drivers/iio/proximity/as3935.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * as3935.c - Support for AS3935 Franklin lightning sensor
   4  *
   5  * Copyright (C) 2014, 2017-2018
   6  * Author: Matt Ranostay <matt.ranostay@konsulko.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/delay.h>
  13 #include <linux/workqueue.h>
  14 #include <linux/mutex.h>
  15 #include <linux/err.h>
  16 #include <linux/irq.h>
  17 #include <linux/spi/spi.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/sysfs.h>
  20 #include <linux/iio/trigger.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include <linux/iio/buffer.h>
  23 #include <linux/iio/triggered_buffer.h>
  24
  25 #define AS3935_AFE_GAIN         0x00
  26 #define AS3935_AFE_MASK         0x3F
  27 #define AS3935_AFE_GAIN_MAX     0x1F
  28 #define AS3935_AFE_PWR_BIT      BIT(0)
  29
  30 #define AS3935_NFLWDTH          0x01
  31 #define AS3935_NFLWDTH_MASK     0x7f
  32
  33 #define AS3935_INT              0x03
  34 #define AS3935_INT_MASK         0x0f
  35 #define AS3935_DISTURB_INT      BIT(2)
  36 #define AS3935_EVENT_INT        BIT(3)
  37 #define AS3935_NOISE_INT        BIT(0)
  38
  39 #define AS3935_DATA             0x07
  40 #define AS3935_DATA_MASK        0x3F
  41
  42 #define AS3935_TUNE_CAP         0x08
  43 #define AS3935_DEFAULTS         0x3C
  44 #define AS3935_CALIBRATE        0x3D
  45
  46 #define AS3935_READ_DATA        BIT(14)
  47 #define AS3935_ADDRESS(x)       ((x) << 8)
  48
  49 #define MAX_PF_CAP              120
  50 #define TUNE_CAP_DIV            8
  51
  52 struct as3935_state {
  53         struct spi_device *spi;
  54         struct iio_trigger *trig;
  55         struct mutex lock;
  56         struct delayed_work work;
  57
  58         unsigned long noise_tripped;
  59         u32 tune_cap;
  60         u32 nflwdth_reg;
  61         u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
  62         u8 buf[2] ____cacheline_aligned;
  63 };
  64
  65 static const struct iio_chan_spec as3935_channels[] = {
  66         {
  67                 .type           = IIO_PROXIMITY,
  68                 .info_mask_separate =
  69                         BIT(IIO_CHAN_INFO_RAW) |
  70                         BIT(IIO_CHAN_INFO_PROCESSED) |
  71                         BIT(IIO_CHAN_INFO_SCALE),
  72                 .scan_index     = 0,
  73                 .scan_type = {
  74                         .sign           = 'u',
  75                         .realbits       = 6,
  76                         .storagebits    = 8,
  77                 },
  78         },
  79         IIO_CHAN_SOFT_TIMESTAMP(1),
  80 };
  81
  82 static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
  83 {
  84         u8 cmd;
  85         int ret;
  86
  87         cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
  88         ret = spi_w8r8(st->spi, cmd);
  89         if (ret < 0)
  90                 return ret;
  91         *val = ret;
  92
  93         return 0;
  94 }
  95
  96 static int as3935_write(struct as3935_state *st,
  97                                 unsigned int reg,
  98                                 unsigned int val)
  99 {
 100         u8 *buf = st->buf;
 101
 102         buf[0] = AS3935_ADDRESS(reg) >> 8;
 103         buf[1] = val;
 104
 105         return spi_write(st->spi, buf, 2);
 106 }
 107
 108 static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
 109                                         struct device_attribute *attr,
 110                                         char *buf)
 111 {
 112         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 113         int val, ret;
 114
 115         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 116         if (ret)
 117                 return ret;
 118         val = (val & AS3935_AFE_MASK) >> 1;
 119
 120         return sprintf(buf, "%d\n", val);
 121 }
 122
 123 static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
 124                                         struct device_attribute *attr,
 125                                         const char *buf, size_t len)
 126 {
 127         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 128         unsigned long val;
 129         int ret;
 130
 131         ret = kstrtoul((const char *) buf, 10, &val);
 132         if (ret)
 133                 return -EINVAL;
 134
 135         if (val > AS3935_AFE_GAIN_MAX)
 136                 return -EINVAL;
 137
 138         as3935_write(st, AS3935_AFE_GAIN, val << 1);
 139
 140         return len;
 141 }
 142
 143 static ssize_t as3935_noise_level_tripped_show(struct device *dev,
 144                                         struct device_attribute *attr,
 145                                         char *buf)
 146 {
 147         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 148         int ret;
 149
 150         mutex_lock(&st->lock);
 151         ret = sprintf(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ));
 152         mutex_unlock(&st->lock);
 153
 154         return ret;
 155 }
 156
 157 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
 158         as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
 159
 160 static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
 161         as3935_noise_level_tripped_show, NULL, 0);
 162
 163 static struct attribute *as3935_attributes[] = {
 164         &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
 165         &iio_dev_attr_noise_level_tripped.dev_attr.attr,
 166         NULL,
 167 };
 168
 169 static const struct attribute_group as3935_attribute_group = {
 170         .attrs = as3935_attributes,
 171 };
 172
 173 static int as3935_read_raw(struct iio_dev *indio_dev,
 174                            struct iio_chan_spec const *chan,
 175                            int *val,
 176                            int *val2,
 177                            long m)
 178 {
 179         struct as3935_state *st = iio_priv(indio_dev);
 180         int ret;
 181
 182
 183         switch (m) {
 184         case IIO_CHAN_INFO_PROCESSED:
 185         case IIO_CHAN_INFO_RAW:
 186                 *val2 = 0;
 187                 ret = as3935_read(st, AS3935_DATA, val);
 188                 if (ret)
 189                         return ret;
 190
 191                 /* storm out of range */
 192                 if (*val == AS3935_DATA_MASK)
 193                         return -EINVAL;
 194
 195                 if (m == IIO_CHAN_INFO_RAW)
 196                         return IIO_VAL_INT;
 197
 198                 if (m == IIO_CHAN_INFO_PROCESSED)
 199                         *val *= 1000;
 200                 break;
 201         case IIO_CHAN_INFO_SCALE:
 202                 *val = 1000;
 203                 break;
 204         default:
 205                 return -EINVAL;
 206         }
 207
 208         return IIO_VAL_INT;
 209 }
 210
 211 static const struct iio_info as3935_info = {
 212         .attrs = &as3935_attribute_group,
 213         .read_raw = &as3935_read_raw,
 214 };
 215
 216 static irqreturn_t as3935_trigger_handler(int irq, void *private)
 217 {
 218         struct iio_poll_func *pf = private;
 219         struct iio_dev *indio_dev = pf->indio_dev;
 220         struct as3935_state *st = iio_priv(indio_dev);
 221         int val, ret;
 222
 223         ret = as3935_read(st, AS3935_DATA, &val);
 224         if (ret)
 225                 goto err_read;
 226
 227         st->buffer[0] = val & AS3935_DATA_MASK;
 228         iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
 229                                            iio_get_time_ns(indio_dev));
 230 err_read:
 231         iio_trigger_notify_done(indio_dev->trig);
 232
 233         return IRQ_HANDLED;
 234 }
 235
 236 static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
 237 };
 238
 239 static void as3935_event_work(struct work_struct *work)
 240 {
 241         struct as3935_state *st;
 242         int val;
 243         int ret;
 244
 245         st = container_of(work, struct as3935_state, work.work);
 246
 247         ret = as3935_read(st, AS3935_INT, &val);
 248         if (ret) {
 249                 dev_warn(&st->spi->dev, "read error\n");
 250                 return;
 251         }
 252
 253         val &= AS3935_INT_MASK;
 254
 255         switch (val) {
 256         case AS3935_EVENT_INT:
 257                 iio_trigger_poll_chained(st->trig);
 258                 break;
 259         case AS3935_DISTURB_INT:
 260         case AS3935_NOISE_INT:
 261                 mutex_lock(&st->lock);
 262                 st->noise_tripped = jiffies;
 263                 mutex_unlock(&st->lock);
 264                 dev_warn(&st->spi->dev, "noise level is too high\n");
 265                 break;
 266         }
 267 }
 268
 269 static irqreturn_t as3935_interrupt_handler(int irq, void *private)
 270 {
 271         struct iio_dev *indio_dev = private;
 272         struct as3935_state *st = iio_priv(indio_dev);
 273
 274         /*
 275          * Delay work for >2 milliseconds after an interrupt to allow
 276          * estimated distance to recalculated.
 277          */
 278
 279         schedule_delayed_work(&st->work, msecs_to_jiffies(3));
 280
 281         return IRQ_HANDLED;
 282 }
 283
 284 static void calibrate_as3935(struct as3935_state *st)
 285 {
 286         as3935_write(st, AS3935_DEFAULTS, 0x96);
 287         as3935_write(st, AS3935_CALIBRATE, 0x96);
 288         as3935_write(st, AS3935_TUNE_CAP,
 289                 BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
 290
 291         mdelay(2);
 292         as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
 293         as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg);
 294 }
 295
 296 #ifdef CONFIG_PM_SLEEP
 297 static int as3935_suspend(struct device *dev)
 298 {
 299         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 300         struct as3935_state *st = iio_priv(indio_dev);
 301         int val, ret;
 302
 303         mutex_lock(&st->lock);
 304         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 305         if (ret)
 306                 goto err_suspend;
 307         val |= AS3935_AFE_PWR_BIT;
 308
 309         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 310
 311 err_suspend:
 312         mutex_unlock(&st->lock);
 313
 314         return ret;
 315 }
 316
 317 static int as3935_resume(struct device *dev)
 318 {
 319         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 320         struct as3935_state *st = iio_priv(indio_dev);
 321         int val, ret;
 322
 323         mutex_lock(&st->lock);
 324         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 325         if (ret)
 326                 goto err_resume;
 327         val &= ~AS3935_AFE_PWR_BIT;
 328         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 329
 330         calibrate_as3935(st);
 331
 332 err_resume:
 333         mutex_unlock(&st->lock);
 334
 335         return ret;
 336 }
 337
 338 static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
 339 #define AS3935_PM_OPS (&as3935_pm_ops)
 340
 341 #else
 342 #define AS3935_PM_OPS NULL
 343 #endif
 344
 345 static void as3935_stop_work(void *data)
 346 {
 347         struct iio_dev *indio_dev = data;
 348         struct as3935_state *st = iio_priv(indio_dev);
 349
 350         cancel_delayed_work_sync(&st->work);
 351 }
 352
 353 static int as3935_probe(struct spi_device *spi)
 354 {
 355         struct iio_dev *indio_dev;
 356         struct iio_trigger *trig;
 357         struct as3935_state *st;
 358         struct device_node *np = spi->dev.of_node;
 359         int ret;
 360
 361         /* Be sure lightning event interrupt is specified */
 362         if (!spi->irq) {
 363                 dev_err(&spi->dev, "unable to get event interrupt\n");
 364                 return -EINVAL;
 365         }
 366
 367         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 368         if (!indio_dev)
 369                 return -ENOMEM;
 370
 371         st = iio_priv(indio_dev);
 372         st->spi = spi;
 373
 374         spi_set_drvdata(spi, indio_dev);
 375         mutex_init(&st->lock);
 376
 377         ret = of_property_read_u32(np,
 378                         "ams,tuning-capacitor-pf", &st->tune_cap);
 379         if (ret) {
 380                 st->tune_cap = 0;
 381                 dev_warn(&spi->dev,
 382                         "no tuning-capacitor-pf set, defaulting to %d",
 383                         st->tune_cap);
 384         }
 385
 386         if (st->tune_cap > MAX_PF_CAP) {
 387                 dev_err(&spi->dev,
 388                         "wrong tuning-capacitor-pf setting of %d\n",
 389                         st->tune_cap);
 390                 return -EINVAL;
 391         }
 392
 393         ret = of_property_read_u32(np,
 394                         "ams,nflwdth", &st->nflwdth_reg);
 395         if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
 396                 dev_err(&spi->dev,
 397                         "invalid nflwdth setting of %d\n",
 398                         st->nflwdth_reg);
 399                 return -EINVAL;
 400         }
 401
 402         indio_dev->dev.parent = &spi->dev;
 403         indio_dev->name = spi_get_device_id(spi)->name;
 404         indio_dev->channels = as3935_channels;
 405         indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
 406         indio_dev->modes = INDIO_DIRECT_MODE;
 407         indio_dev->info = &as3935_info;
 408
 409         trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
 410                                       indio_dev->name, indio_dev->id);
 411
 412         if (!trig)
 413                 return -ENOMEM;
 414
 415         st->trig = trig;
 416         st->noise_tripped = jiffies - HZ;
 417         trig->dev.parent = indio_dev->dev.parent;
 418         iio_trigger_set_drvdata(trig, indio_dev);
 419         trig->ops = &iio_interrupt_trigger_ops;
 420
 421         ret = devm_iio_trigger_register(&spi->dev, trig);
 422         if (ret) {
 423                 dev_err(&spi->dev, "failed to register trigger\n");
 424                 return ret;
 425         }
 426
 427         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
 428                                               iio_pollfunc_store_time,
 429                                               as3935_trigger_handler, NULL);
 430
 431         if (ret) {
 432                 dev_err(&spi->dev, "cannot setup iio trigger\n");
 433                 return ret;
 434         }
 435
 436         calibrate_as3935(st);
 437
 438         INIT_DELAYED_WORK(&st->work, as3935_event_work);
 439         ret = devm_add_action(&spi->dev, as3935_stop_work, indio_dev);
 440         if (ret)
 441                 return ret;
 442
 443         ret = devm_request_irq(&spi->dev, spi->irq,
 444                                 &as3935_interrupt_handler,
 445                                 IRQF_TRIGGER_RISING,
 446                                 dev_name(&spi->dev),
 447                                 indio_dev);
 448
 449         if (ret) {
 450                 dev_err(&spi->dev, "unable to request irq\n");
 451                 return ret;
 452         }
 453
 454         ret = devm_iio_device_register(&spi->dev, indio_dev);
 455         if (ret < 0) {
 456                 dev_err(&spi->dev, "unable to register device\n");
 457                 return ret;
 458         }
 459         return 0;
 460 }
 461
 462 static const struct of_device_id as3935_of_match[] = {
 463         { .compatible = "ams,as3935", },
 464         { /* sentinel */ },
 465 };
 466 MODULE_DEVICE_TABLE(of, as3935_of_match);
 467
 468 static const struct spi_device_id as3935_id[] = {
 469         {"as3935", 0},
 470         {},
 471 };
 472 MODULE_DEVICE_TABLE(spi, as3935_id);
 473
 474 static struct spi_driver as3935_driver = {
 475         .driver = {
 476                 .name   = "as3935",
 477                 .of_match_table = of_match_ptr(as3935_of_match),
 478                 .pm     = AS3935_PM_OPS,
 479         },
 480         .probe          = as3935_probe,
 481         .id_table       = as3935_id,
 482 };
 483 module_spi_driver(as3935_driver);
 484
 485 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
 486 MODULE_DESCRIPTION("AS3935 lightning sensor");
 487 MODULE_LICENSE("GPL");