drivers/staging/iio/adc/ad7606.c

   1 /*
   2  * AD7606 SPI ADC driver
   3  *
   4  * Copyright 2011 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/err.h>
  16 #include <linux/gpio/consumer.h>
  17 #include <linux/delay.h>
  18 #include <linux/sched.h>
  19 #include <linux/module.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 #include "ad7606.h"
  28
  29 /*
  30  * Scales are computed as 5000/32768 and 10000/32768 respectively,
  31  * so that when applied to the raw values they provide mV values
  32  */
  33 static const unsigned int scale_avail[2][2] = {
  34         {0, 152588}, {0, 305176}
  35 };
  36
  37 static int ad7606_reset(struct ad7606_state *st)
  38 {
  39         if (st->gpio_reset) {
  40                 gpiod_set_value(st->gpio_reset, 1);
  41                 ndelay(100); /* t_reset >= 100ns */
  42                 gpiod_set_value(st->gpio_reset, 0);
  43                 return 0;
  44         }
  45
  46         return -ENODEV;
  47 }
  48
  49 static int ad7606_read_samples(struct ad7606_state *st)
  50 {
  51         unsigned int num = st->chip_info->num_channels;
  52         u16 *data = st->data;
  53         int ret;
  54
  55         /*
  56          * The frstdata signal is set to high while and after reading the sample
  57          * of the first channel and low for all other channels. This can be used
  58          * to check that the incoming data is correctly aligned. During normal
  59          * operation the data should never become unaligned, but some glitch or
  60          * electrostatic discharge might cause an extra read or clock cycle.
  61          * Monitoring the frstdata signal allows to recover from such failure
  62          * situations.
  63          */
  64
  65         if (st->gpio_frstdata) {
  66                 ret = st->bops->read_block(st->dev, 1, data);
  67                 if (ret)
  68                         return ret;
  69
  70                 if (!gpiod_get_value(st->gpio_frstdata)) {
  71                         ad7606_reset(st);
  72                         return -EIO;
  73                 }
  74
  75                 data++;
  76                 num--;
  77         }
  78
  79         return st->bops->read_block(st->dev, num, data);
  80 }
  81
  82 static irqreturn_t ad7606_trigger_handler(int irq, void *p)
  83 {
  84         struct iio_poll_func *pf = p;
  85         struct ad7606_state *st = iio_priv(pf->indio_dev);
  86
  87         gpiod_set_value(st->gpio_convst, 1);
  88
  89         return IRQ_HANDLED;
  90 }
  91
  92 /**
  93  * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
  94  * @work_s:     the work struct through which this was scheduled
  95  *
  96  * Currently there is no option in this driver to disable the saving of
  97  * timestamps within the ring.
  98  * I think the one copy of this at a time was to avoid problems if the
  99  * trigger was set far too high and the reads then locked up the computer.
 100  **/
 101 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
 102 {
 103         struct ad7606_state *st = container_of(work_s, struct ad7606_state,
 104                                                 poll_work);
 105         struct iio_dev *indio_dev = iio_priv_to_dev(st);
 106         int ret;
 107
 108         ret = ad7606_read_samples(st);
 109         if (ret == 0)
 110                 iio_push_to_buffers_with_timestamp(indio_dev, st->data,
 111                                                    iio_get_time_ns(indio_dev));
 112
 113         gpiod_set_value(st->gpio_convst, 0);
 114         iio_trigger_notify_done(indio_dev->trig);
 115 }
 116
 117 static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
 118 {
 119         struct ad7606_state *st = iio_priv(indio_dev);
 120         int ret;
 121
 122         st->done = false;
 123         gpiod_set_value(st->gpio_convst, 1);
 124
 125         ret = wait_event_interruptible(st->wq_data_avail, st->done);
 126         if (ret)
 127                 goto error_ret;
 128
 129         ret = ad7606_read_samples(st);
 130         if (ret == 0)
 131                 ret = st->data[ch];
 132
 133 error_ret:
 134         gpiod_set_value(st->gpio_convst, 0);
 135
 136         return ret;
 137 }
 138
 139 static int ad7606_read_raw(struct iio_dev *indio_dev,
 140                            struct iio_chan_spec const *chan,
 141                            int *val,
 142                            int *val2,
 143                            long m)
 144 {
 145         int ret;
 146         struct ad7606_state *st = iio_priv(indio_dev);
 147
 148         switch (m) {
 149         case IIO_CHAN_INFO_RAW:
 150                 ret = iio_device_claim_direct_mode(indio_dev);
 151                 if (ret)
 152                         return ret;
 153
 154                 ret = ad7606_scan_direct(indio_dev, chan->address);
 155                 iio_device_release_direct_mode(indio_dev);
 156
 157                 if (ret < 0)
 158                         return ret;
 159                 *val = (short)ret;
 160                 return IIO_VAL_INT;
 161         case IIO_CHAN_INFO_SCALE:
 162                 *val = scale_avail[st->range][0];
 163                 *val2 = scale_avail[st->range][1];
 164                 return IIO_VAL_INT_PLUS_MICRO;
 165         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 166                 *val = st->oversampling;
 167                 return IIO_VAL_INT;
 168         }
 169         return -EINVAL;
 170 }
 171
 172 static ssize_t in_voltage_scale_available_show(struct device *dev,
 173                                                struct device_attribute *attr,
 174                                                char *buf)
 175 {
 176         int i, len = 0;
 177
 178         for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
 179                 len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
 180                                  scale_avail[i][0], scale_avail[i][1]);
 181
 182         buf[len - 1] = '\n';
 183
 184         return len;
 185 }
 186
 187 static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);
 188
 189 static int ad7606_oversampling_get_index(unsigned int val)
 190 {
 191         unsigned char supported[] = {1, 2, 4, 8, 16, 32, 64};
 192         int i;
 193
 194         for (i = 0; i < ARRAY_SIZE(supported); i++)
 195                 if (val == supported[i])
 196                         return i;
 197
 198         return -EINVAL;
 199 }
 200
 201 static int ad7606_write_raw(struct iio_dev *indio_dev,
 202                             struct iio_chan_spec const *chan,
 203                             int val,
 204                             int val2,
 205                             long mask)
 206 {
 207         struct ad7606_state *st = iio_priv(indio_dev);
 208         DECLARE_BITMAP(values, 3);
 209         int ret, i;
 210
 211         switch (mask) {
 212         case IIO_CHAN_INFO_SCALE:
 213                 ret = -EINVAL;
 214                 mutex_lock(&st->lock);
 215                 for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
 216                         if (val2 == scale_avail[i][1]) {
 217                                 gpiod_set_value(st->gpio_range, i);
 218                                 st->range = i;
 219
 220                                 ret = 0;
 221                                 break;
 222                         }
 223                 mutex_unlock(&st->lock);
 224
 225                 return ret;
 226         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 227                 if (val2)
 228                         return -EINVAL;
 229                 ret = ad7606_oversampling_get_index(val);
 230                 if (ret < 0)
 231                         return ret;
 232
 233                 values[0] = ret;
 234
 235                 mutex_lock(&st->lock);
 236                 gpiod_set_array_value(3, st->gpio_os->desc, st->gpio_os->info,
 237                                       values);
 238                 st->oversampling = val;
 239                 mutex_unlock(&st->lock);
 240
 241                 return 0;
 242         default:
 243                 return -EINVAL;
 244         }
 245 }
 246
 247 static IIO_CONST_ATTR(oversampling_ratio_available, "1 2 4 8 16 32 64");
 248
 249 static struct attribute *ad7606_attributes_os_and_range[] = {
 250         &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
 251         &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
 252         NULL,
 253 };
 254
 255 static const struct attribute_group ad7606_attribute_group_os_and_range = {
 256         .attrs = ad7606_attributes_os_and_range,
 257 };
 258
 259 static struct attribute *ad7606_attributes_os[] = {
 260         &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
 261         NULL,
 262 };
 263
 264 static const struct attribute_group ad7606_attribute_group_os = {
 265         .attrs = ad7606_attributes_os,
 266 };
 267
 268 static struct attribute *ad7606_attributes_range[] = {
 269         &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
 270         NULL,
 271 };
 272
 273 static const struct attribute_group ad7606_attribute_group_range = {
 274         .attrs = ad7606_attributes_range,
 275 };
 276
 277 #define AD760X_CHANNEL(num, mask)                               \
 278         {                                                       \
 279                 .type = IIO_VOLTAGE,                            \
 280                 .indexed = 1,                                   \
 281                 .channel = num,                                 \
 282                 .address = num,                                 \
 283                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 284                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
 285                 .info_mask_shared_by_all = mask,                \
 286                 .scan_index = num,                              \
 287                 .scan_type = {                                  \
 288                         .sign = 's',                            \
 289                         .realbits = 16,                         \
 290                         .storagebits = 16,                      \
 291                         .endianness = IIO_CPU,                  \
 292                 },                                              \
 293         }
 294
 295 #define AD7605_CHANNEL(num)     \
 296         AD760X_CHANNEL(num, 0)
 297
 298 #define AD7606_CHANNEL(num)     \
 299         AD760X_CHANNEL(num, BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO))
 300
 301 static const struct iio_chan_spec ad7605_channels[] = {
 302         IIO_CHAN_SOFT_TIMESTAMP(4),
 303         AD7605_CHANNEL(0),
 304         AD7605_CHANNEL(1),
 305         AD7605_CHANNEL(2),
 306         AD7605_CHANNEL(3),
 307 };
 308
 309 static const struct iio_chan_spec ad7606_channels[] = {
 310         IIO_CHAN_SOFT_TIMESTAMP(8),
 311         AD7606_CHANNEL(0),
 312         AD7606_CHANNEL(1),
 313         AD7606_CHANNEL(2),
 314         AD7606_CHANNEL(3),
 315         AD7606_CHANNEL(4),
 316         AD7606_CHANNEL(5),
 317         AD7606_CHANNEL(6),
 318         AD7606_CHANNEL(7),
 319 };
 320
 321 static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
 322         /*
 323          * More devices added in future
 324          */
 325         [ID_AD7605_4] = {
 326                 .channels = ad7605_channels,
 327                 .num_channels = 5,
 328         },
 329         [ID_AD7606_8] = {
 330                 .channels = ad7606_channels,
 331                 .num_channels = 9,
 332                 .has_oversampling = true,
 333         },
 334         [ID_AD7606_6] = {
 335                 .channels = ad7606_channels,
 336                 .num_channels = 7,
 337                 .has_oversampling = true,
 338         },
 339         [ID_AD7606_4] = {
 340                 .channels = ad7606_channels,
 341                 .num_channels = 5,
 342                 .has_oversampling = true,
 343         },
 344 };
 345
 346 static int ad7606_request_gpios(struct ad7606_state *st)
 347 {
 348         struct device *dev = st->dev;
 349
 350         st->gpio_convst = devm_gpiod_get(dev, "conversion-start",
 351                                          GPIOD_OUT_LOW);
 352         if (IS_ERR(st->gpio_convst))
 353                 return PTR_ERR(st->gpio_convst);
 354
 355         st->gpio_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
 356         if (IS_ERR(st->gpio_reset))
 357                 return PTR_ERR(st->gpio_reset);
 358
 359         st->gpio_range = devm_gpiod_get_optional(dev, "range", GPIOD_OUT_LOW);
 360         if (IS_ERR(st->gpio_range))
 361                 return PTR_ERR(st->gpio_range);
 362
 363         st->gpio_standby = devm_gpiod_get_optional(dev, "standby",
 364                                                    GPIOD_OUT_HIGH);
 365         if (IS_ERR(st->gpio_standby))
 366                 return PTR_ERR(st->gpio_standby);
 367
 368         st->gpio_frstdata = devm_gpiod_get_optional(dev, "first-data",
 369                                                     GPIOD_IN);
 370         if (IS_ERR(st->gpio_frstdata))
 371                 return PTR_ERR(st->gpio_frstdata);
 372
 373         if (!st->chip_info->has_oversampling)
 374                 return 0;
 375
 376         st->gpio_os = devm_gpiod_get_array_optional(dev, "oversampling-ratio",
 377                                                     GPIOD_OUT_LOW);
 378         return PTR_ERR_OR_ZERO(st->gpio_os);
 379 }
 380
 381 /**
 382  *  Interrupt handler
 383  */
 384 static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
 385 {
 386         struct iio_dev *indio_dev = dev_id;
 387         struct ad7606_state *st = iio_priv(indio_dev);
 388
 389         if (iio_buffer_enabled(indio_dev)) {
 390                 schedule_work(&st->poll_work);
 391         } else {
 392                 st->done = true;
 393                 wake_up_interruptible(&st->wq_data_avail);
 394         }
 395
 396         return IRQ_HANDLED;
 397 };
 398
 399 static const struct iio_info ad7606_info_no_os_or_range = {
 400         .read_raw = &ad7606_read_raw,
 401 };
 402
 403 static const struct iio_info ad7606_info_os_and_range = {
 404         .read_raw = &ad7606_read_raw,
 405         .write_raw = &ad7606_write_raw,
 406         .attrs = &ad7606_attribute_group_os_and_range,
 407 };
 408
 409 static const struct iio_info ad7606_info_os = {
 410         .read_raw = &ad7606_read_raw,
 411         .write_raw = &ad7606_write_raw,
 412         .attrs = &ad7606_attribute_group_os,
 413 };
 414
 415 static const struct iio_info ad7606_info_range = {
 416         .read_raw = &ad7606_read_raw,
 417         .write_raw = &ad7606_write_raw,
 418         .attrs = &ad7606_attribute_group_range,
 419 };
 420
 421 int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 422                  const char *name, unsigned int id,
 423                  const struct ad7606_bus_ops *bops)
 424 {
 425         struct ad7606_state *st;
 426         int ret;
 427         struct iio_dev *indio_dev;
 428
 429         indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
 430         if (!indio_dev)
 431                 return -ENOMEM;
 432
 433         st = iio_priv(indio_dev);
 434
 435         st->dev = dev;
 436         mutex_init(&st->lock);
 437         st->bops = bops;
 438         st->base_address = base_address;
 439         /* tied to logic low, analog input range is +/- 5V */
 440         st->range = 0;
 441         st->oversampling = 1;
 442         INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 443
 444         st->reg = devm_regulator_get(dev, "avcc");
 445         if (IS_ERR(st->reg))
 446                 return PTR_ERR(st->reg);
 447
 448         ret = regulator_enable(st->reg);
 449         if (ret) {
 450                 dev_err(dev, "Failed to enable specified AVcc supply\n");
 451                 return ret;
 452         }
 453
 454         st->chip_info = &ad7606_chip_info_tbl[id];
 455
 456         ret = ad7606_request_gpios(st);
 457         if (ret)
 458                 goto error_disable_reg;
 459
 460         indio_dev->dev.parent = dev;
 461         if (st->gpio_os) {
 462                 if (st->gpio_range)
 463                         indio_dev->info = &ad7606_info_os_and_range;
 464                 else
 465                         indio_dev->info = &ad7606_info_os;
 466         } else {
 467                 if (st->gpio_range)
 468                         indio_dev->info = &ad7606_info_range;
 469                 else
 470                         indio_dev->info = &ad7606_info_no_os_or_range;
 471         }
 472         indio_dev->modes = INDIO_DIRECT_MODE;
 473         indio_dev->name = name;
 474         indio_dev->channels = st->chip_info->channels;
 475         indio_dev->num_channels = st->chip_info->num_channels;
 476
 477         init_waitqueue_head(&st->wq_data_avail);
 478
 479         ret = ad7606_reset(st);
 480         if (ret)
 481                 dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
 482
 483         ret = request_irq(irq, ad7606_interrupt, IRQF_TRIGGER_FALLING, name,
 484                           indio_dev);
 485         if (ret)
 486                 goto error_disable_reg;
 487
 488         ret = iio_triggered_buffer_setup(indio_dev, &ad7606_trigger_handler,
 489                                          NULL, NULL);
 490         if (ret)
 491                 goto error_free_irq;
 492
 493         ret = iio_device_register(indio_dev);
 494         if (ret)
 495                 goto error_unregister_ring;
 496
 497         dev_set_drvdata(dev, indio_dev);
 498
 499         return 0;
 500 error_unregister_ring:
 501         iio_triggered_buffer_cleanup(indio_dev);
 502
 503 error_free_irq:
 504         free_irq(irq, indio_dev);
 505
 506 error_disable_reg:
 507         regulator_disable(st->reg);
 508         return ret;
 509 }
 510 EXPORT_SYMBOL_GPL(ad7606_probe);
 511
 512 int ad7606_remove(struct device *dev, int irq)
 513 {
 514         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 515         struct ad7606_state *st = iio_priv(indio_dev);
 516
 517         iio_device_unregister(indio_dev);
 518         iio_triggered_buffer_cleanup(indio_dev);
 519
 520         free_irq(irq, indio_dev);
 521         regulator_disable(st->reg);
 522
 523         return 0;
 524 }
 525 EXPORT_SYMBOL_GPL(ad7606_remove);
 526
 527 #ifdef CONFIG_PM_SLEEP
 528
 529 static int ad7606_suspend(struct device *dev)
 530 {
 531         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 532         struct ad7606_state *st = iio_priv(indio_dev);
 533
 534         if (st->gpio_standby) {
 535                 gpiod_set_value(st->gpio_range, 1);
 536                 gpiod_set_value(st->gpio_standby, 0);
 537         }
 538
 539         return 0;
 540 }
 541
 542 static int ad7606_resume(struct device *dev)
 543 {
 544         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 545         struct ad7606_state *st = iio_priv(indio_dev);
 546
 547         if (st->gpio_standby) {
 548                 gpiod_set_value(st->gpio_range, st->range);
 549                 gpiod_set_value(st->gpio_standby, 1);
 550                 ad7606_reset(st);
 551         }
 552
 553         return 0;
 554 }
 555
 556 SIMPLE_DEV_PM_OPS(ad7606_pm_ops, ad7606_suspend, ad7606_resume);
 557 EXPORT_SYMBOL_GPL(ad7606_pm_ops);
 558
 559 #endif
 560
 561 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 562 MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
 563 MODULE_LICENSE("GPL v2");