2 * as3935.c - Support for AS3935 Franklin lightning sensor
4 * Copyright (C) 2014 Matt Ranostay <mranostay@gmail.com>
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.
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.
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>
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)
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)
47 #define AS3935_DATA 0x07
48 #define AS3935_DATA_MASK 0x3F
50 #define AS3935_TUNE_CAP 0x08
51 #define AS3935_CALIBRATE 0x3D
53 #define AS3935_WRITE_DATA BIT(15)
54 #define AS3935_READ_DATA BIT(14)
55 #define AS3935_ADDRESS(x) ((x) << 8)
57 #define MAX_PF_CAP 120
58 #define TUNE_CAP_DIV 8
61 struct spi_device *spi;
62 struct iio_trigger *trig;
64 struct delayed_work work;
67 u8 buf[2] ____cacheline_aligned;
70 static const struct iio_chan_spec as3935_channels[] = {
72 .type = IIO_PROXIMITY,
74 BIT(IIO_CHAN_INFO_RAW) |
75 BIT(IIO_CHAN_INFO_PROCESSED),
83 IIO_CHAN_SOFT_TIMESTAMP(1),
86 static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
91 cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
92 ret = spi_w8r8(st->spi, cmd);
100 static int as3935_write(struct as3935_state *st,
106 buf[0] = (AS3935_WRITE_DATA | AS3935_ADDRESS(reg)) >> 8;
109 return spi_write(st->spi, buf, 2);
112 static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
113 struct device_attribute *attr,
116 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
119 ret = as3935_read(st, AS3935_AFE_GAIN, &val);
122 val = (val & AS3935_AFE_MASK) >> 1;
124 return sprintf(buf, "%d\n", val);
127 static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
128 struct device_attribute *attr,
129 const char *buf, size_t len)
131 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
135 ret = kstrtoul((const char *) buf, 10, &val);
139 if (val > AS3935_AFE_GAIN_MAX)
142 as3935_write(st, AS3935_AFE_GAIN, val << 1);
147 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
148 as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
151 static struct attribute *as3935_attributes[] = {
152 &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
156 static struct attribute_group as3935_attribute_group = {
157 .attrs = as3935_attributes,
160 static int as3935_read_raw(struct iio_dev *indio_dev,
161 struct iio_chan_spec const *chan,
166 struct as3935_state *st = iio_priv(indio_dev);
171 case IIO_CHAN_INFO_PROCESSED:
172 case IIO_CHAN_INFO_RAW:
174 ret = as3935_read(st, AS3935_DATA, val);
178 if (m == IIO_CHAN_INFO_RAW)
181 /* storm out of range */
182 if (*val == AS3935_DATA_MASK)
193 static const struct iio_info as3935_info = {
194 .driver_module = THIS_MODULE,
195 .attrs = &as3935_attribute_group,
196 .read_raw = &as3935_read_raw,
199 static irqreturn_t as3935_trigger_handler(int irq, void *private)
201 struct iio_poll_func *pf = private;
202 struct iio_dev *indio_dev = pf->indio_dev;
203 struct as3935_state *st = iio_priv(indio_dev);
206 ret = as3935_read(st, AS3935_DATA, &val);
209 val &= AS3935_DATA_MASK;
212 iio_push_to_buffers_with_timestamp(indio_dev, &val, pf->timestamp);
214 iio_trigger_notify_done(indio_dev->trig);
219 static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
220 .owner = THIS_MODULE,
223 static void as3935_event_work(struct work_struct *work)
225 struct as3935_state *st;
228 st = container_of(work, struct as3935_state, work.work);
230 as3935_read(st, AS3935_INT, &val);
231 val &= AS3935_INT_MASK;
234 case AS3935_EVENT_INT:
235 iio_trigger_poll(st->trig, iio_get_time_ns());
237 case AS3935_NOISE_INT:
238 dev_warn(&st->spi->dev, "noise level is too high");
243 static irqreturn_t as3935_interrupt_handler(int irq, void *private)
245 struct iio_dev *indio_dev = private;
246 struct as3935_state *st = iio_priv(indio_dev);
249 * Delay work for >2 milliseconds after an interrupt to allow
250 * estimated distance to recalculated.
253 schedule_delayed_work(&st->work, msecs_to_jiffies(3));
258 static void calibrate_as3935(struct as3935_state *st)
260 mutex_lock(&st->lock);
262 /* mask disturber interrupt bit */
263 as3935_write(st, AS3935_INT, BIT(5));
265 as3935_write(st, AS3935_CALIBRATE, 0x96);
266 as3935_write(st, AS3935_TUNE_CAP,
267 BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
270 as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
272 mutex_unlock(&st->lock);
275 #ifdef CONFIG_PM_SLEEP
276 static int as3935_suspend(struct spi_device *spi, pm_message_t msg)
278 struct iio_dev *indio_dev = spi_get_drvdata(spi);
279 struct as3935_state *st = iio_priv(indio_dev);
282 mutex_lock(&st->lock);
283 ret = as3935_read(st, AS3935_AFE_GAIN, &val);
286 val |= AS3935_AFE_PWR_BIT;
288 ret = as3935_write(st, AS3935_AFE_GAIN, val);
291 mutex_unlock(&st->lock);
296 static int as3935_resume(struct spi_device *spi)
298 struct iio_dev *indio_dev = spi_get_drvdata(spi);
299 struct as3935_state *st = iio_priv(indio_dev);
302 mutex_lock(&st->lock);
303 ret = as3935_read(st, AS3935_AFE_GAIN, &val);
306 val &= ~AS3935_AFE_PWR_BIT;
307 ret = as3935_write(st, AS3935_AFE_GAIN, val);
310 mutex_unlock(&st->lock);
315 #define as3935_suspend NULL
316 #define as3935_resume NULL
319 static int as3935_probe(struct spi_device *spi)
321 struct iio_dev *indio_dev;
322 struct iio_trigger *trig;
323 struct as3935_state *st;
324 struct device_node *np = spi->dev.of_node;
327 /* Be sure lightning event interrupt is specified */
329 dev_err(&spi->dev, "unable to get event interrupt\n");
333 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(st));
337 st = iio_priv(indio_dev);
341 spi_set_drvdata(spi, indio_dev);
342 mutex_init(&st->lock);
343 INIT_DELAYED_WORK(&st->work, as3935_event_work);
345 ret = of_property_read_u32(np,
346 "ams,tuning-capacitor-pf", &st->tune_cap);
350 "no tuning-capacitor-pf set, defaulting to %d",
354 if (st->tune_cap > MAX_PF_CAP) {
356 "wrong tuning-capacitor-pf setting of %d\n",
361 indio_dev->dev.parent = &spi->dev;
362 indio_dev->name = spi_get_device_id(spi)->name;
363 indio_dev->channels = as3935_channels;
364 indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
365 indio_dev->modes = INDIO_DIRECT_MODE;
366 indio_dev->info = &as3935_info;
368 trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
369 indio_dev->name, indio_dev->id);
375 trig->dev.parent = indio_dev->dev.parent;
376 iio_trigger_set_drvdata(trig, indio_dev);
377 trig->ops = &iio_interrupt_trigger_ops;
379 ret = iio_trigger_register(trig);
381 dev_err(&spi->dev, "failed to register trigger\n");
385 ret = iio_triggered_buffer_setup(indio_dev, NULL,
386 &as3935_trigger_handler, NULL);
389 dev_err(&spi->dev, "cannot setup iio trigger\n");
390 goto unregister_trigger;
393 calibrate_as3935(st);
395 ret = devm_request_irq(&spi->dev, spi->irq,
396 &as3935_interrupt_handler,
402 dev_err(&spi->dev, "unable to request irq\n");
403 goto unregister_buffer;
406 ret = iio_device_register(indio_dev);
408 dev_err(&spi->dev, "unable to register device\n");
409 goto unregister_buffer;
414 iio_triggered_buffer_cleanup(indio_dev);
417 iio_trigger_unregister(st->trig);
422 static int as3935_remove(struct spi_device *spi)
424 struct iio_dev *indio_dev = spi_get_drvdata(spi);
425 struct as3935_state *st = iio_priv(indio_dev);
427 iio_device_unregister(indio_dev);
428 iio_triggered_buffer_cleanup(indio_dev);
429 iio_trigger_unregister(st->trig);
434 static const struct spi_device_id as3935_id[] = {
438 MODULE_DEVICE_TABLE(spi, as3935_id);
440 static struct spi_driver as3935_driver = {
443 .owner = THIS_MODULE,
445 .probe = as3935_probe,
446 .remove = as3935_remove,
447 .id_table = as3935_id,
448 .suspend = as3935_suspend,
449 .resume = as3935_resume,
451 module_spi_driver(as3935_driver);
453 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
454 MODULE_DESCRIPTION("AS3935 lightning sensor");
455 MODULE_LICENSE("GPL");
456 MODULE_ALIAS("spi:as3935");