drivers/iio/proximity/as3935.c

   1 /*
   2  * as3935.c - Support for AS3935 Franklin lightning sensor
   3  *
   4  * Copyright (C) 2014 Matt Ranostay <mranostay@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/delay.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/mutex.h>
  24 #include <linux/err.h>
  25 #include <linux/irq.h>
  26 #include <linux/gpio.h>
  27 #include <linux/spi/spi.h>
  28 #include <linux/iio/iio.h>
  29 #include <linux/iio/sysfs.h>
  30 #include <linux/iio/trigger.h>
  31 #include <linux/iio/trigger_consumer.h>
  32 #include <linux/iio/buffer.h>
  33 #include <linux/iio/triggered_buffer.h>
  34 #include <linux/of_gpio.h>
  35
  36
  37 #define AS3935_AFE_GAIN         0x00
  38 #define AS3935_AFE_MASK         0x3F
  39 #define AS3935_AFE_GAIN_MAX     0x1F
  40 #define AS3935_AFE_PWR_BIT      BIT(0)
  41
  42 #define AS3935_NFLWDTH          0x01
  43 #define AS3935_NFLWDTH_MASK     0x7f
  44
  45 #define AS3935_INT              0x03
  46 #define AS3935_INT_MASK         0x0f
  47 #define AS3935_DISTURB_INT      BIT(2)
  48 #define AS3935_EVENT_INT        BIT(3)
  49 #define AS3935_NOISE_INT        BIT(0)
  50
  51 #define AS3935_DATA             0x07
  52 #define AS3935_DATA_MASK        0x3F
  53
  54 #define AS3935_TUNE_CAP         0x08
  55 #define AS3935_DEFAULTS         0x3C
  56 #define AS3935_CALIBRATE        0x3D
  57
  58 #define AS3935_READ_DATA        BIT(14)
  59 #define AS3935_ADDRESS(x)       ((x) << 8)
  60
  61 #define MAX_PF_CAP              120
  62 #define TUNE_CAP_DIV            8
  63
  64 struct as3935_state {
  65         struct spi_device *spi;
  66         struct iio_trigger *trig;
  67         struct mutex lock;
  68         struct delayed_work work;
  69
  70         unsigned long noise_tripped;
  71         u32 tune_cap;
  72         u32 nflwdth_reg;
  73         u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
  74         u8 buf[2] ____cacheline_aligned;
  75 };
  76
  77 static const struct iio_chan_spec as3935_channels[] = {
  78         {
  79                 .type           = IIO_PROXIMITY,
  80                 .info_mask_separate =
  81                         BIT(IIO_CHAN_INFO_RAW) |
  82                         BIT(IIO_CHAN_INFO_PROCESSED) |
  83                         BIT(IIO_CHAN_INFO_SCALE),
  84                 .scan_index     = 0,
  85                 .scan_type = {
  86                         .sign           = 'u',
  87                         .realbits       = 6,
  88                         .storagebits    = 8,
  89                 },
  90         },
  91         IIO_CHAN_SOFT_TIMESTAMP(1),
  92 };
  93
  94 static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
  95 {
  96         u8 cmd;
  97         int ret;
  98
  99         cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
 100         ret = spi_w8r8(st->spi, cmd);
 101         if (ret < 0)
 102                 return ret;
 103         *val = ret;
 104
 105         return 0;
 106 }
 107
 108 static int as3935_write(struct as3935_state *st,
 109                                 unsigned int reg,
 110                                 unsigned int val)
 111 {
 112         u8 *buf = st->buf;
 113
 114         buf[0] = AS3935_ADDRESS(reg) >> 8;
 115         buf[1] = val;
 116
 117         return spi_write(st->spi, buf, 2);
 118 }
 119
 120 static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
 121                                         struct device_attribute *attr,
 122                                         char *buf)
 123 {
 124         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 125         int val, ret;
 126
 127         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 128         if (ret)
 129                 return ret;
 130         val = (val & AS3935_AFE_MASK) >> 1;
 131
 132         return sprintf(buf, "%d\n", val);
 133 }
 134
 135 static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
 136                                         struct device_attribute *attr,
 137                                         const char *buf, size_t len)
 138 {
 139         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 140         unsigned long val;
 141         int ret;
 142
 143         ret = kstrtoul((const char *) buf, 10, &val);
 144         if (ret)
 145                 return -EINVAL;
 146
 147         if (val > AS3935_AFE_GAIN_MAX)
 148                 return -EINVAL;
 149
 150         as3935_write(st, AS3935_AFE_GAIN, val << 1);
 151
 152         return len;
 153 }
 154
 155 static ssize_t as3935_noise_level_tripped_show(struct device *dev,
 156                                         struct device_attribute *attr,
 157                                         char *buf)
 158 {
 159         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 160         int ret;
 161
 162         mutex_lock(&st->lock);
 163         ret = sprintf(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ));
 164         mutex_unlock(&st->lock);
 165
 166         return ret;
 167 }
 168
 169 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
 170         as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
 171
 172 static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
 173         as3935_noise_level_tripped_show, NULL, 0);
 174
 175 static struct attribute *as3935_attributes[] = {
 176         &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
 177         &iio_dev_attr_noise_level_tripped.dev_attr.attr,
 178         NULL,
 179 };
 180
 181 static const struct attribute_group as3935_attribute_group = {
 182         .attrs = as3935_attributes,
 183 };
 184
 185 static int as3935_read_raw(struct iio_dev *indio_dev,
 186                            struct iio_chan_spec const *chan,
 187                            int *val,
 188                            int *val2,
 189                            long m)
 190 {
 191         struct as3935_state *st = iio_priv(indio_dev);
 192         int ret;
 193
 194
 195         switch (m) {
 196         case IIO_CHAN_INFO_PROCESSED:
 197         case IIO_CHAN_INFO_RAW:
 198                 *val2 = 0;
 199                 ret = as3935_read(st, AS3935_DATA, val);
 200                 if (ret)
 201                         return ret;
 202
 203                 /* storm out of range */
 204                 if (*val == AS3935_DATA_MASK)
 205                         return -EINVAL;
 206
 207                 if (m == IIO_CHAN_INFO_RAW)
 208                         return IIO_VAL_INT;
 209
 210                 if (m == IIO_CHAN_INFO_PROCESSED)
 211                         *val *= 1000;
 212                 break;
 213         case IIO_CHAN_INFO_SCALE:
 214                 *val = 1000;
 215                 break;
 216         default:
 217                 return -EINVAL;
 218         }
 219
 220         return IIO_VAL_INT;
 221 }
 222
 223 static const struct iio_info as3935_info = {
 224         .attrs = &as3935_attribute_group,
 225         .read_raw = &as3935_read_raw,
 226 };
 227
 228 static irqreturn_t as3935_trigger_handler(int irq, void *private)
 229 {
 230         struct iio_poll_func *pf = private;
 231         struct iio_dev *indio_dev = pf->indio_dev;
 232         struct as3935_state *st = iio_priv(indio_dev);
 233         int val, ret;
 234
 235         ret = as3935_read(st, AS3935_DATA, &val);
 236         if (ret)
 237                 goto err_read;
 238
 239         st->buffer[0] = val & AS3935_DATA_MASK;
 240         iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
 241                                            iio_get_time_ns(indio_dev));
 242 err_read:
 243         iio_trigger_notify_done(indio_dev->trig);
 244
 245         return IRQ_HANDLED;
 246 }
 247
 248 static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
 249 };
 250
 251 static void as3935_event_work(struct work_struct *work)
 252 {
 253         struct as3935_state *st;
 254         int val;
 255         int ret;
 256
 257         st = container_of(work, struct as3935_state, work.work);
 258
 259         ret = as3935_read(st, AS3935_INT, &val);
 260         if (ret) {
 261                 dev_warn(&st->spi->dev, "read error\n");
 262                 return;
 263         }
 264
 265         val &= AS3935_INT_MASK;
 266
 267         switch (val) {
 268         case AS3935_EVENT_INT:
 269                 iio_trigger_poll_chained(st->trig);
 270                 break;
 271         case AS3935_DISTURB_INT:
 272         case AS3935_NOISE_INT:
 273                 mutex_lock(&st->lock);
 274                 st->noise_tripped = jiffies;
 275                 mutex_unlock(&st->lock);
 276                 dev_warn(&st->spi->dev, "noise level is too high\n");
 277                 break;
 278         }
 279 }
 280
 281 static irqreturn_t as3935_interrupt_handler(int irq, void *private)
 282 {
 283         struct iio_dev *indio_dev = private;
 284         struct as3935_state *st = iio_priv(indio_dev);
 285
 286         /*
 287          * Delay work for >2 milliseconds after an interrupt to allow
 288          * estimated distance to recalculated.
 289          */
 290
 291         schedule_delayed_work(&st->work, msecs_to_jiffies(3));
 292
 293         return IRQ_HANDLED;
 294 }
 295
 296 static void calibrate_as3935(struct as3935_state *st)
 297 {
 298         as3935_write(st, AS3935_DEFAULTS, 0x96);
 299         as3935_write(st, AS3935_CALIBRATE, 0x96);
 300         as3935_write(st, AS3935_TUNE_CAP,
 301                 BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
 302
 303         mdelay(2);
 304         as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
 305         as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg);
 306 }
 307
 308 #ifdef CONFIG_PM_SLEEP
 309 static int as3935_suspend(struct device *dev)
 310 {
 311         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 312         struct as3935_state *st = iio_priv(indio_dev);
 313         int val, ret;
 314
 315         mutex_lock(&st->lock);
 316         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 317         if (ret)
 318                 goto err_suspend;
 319         val |= AS3935_AFE_PWR_BIT;
 320
 321         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 322
 323 err_suspend:
 324         mutex_unlock(&st->lock);
 325
 326         return ret;
 327 }
 328
 329 static int as3935_resume(struct device *dev)
 330 {
 331         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 332         struct as3935_state *st = iio_priv(indio_dev);
 333         int val, ret;
 334
 335         mutex_lock(&st->lock);
 336         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 337         if (ret)
 338                 goto err_resume;
 339         val &= ~AS3935_AFE_PWR_BIT;
 340         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 341
 342         calibrate_as3935(st);
 343
 344 err_resume:
 345         mutex_unlock(&st->lock);
 346
 347         return ret;
 348 }
 349
 350 static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
 351 #define AS3935_PM_OPS (&as3935_pm_ops)
 352
 353 #else
 354 #define AS3935_PM_OPS NULL
 355 #endif
 356
 357 static int as3935_probe(struct spi_device *spi)
 358 {
 359         struct iio_dev *indio_dev;
 360         struct iio_trigger *trig;
 361         struct as3935_state *st;
 362         struct device_node *np = spi->dev.of_node;
 363         int ret;
 364
 365         /* Be sure lightning event interrupt is specified */
 366         if (!spi->irq) {
 367                 dev_err(&spi->dev, "unable to get event interrupt\n");
 368                 return -EINVAL;
 369         }
 370
 371         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 372         if (!indio_dev)
 373                 return -ENOMEM;
 374
 375         st = iio_priv(indio_dev);
 376         st->spi = spi;
 377
 378         spi_set_drvdata(spi, indio_dev);
 379         mutex_init(&st->lock);
 380         INIT_DELAYED_WORK(&st->work, as3935_event_work);
 381
 382         ret = of_property_read_u32(np,
 383                         "ams,tuning-capacitor-pf", &st->tune_cap);
 384         if (ret) {
 385                 st->tune_cap = 0;
 386                 dev_warn(&spi->dev,
 387                         "no tuning-capacitor-pf set, defaulting to %d",
 388                         st->tune_cap);
 389         }
 390
 391         if (st->tune_cap > MAX_PF_CAP) {
 392                 dev_err(&spi->dev,
 393                         "wrong tuning-capacitor-pf setting of %d\n",
 394                         st->tune_cap);
 395                 return -EINVAL;
 396         }
 397
 398         ret = of_property_read_u32(np,
 399                         "ams,nflwdth", &st->nflwdth_reg);
 400         if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
 401                 dev_err(&spi->dev,
 402                         "invalid nflwdth setting of %d\n",
 403                         st->nflwdth_reg);
 404                 return -EINVAL;
 405         }
 406
 407         indio_dev->dev.parent = &spi->dev;
 408         indio_dev->name = spi_get_device_id(spi)->name;
 409         indio_dev->channels = as3935_channels;
 410         indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
 411         indio_dev->modes = INDIO_DIRECT_MODE;
 412         indio_dev->info = &as3935_info;
 413
 414         trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
 415                                       indio_dev->name, indio_dev->id);
 416
 417         if (!trig)
 418                 return -ENOMEM;
 419
 420         st->trig = trig;
 421         st->noise_tripped = jiffies - HZ;
 422         trig->dev.parent = indio_dev->dev.parent;
 423         iio_trigger_set_drvdata(trig, indio_dev);
 424         trig->ops = &iio_interrupt_trigger_ops;
 425
 426         ret = iio_trigger_register(trig);
 427         if (ret) {
 428                 dev_err(&spi->dev, "failed to register trigger\n");
 429                 return ret;
 430         }
 431
 432         ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
 433                 &as3935_trigger_handler, NULL);
 434
 435         if (ret) {
 436                 dev_err(&spi->dev, "cannot setup iio trigger\n");
 437                 goto unregister_trigger;
 438         }
 439
 440         calibrate_as3935(st);
 441
 442         ret = devm_request_irq(&spi->dev, spi->irq,
 443                                 &as3935_interrupt_handler,
 444                                 IRQF_TRIGGER_RISING,
 445                                 dev_name(&spi->dev),
 446                                 indio_dev);
 447
 448         if (ret) {
 449                 dev_err(&spi->dev, "unable to request irq\n");
 450                 goto unregister_buffer;
 451         }
 452
 453         ret = iio_device_register(indio_dev);
 454         if (ret < 0) {
 455                 dev_err(&spi->dev, "unable to register device\n");
 456                 goto unregister_buffer;
 457         }
 458         return 0;
 459
 460 unregister_buffer:
 461         iio_triggered_buffer_cleanup(indio_dev);
 462
 463 unregister_trigger:
 464         iio_trigger_unregister(st->trig);
 465
 466         return ret;
 467 }
 468
 469 static int as3935_remove(struct spi_device *spi)
 470 {
 471         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 472         struct as3935_state *st = iio_priv(indio_dev);
 473
 474         iio_device_unregister(indio_dev);
 475         iio_triggered_buffer_cleanup(indio_dev);
 476         iio_trigger_unregister(st->trig);
 477
 478         return 0;
 479 }
 480
 481 static const struct of_device_id as3935_of_match[] = {
 482         { .compatible = "ams,as3935", },
 483         { /* sentinel */ },
 484 };
 485 MODULE_DEVICE_TABLE(of, as3935_of_match);
 486
 487 static const struct spi_device_id as3935_id[] = {
 488         {"as3935", 0},
 489         {},
 490 };
 491 MODULE_DEVICE_TABLE(spi, as3935_id);
 492
 493 static struct spi_driver as3935_driver = {
 494         .driver = {
 495                 .name   = "as3935",
 496                 .of_match_table = of_match_ptr(as3935_of_match),
 497                 .pm     = AS3935_PM_OPS,
 498         },
 499         .probe          = as3935_probe,
 500         .remove         = as3935_remove,
 501         .id_table       = as3935_id,
 502 };
 503 module_spi_driver(as3935_driver);
 504
 505 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 506 MODULE_DESCRIPTION("AS3935 lightning sensor");
 507 MODULE_LICENSE("GPL");