Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 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 0x0f |
| 44 | #define AS3935_EVENT_INT BIT(3) |
| 45 | #define AS3935_NOISE_INT BIT(0) |
| 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_READ_DATA BIT(14) |
| 54 | #define AS3935_ADDRESS(x) ((x) << 8) |
| 55 | |
| 56 | #define MAX_PF_CAP 120 |
| 57 | #define TUNE_CAP_DIV 8 |
| 58 | |
| 59 | struct as3935_state { |
| 60 | struct spi_device *spi; |
| 61 | struct iio_trigger *trig; |
| 62 | struct mutex lock; |
| 63 | struct delayed_work work; |
| 64 | |
| 65 | u32 tune_cap; |
| 66 | u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */ |
| 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((const char *) 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 IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR, |
| 149 | as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0); |
| 150 | |
| 151 | |
| 152 | static struct attribute *as3935_attributes[] = { |
| 153 | &iio_dev_attr_sensor_sensitivity.dev_attr.attr, |
| 154 | NULL, |
| 155 | }; |
| 156 | |
| 157 | static struct attribute_group as3935_attribute_group = { |
| 158 | .attrs = as3935_attributes, |
| 159 | }; |
| 160 | |
| 161 | static int as3935_read_raw(struct iio_dev *indio_dev, |
| 162 | struct iio_chan_spec const *chan, |
| 163 | int *val, |
| 164 | int *val2, |
| 165 | long m) |
| 166 | { |
| 167 | struct as3935_state *st = iio_priv(indio_dev); |
| 168 | int ret; |
| 169 | |
| 170 | |
| 171 | switch (m) { |
| 172 | case IIO_CHAN_INFO_PROCESSED: |
| 173 | case IIO_CHAN_INFO_RAW: |
| 174 | *val2 = 0; |
| 175 | ret = as3935_read(st, AS3935_DATA, val); |
| 176 | if (ret) |
| 177 | return ret; |
| 178 | |
| 179 | if (m == IIO_CHAN_INFO_RAW) |
| 180 | return IIO_VAL_INT; |
| 181 | |
| 182 | /* storm out of range */ |
| 183 | if (*val == AS3935_DATA_MASK) |
| 184 | return -EINVAL; |
| 185 | |
| 186 | if (m == IIO_CHAN_INFO_PROCESSED) |
| 187 | *val *= 1000; |
| 188 | break; |
| 189 | case IIO_CHAN_INFO_SCALE: |
| 190 | *val = 1000; |
| 191 | break; |
| 192 | default: |
| 193 | return -EINVAL; |
| 194 | } |
| 195 | |
| 196 | return IIO_VAL_INT; |
| 197 | } |
| 198 | |
| 199 | static const struct iio_info as3935_info = { |
| 200 | .driver_module = THIS_MODULE, |
| 201 | .attrs = &as3935_attribute_group, |
| 202 | .read_raw = &as3935_read_raw, |
| 203 | }; |
| 204 | |
| 205 | static irqreturn_t as3935_trigger_handler(int irq, void *private) |
| 206 | { |
| 207 | struct iio_poll_func *pf = private; |
| 208 | struct iio_dev *indio_dev = pf->indio_dev; |
| 209 | struct as3935_state *st = iio_priv(indio_dev); |
| 210 | int val, ret; |
| 211 | |
| 212 | ret = as3935_read(st, AS3935_DATA, &val); |
| 213 | if (ret) |
| 214 | goto err_read; |
| 215 | |
| 216 | st->buffer[0] = val & AS3935_DATA_MASK; |
| 217 | iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer, |
| 218 | pf->timestamp); |
| 219 | err_read: |
| 220 | iio_trigger_notify_done(indio_dev->trig); |
| 221 | |
| 222 | return IRQ_HANDLED; |
| 223 | } |
| 224 | |
| 225 | static const struct iio_trigger_ops iio_interrupt_trigger_ops = { |
| 226 | .owner = THIS_MODULE, |
| 227 | }; |
| 228 | |
| 229 | static void as3935_event_work(struct work_struct *work) |
| 230 | { |
| 231 | struct as3935_state *st; |
| 232 | int val; |
| 233 | |
| 234 | st = container_of(work, struct as3935_state, work.work); |
| 235 | |
| 236 | as3935_read(st, AS3935_INT, &val); |
| 237 | val &= AS3935_INT_MASK; |
| 238 | |
| 239 | switch (val) { |
| 240 | case AS3935_EVENT_INT: |
| 241 | iio_trigger_poll(st->trig); |
| 242 | break; |
| 243 | case AS3935_NOISE_INT: |
| 244 | dev_warn(&st->spi->dev, "noise level is too high"); |
| 245 | break; |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | static irqreturn_t as3935_interrupt_handler(int irq, void *private) |
| 250 | { |
| 251 | struct iio_dev *indio_dev = private; |
| 252 | struct as3935_state *st = iio_priv(indio_dev); |
| 253 | |
| 254 | /* |
| 255 | * Delay work for >2 milliseconds after an interrupt to allow |
| 256 | * estimated distance to recalculated. |
| 257 | */ |
| 258 | |
| 259 | schedule_delayed_work(&st->work, msecs_to_jiffies(3)); |
| 260 | |
| 261 | return IRQ_HANDLED; |
| 262 | } |
| 263 | |
| 264 | static void calibrate_as3935(struct as3935_state *st) |
| 265 | { |
| 266 | /* mask disturber interrupt bit */ |
| 267 | as3935_write(st, AS3935_INT, BIT(5)); |
| 268 | |
| 269 | as3935_write(st, AS3935_CALIBRATE, 0x96); |
| 270 | as3935_write(st, AS3935_TUNE_CAP, |
| 271 | BIT(5) | (st->tune_cap / TUNE_CAP_DIV)); |
| 272 | |
| 273 | mdelay(2); |
| 274 | as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV)); |
| 275 | } |
| 276 | |
| 277 | #ifdef CONFIG_PM_SLEEP |
| 278 | static int as3935_suspend(struct device *dev) |
| 279 | { |
| 280 | struct iio_dev *indio_dev = dev_get_drvdata(dev); |
| 281 | struct as3935_state *st = iio_priv(indio_dev); |
| 282 | int val, ret; |
| 283 | |
| 284 | mutex_lock(&st->lock); |
| 285 | ret = as3935_read(st, AS3935_AFE_GAIN, &val); |
| 286 | if (ret) |
| 287 | goto err_suspend; |
| 288 | val |= AS3935_AFE_PWR_BIT; |
| 289 | |
| 290 | ret = as3935_write(st, AS3935_AFE_GAIN, val); |
| 291 | |
| 292 | err_suspend: |
| 293 | mutex_unlock(&st->lock); |
| 294 | |
| 295 | return ret; |
| 296 | } |
| 297 | |
| 298 | static int as3935_resume(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_resume; |
| 308 | val &= ~AS3935_AFE_PWR_BIT; |
| 309 | ret = as3935_write(st, AS3935_AFE_GAIN, val); |
| 310 | |
| 311 | calibrate_as3935(st); |
| 312 | |
| 313 | err_resume: |
| 314 | mutex_unlock(&st->lock); |
| 315 | |
| 316 | return ret; |
| 317 | } |
| 318 | |
| 319 | static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume); |
| 320 | #define AS3935_PM_OPS (&as3935_pm_ops) |
| 321 | |
| 322 | #else |
| 323 | #define AS3935_PM_OPS NULL |
| 324 | #endif |
| 325 | |
| 326 | static int as3935_probe(struct spi_device *spi) |
| 327 | { |
| 328 | struct iio_dev *indio_dev; |
| 329 | struct iio_trigger *trig; |
| 330 | struct as3935_state *st; |
| 331 | struct device_node *np = spi->dev.of_node; |
| 332 | int ret; |
| 333 | |
| 334 | /* Be sure lightning event interrupt is specified */ |
| 335 | if (!spi->irq) { |
| 336 | dev_err(&spi->dev, "unable to get event interrupt\n"); |
| 337 | return -EINVAL; |
| 338 | } |
| 339 | |
| 340 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); |
| 341 | if (!indio_dev) |
| 342 | return -ENOMEM; |
| 343 | |
| 344 | st = iio_priv(indio_dev); |
| 345 | st->spi = spi; |
| 346 | st->tune_cap = 0; |
| 347 | |
| 348 | spi_set_drvdata(spi, indio_dev); |
| 349 | mutex_init(&st->lock); |
| 350 | INIT_DELAYED_WORK(&st->work, as3935_event_work); |
| 351 | |
| 352 | ret = of_property_read_u32(np, |
| 353 | "ams,tuning-capacitor-pf", &st->tune_cap); |
| 354 | if (ret) { |
| 355 | st->tune_cap = 0; |
| 356 | dev_warn(&spi->dev, |
| 357 | "no tuning-capacitor-pf set, defaulting to %d", |
| 358 | st->tune_cap); |
| 359 | } |
| 360 | |
| 361 | if (st->tune_cap > MAX_PF_CAP) { |
| 362 | dev_err(&spi->dev, |
| 363 | "wrong tuning-capacitor-pf setting of %d\n", |
| 364 | st->tune_cap); |
| 365 | return -EINVAL; |
| 366 | } |
| 367 | |
| 368 | indio_dev->dev.parent = &spi->dev; |
| 369 | indio_dev->name = spi_get_device_id(spi)->name; |
| 370 | indio_dev->channels = as3935_channels; |
| 371 | indio_dev->num_channels = ARRAY_SIZE(as3935_channels); |
| 372 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 373 | indio_dev->info = &as3935_info; |
| 374 | |
| 375 | trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", |
| 376 | indio_dev->name, indio_dev->id); |
| 377 | |
| 378 | if (!trig) |
| 379 | return -ENOMEM; |
| 380 | |
| 381 | st->trig = trig; |
| 382 | trig->dev.parent = indio_dev->dev.parent; |
| 383 | iio_trigger_set_drvdata(trig, indio_dev); |
| 384 | trig->ops = &iio_interrupt_trigger_ops; |
| 385 | |
| 386 | ret = iio_trigger_register(trig); |
| 387 | if (ret) { |
| 388 | dev_err(&spi->dev, "failed to register trigger\n"); |
| 389 | return ret; |
| 390 | } |
| 391 | |
| 392 | ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time, |
| 393 | &as3935_trigger_handler, NULL); |
| 394 | |
| 395 | if (ret) { |
| 396 | dev_err(&spi->dev, "cannot setup iio trigger\n"); |
| 397 | goto unregister_trigger; |
| 398 | } |
| 399 | |
| 400 | calibrate_as3935(st); |
| 401 | |
| 402 | ret = devm_request_irq(&spi->dev, spi->irq, |
| 403 | &as3935_interrupt_handler, |
| 404 | IRQF_TRIGGER_RISING, |
| 405 | dev_name(&spi->dev), |
| 406 | indio_dev); |
| 407 | |
| 408 | if (ret) { |
| 409 | dev_err(&spi->dev, "unable to request irq\n"); |
| 410 | goto unregister_buffer; |
| 411 | } |
| 412 | |
| 413 | ret = iio_device_register(indio_dev); |
| 414 | if (ret < 0) { |
| 415 | dev_err(&spi->dev, "unable to register device\n"); |
| 416 | goto unregister_buffer; |
| 417 | } |
| 418 | return 0; |
| 419 | |
| 420 | unregister_buffer: |
| 421 | iio_triggered_buffer_cleanup(indio_dev); |
| 422 | |
| 423 | unregister_trigger: |
| 424 | iio_trigger_unregister(st->trig); |
| 425 | |
| 426 | return ret; |
| 427 | } |
| 428 | |
| 429 | static int as3935_remove(struct spi_device *spi) |
| 430 | { |
| 431 | struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| 432 | struct as3935_state *st = iio_priv(indio_dev); |
| 433 | |
| 434 | iio_device_unregister(indio_dev); |
| 435 | iio_triggered_buffer_cleanup(indio_dev); |
| 436 | iio_trigger_unregister(st->trig); |
| 437 | |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | static const struct of_device_id as3935_of_match[] = { |
| 442 | { .compatible = "ams,as3935", }, |
| 443 | { /* sentinel */ }, |
| 444 | }; |
| 445 | MODULE_DEVICE_TABLE(of, as3935_of_match); |
| 446 | |
| 447 | static const struct spi_device_id as3935_id[] = { |
| 448 | {"as3935", 0}, |
| 449 | {}, |
| 450 | }; |
| 451 | MODULE_DEVICE_TABLE(spi, as3935_id); |
| 452 | |
| 453 | static struct spi_driver as3935_driver = { |
| 454 | .driver = { |
| 455 | .name = "as3935", |
| 456 | .of_match_table = of_match_ptr(as3935_of_match), |
| 457 | .pm = AS3935_PM_OPS, |
| 458 | }, |
| 459 | .probe = as3935_probe, |
| 460 | .remove = as3935_remove, |
| 461 | .id_table = as3935_id, |
| 462 | }; |
| 463 | module_spi_driver(as3935_driver); |
| 464 | |
| 465 | MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); |
| 466 | MODULE_DESCRIPTION("AS3935 lightning sensor"); |
| 467 | MODULE_LICENSE("GPL"); |
| 468 | MODULE_ALIAS("spi:as3935"); |