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/devm-helpers.h>
  16 #include <linux/mutex.h>
  17 #include <linux/err.h>
  18 #include <linux/irq.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/sysfs.h>
  22 #include <linux/iio/trigger.h>
  23 #include <linux/iio/trigger_consumer.h>
  24 #include <linux/iio/buffer.h>
  25 #include <linux/iio/triggered_buffer.h>
  26
  27 #define AS3935_AFE_GAIN         0x00
  28 #define AS3935_AFE_MASK         0x3F
  29 #define AS3935_AFE_GAIN_MAX     0x1F
  30 #define AS3935_AFE_PWR_BIT      BIT(0)
  31
  32 #define AS3935_NFLWDTH          0x01
  33 #define AS3935_NFLWDTH_MASK     0x7f
  34
  35 #define AS3935_INT              0x03
  36 #define AS3935_INT_MASK         0x0f
  37 #define AS3935_DISTURB_INT      BIT(2)
  38 #define AS3935_EVENT_INT        BIT(3)
  39 #define AS3935_NOISE_INT        BIT(0)
  40
  41 #define AS3935_DATA             0x07
  42 #define AS3935_DATA_MASK        0x3F
  43
  44 #define AS3935_TUNE_CAP         0x08
  45 #define AS3935_DEFAULTS         0x3C
  46 #define AS3935_CALIBRATE        0x3D
  47
  48 #define AS3935_READ_DATA        BIT(14)
  49 #define AS3935_ADDRESS(x)       ((x) << 8)
  50
  51 #define MAX_PF_CAP              120
  52 #define TUNE_CAP_DIV            8
  53
  54 struct as3935_state {
  55         struct spi_device *spi;
  56         struct iio_trigger *trig;
  57         struct mutex lock;
  58         struct delayed_work work;
  59
  60         unsigned long noise_tripped;
  61         u32 tune_cap;
  62         u32 nflwdth_reg;
  63         /* Ensure timestamp is naturally aligned */
  64         struct {
  65                 u8 chan;
  66                 s64 timestamp __aligned(8);
  67         } scan;
  68         u8 buf[2] __aligned(IIO_DMA_MINALIGN);
  69 };
  70
  71 static const struct iio_chan_spec as3935_channels[] = {
  72         {
  73                 .type           = IIO_PROXIMITY,
  74                 .info_mask_separate =
  75                         BIT(IIO_CHAN_INFO_RAW) |
  76                         BIT(IIO_CHAN_INFO_PROCESSED) |
  77                         BIT(IIO_CHAN_INFO_SCALE),
  78                 .scan_index     = 0,
  79                 .scan_type = {
  80                         .sign           = 'u',
  81                         .realbits       = 6,
  82                         .storagebits    = 8,
  83                 },
  84         },
  85         IIO_CHAN_SOFT_TIMESTAMP(1),
  86 };
  87
  88 static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
  89 {
  90         u8 cmd;
  91         int ret;
  92
  93         cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
  94         ret = spi_w8r8(st->spi, cmd);
  95         if (ret < 0)
  96                 return ret;
  97         *val = ret;
  98
  99         return 0;
 100 }
 101
 102 static int as3935_write(struct as3935_state *st,
 103                                 unsigned int reg,
 104                                 unsigned int val)
 105 {
 106         u8 *buf = st->buf;
 107
 108         buf[0] = AS3935_ADDRESS(reg) >> 8;
 109         buf[1] = val;
 110
 111         return spi_write(st->spi, buf, 2);
 112 }
 113
 114 static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
 115                                         struct device_attribute *attr,
 116                                         char *buf)
 117 {
 118         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 119         int val, ret;
 120
 121         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 122         if (ret)
 123                 return ret;
 124         val = (val & AS3935_AFE_MASK) >> 1;
 125
 126         return sysfs_emit(buf, "%d\n", val);
 127 }
 128
 129 static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
 130                                         struct device_attribute *attr,
 131                                         const char *buf, size_t len)
 132 {
 133         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 134         unsigned long val;
 135         int ret;
 136
 137         ret = kstrtoul(buf, 10, &val);
 138         if (ret)
 139                 return -EINVAL;
 140
 141         if (val > AS3935_AFE_GAIN_MAX)
 142                 return -EINVAL;
 143
 144         as3935_write(st, AS3935_AFE_GAIN, val << 1);
 145
 146         return len;
 147 }
 148
 149 static ssize_t as3935_noise_level_tripped_show(struct device *dev,
 150                                         struct device_attribute *attr,
 151                                         char *buf)
 152 {
 153         struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
 154         int ret;
 155
 156         mutex_lock(&st->lock);
 157         ret = sysfs_emit(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ));
 158         mutex_unlock(&st->lock);
 159
 160         return ret;
 161 }
 162
 163 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
 164         as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
 165
 166 static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
 167         as3935_noise_level_tripped_show, NULL, 0);
 168
 169 static struct attribute *as3935_attributes[] = {
 170         &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
 171         &iio_dev_attr_noise_level_tripped.dev_attr.attr,
 172         NULL,
 173 };
 174
 175 static const struct attribute_group as3935_attribute_group = {
 176         .attrs = as3935_attributes,
 177 };
 178
 179 static int as3935_read_raw(struct iio_dev *indio_dev,
 180                            struct iio_chan_spec const *chan,
 181                            int *val,
 182                            int *val2,
 183                            long m)
 184 {
 185         struct as3935_state *st = iio_priv(indio_dev);
 186         int ret;
 187
 188
 189         switch (m) {
 190         case IIO_CHAN_INFO_PROCESSED:
 191         case IIO_CHAN_INFO_RAW:
 192                 *val2 = 0;
 193                 ret = as3935_read(st, AS3935_DATA, val);
 194                 if (ret)
 195                         return ret;
 196
 197                 /* storm out of range */
 198                 if (*val == AS3935_DATA_MASK)
 199                         return -EINVAL;
 200
 201                 if (m == IIO_CHAN_INFO_RAW)
 202                         return IIO_VAL_INT;
 203
 204                 if (m == IIO_CHAN_INFO_PROCESSED)
 205                         *val *= 1000;
 206                 break;
 207         case IIO_CHAN_INFO_SCALE:
 208                 *val = 1000;
 209                 break;
 210         default:
 211                 return -EINVAL;
 212         }
 213
 214         return IIO_VAL_INT;
 215 }
 216
 217 static const struct iio_info as3935_info = {
 218         .attrs = &as3935_attribute_group,
 219         .read_raw = &as3935_read_raw,
 220 };
 221
 222 static irqreturn_t as3935_trigger_handler(int irq, void *private)
 223 {
 224         struct iio_poll_func *pf = private;
 225         struct iio_dev *indio_dev = pf->indio_dev;
 226         struct as3935_state *st = iio_priv(indio_dev);
 227         int val, ret;
 228
 229         ret = as3935_read(st, AS3935_DATA, &val);
 230         if (ret)
 231                 goto err_read;
 232
 233         st->scan.chan = val & AS3935_DATA_MASK;
 234         iio_push_to_buffers_with_timestamp(indio_dev, &st->scan,
 235                                            iio_get_time_ns(indio_dev));
 236 err_read:
 237         iio_trigger_notify_done(indio_dev->trig);
 238
 239         return IRQ_HANDLED;
 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_nested(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 static int as3935_suspend(struct device *dev)
 300 {
 301         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 302         struct as3935_state *st = iio_priv(indio_dev);
 303         int val, ret;
 304
 305         mutex_lock(&st->lock);
 306         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 307         if (ret)
 308                 goto err_suspend;
 309         val |= AS3935_AFE_PWR_BIT;
 310
 311         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 312
 313 err_suspend:
 314         mutex_unlock(&st->lock);
 315
 316         return ret;
 317 }
 318
 319 static int as3935_resume(struct device *dev)
 320 {
 321         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 322         struct as3935_state *st = iio_priv(indio_dev);
 323         int val, ret;
 324
 325         mutex_lock(&st->lock);
 326         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 327         if (ret)
 328                 goto err_resume;
 329         val &= ~AS3935_AFE_PWR_BIT;
 330         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 331
 332         calibrate_as3935(st);
 333
 334 err_resume:
 335         mutex_unlock(&st->lock);
 336
 337         return ret;
 338 }
 339
 340 static DEFINE_SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
 341
 342 static int as3935_probe(struct spi_device *spi)
 343 {
 344         struct device *dev = &spi->dev;
 345         struct iio_dev *indio_dev;
 346         struct iio_trigger *trig;
 347         struct as3935_state *st;
 348         int ret;
 349
 350         /* Be sure lightning event interrupt is specified */
 351         if (!spi->irq) {
 352                 dev_err(dev, "unable to get event interrupt\n");
 353                 return -EINVAL;
 354         }
 355
 356         indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
 357         if (!indio_dev)
 358                 return -ENOMEM;
 359
 360         st = iio_priv(indio_dev);
 361         st->spi = spi;
 362
 363         spi_set_drvdata(spi, indio_dev);
 364         mutex_init(&st->lock);
 365
 366         ret = device_property_read_u32(dev,
 367                         "ams,tuning-capacitor-pf", &st->tune_cap);
 368         if (ret) {
 369                 st->tune_cap = 0;
 370                 dev_warn(dev, "no tuning-capacitor-pf set, defaulting to %d",
 371                         st->tune_cap);
 372         }
 373
 374         if (st->tune_cap > MAX_PF_CAP) {
 375                 dev_err(dev, "wrong tuning-capacitor-pf setting of %d\n",
 376                         st->tune_cap);
 377                 return -EINVAL;
 378         }
 379
 380         ret = device_property_read_u32(dev,
 381                         "ams,nflwdth", &st->nflwdth_reg);
 382         if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
 383                 dev_err(dev, "invalid nflwdth setting of %d\n",
 384                         st->nflwdth_reg);
 385                 return -EINVAL;
 386         }
 387
 388         indio_dev->name = spi_get_device_id(spi)->name;
 389         indio_dev->channels = as3935_channels;
 390         indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
 391         indio_dev->modes = INDIO_DIRECT_MODE;
 392         indio_dev->info = &as3935_info;
 393
 394         trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
 395                                       indio_dev->name,
 396                                       iio_device_id(indio_dev));
 397
 398         if (!trig)
 399                 return -ENOMEM;
 400
 401         st->trig = trig;
 402         st->noise_tripped = jiffies - HZ;
 403         iio_trigger_set_drvdata(trig, indio_dev);
 404
 405         ret = devm_iio_trigger_register(dev, trig);
 406         if (ret) {
 407                 dev_err(dev, "failed to register trigger\n");
 408                 return ret;
 409         }
 410
 411         ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
 412                                               iio_pollfunc_store_time,
 413                                               as3935_trigger_handler, NULL);
 414
 415         if (ret) {
 416                 dev_err(dev, "cannot setup iio trigger\n");
 417                 return ret;
 418         }
 419
 420         calibrate_as3935(st);
 421
 422         ret = devm_delayed_work_autocancel(dev, &st->work, as3935_event_work);
 423         if (ret)
 424                 return ret;
 425
 426         ret = devm_request_irq(dev, spi->irq,
 427                                 &as3935_interrupt_handler,
 428                                 IRQF_TRIGGER_RISING,
 429                                 dev_name(dev),
 430                                 indio_dev);
 431
 432         if (ret) {
 433                 dev_err(dev, "unable to request irq\n");
 434                 return ret;
 435         }
 436
 437         ret = devm_iio_device_register(dev, indio_dev);
 438         if (ret < 0) {
 439                 dev_err(dev, "unable to register device\n");
 440                 return ret;
 441         }
 442         return 0;
 443 }
 444
 445 static const struct of_device_id as3935_of_match[] = {
 446         { .compatible = "ams,as3935", },
 447         { /* sentinel */ },
 448 };
 449 MODULE_DEVICE_TABLE(of, as3935_of_match);
 450
 451 static const struct spi_device_id as3935_id[] = {
 452         {"as3935", 0},
 453         {},
 454 };
 455 MODULE_DEVICE_TABLE(spi, as3935_id);
 456
 457 static struct spi_driver as3935_driver = {
 458         .driver = {
 459                 .name   = "as3935",
 460                 .of_match_table = as3935_of_match,
 461                 .pm     = pm_sleep_ptr(&as3935_pm_ops),
 462         },
 463         .probe          = as3935_probe,
 464         .id_table       = as3935_id,
 465 };
 466 module_spi_driver(as3935_driver);
 467
 468 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
 469 MODULE_DESCRIPTION("AS3935 lightning sensor");
 470 MODULE_LICENSE("GPL");