xref: /openbmc/linux/drivers/iio/light/opt3001.c (revision 77423a62)
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 = 83865,
143 		.val2 = 600000,
144 	},
145 };
146 
147 static int opt3001_find_scale(const struct opt3001 *opt, int val,
148 		int val2, u8 *exponent)
149 {
150 	int i;
151 
152 	for (i = 0; i < ARRAY_SIZE(opt3001_scales); i++) {
153 		const struct opt3001_scale *scale = &opt3001_scales[i];
154 
155 		/*
156 		 * Combine the integer and micro parts for comparison
157 		 * purposes. Use milli lux precision to avoid 32-bit integer
158 		 * overflows.
159 		 */
160 		if ((val * 1000 + val2 / 1000) <=
161 				(scale->val * 1000 + scale->val2 / 1000)) {
162 			*exponent = i;
163 			return 0;
164 		}
165 	}
166 
167 	return -EINVAL;
168 }
169 
170 static void opt3001_to_iio_ret(struct opt3001 *opt, u8 exponent,
171 		u16 mantissa, int *val, int *val2)
172 {
173 	int lux;
174 
175 	lux = 10 * (mantissa << exponent);
176 	*val = lux / 1000;
177 	*val2 = (lux - (*val * 1000)) * 1000;
178 }
179 
180 static void opt3001_set_mode(struct opt3001 *opt, u16 *reg, u16 mode)
181 {
182 	*reg &= ~OPT3001_CONFIGURATION_M_MASK;
183 	*reg |= mode;
184 	opt->mode = mode;
185 }
186 
187 static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.8");
188 
189 static struct attribute *opt3001_attributes[] = {
190 	&iio_const_attr_integration_time_available.dev_attr.attr,
191 	NULL
192 };
193 
194 static const struct attribute_group opt3001_attribute_group = {
195 	.attrs = opt3001_attributes,
196 };
197 
198 static const struct iio_event_spec opt3001_event_spec[] = {
199 	{
200 		.type = IIO_EV_TYPE_THRESH,
201 		.dir = IIO_EV_DIR_RISING,
202 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
203 			BIT(IIO_EV_INFO_ENABLE),
204 	},
205 	{
206 		.type = IIO_EV_TYPE_THRESH,
207 		.dir = IIO_EV_DIR_FALLING,
208 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
209 			BIT(IIO_EV_INFO_ENABLE),
210 	},
211 };
212 
213 static const struct iio_chan_spec opt3001_channels[] = {
214 	{
215 		.type = IIO_LIGHT,
216 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
217 				BIT(IIO_CHAN_INFO_INT_TIME),
218 		.event_spec = opt3001_event_spec,
219 		.num_event_specs = ARRAY_SIZE(opt3001_event_spec),
220 	},
221 	IIO_CHAN_SOFT_TIMESTAMP(1),
222 };
223 
224 static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2)
225 {
226 	int ret;
227 	u16 mantissa;
228 	u16 reg;
229 	u8 exponent;
230 	u16 value;
231 	long timeout;
232 
233 	if (opt->use_irq) {
234 		/*
235 		 * Enable the end-of-conversion interrupt mechanism. Note that
236 		 * doing so will overwrite the low-level limit value however we
237 		 * will restore this value later on.
238 		 */
239 		ret = i2c_smbus_write_word_swapped(opt->client,
240 					OPT3001_LOW_LIMIT,
241 					OPT3001_LOW_LIMIT_EOC_ENABLE);
242 		if (ret < 0) {
243 			dev_err(opt->dev, "failed to write register %02x\n",
244 					OPT3001_LOW_LIMIT);
245 			return ret;
246 		}
247 
248 		/* Allow IRQ to access the device despite lock being set */
249 		opt->ok_to_ignore_lock = true;
250 	}
251 
252 	/* Reset data-ready indicator flag */
253 	opt->result_ready = false;
254 
255 	/* Configure for single-conversion mode and start a new conversion */
256 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
257 	if (ret < 0) {
258 		dev_err(opt->dev, "failed to read register %02x\n",
259 				OPT3001_CONFIGURATION);
260 		goto err;
261 	}
262 
263 	reg = ret;
264 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SINGLE);
265 
266 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
267 			reg);
268 	if (ret < 0) {
269 		dev_err(opt->dev, "failed to write register %02x\n",
270 				OPT3001_CONFIGURATION);
271 		goto err;
272 	}
273 
274 	if (opt->use_irq) {
275 		/* Wait for the IRQ to indicate the conversion is complete */
276 		ret = wait_event_timeout(opt->result_ready_queue,
277 				opt->result_ready,
278 				msecs_to_jiffies(OPT3001_RESULT_READY_LONG));
279 		if (ret == 0)
280 			return -ETIMEDOUT;
281 	} else {
282 		/* Sleep for result ready time */
283 		timeout = (opt->int_time == OPT3001_INT_TIME_SHORT) ?
284 			OPT3001_RESULT_READY_SHORT : OPT3001_RESULT_READY_LONG;
285 		msleep(timeout);
286 
287 		/* Check result ready flag */
288 		ret = i2c_smbus_read_word_swapped(opt->client,
289 						  OPT3001_CONFIGURATION);
290 		if (ret < 0) {
291 			dev_err(opt->dev, "failed to read register %02x\n",
292 				OPT3001_CONFIGURATION);
293 			goto err;
294 		}
295 
296 		if (!(ret & OPT3001_CONFIGURATION_CRF)) {
297 			ret = -ETIMEDOUT;
298 			goto err;
299 		}
300 
301 		/* Obtain value */
302 		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
303 		if (ret < 0) {
304 			dev_err(opt->dev, "failed to read register %02x\n",
305 				OPT3001_RESULT);
306 			goto err;
307 		}
308 		opt->result = ret;
309 		opt->result_ready = true;
310 	}
311 
312 err:
313 	if (opt->use_irq)
314 		/* Disallow IRQ to access the device while lock is active */
315 		opt->ok_to_ignore_lock = false;
316 
317 	if (ret < 0)
318 		return ret;
319 
320 	if (opt->use_irq) {
321 		/*
322 		 * Disable the end-of-conversion interrupt mechanism by
323 		 * restoring the low-level limit value (clearing
324 		 * OPT3001_LOW_LIMIT_EOC_ENABLE). Note that selectively clearing
325 		 * those enable bits would affect the actual limit value due to
326 		 * bit-overlap and therefore can't be done.
327 		 */
328 		value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa;
329 		ret = i2c_smbus_write_word_swapped(opt->client,
330 						   OPT3001_LOW_LIMIT,
331 						   value);
332 		if (ret < 0) {
333 			dev_err(opt->dev, "failed to write register %02x\n",
334 					OPT3001_LOW_LIMIT);
335 			return ret;
336 		}
337 	}
338 
339 	exponent = OPT3001_REG_EXPONENT(opt->result);
340 	mantissa = OPT3001_REG_MANTISSA(opt->result);
341 
342 	opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);
343 
344 	return IIO_VAL_INT_PLUS_MICRO;
345 }
346 
347 static int opt3001_get_int_time(struct opt3001 *opt, int *val, int *val2)
348 {
349 	*val = 0;
350 	*val2 = opt->int_time;
351 
352 	return IIO_VAL_INT_PLUS_MICRO;
353 }
354 
355 static int opt3001_set_int_time(struct opt3001 *opt, int time)
356 {
357 	int ret;
358 	u16 reg;
359 
360 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
361 	if (ret < 0) {
362 		dev_err(opt->dev, "failed to read register %02x\n",
363 				OPT3001_CONFIGURATION);
364 		return ret;
365 	}
366 
367 	reg = ret;
368 
369 	switch (time) {
370 	case OPT3001_INT_TIME_SHORT:
371 		reg &= ~OPT3001_CONFIGURATION_CT;
372 		opt->int_time = OPT3001_INT_TIME_SHORT;
373 		break;
374 	case OPT3001_INT_TIME_LONG:
375 		reg |= OPT3001_CONFIGURATION_CT;
376 		opt->int_time = OPT3001_INT_TIME_LONG;
377 		break;
378 	default:
379 		return -EINVAL;
380 	}
381 
382 	return i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
383 			reg);
384 }
385 
386 static int opt3001_read_raw(struct iio_dev *iio,
387 		struct iio_chan_spec const *chan, int *val, int *val2,
388 		long mask)
389 {
390 	struct opt3001 *opt = iio_priv(iio);
391 	int ret;
392 
393 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
394 		return -EBUSY;
395 
396 	if (chan->type != IIO_LIGHT)
397 		return -EINVAL;
398 
399 	mutex_lock(&opt->lock);
400 
401 	switch (mask) {
402 	case IIO_CHAN_INFO_PROCESSED:
403 		ret = opt3001_get_lux(opt, val, val2);
404 		break;
405 	case IIO_CHAN_INFO_INT_TIME:
406 		ret = opt3001_get_int_time(opt, val, val2);
407 		break;
408 	default:
409 		ret = -EINVAL;
410 	}
411 
412 	mutex_unlock(&opt->lock);
413 
414 	return ret;
415 }
416 
417 static int opt3001_write_raw(struct iio_dev *iio,
418 		struct iio_chan_spec const *chan, int val, int val2,
419 		long mask)
420 {
421 	struct opt3001 *opt = iio_priv(iio);
422 	int ret;
423 
424 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
425 		return -EBUSY;
426 
427 	if (chan->type != IIO_LIGHT)
428 		return -EINVAL;
429 
430 	if (mask != IIO_CHAN_INFO_INT_TIME)
431 		return -EINVAL;
432 
433 	if (val != 0)
434 		return -EINVAL;
435 
436 	mutex_lock(&opt->lock);
437 	ret = opt3001_set_int_time(opt, val2);
438 	mutex_unlock(&opt->lock);
439 
440 	return ret;
441 }
442 
443 static int opt3001_read_event_value(struct iio_dev *iio,
444 		const struct iio_chan_spec *chan, enum iio_event_type type,
445 		enum iio_event_direction dir, enum iio_event_info info,
446 		int *val, int *val2)
447 {
448 	struct opt3001 *opt = iio_priv(iio);
449 	int ret = IIO_VAL_INT_PLUS_MICRO;
450 
451 	mutex_lock(&opt->lock);
452 
453 	switch (dir) {
454 	case IIO_EV_DIR_RISING:
455 		opt3001_to_iio_ret(opt, opt->high_thresh_exp,
456 				opt->high_thresh_mantissa, val, val2);
457 		break;
458 	case IIO_EV_DIR_FALLING:
459 		opt3001_to_iio_ret(opt, opt->low_thresh_exp,
460 				opt->low_thresh_mantissa, val, val2);
461 		break;
462 	default:
463 		ret = -EINVAL;
464 	}
465 
466 	mutex_unlock(&opt->lock);
467 
468 	return ret;
469 }
470 
471 static int opt3001_write_event_value(struct iio_dev *iio,
472 		const struct iio_chan_spec *chan, enum iio_event_type type,
473 		enum iio_event_direction dir, enum iio_event_info info,
474 		int val, int val2)
475 {
476 	struct opt3001 *opt = iio_priv(iio);
477 	int ret;
478 
479 	u16 mantissa;
480 	u16 value;
481 	u16 reg;
482 
483 	u8 exponent;
484 
485 	if (val < 0)
486 		return -EINVAL;
487 
488 	mutex_lock(&opt->lock);
489 
490 	ret = opt3001_find_scale(opt, val, val2, &exponent);
491 	if (ret < 0) {
492 		dev_err(opt->dev, "can't find scale for %d.%06u\n", val, val2);
493 		goto err;
494 	}
495 
496 	mantissa = (((val * 1000) + (val2 / 1000)) / 10) >> exponent;
497 	value = (exponent << 12) | mantissa;
498 
499 	switch (dir) {
500 	case IIO_EV_DIR_RISING:
501 		reg = OPT3001_HIGH_LIMIT;
502 		opt->high_thresh_mantissa = mantissa;
503 		opt->high_thresh_exp = exponent;
504 		break;
505 	case IIO_EV_DIR_FALLING:
506 		reg = OPT3001_LOW_LIMIT;
507 		opt->low_thresh_mantissa = mantissa;
508 		opt->low_thresh_exp = exponent;
509 		break;
510 	default:
511 		ret = -EINVAL;
512 		goto err;
513 	}
514 
515 	ret = i2c_smbus_write_word_swapped(opt->client, reg, value);
516 	if (ret < 0) {
517 		dev_err(opt->dev, "failed to write register %02x\n", reg);
518 		goto err;
519 	}
520 
521 err:
522 	mutex_unlock(&opt->lock);
523 
524 	return ret;
525 }
526 
527 static int opt3001_read_event_config(struct iio_dev *iio,
528 		const struct iio_chan_spec *chan, enum iio_event_type type,
529 		enum iio_event_direction dir)
530 {
531 	struct opt3001 *opt = iio_priv(iio);
532 
533 	return opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS;
534 }
535 
536 static int opt3001_write_event_config(struct iio_dev *iio,
537 		const struct iio_chan_spec *chan, enum iio_event_type type,
538 		enum iio_event_direction dir, int state)
539 {
540 	struct opt3001 *opt = iio_priv(iio);
541 	int ret;
542 	u16 mode;
543 	u16 reg;
544 
545 	if (state && opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
546 		return 0;
547 
548 	if (!state && opt->mode == OPT3001_CONFIGURATION_M_SHUTDOWN)
549 		return 0;
550 
551 	mutex_lock(&opt->lock);
552 
553 	mode = state ? OPT3001_CONFIGURATION_M_CONTINUOUS
554 		: OPT3001_CONFIGURATION_M_SHUTDOWN;
555 
556 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
557 	if (ret < 0) {
558 		dev_err(opt->dev, "failed to read register %02x\n",
559 				OPT3001_CONFIGURATION);
560 		goto err;
561 	}
562 
563 	reg = ret;
564 	opt3001_set_mode(opt, &reg, mode);
565 
566 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
567 			reg);
568 	if (ret < 0) {
569 		dev_err(opt->dev, "failed to write register %02x\n",
570 				OPT3001_CONFIGURATION);
571 		goto err;
572 	}
573 
574 err:
575 	mutex_unlock(&opt->lock);
576 
577 	return ret;
578 }
579 
580 static const struct iio_info opt3001_info = {
581 	.attrs = &opt3001_attribute_group,
582 	.read_raw = opt3001_read_raw,
583 	.write_raw = opt3001_write_raw,
584 	.read_event_value = opt3001_read_event_value,
585 	.write_event_value = opt3001_write_event_value,
586 	.read_event_config = opt3001_read_event_config,
587 	.write_event_config = opt3001_write_event_config,
588 };
589 
590 static int opt3001_read_id(struct opt3001 *opt)
591 {
592 	char manufacturer[2];
593 	u16 device_id;
594 	int ret;
595 
596 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_MANUFACTURER_ID);
597 	if (ret < 0) {
598 		dev_err(opt->dev, "failed to read register %02x\n",
599 				OPT3001_MANUFACTURER_ID);
600 		return ret;
601 	}
602 
603 	manufacturer[0] = ret >> 8;
604 	manufacturer[1] = ret & 0xff;
605 
606 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_DEVICE_ID);
607 	if (ret < 0) {
608 		dev_err(opt->dev, "failed to read register %02x\n",
609 				OPT3001_DEVICE_ID);
610 		return ret;
611 	}
612 
613 	device_id = ret;
614 
615 	dev_info(opt->dev, "Found %c%c OPT%04x\n", manufacturer[0],
616 			manufacturer[1], device_id);
617 
618 	return 0;
619 }
620 
621 static int opt3001_configure(struct opt3001 *opt)
622 {
623 	int ret;
624 	u16 reg;
625 
626 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
627 	if (ret < 0) {
628 		dev_err(opt->dev, "failed to read register %02x\n",
629 				OPT3001_CONFIGURATION);
630 		return ret;
631 	}
632 
633 	reg = ret;
634 
635 	/* Enable automatic full-scale setting mode */
636 	reg &= ~OPT3001_CONFIGURATION_RN_MASK;
637 	reg |= OPT3001_CONFIGURATION_RN_AUTO;
638 
639 	/* Reflect status of the device's integration time setting */
640 	if (reg & OPT3001_CONFIGURATION_CT)
641 		opt->int_time = OPT3001_INT_TIME_LONG;
642 	else
643 		opt->int_time = OPT3001_INT_TIME_SHORT;
644 
645 	/* Ensure device is in shutdown initially */
646 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
647 
648 	/* Configure for latched window-style comparison operation */
649 	reg |= OPT3001_CONFIGURATION_L;
650 	reg &= ~OPT3001_CONFIGURATION_POL;
651 	reg &= ~OPT3001_CONFIGURATION_ME;
652 	reg &= ~OPT3001_CONFIGURATION_FC_MASK;
653 
654 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
655 			reg);
656 	if (ret < 0) {
657 		dev_err(opt->dev, "failed to write register %02x\n",
658 				OPT3001_CONFIGURATION);
659 		return ret;
660 	}
661 
662 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_LOW_LIMIT);
663 	if (ret < 0) {
664 		dev_err(opt->dev, "failed to read register %02x\n",
665 				OPT3001_LOW_LIMIT);
666 		return ret;
667 	}
668 
669 	opt->low_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
670 	opt->low_thresh_exp = OPT3001_REG_EXPONENT(ret);
671 
672 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_HIGH_LIMIT);
673 	if (ret < 0) {
674 		dev_err(opt->dev, "failed to read register %02x\n",
675 				OPT3001_HIGH_LIMIT);
676 		return ret;
677 	}
678 
679 	opt->high_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
680 	opt->high_thresh_exp = OPT3001_REG_EXPONENT(ret);
681 
682 	return 0;
683 }
684 
685 static irqreturn_t opt3001_irq(int irq, void *_iio)
686 {
687 	struct iio_dev *iio = _iio;
688 	struct opt3001 *opt = iio_priv(iio);
689 	int ret;
690 	bool wake_result_ready_queue = false;
691 
692 	if (!opt->ok_to_ignore_lock)
693 		mutex_lock(&opt->lock);
694 
695 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
696 	if (ret < 0) {
697 		dev_err(opt->dev, "failed to read register %02x\n",
698 				OPT3001_CONFIGURATION);
699 		goto out;
700 	}
701 
702 	if ((ret & OPT3001_CONFIGURATION_M_MASK) ==
703 			OPT3001_CONFIGURATION_M_CONTINUOUS) {
704 		if (ret & OPT3001_CONFIGURATION_FH)
705 			iio_push_event(iio,
706 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
707 							IIO_EV_TYPE_THRESH,
708 							IIO_EV_DIR_RISING),
709 					iio_get_time_ns(iio));
710 		if (ret & OPT3001_CONFIGURATION_FL)
711 			iio_push_event(iio,
712 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
713 							IIO_EV_TYPE_THRESH,
714 							IIO_EV_DIR_FALLING),
715 					iio_get_time_ns(iio));
716 	} else if (ret & OPT3001_CONFIGURATION_CRF) {
717 		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
718 		if (ret < 0) {
719 			dev_err(opt->dev, "failed to read register %02x\n",
720 					OPT3001_RESULT);
721 			goto out;
722 		}
723 		opt->result = ret;
724 		opt->result_ready = true;
725 		wake_result_ready_queue = true;
726 	}
727 
728 out:
729 	if (!opt->ok_to_ignore_lock)
730 		mutex_unlock(&opt->lock);
731 
732 	if (wake_result_ready_queue)
733 		wake_up(&opt->result_ready_queue);
734 
735 	return IRQ_HANDLED;
736 }
737 
738 static int opt3001_probe(struct i2c_client *client,
739 		const struct i2c_device_id *id)
740 {
741 	struct device *dev = &client->dev;
742 
743 	struct iio_dev *iio;
744 	struct opt3001 *opt;
745 	int irq = client->irq;
746 	int ret;
747 
748 	iio = devm_iio_device_alloc(dev, sizeof(*opt));
749 	if (!iio)
750 		return -ENOMEM;
751 
752 	opt = iio_priv(iio);
753 	opt->client = client;
754 	opt->dev = dev;
755 
756 	mutex_init(&opt->lock);
757 	init_waitqueue_head(&opt->result_ready_queue);
758 	i2c_set_clientdata(client, iio);
759 
760 	ret = opt3001_read_id(opt);
761 	if (ret)
762 		return ret;
763 
764 	ret = opt3001_configure(opt);
765 	if (ret)
766 		return ret;
767 
768 	iio->name = client->name;
769 	iio->channels = opt3001_channels;
770 	iio->num_channels = ARRAY_SIZE(opt3001_channels);
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 0;
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 	}
823 
824 	return 0;
825 }
826 
827 static const struct i2c_device_id opt3001_id[] = {
828 	{ "opt3001", 0 },
829 	{ } /* Terminating Entry */
830 };
831 MODULE_DEVICE_TABLE(i2c, opt3001_id);
832 
833 static const struct of_device_id opt3001_of_match[] = {
834 	{ .compatible = "ti,opt3001" },
835 	{ }
836 };
837 MODULE_DEVICE_TABLE(of, opt3001_of_match);
838 
839 static struct i2c_driver opt3001_driver = {
840 	.probe = opt3001_probe,
841 	.remove = opt3001_remove,
842 	.id_table = opt3001_id,
843 
844 	.driver = {
845 		.name = "opt3001",
846 		.of_match_table = opt3001_of_match,
847 	},
848 };
849 
850 module_i2c_driver(opt3001_driver);
851 
852 MODULE_LICENSE("GPL v2");
853 MODULE_AUTHOR("Andreas Dannenberg <dannenberg@ti.com>");
854 MODULE_DESCRIPTION("Texas Instruments OPT3001 Light Sensor Driver");
855