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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
53struct 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
63 struct {
64 u8 chan;
65 s64 timestamp __aligned(8);
66 } scan;
67 u8 buf[2] ____cacheline_aligned;
68};
69
70static 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
87static 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
101static 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
113static 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
128static 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
148static 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
162static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
163 as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
164
165static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
166 as3935_noise_level_tripped_show, NULL, 0);
167
168static 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
174static const struct attribute_group as3935_attribute_group = {
175 .attrs = as3935_attributes,
176};
177
178static 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
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
216static const struct iio_info as3935_info = {
217 .attrs = &as3935_attribute_group,
218 .read_raw = &as3935_read_raw,
219};
220
221static 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));
235err_read:
236 iio_trigger_notify_done(indio_dev->trig);
237
238 return IRQ_HANDLED;
239}
240
241static 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
271static 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
278
279
280
281 schedule_delayed_work(&st->work, msecs_to_jiffies(3));
282
283 return IRQ_HANDLED;
284}
285
286static 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
299static 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
313err_suspend:
314 mutex_unlock(&st->lock);
315
316 return ret;
317}
318
319static 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
334err_resume:
335 mutex_unlock(&st->lock);
336
337 return ret;
338}
339
340static 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
347static 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
355static 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
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
459static const struct of_device_id as3935_of_match[] = {
460 { .compatible = "ams,as3935", },
461 { },
462};
463MODULE_DEVICE_TABLE(of, as3935_of_match);
464
465static const struct spi_device_id as3935_id[] = {
466 {"as3935", 0},
467 {},
468};
469MODULE_DEVICE_TABLE(spi, as3935_id);
470
471static 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};
480module_spi_driver(as3935_driver);
481
482MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
483MODULE_DESCRIPTION("AS3935 lightning sensor");
484MODULE_LICENSE("GPL");
485
