xref: /linux/drivers/iio/light/opt3001.c (revision 55d0969c451159cff86949b38c39171cab962069)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * opt3001.c - Texas Instruments OPT3001 Light Sensor
4  *
5  * Copyright (C) 2014 Texas Instruments Incorporated - https://www.ti.com
6  *
7  * Author: Andreas Dannenberg <dannenberg@ti.com>
8  * Based on previous work from: Felipe Balbi <balbi@ti.com>
9  */
10 
11 #include <linux/bitops.h>
12 #include <linux/delay.h>
13 #include <linux/device.h>
14 #include <linux/i2c.h>
15 #include <linux/interrupt.h>
16 #include <linux/irq.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/mod_devicetable.h>
20 #include <linux/mutex.h>
21 #include <linux/slab.h>
22 #include <linux/types.h>
23 
24 #include <linux/iio/events.h>
25 #include <linux/iio/iio.h>
26 #include <linux/iio/sysfs.h>
27 
28 #define OPT3001_RESULT		0x00
29 #define OPT3001_CONFIGURATION	0x01
30 #define OPT3001_LOW_LIMIT	0x02
31 #define OPT3001_HIGH_LIMIT	0x03
32 #define OPT3001_MANUFACTURER_ID	0x7e
33 #define OPT3001_DEVICE_ID	0x7f
34 
35 #define OPT3001_CONFIGURATION_RN_MASK	(0xf << 12)
36 #define OPT3001_CONFIGURATION_RN_AUTO	(0xc << 12)
37 
38 #define OPT3001_CONFIGURATION_CT	BIT(11)
39 
40 #define OPT3001_CONFIGURATION_M_MASK	(3 << 9)
41 #define OPT3001_CONFIGURATION_M_SHUTDOWN (0 << 9)
42 #define OPT3001_CONFIGURATION_M_SINGLE	(1 << 9)
43 #define OPT3001_CONFIGURATION_M_CONTINUOUS (2 << 9) /* also 3 << 9 */
44 
45 #define OPT3001_CONFIGURATION_OVF	BIT(8)
46 #define OPT3001_CONFIGURATION_CRF	BIT(7)
47 #define OPT3001_CONFIGURATION_FH	BIT(6)
48 #define OPT3001_CONFIGURATION_FL	BIT(5)
49 #define OPT3001_CONFIGURATION_L		BIT(4)
50 #define OPT3001_CONFIGURATION_POL	BIT(3)
51 #define OPT3001_CONFIGURATION_ME	BIT(2)
52 
53 #define OPT3001_CONFIGURATION_FC_MASK	(3 << 0)
54 
55 /* The end-of-conversion enable is located in the low-limit register */
56 #define OPT3001_LOW_LIMIT_EOC_ENABLE	0xc000
57 
58 #define OPT3001_REG_EXPONENT(n)		((n) >> 12)
59 #define OPT3001_REG_MANTISSA(n)		((n) & 0xfff)
60 
61 #define OPT3001_INT_TIME_LONG		800000
62 #define OPT3001_INT_TIME_SHORT		100000
63 
64 /*
65  * Time to wait for conversion result to be ready. The device datasheet
66  * sect. 6.5 states results are ready after total integration time plus 3ms.
67  * This results in worst-case max values of 113ms or 883ms, respectively.
68  * Add some slack to be on the safe side.
69  */
70 #define OPT3001_RESULT_READY_SHORT	150
71 #define OPT3001_RESULT_READY_LONG	1000
72 
73 struct opt3001 {
74 	struct i2c_client	*client;
75 	struct device		*dev;
76 
77 	struct mutex		lock;
78 	bool			ok_to_ignore_lock;
79 	bool			result_ready;
80 	wait_queue_head_t	result_ready_queue;
81 	u16			result;
82 
83 	u32			int_time;
84 	u32			mode;
85 
86 	u16			high_thresh_mantissa;
87 	u16			low_thresh_mantissa;
88 
89 	u8			high_thresh_exp;
90 	u8			low_thresh_exp;
91 
92 	bool			use_irq;
93 };
94 
95 struct opt3001_scale {
96 	int	val;
97 	int	val2;
98 };
99 
100 static const struct opt3001_scale opt3001_scales[] = {
101 	{
102 		.val = 40,
103 		.val2 = 950000,
104 	},
105 	{
106 		.val = 81,
107 		.val2 = 900000,
108 	},
109 	{
110 		.val = 163,
111 		.val2 = 800000,
112 	},
113 	{
114 		.val = 327,
115 		.val2 = 600000,
116 	},
117 	{
118 		.val = 655,
119 		.val2 = 200000,
120 	},
121 	{
122 		.val = 1310,
123 		.val2 = 400000,
124 	},
125 	{
126 		.val = 2620,
127 		.val2 = 800000,
128 	},
129 	{
130 		.val = 5241,
131 		.val2 = 600000,
132 	},
133 	{
134 		.val = 10483,
135 		.val2 = 200000,
136 	},
137 	{
138 		.val = 20966,
139 		.val2 = 400000,
140 	},
141 	{
142 		.val = 41932,
143 		.val2 = 800000,
144 	},
145 	{
146 		.val = 83865,
147 		.val2 = 600000,
148 	},
149 };
150 
151 static int opt3001_find_scale(const struct opt3001 *opt, int val,
152 		int val2, u8 *exponent)
153 {
154 	int i;
155 
156 	for (i = 0; i < ARRAY_SIZE(opt3001_scales); i++) {
157 		const struct opt3001_scale *scale = &opt3001_scales[i];
158 
159 		/*
160 		 * Combine the integer and micro parts for comparison
161 		 * purposes. Use milli lux precision to avoid 32-bit integer
162 		 * overflows.
163 		 */
164 		if ((val * 1000 + val2 / 1000) <=
165 				(scale->val * 1000 + scale->val2 / 1000)) {
166 			*exponent = i;
167 			return 0;
168 		}
169 	}
170 
171 	return -EINVAL;
172 }
173 
174 static void opt3001_to_iio_ret(struct opt3001 *opt, u8 exponent,
175 		u16 mantissa, int *val, int *val2)
176 {
177 	int lux;
178 
179 	lux = 10 * (mantissa << exponent);
180 	*val = lux / 1000;
181 	*val2 = (lux - (*val * 1000)) * 1000;
182 }
183 
184 static void opt3001_set_mode(struct opt3001 *opt, u16 *reg, u16 mode)
185 {
186 	*reg &= ~OPT3001_CONFIGURATION_M_MASK;
187 	*reg |= mode;
188 	opt->mode = mode;
189 }
190 
191 static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.8");
192 
193 static struct attribute *opt3001_attributes[] = {
194 	&iio_const_attr_integration_time_available.dev_attr.attr,
195 	NULL
196 };
197 
198 static const struct attribute_group opt3001_attribute_group = {
199 	.attrs = opt3001_attributes,
200 };
201 
202 static const struct iio_event_spec opt3001_event_spec[] = {
203 	{
204 		.type = IIO_EV_TYPE_THRESH,
205 		.dir = IIO_EV_DIR_RISING,
206 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
207 			BIT(IIO_EV_INFO_ENABLE),
208 	},
209 	{
210 		.type = IIO_EV_TYPE_THRESH,
211 		.dir = IIO_EV_DIR_FALLING,
212 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
213 			BIT(IIO_EV_INFO_ENABLE),
214 	},
215 };
216 
217 static const struct iio_chan_spec opt3001_channels[] = {
218 	{
219 		.type = IIO_LIGHT,
220 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
221 				BIT(IIO_CHAN_INFO_INT_TIME),
222 		.event_spec = opt3001_event_spec,
223 		.num_event_specs = ARRAY_SIZE(opt3001_event_spec),
224 	},
225 	IIO_CHAN_SOFT_TIMESTAMP(1),
226 };
227 
228 static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2)
229 {
230 	int ret;
231 	u16 mantissa;
232 	u16 reg;
233 	u8 exponent;
234 	u16 value;
235 	long timeout;
236 
237 	if (opt->use_irq) {
238 		/*
239 		 * Enable the end-of-conversion interrupt mechanism. Note that
240 		 * doing so will overwrite the low-level limit value however we
241 		 * will restore this value later on.
242 		 */
243 		ret = i2c_smbus_write_word_swapped(opt->client,
244 					OPT3001_LOW_LIMIT,
245 					OPT3001_LOW_LIMIT_EOC_ENABLE);
246 		if (ret < 0) {
247 			dev_err(opt->dev, "failed to write register %02x\n",
248 					OPT3001_LOW_LIMIT);
249 			return ret;
250 		}
251 
252 		/* Allow IRQ to access the device despite lock being set */
253 		opt->ok_to_ignore_lock = true;
254 	}
255 
256 	/* Reset data-ready indicator flag */
257 	opt->result_ready = false;
258 
259 	/* Configure for single-conversion mode and start a new conversion */
260 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
261 	if (ret < 0) {
262 		dev_err(opt->dev, "failed to read register %02x\n",
263 				OPT3001_CONFIGURATION);
264 		goto err;
265 	}
266 
267 	reg = ret;
268 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SINGLE);
269 
270 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
271 			reg);
272 	if (ret < 0) {
273 		dev_err(opt->dev, "failed to write register %02x\n",
274 				OPT3001_CONFIGURATION);
275 		goto err;
276 	}
277 
278 	if (opt->use_irq) {
279 		/* Wait for the IRQ to indicate the conversion is complete */
280 		ret = wait_event_timeout(opt->result_ready_queue,
281 				opt->result_ready,
282 				msecs_to_jiffies(OPT3001_RESULT_READY_LONG));
283 		if (ret == 0)
284 			return -ETIMEDOUT;
285 	} else {
286 		/* Sleep for result ready time */
287 		timeout = (opt->int_time == OPT3001_INT_TIME_SHORT) ?
288 			OPT3001_RESULT_READY_SHORT : OPT3001_RESULT_READY_LONG;
289 		msleep(timeout);
290 
291 		/* Check result ready flag */
292 		ret = i2c_smbus_read_word_swapped(opt->client,
293 						  OPT3001_CONFIGURATION);
294 		if (ret < 0) {
295 			dev_err(opt->dev, "failed to read register %02x\n",
296 				OPT3001_CONFIGURATION);
297 			goto err;
298 		}
299 
300 		if (!(ret & OPT3001_CONFIGURATION_CRF)) {
301 			ret = -ETIMEDOUT;
302 			goto err;
303 		}
304 
305 		/* Obtain value */
306 		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
307 		if (ret < 0) {
308 			dev_err(opt->dev, "failed to read register %02x\n",
309 				OPT3001_RESULT);
310 			goto err;
311 		}
312 		opt->result = ret;
313 		opt->result_ready = true;
314 	}
315 
316 err:
317 	if (opt->use_irq)
318 		/* Disallow IRQ to access the device while lock is active */
319 		opt->ok_to_ignore_lock = false;
320 
321 	if (ret < 0)
322 		return ret;
323 
324 	if (opt->use_irq) {
325 		/*
326 		 * Disable the end-of-conversion interrupt mechanism by
327 		 * restoring the low-level limit value (clearing
328 		 * OPT3001_LOW_LIMIT_EOC_ENABLE). Note that selectively clearing
329 		 * those enable bits would affect the actual limit value due to
330 		 * bit-overlap and therefore can't be done.
331 		 */
332 		value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa;
333 		ret = i2c_smbus_write_word_swapped(opt->client,
334 						   OPT3001_LOW_LIMIT,
335 						   value);
336 		if (ret < 0) {
337 			dev_err(opt->dev, "failed to write register %02x\n",
338 					OPT3001_LOW_LIMIT);
339 			return ret;
340 		}
341 	}
342 
343 	exponent = OPT3001_REG_EXPONENT(opt->result);
344 	mantissa = OPT3001_REG_MANTISSA(opt->result);
345 
346 	opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);
347 
348 	return IIO_VAL_INT_PLUS_MICRO;
349 }
350 
351 static int opt3001_get_int_time(struct opt3001 *opt, int *val, int *val2)
352 {
353 	*val = 0;
354 	*val2 = opt->int_time;
355 
356 	return IIO_VAL_INT_PLUS_MICRO;
357 }
358 
359 static int opt3001_set_int_time(struct opt3001 *opt, int time)
360 {
361 	int ret;
362 	u16 reg;
363 
364 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
365 	if (ret < 0) {
366 		dev_err(opt->dev, "failed to read register %02x\n",
367 				OPT3001_CONFIGURATION);
368 		return ret;
369 	}
370 
371 	reg = ret;
372 
373 	switch (time) {
374 	case OPT3001_INT_TIME_SHORT:
375 		reg &= ~OPT3001_CONFIGURATION_CT;
376 		opt->int_time = OPT3001_INT_TIME_SHORT;
377 		break;
378 	case OPT3001_INT_TIME_LONG:
379 		reg |= OPT3001_CONFIGURATION_CT;
380 		opt->int_time = OPT3001_INT_TIME_LONG;
381 		break;
382 	default:
383 		return -EINVAL;
384 	}
385 
386 	return i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
387 			reg);
388 }
389 
390 static int opt3001_read_raw(struct iio_dev *iio,
391 		struct iio_chan_spec const *chan, int *val, int *val2,
392 		long mask)
393 {
394 	struct opt3001 *opt = iio_priv(iio);
395 	int ret;
396 
397 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
398 		return -EBUSY;
399 
400 	if (chan->type != IIO_LIGHT)
401 		return -EINVAL;
402 
403 	mutex_lock(&opt->lock);
404 
405 	switch (mask) {
406 	case IIO_CHAN_INFO_PROCESSED:
407 		ret = opt3001_get_lux(opt, val, val2);
408 		break;
409 	case IIO_CHAN_INFO_INT_TIME:
410 		ret = opt3001_get_int_time(opt, val, val2);
411 		break;
412 	default:
413 		ret = -EINVAL;
414 	}
415 
416 	mutex_unlock(&opt->lock);
417 
418 	return ret;
419 }
420 
421 static int opt3001_write_raw(struct iio_dev *iio,
422 		struct iio_chan_spec const *chan, int val, int val2,
423 		long mask)
424 {
425 	struct opt3001 *opt = iio_priv(iio);
426 	int ret;
427 
428 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
429 		return -EBUSY;
430 
431 	if (chan->type != IIO_LIGHT)
432 		return -EINVAL;
433 
434 	if (mask != IIO_CHAN_INFO_INT_TIME)
435 		return -EINVAL;
436 
437 	if (val != 0)
438 		return -EINVAL;
439 
440 	mutex_lock(&opt->lock);
441 	ret = opt3001_set_int_time(opt, val2);
442 	mutex_unlock(&opt->lock);
443 
444 	return ret;
445 }
446 
447 static int opt3001_read_event_value(struct iio_dev *iio,
448 		const struct iio_chan_spec *chan, enum iio_event_type type,
449 		enum iio_event_direction dir, enum iio_event_info info,
450 		int *val, int *val2)
451 {
452 	struct opt3001 *opt = iio_priv(iio);
453 	int ret = IIO_VAL_INT_PLUS_MICRO;
454 
455 	mutex_lock(&opt->lock);
456 
457 	switch (dir) {
458 	case IIO_EV_DIR_RISING:
459 		opt3001_to_iio_ret(opt, opt->high_thresh_exp,
460 				opt->high_thresh_mantissa, val, val2);
461 		break;
462 	case IIO_EV_DIR_FALLING:
463 		opt3001_to_iio_ret(opt, opt->low_thresh_exp,
464 				opt->low_thresh_mantissa, val, val2);
465 		break;
466 	default:
467 		ret = -EINVAL;
468 	}
469 
470 	mutex_unlock(&opt->lock);
471 
472 	return ret;
473 }
474 
475 static int opt3001_write_event_value(struct iio_dev *iio,
476 		const struct iio_chan_spec *chan, enum iio_event_type type,
477 		enum iio_event_direction dir, enum iio_event_info info,
478 		int val, int val2)
479 {
480 	struct opt3001 *opt = iio_priv(iio);
481 	int ret;
482 
483 	u16 mantissa;
484 	u16 value;
485 	u16 reg;
486 
487 	u8 exponent;
488 
489 	if (val < 0)
490 		return -EINVAL;
491 
492 	mutex_lock(&opt->lock);
493 
494 	ret = opt3001_find_scale(opt, val, val2, &exponent);
495 	if (ret < 0) {
496 		dev_err(opt->dev, "can't find scale for %d.%06u\n", val, val2);
497 		goto err;
498 	}
499 
500 	mantissa = (((val * 1000) + (val2 / 1000)) / 10) >> exponent;
501 	value = (exponent << 12) | mantissa;
502 
503 	switch (dir) {
504 	case IIO_EV_DIR_RISING:
505 		reg = OPT3001_HIGH_LIMIT;
506 		opt->high_thresh_mantissa = mantissa;
507 		opt->high_thresh_exp = exponent;
508 		break;
509 	case IIO_EV_DIR_FALLING:
510 		reg = OPT3001_LOW_LIMIT;
511 		opt->low_thresh_mantissa = mantissa;
512 		opt->low_thresh_exp = exponent;
513 		break;
514 	default:
515 		ret = -EINVAL;
516 		goto err;
517 	}
518 
519 	ret = i2c_smbus_write_word_swapped(opt->client, reg, value);
520 	if (ret < 0) {
521 		dev_err(opt->dev, "failed to write register %02x\n", reg);
522 		goto err;
523 	}
524 
525 err:
526 	mutex_unlock(&opt->lock);
527 
528 	return ret;
529 }
530 
531 static int opt3001_read_event_config(struct iio_dev *iio,
532 		const struct iio_chan_spec *chan, enum iio_event_type type,
533 		enum iio_event_direction dir)
534 {
535 	struct opt3001 *opt = iio_priv(iio);
536 
537 	return opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS;
538 }
539 
540 static int opt3001_write_event_config(struct iio_dev *iio,
541 		const struct iio_chan_spec *chan, enum iio_event_type type,
542 		enum iio_event_direction dir, int state)
543 {
544 	struct opt3001 *opt = iio_priv(iio);
545 	int ret;
546 	u16 mode;
547 	u16 reg;
548 
549 	if (state && opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
550 		return 0;
551 
552 	if (!state && opt->mode == OPT3001_CONFIGURATION_M_SHUTDOWN)
553 		return 0;
554 
555 	mutex_lock(&opt->lock);
556 
557 	mode = state ? OPT3001_CONFIGURATION_M_CONTINUOUS
558 		: OPT3001_CONFIGURATION_M_SHUTDOWN;
559 
560 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
561 	if (ret < 0) {
562 		dev_err(opt->dev, "failed to read register %02x\n",
563 				OPT3001_CONFIGURATION);
564 		goto err;
565 	}
566 
567 	reg = ret;
568 	opt3001_set_mode(opt, &reg, mode);
569 
570 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
571 			reg);
572 	if (ret < 0) {
573 		dev_err(opt->dev, "failed to write register %02x\n",
574 				OPT3001_CONFIGURATION);
575 		goto err;
576 	}
577 
578 err:
579 	mutex_unlock(&opt->lock);
580 
581 	return ret;
582 }
583 
584 static const struct iio_info opt3001_info = {
585 	.attrs = &opt3001_attribute_group,
586 	.read_raw = opt3001_read_raw,
587 	.write_raw = opt3001_write_raw,
588 	.read_event_value = opt3001_read_event_value,
589 	.write_event_value = opt3001_write_event_value,
590 	.read_event_config = opt3001_read_event_config,
591 	.write_event_config = opt3001_write_event_config,
592 };
593 
594 static int opt3001_read_id(struct opt3001 *opt)
595 {
596 	char manufacturer[2];
597 	u16 device_id;
598 	int ret;
599 
600 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_MANUFACTURER_ID);
601 	if (ret < 0) {
602 		dev_err(opt->dev, "failed to read register %02x\n",
603 				OPT3001_MANUFACTURER_ID);
604 		return ret;
605 	}
606 
607 	manufacturer[0] = ret >> 8;
608 	manufacturer[1] = ret & 0xff;
609 
610 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_DEVICE_ID);
611 	if (ret < 0) {
612 		dev_err(opt->dev, "failed to read register %02x\n",
613 				OPT3001_DEVICE_ID);
614 		return ret;
615 	}
616 
617 	device_id = ret;
618 
619 	dev_info(opt->dev, "Found %c%c OPT%04x\n", manufacturer[0],
620 			manufacturer[1], device_id);
621 
622 	return 0;
623 }
624 
625 static int opt3001_configure(struct opt3001 *opt)
626 {
627 	int ret;
628 	u16 reg;
629 
630 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
631 	if (ret < 0) {
632 		dev_err(opt->dev, "failed to read register %02x\n",
633 				OPT3001_CONFIGURATION);
634 		return ret;
635 	}
636 
637 	reg = ret;
638 
639 	/* Enable automatic full-scale setting mode */
640 	reg &= ~OPT3001_CONFIGURATION_RN_MASK;
641 	reg |= OPT3001_CONFIGURATION_RN_AUTO;
642 
643 	/* Reflect status of the device's integration time setting */
644 	if (reg & OPT3001_CONFIGURATION_CT)
645 		opt->int_time = OPT3001_INT_TIME_LONG;
646 	else
647 		opt->int_time = OPT3001_INT_TIME_SHORT;
648 
649 	/* Ensure device is in shutdown initially */
650 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
651 
652 	/* Configure for latched window-style comparison operation */
653 	reg |= OPT3001_CONFIGURATION_L;
654 	reg &= ~OPT3001_CONFIGURATION_POL;
655 	reg &= ~OPT3001_CONFIGURATION_ME;
656 	reg &= ~OPT3001_CONFIGURATION_FC_MASK;
657 
658 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
659 			reg);
660 	if (ret < 0) {
661 		dev_err(opt->dev, "failed to write register %02x\n",
662 				OPT3001_CONFIGURATION);
663 		return ret;
664 	}
665 
666 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_LOW_LIMIT);
667 	if (ret < 0) {
668 		dev_err(opt->dev, "failed to read register %02x\n",
669 				OPT3001_LOW_LIMIT);
670 		return ret;
671 	}
672 
673 	opt->low_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
674 	opt->low_thresh_exp = OPT3001_REG_EXPONENT(ret);
675 
676 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_HIGH_LIMIT);
677 	if (ret < 0) {
678 		dev_err(opt->dev, "failed to read register %02x\n",
679 				OPT3001_HIGH_LIMIT);
680 		return ret;
681 	}
682 
683 	opt->high_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
684 	opt->high_thresh_exp = OPT3001_REG_EXPONENT(ret);
685 
686 	return 0;
687 }
688 
689 static irqreturn_t opt3001_irq(int irq, void *_iio)
690 {
691 	struct iio_dev *iio = _iio;
692 	struct opt3001 *opt = iio_priv(iio);
693 	int ret;
694 	bool wake_result_ready_queue = false;
695 
696 	if (!opt->ok_to_ignore_lock)
697 		mutex_lock(&opt->lock);
698 
699 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
700 	if (ret < 0) {
701 		dev_err(opt->dev, "failed to read register %02x\n",
702 				OPT3001_CONFIGURATION);
703 		goto out;
704 	}
705 
706 	if ((ret & OPT3001_CONFIGURATION_M_MASK) ==
707 			OPT3001_CONFIGURATION_M_CONTINUOUS) {
708 		if (ret & OPT3001_CONFIGURATION_FH)
709 			iio_push_event(iio,
710 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
711 							IIO_EV_TYPE_THRESH,
712 							IIO_EV_DIR_RISING),
713 					iio_get_time_ns(iio));
714 		if (ret & OPT3001_CONFIGURATION_FL)
715 			iio_push_event(iio,
716 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
717 							IIO_EV_TYPE_THRESH,
718 							IIO_EV_DIR_FALLING),
719 					iio_get_time_ns(iio));
720 	} else if (ret & OPT3001_CONFIGURATION_CRF) {
721 		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
722 		if (ret < 0) {
723 			dev_err(opt->dev, "failed to read register %02x\n",
724 					OPT3001_RESULT);
725 			goto out;
726 		}
727 		opt->result = ret;
728 		opt->result_ready = true;
729 		wake_result_ready_queue = true;
730 	}
731 
732 out:
733 	if (!opt->ok_to_ignore_lock)
734 		mutex_unlock(&opt->lock);
735 
736 	if (wake_result_ready_queue)
737 		wake_up(&opt->result_ready_queue);
738 
739 	return IRQ_HANDLED;
740 }
741 
742 static int opt3001_probe(struct i2c_client *client)
743 {
744 	struct device *dev = &client->dev;
745 
746 	struct iio_dev *iio;
747 	struct opt3001 *opt;
748 	int irq = client->irq;
749 	int ret;
750 
751 	iio = devm_iio_device_alloc(dev, sizeof(*opt));
752 	if (!iio)
753 		return -ENOMEM;
754 
755 	opt = iio_priv(iio);
756 	opt->client = client;
757 	opt->dev = dev;
758 
759 	mutex_init(&opt->lock);
760 	init_waitqueue_head(&opt->result_ready_queue);
761 	i2c_set_clientdata(client, iio);
762 
763 	ret = opt3001_read_id(opt);
764 	if (ret)
765 		return ret;
766 
767 	ret = opt3001_configure(opt);
768 	if (ret)
769 		return ret;
770 
771 	iio->name = client->name;
772 	iio->channels = opt3001_channels;
773 	iio->num_channels = ARRAY_SIZE(opt3001_channels);
774 	iio->modes = INDIO_DIRECT_MODE;
775 	iio->info = &opt3001_info;
776 
777 	ret = devm_iio_device_register(dev, iio);
778 	if (ret) {
779 		dev_err(dev, "failed to register IIO device\n");
780 		return ret;
781 	}
782 
783 	/* Make use of INT pin only if valid IRQ no. is given */
784 	if (irq > 0) {
785 		ret = request_threaded_irq(irq, NULL, opt3001_irq,
786 				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
787 				"opt3001", iio);
788 		if (ret) {
789 			dev_err(dev, "failed to request IRQ #%d\n", irq);
790 			return ret;
791 		}
792 		opt->use_irq = true;
793 	} else {
794 		dev_dbg(opt->dev, "enabling interrupt-less operation\n");
795 	}
796 
797 	return 0;
798 }
799 
800 static void opt3001_remove(struct i2c_client *client)
801 {
802 	struct iio_dev *iio = i2c_get_clientdata(client);
803 	struct opt3001 *opt = iio_priv(iio);
804 	int ret;
805 	u16 reg;
806 
807 	if (opt->use_irq)
808 		free_irq(client->irq, iio);
809 
810 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
811 	if (ret < 0) {
812 		dev_err(opt->dev, "failed to read register %02x\n",
813 				OPT3001_CONFIGURATION);
814 		return;
815 	}
816 
817 	reg = ret;
818 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
819 
820 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
821 			reg);
822 	if (ret < 0) {
823 		dev_err(opt->dev, "failed to write register %02x\n",
824 				OPT3001_CONFIGURATION);
825 	}
826 }
827 
828 static const struct i2c_device_id opt3001_id[] = {
829 	{ "opt3001" },
830 	{ } /* Terminating Entry */
831 };
832 MODULE_DEVICE_TABLE(i2c, opt3001_id);
833 
834 static const struct of_device_id opt3001_of_match[] = {
835 	{ .compatible = "ti,opt3001" },
836 	{ }
837 };
838 MODULE_DEVICE_TABLE(of, opt3001_of_match);
839 
840 static struct i2c_driver opt3001_driver = {
841 	.probe = opt3001_probe,
842 	.remove = opt3001_remove,
843 	.id_table = opt3001_id,
844 
845 	.driver = {
846 		.name = "opt3001",
847 		.of_match_table = opt3001_of_match,
848 	},
849 };
850 
851 module_i2c_driver(opt3001_driver);
852 
853 MODULE_LICENSE("GPL v2");
854 MODULE_AUTHOR("Andreas Dannenberg <dannenberg@ti.com>");
855 MODULE_DESCRIPTION("Texas Instruments OPT3001 Light Sensor Driver");
856