xref: /openbmc/linux/drivers/iio/light/opt3001.c (revision dc6a81c3)
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 - http://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/mutex.h>
20 #include <linux/slab.h>
21 #include <linux/types.h>
22 
23 #include <linux/iio/events.h>
24 #include <linux/iio/iio.h>
25 #include <linux/iio/sysfs.h>
26 
27 #define OPT3001_RESULT		0x00
28 #define OPT3001_CONFIGURATION	0x01
29 #define OPT3001_LOW_LIMIT	0x02
30 #define OPT3001_HIGH_LIMIT	0x03
31 #define OPT3001_MANUFACTURER_ID	0x7e
32 #define OPT3001_DEVICE_ID	0x7f
33 
34 #define OPT3001_CONFIGURATION_RN_MASK	(0xf << 12)
35 #define OPT3001_CONFIGURATION_RN_AUTO	(0xc << 12)
36 
37 #define OPT3001_CONFIGURATION_CT	BIT(11)
38 
39 #define OPT3001_CONFIGURATION_M_MASK	(3 << 9)
40 #define OPT3001_CONFIGURATION_M_SHUTDOWN (0 << 9)
41 #define OPT3001_CONFIGURATION_M_SINGLE	(1 << 9)
42 #define OPT3001_CONFIGURATION_M_CONTINUOUS (2 << 9) /* also 3 << 9 */
43 
44 #define OPT3001_CONFIGURATION_OVF	BIT(8)
45 #define OPT3001_CONFIGURATION_CRF	BIT(7)
46 #define OPT3001_CONFIGURATION_FH	BIT(6)
47 #define OPT3001_CONFIGURATION_FL	BIT(5)
48 #define OPT3001_CONFIGURATION_L		BIT(4)
49 #define OPT3001_CONFIGURATION_POL	BIT(3)
50 #define OPT3001_CONFIGURATION_ME	BIT(2)
51 
52 #define OPT3001_CONFIGURATION_FC_MASK	(3 << 0)
53 
54 /* The end-of-conversion enable is located in the low-limit register */
55 #define OPT3001_LOW_LIMIT_EOC_ENABLE	0xc000
56 
57 #define OPT3001_REG_EXPONENT(n)		((n) >> 12)
58 #define OPT3001_REG_MANTISSA(n)		((n) & 0xfff)
59 
60 #define OPT3001_INT_TIME_LONG		800000
61 #define OPT3001_INT_TIME_SHORT		100000
62 
63 /*
64  * Time to wait for conversion result to be ready. The device datasheet
65  * sect. 6.5 states results are ready after total integration time plus 3ms.
66  * This results in worst-case max values of 113ms or 883ms, respectively.
67  * Add some slack to be on the safe side.
68  */
69 #define OPT3001_RESULT_READY_SHORT	150
70 #define OPT3001_RESULT_READY_LONG	1000
71 
72 struct opt3001 {
73 	struct i2c_client	*client;
74 	struct device		*dev;
75 
76 	struct mutex		lock;
77 	bool			ok_to_ignore_lock;
78 	bool			result_ready;
79 	wait_queue_head_t	result_ready_queue;
80 	u16			result;
81 
82 	u32			int_time;
83 	u32			mode;
84 
85 	u16			high_thresh_mantissa;
86 	u16			low_thresh_mantissa;
87 
88 	u8			high_thresh_exp;
89 	u8			low_thresh_exp;
90 
91 	bool			use_irq;
92 };
93 
94 struct opt3001_scale {
95 	int	val;
96 	int	val2;
97 };
98 
99 static const struct opt3001_scale opt3001_scales[] = {
100 	{
101 		.val = 40,
102 		.val2 = 950000,
103 	},
104 	{
105 		.val = 81,
106 		.val2 = 900000,
107 	},
108 	{
109 		.val = 163,
110 		.val2 = 800000,
111 	},
112 	{
113 		.val = 327,
114 		.val2 = 600000,
115 	},
116 	{
117 		.val = 655,
118 		.val2 = 200000,
119 	},
120 	{
121 		.val = 1310,
122 		.val2 = 400000,
123 	},
124 	{
125 		.val = 2620,
126 		.val2 = 800000,
127 	},
128 	{
129 		.val = 5241,
130 		.val2 = 600000,
131 	},
132 	{
133 		.val = 10483,
134 		.val2 = 200000,
135 	},
136 	{
137 		.val = 20966,
138 		.val2 = 400000,
139 	},
140 	{
141 		.val = 83865,
142 		.val2 = 600000,
143 	},
144 };
145 
146 static int opt3001_find_scale(const struct opt3001 *opt, int val,
147 		int val2, u8 *exponent)
148 {
149 	int i;
150 
151 	for (i = 0; i < ARRAY_SIZE(opt3001_scales); i++) {
152 		const struct opt3001_scale *scale = &opt3001_scales[i];
153 
154 		/*
155 		 * Combine the integer and micro parts for comparison
156 		 * purposes. Use milli lux precision to avoid 32-bit integer
157 		 * overflows.
158 		 */
159 		if ((val * 1000 + val2 / 1000) <=
160 				(scale->val * 1000 + scale->val2 / 1000)) {
161 			*exponent = i;
162 			return 0;
163 		}
164 	}
165 
166 	return -EINVAL;
167 }
168 
169 static void opt3001_to_iio_ret(struct opt3001 *opt, u8 exponent,
170 		u16 mantissa, int *val, int *val2)
171 {
172 	int lux;
173 
174 	lux = 10 * (mantissa << exponent);
175 	*val = lux / 1000;
176 	*val2 = (lux - (*val * 1000)) * 1000;
177 }
178 
179 static void opt3001_set_mode(struct opt3001 *opt, u16 *reg, u16 mode)
180 {
181 	*reg &= ~OPT3001_CONFIGURATION_M_MASK;
182 	*reg |= mode;
183 	opt->mode = mode;
184 }
185 
186 static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.8");
187 
188 static struct attribute *opt3001_attributes[] = {
189 	&iio_const_attr_integration_time_available.dev_attr.attr,
190 	NULL
191 };
192 
193 static const struct attribute_group opt3001_attribute_group = {
194 	.attrs = opt3001_attributes,
195 };
196 
197 static const struct iio_event_spec opt3001_event_spec[] = {
198 	{
199 		.type = IIO_EV_TYPE_THRESH,
200 		.dir = IIO_EV_DIR_RISING,
201 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
202 			BIT(IIO_EV_INFO_ENABLE),
203 	},
204 	{
205 		.type = IIO_EV_TYPE_THRESH,
206 		.dir = IIO_EV_DIR_FALLING,
207 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
208 			BIT(IIO_EV_INFO_ENABLE),
209 	},
210 };
211 
212 static const struct iio_chan_spec opt3001_channels[] = {
213 	{
214 		.type = IIO_LIGHT,
215 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
216 				BIT(IIO_CHAN_INFO_INT_TIME),
217 		.event_spec = opt3001_event_spec,
218 		.num_event_specs = ARRAY_SIZE(opt3001_event_spec),
219 	},
220 	IIO_CHAN_SOFT_TIMESTAMP(1),
221 };
222 
223 static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2)
224 {
225 	int ret;
226 	u16 mantissa;
227 	u16 reg;
228 	u8 exponent;
229 	u16 value;
230 	long timeout;
231 
232 	if (opt->use_irq) {
233 		/*
234 		 * Enable the end-of-conversion interrupt mechanism. Note that
235 		 * doing so will overwrite the low-level limit value however we
236 		 * will restore this value later on.
237 		 */
238 		ret = i2c_smbus_write_word_swapped(opt->client,
239 					OPT3001_LOW_LIMIT,
240 					OPT3001_LOW_LIMIT_EOC_ENABLE);
241 		if (ret < 0) {
242 			dev_err(opt->dev, "failed to write register %02x\n",
243 					OPT3001_LOW_LIMIT);
244 			return ret;
245 		}
246 
247 		/* Allow IRQ to access the device despite lock being set */
248 		opt->ok_to_ignore_lock = true;
249 	}
250 
251 	/* Reset data-ready indicator flag */
252 	opt->result_ready = false;
253 
254 	/* Configure for single-conversion mode and start a new conversion */
255 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
256 	if (ret < 0) {
257 		dev_err(opt->dev, "failed to read register %02x\n",
258 				OPT3001_CONFIGURATION);
259 		goto err;
260 	}
261 
262 	reg = ret;
263 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SINGLE);
264 
265 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
266 			reg);
267 	if (ret < 0) {
268 		dev_err(opt->dev, "failed to write register %02x\n",
269 				OPT3001_CONFIGURATION);
270 		goto err;
271 	}
272 
273 	if (opt->use_irq) {
274 		/* Wait for the IRQ to indicate the conversion is complete */
275 		ret = wait_event_timeout(opt->result_ready_queue,
276 				opt->result_ready,
277 				msecs_to_jiffies(OPT3001_RESULT_READY_LONG));
278 	} else {
279 		/* Sleep for result ready time */
280 		timeout = (opt->int_time == OPT3001_INT_TIME_SHORT) ?
281 			OPT3001_RESULT_READY_SHORT : OPT3001_RESULT_READY_LONG;
282 		msleep(timeout);
283 
284 		/* Check result ready flag */
285 		ret = i2c_smbus_read_word_swapped(opt->client,
286 						  OPT3001_CONFIGURATION);
287 		if (ret < 0) {
288 			dev_err(opt->dev, "failed to read register %02x\n",
289 				OPT3001_CONFIGURATION);
290 			goto err;
291 		}
292 
293 		if (!(ret & OPT3001_CONFIGURATION_CRF)) {
294 			ret = -ETIMEDOUT;
295 			goto err;
296 		}
297 
298 		/* Obtain value */
299 		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
300 		if (ret < 0) {
301 			dev_err(opt->dev, "failed to read register %02x\n",
302 				OPT3001_RESULT);
303 			goto err;
304 		}
305 		opt->result = ret;
306 		opt->result_ready = true;
307 	}
308 
309 err:
310 	if (opt->use_irq)
311 		/* Disallow IRQ to access the device while lock is active */
312 		opt->ok_to_ignore_lock = false;
313 
314 	if (ret == 0)
315 		return -ETIMEDOUT;
316 	else if (ret < 0)
317 		return ret;
318 
319 	if (opt->use_irq) {
320 		/*
321 		 * Disable the end-of-conversion interrupt mechanism by
322 		 * restoring the low-level limit value (clearing
323 		 * OPT3001_LOW_LIMIT_EOC_ENABLE). Note that selectively clearing
324 		 * those enable bits would affect the actual limit value due to
325 		 * bit-overlap and therefore can't be done.
326 		 */
327 		value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa;
328 		ret = i2c_smbus_write_word_swapped(opt->client,
329 						   OPT3001_LOW_LIMIT,
330 						   value);
331 		if (ret < 0) {
332 			dev_err(opt->dev, "failed to write register %02x\n",
333 					OPT3001_LOW_LIMIT);
334 			return ret;
335 		}
336 	}
337 
338 	exponent = OPT3001_REG_EXPONENT(opt->result);
339 	mantissa = OPT3001_REG_MANTISSA(opt->result);
340 
341 	opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);
342 
343 	return IIO_VAL_INT_PLUS_MICRO;
344 }
345 
346 static int opt3001_get_int_time(struct opt3001 *opt, int *val, int *val2)
347 {
348 	*val = 0;
349 	*val2 = opt->int_time;
350 
351 	return IIO_VAL_INT_PLUS_MICRO;
352 }
353 
354 static int opt3001_set_int_time(struct opt3001 *opt, int time)
355 {
356 	int ret;
357 	u16 reg;
358 
359 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
360 	if (ret < 0) {
361 		dev_err(opt->dev, "failed to read register %02x\n",
362 				OPT3001_CONFIGURATION);
363 		return ret;
364 	}
365 
366 	reg = ret;
367 
368 	switch (time) {
369 	case OPT3001_INT_TIME_SHORT:
370 		reg &= ~OPT3001_CONFIGURATION_CT;
371 		opt->int_time = OPT3001_INT_TIME_SHORT;
372 		break;
373 	case OPT3001_INT_TIME_LONG:
374 		reg |= OPT3001_CONFIGURATION_CT;
375 		opt->int_time = OPT3001_INT_TIME_LONG;
376 		break;
377 	default:
378 		return -EINVAL;
379 	}
380 
381 	return i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
382 			reg);
383 }
384 
385 static int opt3001_read_raw(struct iio_dev *iio,
386 		struct iio_chan_spec const *chan, int *val, int *val2,
387 		long mask)
388 {
389 	struct opt3001 *opt = iio_priv(iio);
390 	int ret;
391 
392 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
393 		return -EBUSY;
394 
395 	if (chan->type != IIO_LIGHT)
396 		return -EINVAL;
397 
398 	mutex_lock(&opt->lock);
399 
400 	switch (mask) {
401 	case IIO_CHAN_INFO_PROCESSED:
402 		ret = opt3001_get_lux(opt, val, val2);
403 		break;
404 	case IIO_CHAN_INFO_INT_TIME:
405 		ret = opt3001_get_int_time(opt, val, val2);
406 		break;
407 	default:
408 		ret = -EINVAL;
409 	}
410 
411 	mutex_unlock(&opt->lock);
412 
413 	return ret;
414 }
415 
416 static int opt3001_write_raw(struct iio_dev *iio,
417 		struct iio_chan_spec const *chan, int val, int val2,
418 		long mask)
419 {
420 	struct opt3001 *opt = iio_priv(iio);
421 	int ret;
422 
423 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
424 		return -EBUSY;
425 
426 	if (chan->type != IIO_LIGHT)
427 		return -EINVAL;
428 
429 	if (mask != IIO_CHAN_INFO_INT_TIME)
430 		return -EINVAL;
431 
432 	if (val != 0)
433 		return -EINVAL;
434 
435 	mutex_lock(&opt->lock);
436 	ret = opt3001_set_int_time(opt, val2);
437 	mutex_unlock(&opt->lock);
438 
439 	return ret;
440 }
441 
442 static int opt3001_read_event_value(struct iio_dev *iio,
443 		const struct iio_chan_spec *chan, enum iio_event_type type,
444 		enum iio_event_direction dir, enum iio_event_info info,
445 		int *val, int *val2)
446 {
447 	struct opt3001 *opt = iio_priv(iio);
448 	int ret = IIO_VAL_INT_PLUS_MICRO;
449 
450 	mutex_lock(&opt->lock);
451 
452 	switch (dir) {
453 	case IIO_EV_DIR_RISING:
454 		opt3001_to_iio_ret(opt, opt->high_thresh_exp,
455 				opt->high_thresh_mantissa, val, val2);
456 		break;
457 	case IIO_EV_DIR_FALLING:
458 		opt3001_to_iio_ret(opt, opt->low_thresh_exp,
459 				opt->low_thresh_mantissa, val, val2);
460 		break;
461 	default:
462 		ret = -EINVAL;
463 	}
464 
465 	mutex_unlock(&opt->lock);
466 
467 	return ret;
468 }
469 
470 static int opt3001_write_event_value(struct iio_dev *iio,
471 		const struct iio_chan_spec *chan, enum iio_event_type type,
472 		enum iio_event_direction dir, enum iio_event_info info,
473 		int val, int val2)
474 {
475 	struct opt3001 *opt = iio_priv(iio);
476 	int ret;
477 
478 	u16 mantissa;
479 	u16 value;
480 	u16 reg;
481 
482 	u8 exponent;
483 
484 	if (val < 0)
485 		return -EINVAL;
486 
487 	mutex_lock(&opt->lock);
488 
489 	ret = opt3001_find_scale(opt, val, val2, &exponent);
490 	if (ret < 0) {
491 		dev_err(opt->dev, "can't find scale for %d.%06u\n", val, val2);
492 		goto err;
493 	}
494 
495 	mantissa = (((val * 1000) + (val2 / 1000)) / 10) >> exponent;
496 	value = (exponent << 12) | mantissa;
497 
498 	switch (dir) {
499 	case IIO_EV_DIR_RISING:
500 		reg = OPT3001_HIGH_LIMIT;
501 		opt->high_thresh_mantissa = mantissa;
502 		opt->high_thresh_exp = exponent;
503 		break;
504 	case IIO_EV_DIR_FALLING:
505 		reg = OPT3001_LOW_LIMIT;
506 		opt->low_thresh_mantissa = mantissa;
507 		opt->low_thresh_exp = exponent;
508 		break;
509 	default:
510 		ret = -EINVAL;
511 		goto err;
512 	}
513 
514 	ret = i2c_smbus_write_word_swapped(opt->client, reg, value);
515 	if (ret < 0) {
516 		dev_err(opt->dev, "failed to write register %02x\n", reg);
517 		goto err;
518 	}
519 
520 err:
521 	mutex_unlock(&opt->lock);
522 
523 	return ret;
524 }
525 
526 static int opt3001_read_event_config(struct iio_dev *iio,
527 		const struct iio_chan_spec *chan, enum iio_event_type type,
528 		enum iio_event_direction dir)
529 {
530 	struct opt3001 *opt = iio_priv(iio);
531 
532 	return opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS;
533 }
534 
535 static int opt3001_write_event_config(struct iio_dev *iio,
536 		const struct iio_chan_spec *chan, enum iio_event_type type,
537 		enum iio_event_direction dir, int state)
538 {
539 	struct opt3001 *opt = iio_priv(iio);
540 	int ret;
541 	u16 mode;
542 	u16 reg;
543 
544 	if (state && opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
545 		return 0;
546 
547 	if (!state && opt->mode == OPT3001_CONFIGURATION_M_SHUTDOWN)
548 		return 0;
549 
550 	mutex_lock(&opt->lock);
551 
552 	mode = state ? OPT3001_CONFIGURATION_M_CONTINUOUS
553 		: OPT3001_CONFIGURATION_M_SHUTDOWN;
554 
555 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
556 	if (ret < 0) {
557 		dev_err(opt->dev, "failed to read register %02x\n",
558 				OPT3001_CONFIGURATION);
559 		goto err;
560 	}
561 
562 	reg = ret;
563 	opt3001_set_mode(opt, &reg, mode);
564 
565 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
566 			reg);
567 	if (ret < 0) {
568 		dev_err(opt->dev, "failed to write register %02x\n",
569 				OPT3001_CONFIGURATION);
570 		goto err;
571 	}
572 
573 err:
574 	mutex_unlock(&opt->lock);
575 
576 	return ret;
577 }
578 
579 static const struct iio_info opt3001_info = {
580 	.attrs = &opt3001_attribute_group,
581 	.read_raw = opt3001_read_raw,
582 	.write_raw = opt3001_write_raw,
583 	.read_event_value = opt3001_read_event_value,
584 	.write_event_value = opt3001_write_event_value,
585 	.read_event_config = opt3001_read_event_config,
586 	.write_event_config = opt3001_write_event_config,
587 };
588 
589 static int opt3001_read_id(struct opt3001 *opt)
590 {
591 	char manufacturer[2];
592 	u16 device_id;
593 	int ret;
594 
595 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_MANUFACTURER_ID);
596 	if (ret < 0) {
597 		dev_err(opt->dev, "failed to read register %02x\n",
598 				OPT3001_MANUFACTURER_ID);
599 		return ret;
600 	}
601 
602 	manufacturer[0] = ret >> 8;
603 	manufacturer[1] = ret & 0xff;
604 
605 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_DEVICE_ID);
606 	if (ret < 0) {
607 		dev_err(opt->dev, "failed to read register %02x\n",
608 				OPT3001_DEVICE_ID);
609 		return ret;
610 	}
611 
612 	device_id = ret;
613 
614 	dev_info(opt->dev, "Found %c%c OPT%04x\n", manufacturer[0],
615 			manufacturer[1], device_id);
616 
617 	return 0;
618 }
619 
620 static int opt3001_configure(struct opt3001 *opt)
621 {
622 	int ret;
623 	u16 reg;
624 
625 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
626 	if (ret < 0) {
627 		dev_err(opt->dev, "failed to read register %02x\n",
628 				OPT3001_CONFIGURATION);
629 		return ret;
630 	}
631 
632 	reg = ret;
633 
634 	/* Enable automatic full-scale setting mode */
635 	reg &= ~OPT3001_CONFIGURATION_RN_MASK;
636 	reg |= OPT3001_CONFIGURATION_RN_AUTO;
637 
638 	/* Reflect status of the device's integration time setting */
639 	if (reg & OPT3001_CONFIGURATION_CT)
640 		opt->int_time = OPT3001_INT_TIME_LONG;
641 	else
642 		opt->int_time = OPT3001_INT_TIME_SHORT;
643 
644 	/* Ensure device is in shutdown initially */
645 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
646 
647 	/* Configure for latched window-style comparison operation */
648 	reg |= OPT3001_CONFIGURATION_L;
649 	reg &= ~OPT3001_CONFIGURATION_POL;
650 	reg &= ~OPT3001_CONFIGURATION_ME;
651 	reg &= ~OPT3001_CONFIGURATION_FC_MASK;
652 
653 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
654 			reg);
655 	if (ret < 0) {
656 		dev_err(opt->dev, "failed to write register %02x\n",
657 				OPT3001_CONFIGURATION);
658 		return ret;
659 	}
660 
661 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_LOW_LIMIT);
662 	if (ret < 0) {
663 		dev_err(opt->dev, "failed to read register %02x\n",
664 				OPT3001_LOW_LIMIT);
665 		return ret;
666 	}
667 
668 	opt->low_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
669 	opt->low_thresh_exp = OPT3001_REG_EXPONENT(ret);
670 
671 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_HIGH_LIMIT);
672 	if (ret < 0) {
673 		dev_err(opt->dev, "failed to read register %02x\n",
674 				OPT3001_HIGH_LIMIT);
675 		return ret;
676 	}
677 
678 	opt->high_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
679 	opt->high_thresh_exp = OPT3001_REG_EXPONENT(ret);
680 
681 	return 0;
682 }
683 
684 static irqreturn_t opt3001_irq(int irq, void *_iio)
685 {
686 	struct iio_dev *iio = _iio;
687 	struct opt3001 *opt = iio_priv(iio);
688 	int ret;
689 	bool wake_result_ready_queue = false;
690 
691 	if (!opt->ok_to_ignore_lock)
692 		mutex_lock(&opt->lock);
693 
694 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
695 	if (ret < 0) {
696 		dev_err(opt->dev, "failed to read register %02x\n",
697 				OPT3001_CONFIGURATION);
698 		goto out;
699 	}
700 
701 	if ((ret & OPT3001_CONFIGURATION_M_MASK) ==
702 			OPT3001_CONFIGURATION_M_CONTINUOUS) {
703 		if (ret & OPT3001_CONFIGURATION_FH)
704 			iio_push_event(iio,
705 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
706 							IIO_EV_TYPE_THRESH,
707 							IIO_EV_DIR_RISING),
708 					iio_get_time_ns(iio));
709 		if (ret & OPT3001_CONFIGURATION_FL)
710 			iio_push_event(iio,
711 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
712 							IIO_EV_TYPE_THRESH,
713 							IIO_EV_DIR_FALLING),
714 					iio_get_time_ns(iio));
715 	} else if (ret & OPT3001_CONFIGURATION_CRF) {
716 		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
717 		if (ret < 0) {
718 			dev_err(opt->dev, "failed to read register %02x\n",
719 					OPT3001_RESULT);
720 			goto out;
721 		}
722 		opt->result = ret;
723 		opt->result_ready = true;
724 		wake_result_ready_queue = true;
725 	}
726 
727 out:
728 	if (!opt->ok_to_ignore_lock)
729 		mutex_unlock(&opt->lock);
730 
731 	if (wake_result_ready_queue)
732 		wake_up(&opt->result_ready_queue);
733 
734 	return IRQ_HANDLED;
735 }
736 
737 static int opt3001_probe(struct i2c_client *client,
738 		const struct i2c_device_id *id)
739 {
740 	struct device *dev = &client->dev;
741 
742 	struct iio_dev *iio;
743 	struct opt3001 *opt;
744 	int irq = client->irq;
745 	int ret;
746 
747 	iio = devm_iio_device_alloc(dev, sizeof(*opt));
748 	if (!iio)
749 		return -ENOMEM;
750 
751 	opt = iio_priv(iio);
752 	opt->client = client;
753 	opt->dev = dev;
754 
755 	mutex_init(&opt->lock);
756 	init_waitqueue_head(&opt->result_ready_queue);
757 	i2c_set_clientdata(client, iio);
758 
759 	ret = opt3001_read_id(opt);
760 	if (ret)
761 		return ret;
762 
763 	ret = opt3001_configure(opt);
764 	if (ret)
765 		return ret;
766 
767 	iio->name = client->name;
768 	iio->channels = opt3001_channels;
769 	iio->num_channels = ARRAY_SIZE(opt3001_channels);
770 	iio->dev.parent = dev;
771 	iio->modes = INDIO_DIRECT_MODE;
772 	iio->info = &opt3001_info;
773 
774 	ret = devm_iio_device_register(dev, iio);
775 	if (ret) {
776 		dev_err(dev, "failed to register IIO device\n");
777 		return ret;
778 	}
779 
780 	/* Make use of INT pin only if valid IRQ no. is given */
781 	if (irq > 0) {
782 		ret = request_threaded_irq(irq, NULL, opt3001_irq,
783 				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
784 				"opt3001", iio);
785 		if (ret) {
786 			dev_err(dev, "failed to request IRQ #%d\n", irq);
787 			return ret;
788 		}
789 		opt->use_irq = true;
790 	} else {
791 		dev_dbg(opt->dev, "enabling interrupt-less operation\n");
792 	}
793 
794 	return 0;
795 }
796 
797 static int opt3001_remove(struct i2c_client *client)
798 {
799 	struct iio_dev *iio = i2c_get_clientdata(client);
800 	struct opt3001 *opt = iio_priv(iio);
801 	int ret;
802 	u16 reg;
803 
804 	if (opt->use_irq)
805 		free_irq(client->irq, iio);
806 
807 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
808 	if (ret < 0) {
809 		dev_err(opt->dev, "failed to read register %02x\n",
810 				OPT3001_CONFIGURATION);
811 		return ret;
812 	}
813 
814 	reg = ret;
815 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
816 
817 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
818 			reg);
819 	if (ret < 0) {
820 		dev_err(opt->dev, "failed to write register %02x\n",
821 				OPT3001_CONFIGURATION);
822 		return ret;
823 	}
824 
825 	return 0;
826 }
827 
828 static const struct i2c_device_id opt3001_id[] = {
829 	{ "opt3001", 0 },
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 = of_match_ptr(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