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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 0x07 | |
44 | #define AS3935_EVENT_INT BIT(3) | |
45 | #define AS3935_NOISE_INT BIT(1) | |
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_WRITE_DATA BIT(15) | |
54 | #define AS3935_READ_DATA BIT(14) | |
55 | #define AS3935_ADDRESS(x) ((x) << 8) | |
56 | ||
57 | #define MAX_PF_CAP 120 | |
58 | #define TUNE_CAP_DIV 8 | |
59 | ||
60 | struct as3935_state { | |
61 | struct spi_device *spi; | |
62 | struct iio_trigger *trig; | |
63 | struct mutex lock; | |
64 | struct delayed_work work; | |
65 | ||
66 | u32 tune_cap; | |
67 | u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */ | |
68 | u8 buf[2] ____cacheline_aligned; | |
69 | }; | |
70 | ||
71 | static const struct iio_chan_spec as3935_channels[] = { | |
72 | { | |
73 | .type = IIO_PROXIMITY, | |
74 | .info_mask_separate = | |
75 | BIT(IIO_CHAN_INFO_RAW) | | |
76 | BIT(IIO_CHAN_INFO_PROCESSED) | | |
77 | BIT(IIO_CHAN_INFO_SCALE), | |
78 | .scan_index = 0, | |
79 | .scan_type = { | |
80 | .sign = 'u', | |
81 | .realbits = 6, | |
82 | .storagebits = 8, | |
83 | }, | |
84 | }, | |
85 | IIO_CHAN_SOFT_TIMESTAMP(1), | |
86 | }; | |
87 | ||
88 | static int as3935_read(struct as3935_state *st, unsigned int reg, int *val) | |
89 | { | |
90 | u8 cmd; | |
91 | int ret; | |
92 | ||
93 | cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8; | |
94 | ret = spi_w8r8(st->spi, cmd); | |
95 | if (ret < 0) | |
96 | return ret; | |
97 | *val = ret; | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | static int as3935_write(struct as3935_state *st, | |
103 | unsigned int reg, | |
104 | unsigned int val) | |
105 | { | |
106 | u8 *buf = st->buf; | |
107 | ||
108 | buf[0] = (AS3935_WRITE_DATA | AS3935_ADDRESS(reg)) >> 8; | |
109 | buf[1] = val; | |
110 | ||
111 | return spi_write(st->spi, buf, 2); | |
112 | } | |
113 | ||
114 | static ssize_t as3935_sensor_sensitivity_show(struct device *dev, | |
115 | struct device_attribute *attr, | |
116 | char *buf) | |
117 | { | |
118 | struct as3935_state *st = iio_priv(dev_to_iio_dev(dev)); | |
119 | int val, ret; | |
120 | ||
121 | ret = as3935_read(st, AS3935_AFE_GAIN, &val); | |
122 | if (ret) | |
123 | return ret; | |
124 | val = (val & AS3935_AFE_MASK) >> 1; | |
125 | ||
126 | return sprintf(buf, "%d\n", val); | |
127 | } | |
128 | ||
129 | static ssize_t as3935_sensor_sensitivity_store(struct device *dev, | |
130 | struct device_attribute *attr, | |
131 | const char *buf, size_t len) | |
132 | { | |
133 | struct as3935_state *st = iio_priv(dev_to_iio_dev(dev)); | |
134 | unsigned long val; | |
135 | int ret; | |
136 | ||
137 | ret = kstrtoul((const char *) buf, 10, &val); | |
138 | if (ret) | |
139 | return -EINVAL; | |
140 | ||
141 | if (val > AS3935_AFE_GAIN_MAX) | |
142 | return -EINVAL; | |
143 | ||
144 | as3935_write(st, AS3935_AFE_GAIN, val << 1); | |
145 | ||
146 | return len; | |
147 | } | |
148 | ||
149 | static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR, | |
150 | as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0); | |
151 | ||
152 | ||
153 | static struct attribute *as3935_attributes[] = { | |
154 | &iio_dev_attr_sensor_sensitivity.dev_attr.attr, | |
155 | NULL, | |
156 | }; | |
157 | ||
158 | static struct attribute_group as3935_attribute_group = { | |
159 | .attrs = as3935_attributes, | |
160 | }; | |
161 | ||
162 | static int as3935_read_raw(struct iio_dev *indio_dev, | |
163 | struct iio_chan_spec const *chan, | |
164 | int *val, | |
165 | int *val2, | |
166 | long m) | |
167 | { | |
168 | struct as3935_state *st = iio_priv(indio_dev); | |
169 | int ret; | |
170 | ||
171 | ||
172 | switch (m) { | |
173 | case IIO_CHAN_INFO_PROCESSED: | |
174 | case IIO_CHAN_INFO_RAW: | |
175 | *val2 = 0; | |
176 | ret = as3935_read(st, AS3935_DATA, val); | |
177 | if (ret) | |
178 | return ret; | |
179 | ||
180 | if (m == IIO_CHAN_INFO_RAW) | |
181 | return IIO_VAL_INT; | |
182 | ||
183 | /* storm out of range */ | |
184 | if (*val == AS3935_DATA_MASK) | |
185 | return -EINVAL; | |
186 | ||
187 | if (m == IIO_CHAN_INFO_PROCESSED) | |
188 | *val *= 1000; | |
189 | break; | |
190 | case IIO_CHAN_INFO_SCALE: | |
191 | *val = 1000; | |
192 | break; | |
193 | default: | |
194 | return -EINVAL; | |
195 | } | |
196 | ||
197 | return IIO_VAL_INT; | |
198 | } | |
199 | ||
200 | static const struct iio_info as3935_info = { | |
201 | .driver_module = THIS_MODULE, | |
202 | .attrs = &as3935_attribute_group, | |
203 | .read_raw = &as3935_read_raw, | |
204 | }; | |
205 | ||
206 | static irqreturn_t as3935_trigger_handler(int irq, void *private) | |
207 | { | |
208 | struct iio_poll_func *pf = private; | |
209 | struct iio_dev *indio_dev = pf->indio_dev; | |
210 | struct as3935_state *st = iio_priv(indio_dev); | |
211 | int val, ret; | |
212 | ||
213 | ret = as3935_read(st, AS3935_DATA, &val); | |
214 | if (ret) | |
215 | goto err_read; | |
216 | ||
217 | st->buffer[0] = val & AS3935_DATA_MASK; | |
218 | iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer, | |
219 | pf->timestamp); | |
220 | err_read: | |
221 | iio_trigger_notify_done(indio_dev->trig); | |
222 | ||
223 | return IRQ_HANDLED; | |
224 | } | |
225 | ||
226 | static const struct iio_trigger_ops iio_interrupt_trigger_ops = { | |
227 | .owner = THIS_MODULE, | |
228 | }; | |
229 | ||
230 | static void as3935_event_work(struct work_struct *work) | |
231 | { | |
232 | struct as3935_state *st; | |
233 | int val; | |
234 | ||
235 | st = container_of(work, struct as3935_state, work.work); | |
236 | ||
237 | as3935_read(st, AS3935_INT, &val); | |
238 | val &= AS3935_INT_MASK; | |
239 | ||
240 | switch (val) { | |
241 | case AS3935_EVENT_INT: | |
242 | iio_trigger_poll(st->trig); | |
243 | break; | |
244 | case AS3935_NOISE_INT: | |
245 | dev_warn(&st->spi->dev, "noise level is too high"); | |
246 | break; | |
247 | } | |
248 | } | |
249 | ||
250 | static irqreturn_t as3935_interrupt_handler(int irq, void *private) | |
251 | { | |
252 | struct iio_dev *indio_dev = private; | |
253 | struct as3935_state *st = iio_priv(indio_dev); | |
254 | ||
255 | /* | |
256 | * Delay work for >2 milliseconds after an interrupt to allow | |
257 | * estimated distance to recalculated. | |
258 | */ | |
259 | ||
260 | schedule_delayed_work(&st->work, msecs_to_jiffies(3)); | |
261 | ||
262 | return IRQ_HANDLED; | |
263 | } | |
264 | ||
265 | static void calibrate_as3935(struct as3935_state *st) | |
266 | { | |
267 | mutex_lock(&st->lock); | |
268 | ||
269 | /* mask disturber interrupt bit */ | |
270 | as3935_write(st, AS3935_INT, BIT(5)); | |
271 | ||
272 | as3935_write(st, AS3935_CALIBRATE, 0x96); | |
273 | as3935_write(st, AS3935_TUNE_CAP, | |
274 | BIT(5) | (st->tune_cap / TUNE_CAP_DIV)); | |
275 | ||
276 | mdelay(2); | |
277 | as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV)); | |
278 | ||
279 | mutex_unlock(&st->lock); | |
280 | } | |
281 | ||
282 | #ifdef CONFIG_PM_SLEEP | |
283 | static int as3935_suspend(struct device *dev) | |
284 | { | |
285 | struct iio_dev *indio_dev = dev_get_drvdata(dev); | |
286 | struct as3935_state *st = iio_priv(indio_dev); | |
287 | int val, ret; | |
288 | ||
289 | mutex_lock(&st->lock); | |
290 | ret = as3935_read(st, AS3935_AFE_GAIN, &val); | |
291 | if (ret) | |
292 | goto err_suspend; | |
293 | val |= AS3935_AFE_PWR_BIT; | |
294 | ||
295 | ret = as3935_write(st, AS3935_AFE_GAIN, val); | |
296 | ||
297 | err_suspend: | |
298 | mutex_unlock(&st->lock); | |
299 | ||
300 | return ret; | |
301 | } | |
302 | ||
303 | static int as3935_resume(struct device *dev) | |
304 | { | |
305 | struct iio_dev *indio_dev = dev_get_drvdata(dev); | |
306 | struct as3935_state *st = iio_priv(indio_dev); | |
307 | int val, ret; | |
308 | ||
309 | mutex_lock(&st->lock); | |
310 | ret = as3935_read(st, AS3935_AFE_GAIN, &val); | |
311 | if (ret) | |
312 | goto err_resume; | |
313 | val &= ~AS3935_AFE_PWR_BIT; | |
314 | ret = as3935_write(st, AS3935_AFE_GAIN, val); | |
315 | ||
316 | err_resume: | |
317 | mutex_unlock(&st->lock); | |
318 | ||
319 | return ret; | |
320 | } | |
321 | ||
322 | static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume); | |
323 | #define AS3935_PM_OPS (&as3935_pm_ops) | |
324 | ||
325 | #else | |
326 | #define AS3935_PM_OPS NULL | |
327 | #endif | |
328 | ||
329 | static int as3935_probe(struct spi_device *spi) | |
330 | { | |
331 | struct iio_dev *indio_dev; | |
332 | struct iio_trigger *trig; | |
333 | struct as3935_state *st; | |
334 | struct device_node *np = spi->dev.of_node; | |
335 | int ret; | |
336 | ||
337 | /* Be sure lightning event interrupt is specified */ | |
338 | if (!spi->irq) { | |
339 | dev_err(&spi->dev, "unable to get event interrupt\n"); | |
340 | return -EINVAL; | |
341 | } | |
342 | ||
343 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); | |
344 | if (!indio_dev) | |
345 | return -ENOMEM; | |
346 | ||
347 | st = iio_priv(indio_dev); | |
348 | st->spi = spi; | |
349 | st->tune_cap = 0; | |
350 | ||
351 | spi_set_drvdata(spi, indio_dev); | |
352 | mutex_init(&st->lock); | |
353 | INIT_DELAYED_WORK(&st->work, as3935_event_work); | |
354 | ||
355 | ret = of_property_read_u32(np, | |
356 | "ams,tuning-capacitor-pf", &st->tune_cap); | |
357 | if (ret) { | |
358 | st->tune_cap = 0; | |
359 | dev_warn(&spi->dev, | |
360 | "no tuning-capacitor-pf set, defaulting to %d", | |
361 | st->tune_cap); | |
362 | } | |
363 | ||
364 | if (st->tune_cap > MAX_PF_CAP) { | |
365 | dev_err(&spi->dev, | |
366 | "wrong tuning-capacitor-pf setting of %d\n", | |
367 | st->tune_cap); | |
368 | return -EINVAL; | |
369 | } | |
370 | ||
371 | indio_dev->dev.parent = &spi->dev; | |
372 | indio_dev->name = spi_get_device_id(spi)->name; | |
373 | indio_dev->channels = as3935_channels; | |
374 | indio_dev->num_channels = ARRAY_SIZE(as3935_channels); | |
375 | indio_dev->modes = INDIO_DIRECT_MODE; | |
376 | indio_dev->info = &as3935_info; | |
377 | ||
378 | trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d", | |
379 | indio_dev->name, indio_dev->id); | |
380 | ||
381 | if (!trig) | |
382 | return -ENOMEM; | |
383 | ||
384 | st->trig = trig; | |
385 | trig->dev.parent = indio_dev->dev.parent; | |
386 | iio_trigger_set_drvdata(trig, indio_dev); | |
387 | trig->ops = &iio_interrupt_trigger_ops; | |
388 | ||
389 | ret = iio_trigger_register(trig); | |
390 | if (ret) { | |
391 | dev_err(&spi->dev, "failed to register trigger\n"); | |
392 | return ret; | |
393 | } | |
394 | ||
395 | ret = iio_triggered_buffer_setup(indio_dev, NULL, | |
396 | &as3935_trigger_handler, NULL); | |
397 | ||
398 | if (ret) { | |
399 | dev_err(&spi->dev, "cannot setup iio trigger\n"); | |
400 | goto unregister_trigger; | |
401 | } | |
402 | ||
403 | calibrate_as3935(st); | |
404 | ||
405 | ret = devm_request_irq(&spi->dev, spi->irq, | |
406 | &as3935_interrupt_handler, | |
407 | IRQF_TRIGGER_RISING, | |
408 | dev_name(&spi->dev), | |
409 | indio_dev); | |
410 | ||
411 | if (ret) { | |
412 | dev_err(&spi->dev, "unable to request irq\n"); | |
413 | goto unregister_buffer; | |
414 | } | |
415 | ||
416 | ret = iio_device_register(indio_dev); | |
417 | if (ret < 0) { | |
418 | dev_err(&spi->dev, "unable to register device\n"); | |
419 | goto unregister_buffer; | |
420 | } | |
421 | return 0; | |
422 | ||
423 | unregister_buffer: | |
424 | iio_triggered_buffer_cleanup(indio_dev); | |
425 | ||
426 | unregister_trigger: | |
427 | iio_trigger_unregister(st->trig); | |
428 | ||
429 | return ret; | |
430 | } | |
431 | ||
432 | static int as3935_remove(struct spi_device *spi) | |
433 | { | |
434 | struct iio_dev *indio_dev = spi_get_drvdata(spi); | |
435 | struct as3935_state *st = iio_priv(indio_dev); | |
436 | ||
437 | iio_device_unregister(indio_dev); | |
438 | iio_triggered_buffer_cleanup(indio_dev); | |
439 | iio_trigger_unregister(st->trig); | |
440 | ||
441 | return 0; | |
442 | } | |
443 | ||
444 | static const struct of_device_id as3935_of_match[] = { | |
445 | { .compatible = "ams,as3935", }, | |
446 | { /* sentinel */ }, | |
447 | }; | |
448 | MODULE_DEVICE_TABLE(of, as3935_of_match); | |
449 | ||
450 | static const struct spi_device_id as3935_id[] = { | |
451 | {"as3935", 0}, | |
452 | {}, | |
453 | }; | |
454 | MODULE_DEVICE_TABLE(spi, as3935_id); | |
455 | ||
456 | static struct spi_driver as3935_driver = { | |
457 | .driver = { | |
458 | .name = "as3935", | |
459 | .of_match_table = of_match_ptr(as3935_of_match), | |
460 | .pm = AS3935_PM_OPS, | |
461 | }, | |
462 | .probe = as3935_probe, | |
463 | .remove = as3935_remove, | |
464 | .id_table = as3935_id, | |
465 | }; | |
466 | module_spi_driver(as3935_driver); | |
467 | ||
468 | MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); | |
469 | MODULE_DESCRIPTION("AS3935 lightning sensor"); | |
470 | MODULE_LICENSE("GPL"); | |
471 | MODULE_ALIAS("spi:as3935"); |