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