summaryrefslogtreecommitdiff
path: root/drivers/iio/proximity/as3935.c
blob: 1b8b4723bccaffcce004db5dccb6aa2a9c5a2a55 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
/*
 * as3935.c - Support for AS3935 Franklin lightning sensor
 *
 * Copyright (C) 2014 Matt Ranostay <mranostay@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/of_gpio.h>


#define AS3935_AFE_GAIN		0x00
#define AS3935_AFE_MASK		0x3F
#define AS3935_AFE_GAIN_MAX	0x1F
#define AS3935_AFE_PWR_BIT	BIT(0)

#define AS3935_INT		0x03
#define AS3935_INT_MASK		0x07
#define AS3935_EVENT_INT	BIT(3)
#define AS3935_NOISE_INT	BIT(1)

#define AS3935_DATA		0x07
#define AS3935_DATA_MASK	0x3F

#define AS3935_TUNE_CAP		0x08
#define AS3935_CALIBRATE	0x3D

#define AS3935_WRITE_DATA	BIT(15)
#define AS3935_READ_DATA	BIT(14)
#define AS3935_ADDRESS(x)	((x) << 8)

#define MAX_PF_CAP		120
#define TUNE_CAP_DIV		8

struct as3935_state {
	struct spi_device *spi;
	struct iio_trigger *trig;
	struct mutex lock;
	struct delayed_work work;

	u32 tune_cap;
	u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
	u8 buf[2] ____cacheline_aligned;
};

static const struct iio_chan_spec as3935_channels[] = {
	{
		.type           = IIO_PROXIMITY,
		.info_mask_separate =
			BIT(IIO_CHAN_INFO_RAW) |
			BIT(IIO_CHAN_INFO_PROCESSED) |
			BIT(IIO_CHAN_INFO_SCALE),
		.scan_index     = 0,
		.scan_type = {
			.sign           = 'u',
			.realbits       = 6,
			.storagebits    = 8,
		},
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
};

static int as3935_read(struct as3935_state *st, unsigned int reg, int *val)
{
	u8 cmd;
	int ret;

	cmd = (AS3935_READ_DATA | AS3935_ADDRESS(reg)) >> 8;
	ret = spi_w8r8(st->spi, cmd);
	if (ret < 0)
		return ret;
	*val = ret;

	return 0;
}

static int as3935_write(struct as3935_state *st,
				unsigned int reg,
				unsigned int val)
{
	u8 *buf = st->buf;

	buf[0] = (AS3935_WRITE_DATA | AS3935_ADDRESS(reg)) >> 8;
	buf[1] = val;

	return spi_write(st->spi, buf, 2);
}

static ssize_t as3935_sensor_sensitivity_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
	int val, ret;

	ret = as3935_read(st, AS3935_AFE_GAIN, &val);
	if (ret)
		return ret;
	val = (val & AS3935_AFE_MASK) >> 1;

	return sprintf(buf, "%d\n", val);
}

static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
					struct device_attribute *attr,
					const char *buf, size_t len)
{
	struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
	unsigned long val;
	int ret;

	ret = kstrtoul((const char *) buf, 10, &val);
	if (ret)
		return -EINVAL;

	if (val > AS3935_AFE_GAIN_MAX)
		return -EINVAL;

	as3935_write(st, AS3935_AFE_GAIN, val << 1);

	return len;
}

static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
	as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);


static struct attribute *as3935_attributes[] = {
	&iio_dev_attr_sensor_sensitivity.dev_attr.attr,
	NULL,
};

static const struct attribute_group as3935_attribute_group = {
	.attrs = as3935_attributes,
};

static int as3935_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val,
			   int *val2,
			   long m)
{
	struct as3935_state *st = iio_priv(indio_dev);
	int ret;


	switch (m) {
	case IIO_CHAN_INFO_PROCESSED:
	case IIO_CHAN_INFO_RAW:
		*val2 = 0;
		ret = as3935_read(st, AS3935_DATA, val);
		if (ret)
			return ret;

		if (m == IIO_CHAN_INFO_RAW)
			return IIO_VAL_INT;

		/* storm out of range */
		if (*val == AS3935_DATA_MASK)
			return -EINVAL;

		if (m == IIO_CHAN_INFO_PROCESSED)
			*val *= 1000;
		break;
	case IIO_CHAN_INFO_SCALE:
		*val = 1000;
		break;
	default:
		return -EINVAL;
	}

	return IIO_VAL_INT;
}

static const struct iio_info as3935_info = {
	.driver_module = THIS_MODULE,
	.attrs = &as3935_attribute_group,
	.read_raw = &as3935_read_raw,
};

static irqreturn_t as3935_trigger_handler(int irq, void *private)
{
	struct iio_poll_func *pf = private;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct as3935_state *st = iio_priv(indio_dev);
	int val, ret;

	ret = as3935_read(st, AS3935_DATA, &val);
	if (ret)
		goto err_read;

	st->buffer[0] = val & AS3935_DATA_MASK;
	iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
					   pf->timestamp);
err_read:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
	.owner = THIS_MODULE,
};

static void as3935_event_work(struct work_struct *work)
{
	struct as3935_state *st;
	int val;
	int ret;

	st = container_of(work, struct as3935_state, work.work);

	ret = as3935_read(st, AS3935_INT, &val);
	if (ret) {
		dev_warn(&st->spi->dev, "read error\n");
		return;
	}

	val &= AS3935_INT_MASK;

	switch (val) {
	case AS3935_EVENT_INT:
		iio_trigger_poll(st->trig);
		break;
	case AS3935_NOISE_INT:
		dev_warn(&st->spi->dev, "noise level is too high\n");
		break;
	}
}

static irqreturn_t as3935_interrupt_handler(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct as3935_state *st = iio_priv(indio_dev);

	/*
	 * Delay work for >2 milliseconds after an interrupt to allow
	 * estimated distance to recalculated.
	 */

	schedule_delayed_work(&st->work, msecs_to_jiffies(3));

	return IRQ_HANDLED;
}

static void calibrate_as3935(struct as3935_state *st)
{
	mutex_lock(&st->lock);

	/* mask disturber interrupt bit */
	as3935_write(st, AS3935_INT, BIT(5));

	as3935_write(st, AS3935_CALIBRATE, 0x96);
	as3935_write(st, AS3935_TUNE_CAP,
		BIT(5) | (st->tune_cap / TUNE_CAP_DIV));

	mdelay(2);
	as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));

	mutex_unlock(&st->lock);
}

#ifdef CONFIG_PM_SLEEP
static int as3935_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct as3935_state *st = iio_priv(indio_dev);
	int val, ret;

	mutex_lock(&st->lock);
	ret = as3935_read(st, AS3935_AFE_GAIN, &val);
	if (ret)
		goto err_suspend;
	val |= AS3935_AFE_PWR_BIT;

	ret = as3935_write(st, AS3935_AFE_GAIN, val);

err_suspend:
	mutex_unlock(&st->lock);

	return ret;
}

static int as3935_resume(struct device *dev)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct as3935_state *st = iio_priv(indio_dev);
	int val, ret;

	mutex_lock(&st->lock);
	ret = as3935_read(st, AS3935_AFE_GAIN, &val);
	if (ret)
		goto err_resume;
	val &= ~AS3935_AFE_PWR_BIT;
	ret = as3935_write(st, AS3935_AFE_GAIN, val);

err_resume:
	mutex_unlock(&st->lock);

	return ret;
}

static SIMPLE_DEV_PM_OPS(as3935_pm_ops, as3935_suspend, as3935_resume);
#define AS3935_PM_OPS (&as3935_pm_ops)

#else
#define AS3935_PM_OPS NULL
#endif

static int as3935_probe(struct spi_device *spi)
{
	struct iio_dev *indio_dev;
	struct iio_trigger *trig;
	struct as3935_state *st;
	struct device_node *np = spi->dev.of_node;
	int ret;

	/* Be sure lightning event interrupt is specified */
	if (!spi->irq) {
		dev_err(&spi->dev, "unable to get event interrupt\n");
		return -EINVAL;
	}

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (!indio_dev)
		return -ENOMEM;

	st = iio_priv(indio_dev);
	st->spi = spi;

	spi_set_drvdata(spi, indio_dev);
	mutex_init(&st->lock);
	INIT_DELAYED_WORK(&st->work, as3935_event_work);

	ret = of_property_read_u32(np,
			"ams,tuning-capacitor-pf", &st->tune_cap);
	if (ret) {
		st->tune_cap = 0;
		dev_warn(&spi->dev,
			"no tuning-capacitor-pf set, defaulting to %d",
			st->tune_cap);
	}

	if (st->tune_cap > MAX_PF_CAP) {
		dev_err(&spi->dev,
			"wrong tuning-capacitor-pf setting of %d\n",
			st->tune_cap);
		return -EINVAL;
	}

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->channels = as3935_channels;
	indio_dev->num_channels = ARRAY_SIZE(as3935_channels);
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &as3935_info;

	trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
				      indio_dev->name, indio_dev->id);

	if (!trig)
		return -ENOMEM;

	st->trig = trig;
	trig->dev.parent = indio_dev->dev.parent;
	iio_trigger_set_drvdata(trig, indio_dev);
	trig->ops = &iio_interrupt_trigger_ops;

	ret = iio_trigger_register(trig);
	if (ret) {
		dev_err(&spi->dev, "failed to register trigger\n");
		return ret;
	}

	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
		&as3935_trigger_handler, NULL);

	if (ret) {
		dev_err(&spi->dev, "cannot setup iio trigger\n");
		goto unregister_trigger;
	}

	calibrate_as3935(st);

	ret = devm_request_irq(&spi->dev, spi->irq,
				&as3935_interrupt_handler,
				IRQF_TRIGGER_RISING,
				dev_name(&spi->dev),
				indio_dev);

	if (ret) {
		dev_err(&spi->dev, "unable to request irq\n");
		goto unregister_buffer;
	}

	ret = iio_device_register(indio_dev);
	if (ret < 0) {
		dev_err(&spi->dev, "unable to register device\n");
		goto unregister_buffer;
	}
	return 0;

unregister_buffer:
	iio_triggered_buffer_cleanup(indio_dev);

unregister_trigger:
	iio_trigger_unregister(st->trig);

	return ret;
}

static int as3935_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct as3935_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	iio_trigger_unregister(st->trig);

	return 0;
}

static const struct of_device_id as3935_of_match[] = {
	{ .compatible = "ams,as3935", },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, as3935_of_match);

static const struct spi_device_id as3935_id[] = {
	{"as3935", 0},
	{},
};
MODULE_DEVICE_TABLE(spi, as3935_id);

static struct spi_driver as3935_driver = {
	.driver = {
		.name	= "as3935",
		.of_match_table = of_match_ptr(as3935_of_match),
		.pm	= AS3935_PM_OPS,
	},
	.probe		= as3935_probe,
	.remove		= as3935_remove,
	.id_table	= as3935_id,
};
module_spi_driver(as3935_driver);

MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
MODULE_DESCRIPTION("AS3935 lightning sensor");
MODULE_LICENSE("GPL");