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_INT              0x03
  43 #define AS3935_INT_MASK         0x07
  44 #define AS3935_EVENT_INT        BIT(3)
  45 #define AS3935_NOISE_INT        BIT(1)
  46
  47 #define AS3935_DATA             0x07
  48 #define AS3935_DATA_MASK        0x3F
  49
  50 #define AS3935_TUNE_CAP         0x08
  51 #define AS3935_CALIBRATE        0x3D
  52
  53 #define AS3935_WRITE_DATA       BIT(15)
  54 #define AS3935_READ_DATA        BIT(14)
  55 #define AS3935_ADDRESS(x)       ((x) << 8)
  56
  57 #define MAX_PF_CAP              120
  58 #define TUNE_CAP_DIV            8
  59
  60 struct as3935_state {
  61         struct spi_device *spi;
  62         struct iio_trigger *trig;
  63         struct mutex lock;
  64         struct delayed_work work;
  65
  66         u32 tune_cap;
  67         u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
  68         u8 buf[2] ____cacheline_aligned;
  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_WRITE_DATA | 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 sprintf(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((const char *) 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 IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
 150         as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
 151
 152
 153 static struct attribute *as3935_attributes[] = {
 154         &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
 155         NULL,
 156 };
 157
 158 static struct attribute_group as3935_attribute_group = {
 159         .attrs = as3935_attributes,
 160 };
 161
 162 static int as3935_read_raw(struct iio_dev *indio_dev,
 163                            struct iio_chan_spec const *chan,
 164                            int *val,
 165                            int *val2,
 166                            long m)
 167 {
 168         struct as3935_state *st = iio_priv(indio_dev);
 169         int ret;
 170
 171
 172         switch (m) {
 173         case IIO_CHAN_INFO_PROCESSED:
 174         case IIO_CHAN_INFO_RAW:
 175                 *val2 = 0;
 176                 ret = as3935_read(st, AS3935_DATA, val);
 177                 if (ret)
 178                         return ret;
 179
 180                 if (m == IIO_CHAN_INFO_RAW)
 181                         return IIO_VAL_INT;
 182
 183                 /* storm out of range */
 184                 if (*val == AS3935_DATA_MASK)
 185                         return -EINVAL;
 186
 187                 if (m == IIO_CHAN_INFO_PROCESSED)
 188                         *val *= 1000;
 189                 break;
 190         case IIO_CHAN_INFO_SCALE:
 191                 *val = 1000;
 192                 break;
 193         default:
 194                 return -EINVAL;
 195         }
 196
 197         return IIO_VAL_INT;
 198 }
 199
 200 static const struct iio_info as3935_info = {
 201         .driver_module = THIS_MODULE,
 202         .attrs = &as3935_attribute_group,
 203         .read_raw = &as3935_read_raw,
 204 };
 205
 206 static irqreturn_t as3935_trigger_handler(int irq, void *private)
 207 {
 208         struct iio_poll_func *pf = private;
 209         struct iio_dev *indio_dev = pf->indio_dev;
 210         struct as3935_state *st = iio_priv(indio_dev);
 211         int val, ret;
 212
 213         ret = as3935_read(st, AS3935_DATA, &val);
 214         if (ret)
 215                 goto err_read;
 216
 217         st->buffer[0] = val & AS3935_DATA_MASK;
 218         iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
 219                                            pf->timestamp);
 220 err_read:
 221         iio_trigger_notify_done(indio_dev->trig);
 222
 223         return IRQ_HANDLED;
 224 }
 225
 226 static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
 227         .owner = THIS_MODULE,
 228 };
 229
 230 static void as3935_event_work(struct work_struct *work)
 231 {
 232         struct as3935_state *st;
 233         int val;
 234         int ret;
 235
 236         st = container_of(work, struct as3935_state, work.work);
 237
 238         ret = as3935_read(st, AS3935_INT, &val);
 239         if (ret) {
 240                 dev_warn(&st->spi->dev, "read error\n");
 241                 return;
 242         }
 243
 244         val &= AS3935_INT_MASK;
 245
 246         switch (val) {
 247         case AS3935_EVENT_INT:
 248                 iio_trigger_poll(st->trig);
 249                 break;
 250         case AS3935_NOISE_INT:
 251                 dev_warn(&st->spi->dev, "noise level is too high\n");
 252                 break;
 253         }
 254 }
 255
 256 static irqreturn_t as3935_interrupt_handler(int irq, void *private)
 257 {
 258         struct iio_dev *indio_dev = private;
 259         struct as3935_state *st = iio_priv(indio_dev);
 260
 261         /*
 262          * Delay work for >2 milliseconds after an interrupt to allow
 263          * estimated distance to recalculated.
 264          */
 265
 266         schedule_delayed_work(&st->work, msecs_to_jiffies(3));
 267
 268         return IRQ_HANDLED;
 269 }
 270
 271 static void calibrate_as3935(struct as3935_state *st)
 272 {
 273         mutex_lock(&st->lock);
 274
 275         /* mask disturber interrupt bit */
 276         as3935_write(st, AS3935_INT, BIT(5));
 277
 278         as3935_write(st, AS3935_CALIBRATE, 0x96);
 279         as3935_write(st, AS3935_TUNE_CAP,
 280                 BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
 281
 282         mdelay(2);
 283         as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
 284
 285         mutex_unlock(&st->lock);
 286 }
 287
 288 #ifdef CONFIG_PM_SLEEP
 289 static int as3935_suspend(struct device *dev)
 290 {
 291         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 292         struct as3935_state *st = iio_priv(indio_dev);
 293         int val, ret;
 294
 295         mutex_lock(&st->lock);
 296         ret = as3935_read(st, AS3935_AFE_GAIN, &val);
 297         if (ret)
 298                 goto err_suspend;
 299         val |= AS3935_AFE_PWR_BIT;
 300
 301         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 302
 303 err_suspend:
 304         mutex_unlock(&st->lock);
 305
 306         return ret;
 307 }
 308
 309 static int as3935_resume(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_resume;
 319         val &= ~AS3935_AFE_PWR_BIT;
 320         ret = as3935_write(st, AS3935_AFE_GAIN, val);
 321
 322 err_resume:
 323         mutex_unlock(&st->lock);
 324
 325         return ret;
 326 }
 327
 328 static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
 329 #define AS3935_PM_OPS (&as3935_pm_ops)
 330
 331 #else
 332 #define AS3935_PM_OPS NULL
 333 #endif
 334
 335 static int as3935_probe(struct spi_device *spi)
 336 {
 337         struct iio_dev *indio_dev;
 338         struct iio_trigger *trig;
 339         struct as3935_state *st;
 340         struct device_node *np = spi->dev.of_node;
 341         int ret;
 342
 343         /* Be sure lightning event interrupt is specified */
 344         if (!spi->irq) {
 345                 dev_err(&spi->dev, "unable to get event interrupt\n");
 346                 return -EINVAL;
 347         }
 348
 349         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 350         if (!indio_dev)
 351                 return -ENOMEM;
 352
 353         st = iio_priv(indio_dev);
 354         st->spi = spi;
 355
 356         spi_set_drvdata(spi, indio_dev);
 357         mutex_init(&st->lock);
 358         INIT_DELAYED_WORK(&st->work, as3935_event_work);
 359
 360         ret = of_property_read_u32(np,
 361                         "ams,tuning-capacitor-pf", &st->tune_cap);
 362         if (ret) {
 363                 st->tune_cap = 0;
 364                 dev_warn(&spi->dev,
 365                         "no tuning-capacitor-pf set, defaulting to %d",
 366                         st->tune_cap);
 367         }
 368
 369         if (st->tune_cap > MAX_PF_CAP) {
 370                 dev_err(&spi->dev,
 371                         "wrong tuning-capacitor-pf setting of %d\n",
 372                         st->tune_cap);
 373                 return -EINVAL;
 374         }
 375
 376         indio_dev->dev.parent = &spi->dev;
 377         indio_dev->name = spi_get_device_id(spi)->name;
 378         indio_dev->channels = as3935_channels;
 379         indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
 380         indio_dev->modes = INDIO_DIRECT_MODE;
 381         indio_dev->info = &as3935_info;
 382
 383         trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
 384                                       indio_dev->name, indio_dev->id);
 385
 386         if (!trig)
 387                 return -ENOMEM;
 388
 389         st->trig = trig;
 390         trig->dev.parent = indio_dev->dev.parent;
 391         iio_trigger_set_drvdata(trig, indio_dev);
 392         trig->ops = &iio_interrupt_trigger_ops;
 393
 394         ret = iio_trigger_register(trig);
 395         if (ret) {
 396                 dev_err(&spi->dev, "failed to register trigger\n");
 397                 return ret;
 398         }
 399
 400         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 401                 &as3935_trigger_handler, NULL);
 402
 403         if (ret) {
 404                 dev_err(&spi->dev, "cannot setup iio trigger\n");
 405                 goto unregister_trigger;
 406         }
 407
 408         calibrate_as3935(st);
 409
 410         ret = devm_request_irq(&spi->dev, spi->irq,
 411                                 &as3935_interrupt_handler,
 412                                 IRQF_TRIGGER_RISING,
 413                                 dev_name(&spi->dev),
 414                                 indio_dev);
 415
 416         if (ret) {
 417                 dev_err(&spi->dev, "unable to request irq\n");
 418                 goto unregister_buffer;
 419         }
 420
 421         ret = iio_device_register(indio_dev);
 422         if (ret < 0) {
 423                 dev_err(&spi->dev, "unable to register device\n");
 424                 goto unregister_buffer;
 425         }
 426         return 0;
 427
 428 unregister_buffer:
 429         iio_triggered_buffer_cleanup(indio_dev);
 430
 431 unregister_trigger:
 432         iio_trigger_unregister(st->trig);
 433
 434         return ret;
 435 }
 436
 437 static int as3935_remove(struct spi_device *spi)
 438 {
 439         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 440         struct as3935_state *st = iio_priv(indio_dev);
 441
 442         iio_device_unregister(indio_dev);
 443         iio_triggered_buffer_cleanup(indio_dev);
 444         iio_trigger_unregister(st->trig);
 445
 446         return 0;
 447 }
 448
 449 static const struct of_device_id as3935_of_match[] = {
 450         { .compatible = "ams,as3935", },
 451         { /* sentinel */ },
 452 };
 453 MODULE_DEVICE_TABLE(of, as3935_of_match);
 454
 455 static const struct spi_device_id as3935_id[] = {
 456         {"as3935", 0},
 457         {},
 458 };
 459 MODULE_DEVICE_TABLE(spi, as3935_id);
 460
 461 static struct spi_driver as3935_driver = {
 462         .driver = {
 463                 .name   = "as3935",
 464                 .of_match_table = of_match_ptr(as3935_of_match),
 465                 .pm     = AS3935_PM_OPS,
 466         },
 467         .probe          = as3935_probe,
 468         .remove         = as3935_remove,
 469         .id_table       = as3935_id,
 470 };
 471 module_spi_driver(as3935_driver);
 472
 473 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 474 MODULE_DESCRIPTION("AS3935 lightning sensor");
 475 MODULE_LICENSE("GPL");