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 /* Ensure timestamp is naturally aligned */ 63 struct { 64 u8 chan; 65 s64 timestamp __aligned(8); 66 } scan; 67 u8 buf[2] ____cacheline_aligned; 68 }; 69 70 static const struct iio_chan_spec as3935_channels[] = { 71 { 72 .type = IIO_PROXIMITY, 73 .info_mask_separate = 74 BIT(IIO_CHAN_INFO_RAW) | 75 BIT(IIO_CHAN_INFO_PROCESSED) | 76 BIT(IIO_CHAN_INFO_SCALE), 77 .scan_index = 0, 78 .scan_type = { 79 .sign = 'u', 80 .realbits = 6, 81 .storagebits = 8, 82 }, 83 }, 84 IIO_CHAN_SOFT_TIMESTAMP(1), 85 }; 86 87 static int as3935_read(struct as3935_state *st, unsigned int reg, int *val) 88 { 89 u8 cmd; 90 int ret; 91 92 cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8; 93 ret = spi_w8r8(st->spi, cmd); 94 if (ret < 0) 95 return ret; 96 *val = ret; 97 98 return 0; 99 } 100 101 static int as3935_write(struct as3935_state *st, 102 unsigned int reg, 103 unsigned int val) 104 { 105 u8 *buf = st->buf; 106 107 buf[0] = AS3935_ADDRESS(reg) >> 8; 108 buf[1] = val; 109 110 return spi_write(st->spi, buf, 2); 111 } 112 113 static ssize_t as3935_sensor_sensitivity_show(struct device *dev, 114 struct device_attribute *attr, 115 char *buf) 116 { 117 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev)); 118 int val, ret; 119 120 ret = as3935_read(st, AS3935_AFE_GAIN, &val); 121 if (ret) 122 return ret; 123 val = (val & AS3935_AFE_MASK) >> 1; 124 125 return sprintf(buf, "%d\n", val); 126 } 127 128 static ssize_t as3935_sensor_sensitivity_store(struct device *dev, 129 struct device_attribute *attr, 130 const char *buf, size_t len) 131 { 132 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev)); 133 unsigned long val; 134 int ret; 135 136 ret = kstrtoul(buf, 10, &val); 137 if (ret) 138 return -EINVAL; 139 140 if (val > AS3935_AFE_GAIN_MAX) 141 return -EINVAL; 142 143 as3935_write(st, AS3935_AFE_GAIN, val << 1); 144 145 return len; 146 } 147 148 static ssize_t as3935_noise_level_tripped_show(struct device *dev, 149 struct device_attribute *attr, 150 char *buf) 151 { 152 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev)); 153 int ret; 154 155 mutex_lock(&st->lock); 156 ret = sprintf(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ)); 157 mutex_unlock(&st->lock); 158 159 return ret; 160 } 161 162 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR, 163 as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0); 164 165 static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO, 166 as3935_noise_level_tripped_show, NULL, 0); 167 168 static struct attribute *as3935_attributes[] = { 169 &iio_dev_attr_sensor_sensitivity.dev_attr.attr, 170 &iio_dev_attr_noise_level_tripped.dev_attr.attr, 171 NULL, 172 }; 173 174 static const struct attribute_group as3935_attribute_group = { 175 .attrs = as3935_attributes, 176 }; 177 178 static int as3935_read_raw(struct iio_dev *indio_dev, 179 struct iio_chan_spec const *chan, 180 int *val, 181 int *val2, 182 long m) 183 { 184 struct as3935_state *st = iio_priv(indio_dev); 185 int ret; 186 187 188 switch (m) { 189 case IIO_CHAN_INFO_PROCESSED: 190 case IIO_CHAN_INFO_RAW: 191 *val2 = 0; 192 ret = as3935_read(st, AS3935_DATA, val); 193 if (ret) 194 return ret; 195 196 /* storm out of range */ 197 if (*val == AS3935_DATA_MASK) 198 return -EINVAL; 199 200 if (m == IIO_CHAN_INFO_RAW) 201 return IIO_VAL_INT; 202 203 if (m == IIO_CHAN_INFO_PROCESSED) 204 *val *= 1000; 205 break; 206 case IIO_CHAN_INFO_SCALE: 207 *val = 1000; 208 break; 209 default: 210 return -EINVAL; 211 } 212 213 return IIO_VAL_INT; 214 } 215 216 static const struct iio_info as3935_info = { 217 .attrs = &as3935_attribute_group, 218 .read_raw = &as3935_read_raw, 219 }; 220 221 static irqreturn_t as3935_trigger_handler(int irq, void *private) 222 { 223 struct iio_poll_func *pf = private; 224 struct iio_dev *indio_dev = pf->indio_dev; 225 struct as3935_state *st = iio_priv(indio_dev); 226 int val, ret; 227 228 ret = as3935_read(st, AS3935_DATA, &val); 229 if (ret) 230 goto err_read; 231 232 st->scan.chan = val & AS3935_DATA_MASK; 233 iio_push_to_buffers_with_timestamp(indio_dev, &st->scan, 234 iio_get_time_ns(indio_dev)); 235 err_read: 236 iio_trigger_notify_done(indio_dev->trig); 237 238 return IRQ_HANDLED; 239 } 240 241 static void as3935_event_work(struct work_struct *work) 242 { 243 struct as3935_state *st; 244 int val; 245 int ret; 246 247 st = container_of(work, struct as3935_state, work.work); 248 249 ret = as3935_read(st, AS3935_INT, &val); 250 if (ret) { 251 dev_warn(&st->spi->dev, "read error\n"); 252 return; 253 } 254 255 val &= AS3935_INT_MASK; 256 257 switch (val) { 258 case AS3935_EVENT_INT: 259 iio_trigger_poll_chained(st->trig); 260 break; 261 case AS3935_DISTURB_INT: 262 case AS3935_NOISE_INT: 263 mutex_lock(&st->lock); 264 st->noise_tripped = jiffies; 265 mutex_unlock(&st->lock); 266 dev_warn(&st->spi->dev, "noise level is too high\n"); 267 break; 268 } 269 } 270 271 static irqreturn_t as3935_interrupt_handler(int irq, void *private) 272 { 273 struct iio_dev *indio_dev = private; 274 struct as3935_state *st = iio_priv(indio_dev); 275 276 /* 277 * Delay work for >2 milliseconds after an interrupt to allow 278 * estimated distance to recalculated. 279 */ 280 281 schedule_delayed_work(&st->work, msecs_to_jiffies(3)); 282 283 return IRQ_HANDLED; 284 } 285 286 static void calibrate_as3935(struct as3935_state *st) 287 { 288 as3935_write(st, AS3935_DEFAULTS, 0x96); 289 as3935_write(st, AS3935_CALIBRATE, 0x96); 290 as3935_write(st, AS3935_TUNE_CAP, 291 BIT(5) | (st->tune_cap / TUNE_CAP_DIV)); 292 293 mdelay(2); 294 as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV)); 295 as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg); 296 } 297 298 #ifdef CONFIG_PM_SLEEP 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 SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume); 341 #define AS3935_PM_OPS (&as3935_pm_ops) 342 343 #else 344 #define AS3935_PM_OPS NULL 345 #endif 346 347 static void as3935_stop_work(void *data) 348 { 349 struct iio_dev *indio_dev = data; 350 struct as3935_state *st = iio_priv(indio_dev); 351 352 cancel_delayed_work_sync(&st->work); 353 } 354 355 static int as3935_probe(struct spi_device *spi) 356 { 357 struct device *dev = &spi->dev; 358 struct iio_dev *indio_dev; 359 struct iio_trigger *trig; 360 struct as3935_state *st; 361 int ret; 362 363 /* Be sure lightning event interrupt is specified */ 364 if (!spi->irq) { 365 dev_err(dev, "unable to get event interrupt\n"); 366 return -EINVAL; 367 } 368 369 indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); 370 if (!indio_dev) 371 return -ENOMEM; 372 373 st = iio_priv(indio_dev); 374 st->spi = spi; 375 376 spi_set_drvdata(spi, indio_dev); 377 mutex_init(&st->lock); 378 379 ret = device_property_read_u32(dev, 380 "ams,tuning-capacitor-pf", &st->tune_cap); 381 if (ret) { 382 st->tune_cap = 0; 383 dev_warn(dev, "no tuning-capacitor-pf set, defaulting to %d", 384 st->tune_cap); 385 } 386 387 if (st->tune_cap > MAX_PF_CAP) { 388 dev_err(dev, "wrong tuning-capacitor-pf setting of %d\n", 389 st->tune_cap); 390 return -EINVAL; 391 } 392 393 ret = device_property_read_u32(dev, 394 "ams,nflwdth", &st->nflwdth_reg); 395 if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) { 396 dev_err(dev, "invalid nflwdth setting of %d\n", 397 st->nflwdth_reg); 398 return -EINVAL; 399 } 400 401 indio_dev->name = spi_get_device_id(spi)->name; 402 indio_dev->channels = as3935_channels; 403 indio_dev->num_channels = ARRAY_SIZE(as3935_channels); 404 indio_dev->modes = INDIO_DIRECT_MODE; 405 indio_dev->info = &as3935_info; 406 407 trig = devm_iio_trigger_alloc(dev, "%s-dev%d", 408 indio_dev->name, 409 iio_device_id(indio_dev)); 410 411 if (!trig) 412 return -ENOMEM; 413 414 st->trig = trig; 415 st->noise_tripped = jiffies - HZ; 416 iio_trigger_set_drvdata(trig, indio_dev); 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"); 485