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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((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
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 const struct iio_trigger_ops iio_interrupt_trigger_ops = {
242};
243
244static void as3935_event_work(struct work_struct *work)
245{
246 struct as3935_state *st;
247 int val;
248 int ret;
249
250 st = container_of(work, struct as3935_state, work.work);
251
252 ret = as3935_read(st, AS3935_INT, &val);
253 if (ret) {
254 dev_warn(&st->spi->dev, "read error\n");
255 return;
256 }
257
258 val &= AS3935_INT_MASK;
259
260 switch (val) {
261 case AS3935_EVENT_INT:
262 iio_trigger_poll_chained(st->trig);
263 break;
264 case AS3935_DISTURB_INT:
265 case AS3935_NOISE_INT:
266 mutex_lock(&st->lock);
267 st->noise_tripped = jiffies;
268 mutex_unlock(&st->lock);
269 dev_warn(&st->spi->dev, "noise level is too high\n");
270 break;
271 }
272}
273
274static irqreturn_t as3935_interrupt_handler(int irq, void *private)
275{
276 struct iio_dev *indio_dev = private;
277 struct as3935_state *st = iio_priv(indio_dev);
278
279
280
281
282
283
284 schedule_delayed_work(&st->work, msecs_to_jiffies(3));
285
286 return IRQ_HANDLED;
287}
288
289static void calibrate_as3935(struct as3935_state *st)
290{
291 as3935_write(st, AS3935_DEFAULTS, 0x96);
292 as3935_write(st, AS3935_CALIBRATE, 0x96);
293 as3935_write(st, AS3935_TUNE_CAP,
294 BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
295
296 mdelay(2);
297 as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
298 as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg);
299}
300
301#ifdef CONFIG_PM_SLEEP
302static int as3935_suspend(struct device *dev)
303{
304 struct iio_dev *indio_dev = dev_get_drvdata(dev);
305 struct as3935_state *st = iio_priv(indio_dev);
306 int val, ret;
307
308 mutex_lock(&st->lock);
309 ret = as3935_read(st, AS3935_AFE_GAIN, &val);
310 if (ret)
311 goto err_suspend;
312 val |= AS3935_AFE_PWR_BIT;
313
314 ret = as3935_write(st, AS3935_AFE_GAIN, val);
315
316err_suspend:
317 mutex_unlock(&st->lock);
318
319 return ret;
320}
321
322static int as3935_resume(struct device *dev)
323{
324 struct iio_dev *indio_dev = dev_get_drvdata(dev);
325 struct as3935_state *st = iio_priv(indio_dev);
326 int val, ret;
327
328 mutex_lock(&st->lock);
329 ret = as3935_read(st, AS3935_AFE_GAIN, &val);
330 if (ret)
331 goto err_resume;
332 val &= ~AS3935_AFE_PWR_BIT;
333 ret = as3935_write(st, AS3935_AFE_GAIN, val);
334
335 calibrate_as3935(st);
336
337err_resume:
338 mutex_unlock(&st->lock);
339
340 return ret;
341}
342
343static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
344#define AS3935_PM_OPS (&as3935_pm_ops)
345
346#else
347#define AS3935_PM_OPS NULL
348#endif
349
350static void as3935_stop_work(void *data)
351{
352 struct iio_dev *indio_dev = data;
353 struct as3935_state *st = iio_priv(indio_dev);
354
355 cancel_delayed_work_sync(&st->work);
356}
357
358static int as3935_probe(struct spi_device *spi)
359{
360 struct device *dev = &spi->dev;
361 struct iio_dev *indio_dev;
362 struct iio_trigger *trig;
363 struct as3935_state *st;
364 int ret;
365
366
367 if (!spi->irq) {
368 dev_err(dev, "unable to get event interrupt\n");
369 return -EINVAL;
370 }
371
372 indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
373 if (!indio_dev)
374 return -ENOMEM;
375
376 st = iio_priv(indio_dev);
377 st->spi = spi;
378
379 spi_set_drvdata(spi, indio_dev);
380 mutex_init(&st->lock);
381
382 ret = device_property_read_u32(dev,
383 "ams,tuning-capacitor-pf", &st->tune_cap);
384 if (ret) {
385 st->tune_cap = 0;
386 dev_warn(dev, "no tuning-capacitor-pf set, defaulting to %d",
387 st->tune_cap);
388 }
389
390 if (st->tune_cap > MAX_PF_CAP) {
391 dev_err(dev, "wrong tuning-capacitor-pf setting of %d\n",
392 st->tune_cap);
393 return -EINVAL;
394 }
395
396 ret = device_property_read_u32(dev,
397 "ams,nflwdth", &st->nflwdth_reg);
398 if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
399 dev_err(dev, "invalid nflwdth setting of %d\n",
400 st->nflwdth_reg);
401 return -EINVAL;
402 }
403
404 indio_dev->name = spi_get_device_id(spi)->name;
405 indio_dev->channels = as3935_channels;
406 indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
407 indio_dev->modes = INDIO_DIRECT_MODE;
408 indio_dev->info = &as3935_info;
409
410 trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
411 indio_dev->name,
412 iio_device_id(indio_dev));
413
414 if (!trig)
415 return -ENOMEM;
416
417 st->trig = trig;
418 st->noise_tripped = jiffies - HZ;
419 iio_trigger_set_drvdata(trig, indio_dev);
420 trig->ops = &iio_interrupt_trigger_ops;
421
422 ret = devm_iio_trigger_register(dev, trig);
423 if (ret) {
424 dev_err(dev, "failed to register trigger\n");
425 return ret;
426 }
427
428 ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
429 iio_pollfunc_store_time,
430 as3935_trigger_handler, NULL);
431
432 if (ret) {
433 dev_err(dev, "cannot setup iio trigger\n");
434 return ret;
435 }
436
437 calibrate_as3935(st);
438
439 INIT_DELAYED_WORK(&st->work, as3935_event_work);
440 ret = devm_add_action(dev, as3935_stop_work, indio_dev);
441 if (ret)
442 return ret;
443
444 ret = devm_request_irq(dev, spi->irq,
445 &as3935_interrupt_handler,
446 IRQF_TRIGGER_RISING,
447 dev_name(dev),
448 indio_dev);
449
450 if (ret) {
451 dev_err(dev, "unable to request irq\n");
452 return ret;
453 }
454
455 ret = devm_iio_device_register(dev, indio_dev);
456 if (ret < 0) {
457 dev_err(dev, "unable to register device\n");
458 return ret;
459 }
460 return 0;
461}
462
463static const struct of_device_id as3935_of_match[] = {
464 { .compatible = "ams,as3935", },
465 { },
466};
467MODULE_DEVICE_TABLE(of, as3935_of_match);
468
469static const struct spi_device_id as3935_id[] = {
470 {"as3935", 0},
471 {},
472};
473MODULE_DEVICE_TABLE(spi, as3935_id);
474
475static struct spi_driver as3935_driver = {
476 .driver = {
477 .name = "as3935",
478 .of_match_table = as3935_of_match,
479 .pm = AS3935_PM_OPS,
480 },
481 .probe = as3935_probe,
482 .id_table = as3935_id,
483};
484module_spi_driver(as3935_driver);
485
486MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
487MODULE_DESCRIPTION("AS3935 lightning sensor");
488MODULE_LICENSE("GPL");
489
