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 u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
63 u8 buf[2] ____cacheline_aligned;
64 };
65
66 static const struct iio_chan_spec as3935_channels[] = {
67 {
68 .type = IIO_PROXIMITY,
69 .info_mask_separate =
70 BIT(IIO_CHAN_INFO_RAW) |
71 BIT(IIO_CHAN_INFO_PROCESSED) |
72 BIT(IIO_CHAN_INFO_SCALE),
73 .scan_index = 0,
74 .scan_type = {
75 .sign = 'u',
76 .realbits = 6,
77 .storagebits = 8,
78 },
79 },
80 IIO_CHAN_SOFT_TIMESTAMP(1),
81 };
82
as3935_read(struct as3935_state * st,unsigned int reg,int * val)83 static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
84 {
85 u8 cmd;
86 int ret;
87
88 cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
89 ret = spi_w8r8(st->spi, cmd);
90 if (ret < 0)
91 return ret;
92 *val = ret;
93
94 return 0;
95 }
96
as3935_write(struct as3935_state * st,unsigned int reg,unsigned int val)97 static int as3935_write(struct as3935_state *st,
98 unsigned int reg,
99 unsigned int val)
100 {
101 u8 *buf = st->buf;
102
103 buf[0] = AS3935_ADDRESS(reg) >> 8;
104 buf[1] = val;
105
106 return spi_write(st->spi, buf, 2);
107 }
108
as3935_sensor_sensitivity_show(struct device * dev,struct device_attribute * attr,char * buf)109 static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
110 struct device_attribute *attr,
111 char *buf)
112 {
113 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
114 int val, ret;
115
116 ret = as3935_read(st, AS3935_AFE_GAIN, &val);
117 if (ret)
118 return ret;
119 val = (val & AS3935_AFE_MASK) >> 1;
120
121 return sprintf(buf, "%d\n", val);
122 }
123
as3935_sensor_sensitivity_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)124 static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
125 struct device_attribute *attr,
126 const char *buf, size_t len)
127 {
128 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
129 unsigned long val;
130 int ret;
131
132 ret = kstrtoul((const char *) buf, 10, &val);
133 if (ret)
134 return -EINVAL;
135
136 if (val > AS3935_AFE_GAIN_MAX)
137 return -EINVAL;
138
139 as3935_write(st, AS3935_AFE_GAIN, val << 1);
140
141 return len;
142 }
143
as3935_noise_level_tripped_show(struct device * dev,struct device_attribute * attr,char * buf)144 static ssize_t as3935_noise_level_tripped_show(struct device *dev,
145 struct device_attribute *attr,
146 char *buf)
147 {
148 struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
149 int ret;
150
151 mutex_lock(&st->lock);
152 ret = sprintf(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ));
153 mutex_unlock(&st->lock);
154
155 return ret;
156 }
157
158 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
159 as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
160
161 static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
162 as3935_noise_level_tripped_show, NULL, 0);
163
164 static struct attribute *as3935_attributes[] = {
165 &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
166 &iio_dev_attr_noise_level_tripped.dev_attr.attr,
167 NULL,
168 };
169
170 static const struct attribute_group as3935_attribute_group = {
171 .attrs = as3935_attributes,
172 };
173
as3935_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)174 static int as3935_read_raw(struct iio_dev *indio_dev,
175 struct iio_chan_spec const *chan,
176 int *val,
177 int *val2,
178 long m)
179 {
180 struct as3935_state *st = iio_priv(indio_dev);
181 int ret;
182
183
184 switch (m) {
185 case IIO_CHAN_INFO_PROCESSED:
186 case IIO_CHAN_INFO_RAW:
187 *val2 = 0;
188 ret = as3935_read(st, AS3935_DATA, val);
189 if (ret)
190 return ret;
191
192 /* storm out of range */
193 if (*val == AS3935_DATA_MASK)
194 return -EINVAL;
195
196 if (m == IIO_CHAN_INFO_RAW)
197 return IIO_VAL_INT;
198
199 if (m == IIO_CHAN_INFO_PROCESSED)
200 *val *= 1000;
201 break;
202 case IIO_CHAN_INFO_SCALE:
203 *val = 1000;
204 break;
205 default:
206 return -EINVAL;
207 }
208
209 return IIO_VAL_INT;
210 }
211
212 static const struct iio_info as3935_info = {
213 .attrs = &as3935_attribute_group,
214 .read_raw = &as3935_read_raw,
215 };
216
as3935_trigger_handler(int irq,void * private)217 static irqreturn_t as3935_trigger_handler(int irq, void *private)
218 {
219 struct iio_poll_func *pf = private;
220 struct iio_dev *indio_dev = pf->indio_dev;
221 struct as3935_state *st = iio_priv(indio_dev);
222 int val, ret;
223
224 ret = as3935_read(st, AS3935_DATA, &val);
225 if (ret)
226 goto err_read;
227
228 st->buffer[0] = val & AS3935_DATA_MASK;
229 iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
230 iio_get_time_ns(indio_dev));
231 err_read:
232 iio_trigger_notify_done(indio_dev->trig);
233
234 return IRQ_HANDLED;
235 }
236
237 static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
238 };
239
as3935_event_work(struct work_struct * work)240 static void as3935_event_work(struct work_struct *work)
241 {
242 struct as3935_state *st;
243 int val;
244 int ret;
245
246 st = container_of(work, struct as3935_state, work.work);
247
248 ret = as3935_read(st, AS3935_INT, &val);
249 if (ret) {
250 dev_warn(&st->spi->dev, "read error\n");
251 return;
252 }
253
254 val &= AS3935_INT_MASK;
255
256 switch (val) {
257 case AS3935_EVENT_INT:
258 iio_trigger_poll_chained(st->trig);
259 break;
260 case AS3935_DISTURB_INT:
261 case AS3935_NOISE_INT:
262 mutex_lock(&st->lock);
263 st->noise_tripped = jiffies;
264 mutex_unlock(&st->lock);
265 dev_warn(&st->spi->dev, "noise level is too high\n");
266 break;
267 }
268 }
269
as3935_interrupt_handler(int irq,void * private)270 static irqreturn_t as3935_interrupt_handler(int irq, void *private)
271 {
272 struct iio_dev *indio_dev = private;
273 struct as3935_state *st = iio_priv(indio_dev);
274
275 /*
276 * Delay work for >2 milliseconds after an interrupt to allow
277 * estimated distance to recalculated.
278 */
279
280 schedule_delayed_work(&st->work, msecs_to_jiffies(3));
281
282 return IRQ_HANDLED;
283 }
284
calibrate_as3935(struct as3935_state * st)285 static void calibrate_as3935(struct as3935_state *st)
286 {
287 as3935_write(st, AS3935_DEFAULTS, 0x96);
288 as3935_write(st, AS3935_CALIBRATE, 0x96);
289 as3935_write(st, AS3935_TUNE_CAP,
290 BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
291
292 mdelay(2);
293 as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
294 as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg);
295 }
296
297 #ifdef CONFIG_PM_SLEEP
as3935_suspend(struct device * dev)298 static int as3935_suspend(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_suspend;
308 val |= AS3935_AFE_PWR_BIT;
309
310 ret = as3935_write(st, AS3935_AFE_GAIN, val);
311
312 err_suspend:
313 mutex_unlock(&st->lock);
314
315 return ret;
316 }
317
as3935_resume(struct device * dev)318 static int as3935_resume(struct device *dev)
319 {
320 struct iio_dev *indio_dev = dev_get_drvdata(dev);
321 struct as3935_state *st = iio_priv(indio_dev);
322 int val, ret;
323
324 mutex_lock(&st->lock);
325 ret = as3935_read(st, AS3935_AFE_GAIN, &val);
326 if (ret)
327 goto err_resume;
328 val &= ~AS3935_AFE_PWR_BIT;
329 ret = as3935_write(st, AS3935_AFE_GAIN, val);
330
331 calibrate_as3935(st);
332
333 err_resume:
334 mutex_unlock(&st->lock);
335
336 return ret;
337 }
338
339 static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
340 #define AS3935_PM_OPS (&as3935_pm_ops)
341
342 #else
343 #define AS3935_PM_OPS NULL
344 #endif
345
as3935_stop_work(void * data)346 static void as3935_stop_work(void *data)
347 {
348 struct iio_dev *indio_dev = data;
349 struct as3935_state *st = iio_priv(indio_dev);
350
351 cancel_delayed_work_sync(&st->work);
352 }
353
as3935_probe(struct spi_device * spi)354 static int as3935_probe(struct spi_device *spi)
355 {
356 struct device *dev = &spi->dev;
357 struct iio_dev *indio_dev;
358 struct iio_trigger *trig;
359 struct as3935_state *st;
360 int ret;
361
362 /* Be sure lightning event interrupt is specified */
363 if (!spi->irq) {
364 dev_err(dev, "unable to get event interrupt\n");
365 return -EINVAL;
366 }
367
368 indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
369 if (!indio_dev)
370 return -ENOMEM;
371
372 st = iio_priv(indio_dev);
373 st->spi = spi;
374
375 spi_set_drvdata(spi, indio_dev);
376 mutex_init(&st->lock);
377
378 ret = device_property_read_u32(dev,
379 "ams,tuning-capacitor-pf", &st->tune_cap);
380 if (ret) {
381 st->tune_cap = 0;
382 dev_warn(dev, "no tuning-capacitor-pf set, defaulting to %d",
383 st->tune_cap);
384 }
385
386 if (st->tune_cap > MAX_PF_CAP) {
387 dev_err(dev, "wrong tuning-capacitor-pf setting of %d\n",
388 st->tune_cap);
389 return -EINVAL;
390 }
391
392 ret = device_property_read_u32(dev,
393 "ams,nflwdth", &st->nflwdth_reg);
394 if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
395 dev_err(dev, "invalid nflwdth setting of %d\n",
396 st->nflwdth_reg);
397 return -EINVAL;
398 }
399
400 indio_dev->name = spi_get_device_id(spi)->name;
401 indio_dev->channels = as3935_channels;
402 indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
403 indio_dev->modes = INDIO_DIRECT_MODE;
404 indio_dev->info = &as3935_info;
405
406 trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
407 indio_dev->name, indio_dev->id);
408
409 if (!trig)
410 return -ENOMEM;
411
412 st->trig = trig;
413 st->noise_tripped = jiffies - HZ;
414 trig->dev.parent = indio_dev->dev.parent;
415 iio_trigger_set_drvdata(trig, indio_dev);
416 trig->ops = &iio_interrupt_trigger_ops;
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