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"); 471