /* Setup default message */
 332
 333         st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
 334         st->scan_single_xfer[0].len = 2;
 335         st->scan_single_xfer[0].cs_change = 1;
 336         st->scan_single_xfer[1].rx_buf = &st->rx_buf[0];
 337         st->scan_single_xfer[1].len = 2;
 338
 339         spi_message_init(&st->scan_single_msg);
 340         spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
 341         spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
 342
 343         st->reg = devm_regulator_get(&spi->dev, "refin");
 344         if (IS_ERR(st->reg))
 345                 return PTR_ERR(st->reg);
 346
 347         ret = regulator_enable(st->reg);
 348         if (ret)
 349                 return ret;
 350
 351         ret = devm_add_action_or_reset(&spi->dev, ad7923_regulator_disable, st);
 352         if (ret)
 353                 return ret;
 354
 355         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
 356                                               &ad7923_trigger_handler, NULL);
 357         if (ret)
 358                 return ret;
 359
 360         return devm_iio_device_register(&spi->dev, indio_dev);
 361 }
 362
 363 static const struct spi_device_id ad7923_id[] = {
 364         {"ad7904", AD7904},
 365         {"ad7914", AD7914},
 366         {"ad7923", AD7924},
 367         {"ad7924", AD7924},
 368         {"ad7908", AD7908},
 369         {"ad7918", AD7918},
 370         {"ad7928", AD7928},
 371         {}
 372 };
 373 MODULE_DEVICE_TABLE(spi, ad7923_id);
 374
 375 static const struct of_device_id ad7923_of_match[] = {
 376         { .compatible = "adi,ad7904", },
 377         { .compatible = "adi,ad7914", },
 378         { .compatible = "adi,ad7923", },
 379         { .compatible = "adi,ad7924", },
 380         { .compatible = "adi,ad7908", },
 381         { .compatible = "adi,ad7918", },
 382         { .compatible = "adi,ad7928", },
 383         { },
 384 };
 385 MODULE_DEVICE_TABLE(of, ad7923_of_match);
 386
 387 static struct spi_driver ad7923_driver = {
 388         .driver = {
 389                 .name   = "ad7923",
 390                 .of_match_table = ad7923_of_match,
 391         },
 392         .probe          = ad7923_probe,
 393         .id_table       = ad7923_id,
 394 };
 395 module_spi_driver(ad7923_driver);
 396
 397 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 398 MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>");
 399 MODULE_DESCRIPTION("Analog Devices AD7923 and similar ADC");
 400 MODULE_LICENSE("GPL v2");