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/mod_devicetable.h>
  11 #include <linux/init.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/delay.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/mutex.h>
  16 #include <linux/err.h>
  17 #include <linux/irq.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
  26 #define AS3935_AFE_GAIN         0x00
  27 #define AS3935_AFE_MASK         0x3F
  28 #define AS3935_AFE_GAIN_MAX     0x1F
  29 #define AS3935_AFE_PWR_BIT      BIT(0)
  30
  31 #define AS3935_NFLWDTH          0x01
  32 #define AS3935_NFLWDTH_MASK     0x7f
  33
  34 #define AS3935_INT              0x03
  35 #define AS3935_INT_MASK         0x0f
  36 #define AS3935_DISTURB_INT      BIT(2)
  37 #define AS3935_EVENT_INT        BIT(3)
  38 #define AS3935_NOISE_INT        BIT(0)
  39
  40 #define AS3935_DATA             0x07
  41 #define AS3935_DATA_MASK        0x3F
  42
  43 #define AS3935_TUNE_CAP         0x08
  44 #define AS3935_DEFAULTS         0x3C
  45 #define AS3935_CALIBRATE        0x3D
  46
  47 #define AS3935_READ_DATA        BIT(14)
  48 #define AS3935_ADDRESS(x)       ((x) << 8)
  49
  50 #define MAX_PF_CAP              120
  51 #define TUNE_CAP_DIV            8
  52
  53 struct as3935_state {
  54         struct spi_device *spi;
  55         struct iio_trigger *trig;
  56         struct mutex lock;
  57         struct delayed_work work;
  58
  59         unsigned long noise_tripped;
  60         u32 tune_cap;
  61         u32 nflwdth_reg;
  62         u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
  63         u8 buf[2] ____cacheline_aligned;
  64 };
  65
  66 static const struct iio_chan_spec as3935_channels[] = {
  67         {
  68                 .type           = IIO_PROXIMITY,
  69                 .info_mask_separate =
  70                         BIT(IIO_CHAN_INFO_RAW) |
  71                         BIT(IIO_CHAN_INFO_PROCESSED) |
  72                         BIT(IIO_CHAN_INFO_SCALE),
  73                 .scan_index     = 0,
  74                 .scan_type = {
  75                         .sign           = 'u',
  76                         .realbits       = 6,
  77                         .storagebits    = 8,
  78                 },
  79         },
  80         IIO_CHAN_SOFT_TIMESTAMP(1),
  81 };
  82
  83 static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
  84 {
  85         u8 cmd;
  86         int ret;
  87
  88         cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
  89         ret = spi_w8r8(st->spi, cmd);
  90         if (ret < 0)
  91                 return ret;
  92         *val = ret;
  93
  94         return 0;
  95 }
  96
  97 static int as3935_write(struct as3935_state *st,
  98                                 unsigned int reg,
  99                                 unsigned int val)
 100 {
 101         u8 *buf = st->buf;
 102
 103         buf[0] = AS3935_ADDRESS(reg) >> 8;
 104         buf[1] = val;
 105
 106         return spi_write(st->spi, buf, 2);
 107 }
 108
 109 static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
 110                                         struct device_attribute *attr,
 111                                         char *buf)
 112 {
 113         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 114         int val, ret;
 115
 116         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 117         if (ret)
 118                 return ret;
 119         val = (val & AS3935_AFE_MASK) >> 1;
 120
 121         return sprintf(buf, "%d\n", val);
 122 }
 123
 124 static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
 125                                         struct device_attribute *attr,
 126                                         const char *buf, size_t len)
 127 {
 128         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 129         unsigned long val;
 130         int ret;
 131
 132         ret = kstrtoul((const char *) buf, 10, &val);
 133         if (ret)
 134                 return -EINVAL;
 135
 136         if (val > AS3935_AFE_GAIN_MAX)
 137                 return -EINVAL;
 138
 139         as3935_write(st, AS3935_AFE_GAIN, val << 1);
 140
 141         return len;
 142 }
 143
 144 static ssize_t as3935_noise_level_tripped_show(struct device *dev,
 145                                         struct device_attribute *attr,
 146                                         char *buf)
 147 {
 148         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 149         int ret;
 150
 151         mutex_lock(&st->lock);
 152         ret = sprintf(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ));
 153         mutex_unlock(&st->lock);
 154
 155         return ret;
 156 }
 157
 158 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
 159         as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
 160
 161 static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
 162         as3935_noise_level_tripped_show, NULL, 0);
 163
 164 static struct attribute *as3935_attributes[] = {
 165         &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
 166         &iio_dev_attr_noise_level_tripped.dev_attr.attr,
 167         NULL,
 168 };
 169
 170 static const struct attribute_group as3935_attribute_group = {
 171         .attrs = as3935_attributes,
 172 };
 173
 174 static int as3935_read_raw(struct iio_dev *indio_dev,
 175                            struct iio_chan_spec const *chan,
 176                            int *val,
 177                            int *val2,
 178                            long m)
 179 {
 180         struct as3935_state *st = iio_priv(indio_dev);
 181         int ret;
 182
 183
 184         switch (m) {
 185         case IIO_CHAN_INFO_PROCESSED:
 186         case IIO_CHAN_INFO_RAW:
 187                 *val2 = 0;
 188                 ret = as3935_read(st, AS3935_DATA, val);
 189                 if (ret)
 190                         return ret;
 191
 192                 /* storm out of range */
 193                 if (*val == AS3935_DATA_MASK)
 194                         return -EINVAL;
 195
 196                 if (m == IIO_CHAN_INFO_RAW)
 197                         return IIO_VAL_INT;
 198
 199                 if (m == IIO_CHAN_INFO_PROCESSED)
 200                         *val *= 1000;
 201                 break;
 202         case IIO_CHAN_INFO_SCALE:
 203                 *val = 1000;
 204                 break;
 205         default:
 206                 return -EINVAL;
 207         }
 208
 209         return IIO_VAL_INT;
 210 }
 211
 212 static const struct iio_info as3935_info = {
 213         .attrs = &as3935_attribute_group,
 214         .read_raw = &as3935_read_raw,
 215 };
 216
 217 static irqreturn_t as3935_trigger_handler(int irq, void *private)
 218 {
 219         struct iio_poll_func *pf = private;
 220         struct iio_dev *indio_dev = pf->indio_dev;
 221         struct as3935_state *st = iio_priv(indio_dev);
 222         int val, ret;
 223
 224         ret = as3935_read(st, AS3935_DATA, &val);
 225         if (ret)
 226                 goto err_read;
 227
 228         st->buffer[0] = val & AS3935_DATA_MASK;
 229         iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
 230                                            iio_get_time_ns(indio_dev));
 231 err_read:
 232         iio_trigger_notify_done(indio_dev->trig);
 233
 234         return IRQ_HANDLED;
 235 }
 236
 237 static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
 238 };
 239
 240 static void as3935_event_work(struct work_struct *work)
 241 {
 242         struct as3935_state *st;
 243         int val;
 244         int ret;
 245
 246         st = container_of(work, struct as3935_state, work.work);
 247
 248         ret = as3935_read(st, AS3935_INT, &val);
 249         if (ret) {
 250                 dev_warn(&st->spi->dev, "read error\n");
 251                 return;
 252         }
 253
 254         val &= AS3935_INT_MASK;
 255
 256         switch (val) {
 257         case AS3935_EVENT_INT:
 258                 iio_trigger_poll_chained(st->trig);
 259                 break;
 260         case AS3935_DISTURB_INT:
 261         case AS3935_NOISE_INT:
 262                 mutex_lock(&st->lock);
 263                 st->noise_tripped = jiffies;
 264                 mutex_unlock(&st->lock);
 265                 dev_warn(&st->spi->dev, "noise level is too high\n");
 266                 break;
 267         }
 268 }
 269
 270 static irqreturn_t as3935_interrupt_handler(int irq, void *private)
 271 {
 272         struct iio_dev *indio_dev = private;
 273         struct as3935_state *st = iio_priv(indio_dev);
 274
 275         /*
 276          * Delay work for >2 milliseconds after an interrupt to allow
 277          * estimated distance to recalculated.
 278          */
 279
 280         schedule_delayed_work(&st->work, msecs_to_jiffies(3));
 281
 282         return IRQ_HANDLED;
 283 }
 284
 285 static void calibrate_as3935(struct as3935_state *st)
 286 {
 287         as3935_write(st, AS3935_DEFAULTS, 0x96);
 288         as3935_write(st, AS3935_CALIBRATE, 0x96);
 289         as3935_write(st, AS3935_TUNE_CAP,
 290                 BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
 291
 292         mdelay(2);
 293         as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
 294         as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg);
 295 }
 296
 297 #ifdef CONFIG_PM_SLEEP
 298 static int as3935_suspend(struct device *dev)
 299 {
 300         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 301         struct as3935_state *st = iio_priv(indio_dev);
 302         int val, ret;
 303
 304         mutex_lock(&st->lock);
 305         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 306         if (ret)
 307                 goto err_suspend;
 308         val |= AS3935_AFE_PWR_BIT;
 309
 310         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 311
 312 err_suspend:
 313         mutex_unlock(&st->lock);
 314
 315         return ret;
 316 }
 317
 318 static int as3935_resume(struct device *dev)
 319 {
 320         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 321         struct as3935_state *st = iio_priv(indio_dev);
 322         int val, ret;
 323
 324         mutex_lock(&st->lock);
 325         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 326         if (ret)
 327                 goto err_resume;
 328         val &= ~AS3935_AFE_PWR_BIT;
 329         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 330
 331         calibrate_as3935(st);
 332
 333 err_resume:
 334         mutex_unlock(&st->lock);
 335
 336         return ret;
 337 }
 338
 339 static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
 340 #define AS3935_PM_OPS (&as3935_pm_ops)
 341
 342 #else
 343 #define AS3935_PM_OPS NULL
 344 #endif
 345
 346 static void as3935_stop_work(void *data)
 347 {
 348         struct iio_dev *indio_dev = data;
 349         struct as3935_state *st = iio_priv(indio_dev);
 350
 351         cancel_delayed_work_sync(&st->work);
 352 }
 353
 354 static int as3935_probe(struct spi_device *spi)
 355 {
 356         struct device *dev = &spi->dev;
 357         struct iio_dev *indio_dev;
 358         struct iio_trigger *trig;
 359         struct as3935_state *st;
 360         int ret;
 361
 362         /* Be sure lightning event interrupt is specified */
 363         if (!spi->irq) {
 364                 dev_err(dev, "unable to get event interrupt\n");
 365                 return -EINVAL;
 366         }
 367
 368         indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
 369         if (!indio_dev)
 370                 return -ENOMEM;
 371
 372         st = iio_priv(indio_dev);
 373         st->spi = spi;
 374
 375         spi_set_drvdata(spi, indio_dev);
 376         mutex_init(&st->lock);
 377
 378         ret = device_property_read_u32(dev,
 379                         "ams,tuning-capacitor-pf", &st->tune_cap);
 380         if (ret) {
 381                 st->tune_cap = 0;
 382                 dev_warn(dev, "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(dev, "wrong tuning-capacitor-pf setting of %d\n",
 388                         st->tune_cap);
 389                 return -EINVAL;
 390         }
 391
 392         ret = device_property_read_u32(dev,
 393                         "ams,nflwdth", &st->nflwdth_reg);
 394         if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
 395                 dev_err(dev, "invalid nflwdth setting of %d\n",
 396                         st->nflwdth_reg);
 397                 return -EINVAL;
 398         }
 399
 400         indio_dev->name = spi_get_device_id(spi)->name;
 401         indio_dev->channels = as3935_channels;
 402         indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
 403         indio_dev->modes = INDIO_DIRECT_MODE;
 404         indio_dev->info = &as3935_info;
 405
 406         trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
 407                                       indio_dev->name, indio_dev->id);
 408
 409         if (!trig)
 410                 return -ENOMEM;
 411
 412         st->trig = trig;
 413         st->noise_tripped = jiffies - HZ;
 414         trig->dev.parent = indio_dev->dev.parent;
 415         iio_trigger_set_drvdata(trig, indio_dev);
 416         trig->ops = &iio_interrupt_trigger_ops;
 417
 418         ret = devm_iio_trigger_register(dev, trig);
 419         if (ret) {
 420                 dev_err(dev, "failed to register trigger\n");
 421                 return ret;
 422         }
 423
 424         ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
 425                                               iio_pollfunc_store_time,
 426                                               as3935_trigger_handler, NULL);
 427
 428         if (ret) {
 429                 dev_err(dev, "cannot setup iio trigger\n");
 430                 return ret;
 431         }
 432
 433         calibrate_as3935(st);
 434
 435         INIT_DELAYED_WORK(&st->work, as3935_event_work);
 436         ret = devm_add_action(dev, as3935_stop_work, indio_dev);
 437         if (ret)
 438                 return ret;
 439
 440         ret = devm_request_irq(dev, spi->irq,
 441                                 &as3935_interrupt_handler,
 442                                 IRQF_TRIGGER_RISING,
 443                                 dev_name(dev),
 444                                 indio_dev);
 445
 446         if (ret) {
 447                 dev_err(dev, "unable to request irq\n");
 448                 return ret;
 449         }
 450
 451         ret = devm_iio_device_register(dev, indio_dev);
 452         if (ret < 0) {
 453                 dev_err(dev, "unable to register device\n");
 454                 return ret;
 455         }
 456         return 0;
 457 }
 458
 459 static const struct of_device_id as3935_of_match[] = {
 460         { .compatible = "ams,as3935", },
 461         { /* sentinel */ },
 462 };
 463 MODULE_DEVICE_TABLE(of, as3935_of_match);
 464
 465 static const struct spi_device_id as3935_id[] = {
 466         {"as3935", 0},
 467         {},
 468 };
 469 MODULE_DEVICE_TABLE(spi, as3935_id);
 470
 471 static struct spi_driver as3935_driver = {
 472         .driver = {
 473                 .name   = "as3935",
 474                 .of_match_table = as3935_of_match,
 475                 .pm     = AS3935_PM_OPS,
 476         },
 477         .probe          = as3935_probe,
 478         .id_table       = as3935_id,
 479 };
 480 module_spi_driver(as3935_driver);
 481
 482 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
 483 MODULE_DESCRIPTION("AS3935 lightning sensor");
 484 MODULE_LICENSE("GPL");