xref: /openbmc/linux/drivers/iio/light/opt3001.c (revision b96fc2f3)
1 /**
2  * opt3001.c - Texas Instruments OPT3001 Light Sensor
3  *
4  * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
5  *
6  * Author: Andreas Dannenberg <dannenberg@ti.com>
7  * Based on previous work from: Felipe Balbi <balbi@ti.com>
8  *
9  * This program is free software: you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License version 2 of the License
11  * as published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but WITHOUT
14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
16  * more details.
17  */
18 
19 #include <linux/bitops.h>
20 #include <linux/delay.h>
21 #include <linux/device.h>
22 #include <linux/i2c.h>
23 #include <linux/interrupt.h>
24 #include <linux/irq.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/mutex.h>
28 #include <linux/slab.h>
29 #include <linux/types.h>
30 
31 #include <linux/iio/events.h>
32 #include <linux/iio/iio.h>
33 #include <linux/iio/sysfs.h>
34 
35 #define OPT3001_RESULT		0x00
36 #define OPT3001_CONFIGURATION	0x01
37 #define OPT3001_LOW_LIMIT	0x02
38 #define OPT3001_HIGH_LIMIT	0x03
39 #define OPT3001_MANUFACTURER_ID	0x7e
40 #define OPT3001_DEVICE_ID	0x7f
41 
42 #define OPT3001_CONFIGURATION_RN_MASK	(0xf << 12)
43 #define OPT3001_CONFIGURATION_RN_AUTO	(0xc << 12)
44 
45 #define OPT3001_CONFIGURATION_CT	BIT(11)
46 
47 #define OPT3001_CONFIGURATION_M_MASK	(3 << 9)
48 #define OPT3001_CONFIGURATION_M_SHUTDOWN (0 << 9)
49 #define OPT3001_CONFIGURATION_M_SINGLE	(1 << 9)
50 #define OPT3001_CONFIGURATION_M_CONTINUOUS (2 << 9) /* also 3 << 9 */
51 
52 #define OPT3001_CONFIGURATION_OVF	BIT(8)
53 #define OPT3001_CONFIGURATION_CRF	BIT(7)
54 #define OPT3001_CONFIGURATION_FH	BIT(6)
55 #define OPT3001_CONFIGURATION_FL	BIT(5)
56 #define OPT3001_CONFIGURATION_L		BIT(4)
57 #define OPT3001_CONFIGURATION_POL	BIT(3)
58 #define OPT3001_CONFIGURATION_ME	BIT(2)
59 
60 #define OPT3001_CONFIGURATION_FC_MASK	(3 << 0)
61 
62 /* The end-of-conversion enable is located in the low-limit register */
63 #define OPT3001_LOW_LIMIT_EOC_ENABLE	0xc000
64 
65 #define OPT3001_REG_EXPONENT(n)		((n) >> 12)
66 #define OPT3001_REG_MANTISSA(n)		((n) & 0xfff)
67 
68 /*
69  * Time to wait for conversion result to be ready. The device datasheet
70  * worst-case max value is 880ms. Add some slack to be on the safe side.
71  */
72 #define OPT3001_RESULT_READY_TIMEOUT	msecs_to_jiffies(1000)
73 
74 struct opt3001 {
75 	struct i2c_client	*client;
76 	struct device		*dev;
77 
78 	struct mutex		lock;
79 	u16			ok_to_ignore_lock:1;
80 	u16			result_ready:1;
81 	wait_queue_head_t	result_ready_queue;
82 	u16			result;
83 
84 	u32			int_time;
85 	u32			mode;
86 
87 	u16			high_thresh_mantissa;
88 	u16			low_thresh_mantissa;
89 
90 	u8			high_thresh_exp;
91 	u8			low_thresh_exp;
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 
231 	/*
232 	 * Enable the end-of-conversion interrupt mechanism. Note that doing
233 	 * so will overwrite the low-level limit value however we will restore
234 	 * this value later on.
235 	 */
236 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_LOW_LIMIT,
237 			OPT3001_LOW_LIMIT_EOC_ENABLE);
238 	if (ret < 0) {
239 		dev_err(opt->dev, "failed to write register %02x\n",
240 				OPT3001_LOW_LIMIT);
241 		return ret;
242 	}
243 
244 	/* Reset data-ready indicator flag (will be set in the IRQ routine) */
245 	opt->result_ready = false;
246 
247 	/* Allow IRQ to access the device despite lock being set */
248 	opt->ok_to_ignore_lock = true;
249 
250 	/* Configure for single-conversion mode and start a new conversion */
251 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
252 	if (ret < 0) {
253 		dev_err(opt->dev, "failed to read register %02x\n",
254 				OPT3001_CONFIGURATION);
255 		goto err;
256 	}
257 
258 	reg = ret;
259 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SINGLE);
260 
261 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
262 			reg);
263 	if (ret < 0) {
264 		dev_err(opt->dev, "failed to write register %02x\n",
265 				OPT3001_CONFIGURATION);
266 		goto err;
267 	}
268 
269 	/* Wait for the IRQ to indicate the conversion is complete */
270 	ret = wait_event_timeout(opt->result_ready_queue, opt->result_ready,
271 			OPT3001_RESULT_READY_TIMEOUT);
272 
273 err:
274 	/* Disallow IRQ to access the device while lock is active */
275 	opt->ok_to_ignore_lock = false;
276 
277 	if (ret == 0)
278 		return -ETIMEDOUT;
279 	else if (ret < 0)
280 		return ret;
281 
282 	/*
283 	 * Disable the end-of-conversion interrupt mechanism by restoring the
284 	 * low-level limit value (clearing OPT3001_LOW_LIMIT_EOC_ENABLE). Note
285 	 * that selectively clearing those enable bits would affect the actual
286 	 * limit value due to bit-overlap and therefore can't be done.
287 	 */
288 	value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa;
289 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_LOW_LIMIT,
290 			value);
291 	if (ret < 0) {
292 		dev_err(opt->dev, "failed to write register %02x\n",
293 				OPT3001_LOW_LIMIT);
294 		return ret;
295 	}
296 
297 	exponent = OPT3001_REG_EXPONENT(opt->result);
298 	mantissa = OPT3001_REG_MANTISSA(opt->result);
299 
300 	opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);
301 
302 	return IIO_VAL_INT_PLUS_MICRO;
303 }
304 
305 static int opt3001_get_int_time(struct opt3001 *opt, int *val, int *val2)
306 {
307 	*val = 0;
308 	*val2 = opt->int_time;
309 
310 	return IIO_VAL_INT_PLUS_MICRO;
311 }
312 
313 static int opt3001_set_int_time(struct opt3001 *opt, int time)
314 {
315 	int ret;
316 	u16 reg;
317 
318 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
319 	if (ret < 0) {
320 		dev_err(opt->dev, "failed to read register %02x\n",
321 				OPT3001_CONFIGURATION);
322 		return ret;
323 	}
324 
325 	reg = ret;
326 
327 	switch (time) {
328 	case 100000:
329 		reg &= ~OPT3001_CONFIGURATION_CT;
330 		opt->int_time = 100000;
331 		break;
332 	case 800000:
333 		reg |= OPT3001_CONFIGURATION_CT;
334 		opt->int_time = 800000;
335 		break;
336 	default:
337 		return -EINVAL;
338 	}
339 
340 	return i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
341 			reg);
342 }
343 
344 static int opt3001_read_raw(struct iio_dev *iio,
345 		struct iio_chan_spec const *chan, int *val, int *val2,
346 		long mask)
347 {
348 	struct opt3001 *opt = iio_priv(iio);
349 	int ret;
350 
351 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
352 		return -EBUSY;
353 
354 	if (chan->type != IIO_LIGHT)
355 		return -EINVAL;
356 
357 	mutex_lock(&opt->lock);
358 
359 	switch (mask) {
360 	case IIO_CHAN_INFO_PROCESSED:
361 		ret = opt3001_get_lux(opt, val, val2);
362 		break;
363 	case IIO_CHAN_INFO_INT_TIME:
364 		ret = opt3001_get_int_time(opt, val, val2);
365 		break;
366 	default:
367 		ret = -EINVAL;
368 	}
369 
370 	mutex_unlock(&opt->lock);
371 
372 	return ret;
373 }
374 
375 static int opt3001_write_raw(struct iio_dev *iio,
376 		struct iio_chan_spec const *chan, int val, int val2,
377 		long mask)
378 {
379 	struct opt3001 *opt = iio_priv(iio);
380 	int ret;
381 
382 	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
383 		return -EBUSY;
384 
385 	if (chan->type != IIO_LIGHT)
386 		return -EINVAL;
387 
388 	if (mask != IIO_CHAN_INFO_INT_TIME)
389 		return -EINVAL;
390 
391 	if (val != 0)
392 		return -EINVAL;
393 
394 	mutex_lock(&opt->lock);
395 	ret = opt3001_set_int_time(opt, val2);
396 	mutex_unlock(&opt->lock);
397 
398 	return ret;
399 }
400 
401 static int opt3001_read_event_value(struct iio_dev *iio,
402 		const struct iio_chan_spec *chan, enum iio_event_type type,
403 		enum iio_event_direction dir, enum iio_event_info info,
404 		int *val, int *val2)
405 {
406 	struct opt3001 *opt = iio_priv(iio);
407 	int ret = IIO_VAL_INT_PLUS_MICRO;
408 
409 	mutex_lock(&opt->lock);
410 
411 	switch (dir) {
412 	case IIO_EV_DIR_RISING:
413 		opt3001_to_iio_ret(opt, opt->high_thresh_exp,
414 				opt->high_thresh_mantissa, val, val2);
415 		break;
416 	case IIO_EV_DIR_FALLING:
417 		opt3001_to_iio_ret(opt, opt->low_thresh_exp,
418 				opt->low_thresh_mantissa, val, val2);
419 		break;
420 	default:
421 		ret = -EINVAL;
422 	}
423 
424 	mutex_unlock(&opt->lock);
425 
426 	return ret;
427 }
428 
429 static int opt3001_write_event_value(struct iio_dev *iio,
430 		const struct iio_chan_spec *chan, enum iio_event_type type,
431 		enum iio_event_direction dir, enum iio_event_info info,
432 		int val, int val2)
433 {
434 	struct opt3001 *opt = iio_priv(iio);
435 	int ret;
436 
437 	u16 mantissa;
438 	u16 value;
439 	u16 reg;
440 
441 	u8 exponent;
442 
443 	if (val < 0)
444 		return -EINVAL;
445 
446 	mutex_lock(&opt->lock);
447 
448 	ret = opt3001_find_scale(opt, val, val2, &exponent);
449 	if (ret < 0) {
450 		dev_err(opt->dev, "can't find scale for %d.%06u\n", val, val2);
451 		goto err;
452 	}
453 
454 	mantissa = (((val * 1000) + (val2 / 1000)) / 10) >> exponent;
455 	value = (exponent << 12) | mantissa;
456 
457 	switch (dir) {
458 	case IIO_EV_DIR_RISING:
459 		reg = OPT3001_HIGH_LIMIT;
460 		opt->high_thresh_mantissa = mantissa;
461 		opt->high_thresh_exp = exponent;
462 		break;
463 	case IIO_EV_DIR_FALLING:
464 		reg = OPT3001_LOW_LIMIT;
465 		opt->low_thresh_mantissa = mantissa;
466 		opt->low_thresh_exp = exponent;
467 		break;
468 	default:
469 		ret = -EINVAL;
470 		goto err;
471 	}
472 
473 	ret = i2c_smbus_write_word_swapped(opt->client, reg, value);
474 	if (ret < 0) {
475 		dev_err(opt->dev, "failed to write register %02x\n", reg);
476 		goto err;
477 	}
478 
479 err:
480 	mutex_unlock(&opt->lock);
481 
482 	return ret;
483 }
484 
485 static int opt3001_read_event_config(struct iio_dev *iio,
486 		const struct iio_chan_spec *chan, enum iio_event_type type,
487 		enum iio_event_direction dir)
488 {
489 	struct opt3001 *opt = iio_priv(iio);
490 
491 	return opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS;
492 }
493 
494 static int opt3001_write_event_config(struct iio_dev *iio,
495 		const struct iio_chan_spec *chan, enum iio_event_type type,
496 		enum iio_event_direction dir, int state)
497 {
498 	struct opt3001 *opt = iio_priv(iio);
499 	int ret;
500 	u16 mode;
501 	u16 reg;
502 
503 	if (state && opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
504 		return 0;
505 
506 	if (!state && opt->mode == OPT3001_CONFIGURATION_M_SHUTDOWN)
507 		return 0;
508 
509 	mutex_lock(&opt->lock);
510 
511 	mode = state ? OPT3001_CONFIGURATION_M_CONTINUOUS
512 		: OPT3001_CONFIGURATION_M_SHUTDOWN;
513 
514 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
515 	if (ret < 0) {
516 		dev_err(opt->dev, "failed to read register %02x\n",
517 				OPT3001_CONFIGURATION);
518 		goto err;
519 	}
520 
521 	reg = ret;
522 	opt3001_set_mode(opt, &reg, mode);
523 
524 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
525 			reg);
526 	if (ret < 0) {
527 		dev_err(opt->dev, "failed to write register %02x\n",
528 				OPT3001_CONFIGURATION);
529 		goto err;
530 	}
531 
532 err:
533 	mutex_unlock(&opt->lock);
534 
535 	return ret;
536 }
537 
538 static const struct iio_info opt3001_info = {
539 	.driver_module = THIS_MODULE,
540 	.attrs = &opt3001_attribute_group,
541 	.read_raw = opt3001_read_raw,
542 	.write_raw = opt3001_write_raw,
543 	.read_event_value = opt3001_read_event_value,
544 	.write_event_value = opt3001_write_event_value,
545 	.read_event_config = opt3001_read_event_config,
546 	.write_event_config = opt3001_write_event_config,
547 };
548 
549 static int opt3001_read_id(struct opt3001 *opt)
550 {
551 	char manufacturer[2];
552 	u16 device_id;
553 	int ret;
554 
555 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_MANUFACTURER_ID);
556 	if (ret < 0) {
557 		dev_err(opt->dev, "failed to read register %02x\n",
558 				OPT3001_MANUFACTURER_ID);
559 		return ret;
560 	}
561 
562 	manufacturer[0] = ret >> 8;
563 	manufacturer[1] = ret & 0xff;
564 
565 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_DEVICE_ID);
566 	if (ret < 0) {
567 		dev_err(opt->dev, "failed to read register %02x\n",
568 				OPT3001_DEVICE_ID);
569 		return ret;
570 	}
571 
572 	device_id = ret;
573 
574 	dev_info(opt->dev, "Found %c%c OPT%04x\n", manufacturer[0],
575 			manufacturer[1], device_id);
576 
577 	return 0;
578 }
579 
580 static int opt3001_configure(struct opt3001 *opt)
581 {
582 	int ret;
583 	u16 reg;
584 
585 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
586 	if (ret < 0) {
587 		dev_err(opt->dev, "failed to read register %02x\n",
588 				OPT3001_CONFIGURATION);
589 		return ret;
590 	}
591 
592 	reg = ret;
593 
594 	/* Enable automatic full-scale setting mode */
595 	reg &= ~OPT3001_CONFIGURATION_RN_MASK;
596 	reg |= OPT3001_CONFIGURATION_RN_AUTO;
597 
598 	/* Reflect status of the device's integration time setting */
599 	if (reg & OPT3001_CONFIGURATION_CT)
600 		opt->int_time = 800000;
601 	else
602 		opt->int_time = 100000;
603 
604 	/* Ensure device is in shutdown initially */
605 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
606 
607 	/* Configure for latched window-style comparison operation */
608 	reg |= OPT3001_CONFIGURATION_L;
609 	reg &= ~OPT3001_CONFIGURATION_POL;
610 	reg &= ~OPT3001_CONFIGURATION_ME;
611 	reg &= ~OPT3001_CONFIGURATION_FC_MASK;
612 
613 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
614 			reg);
615 	if (ret < 0) {
616 		dev_err(opt->dev, "failed to write register %02x\n",
617 				OPT3001_CONFIGURATION);
618 		return ret;
619 	}
620 
621 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_LOW_LIMIT);
622 	if (ret < 0) {
623 		dev_err(opt->dev, "failed to read register %02x\n",
624 				OPT3001_LOW_LIMIT);
625 		return ret;
626 	}
627 
628 	opt->low_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
629 	opt->low_thresh_exp = OPT3001_REG_EXPONENT(ret);
630 
631 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_HIGH_LIMIT);
632 	if (ret < 0) {
633 		dev_err(opt->dev, "failed to read register %02x\n",
634 				OPT3001_HIGH_LIMIT);
635 		return ret;
636 	}
637 
638 	opt->high_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
639 	opt->high_thresh_exp = OPT3001_REG_EXPONENT(ret);
640 
641 	return 0;
642 }
643 
644 static irqreturn_t opt3001_irq(int irq, void *_iio)
645 {
646 	struct iio_dev *iio = _iio;
647 	struct opt3001 *opt = iio_priv(iio);
648 	int ret;
649 
650 	if (!opt->ok_to_ignore_lock)
651 		mutex_lock(&opt->lock);
652 
653 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
654 	if (ret < 0) {
655 		dev_err(opt->dev, "failed to read register %02x\n",
656 				OPT3001_CONFIGURATION);
657 		goto out;
658 	}
659 
660 	if ((ret & OPT3001_CONFIGURATION_M_MASK) ==
661 			OPT3001_CONFIGURATION_M_CONTINUOUS) {
662 		if (ret & OPT3001_CONFIGURATION_FH)
663 			iio_push_event(iio,
664 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
665 							IIO_EV_TYPE_THRESH,
666 							IIO_EV_DIR_RISING),
667 					iio_get_time_ns());
668 		if (ret & OPT3001_CONFIGURATION_FL)
669 			iio_push_event(iio,
670 					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
671 							IIO_EV_TYPE_THRESH,
672 							IIO_EV_DIR_FALLING),
673 					iio_get_time_ns());
674 	} else if (ret & OPT3001_CONFIGURATION_CRF) {
675 		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
676 		if (ret < 0) {
677 			dev_err(opt->dev, "failed to read register %02x\n",
678 					OPT3001_RESULT);
679 			goto out;
680 		}
681 		opt->result = ret;
682 		opt->result_ready = true;
683 		wake_up(&opt->result_ready_queue);
684 	}
685 
686 out:
687 	if (!opt->ok_to_ignore_lock)
688 		mutex_unlock(&opt->lock);
689 
690 	return IRQ_HANDLED;
691 }
692 
693 static int opt3001_probe(struct i2c_client *client,
694 		const struct i2c_device_id *id)
695 {
696 	struct device *dev = &client->dev;
697 
698 	struct iio_dev *iio;
699 	struct opt3001 *opt;
700 	int irq = client->irq;
701 	int ret;
702 
703 	iio = devm_iio_device_alloc(dev, sizeof(*opt));
704 	if (!iio)
705 		return -ENOMEM;
706 
707 	opt = iio_priv(iio);
708 	opt->client = client;
709 	opt->dev = dev;
710 
711 	mutex_init(&opt->lock);
712 	init_waitqueue_head(&opt->result_ready_queue);
713 	i2c_set_clientdata(client, iio);
714 
715 	ret = opt3001_read_id(opt);
716 	if (ret)
717 		return ret;
718 
719 	ret = opt3001_configure(opt);
720 	if (ret)
721 		return ret;
722 
723 	iio->name = client->name;
724 	iio->channels = opt3001_channels;
725 	iio->num_channels = ARRAY_SIZE(opt3001_channels);
726 	iio->dev.parent = dev;
727 	iio->modes = INDIO_DIRECT_MODE;
728 	iio->info = &opt3001_info;
729 
730 	ret = devm_iio_device_register(dev, iio);
731 	if (ret) {
732 		dev_err(dev, "failed to register IIO device\n");
733 		return ret;
734 	}
735 
736 	ret = request_threaded_irq(irq, NULL, opt3001_irq,
737 			IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
738 			"opt3001", iio);
739 	if (ret) {
740 		dev_err(dev, "failed to request IRQ #%d\n", irq);
741 		return ret;
742 	}
743 
744 	return 0;
745 }
746 
747 static int opt3001_remove(struct i2c_client *client)
748 {
749 	struct iio_dev *iio = i2c_get_clientdata(client);
750 	struct opt3001 *opt = iio_priv(iio);
751 	int ret;
752 	u16 reg;
753 
754 	free_irq(client->irq, iio);
755 
756 	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
757 	if (ret < 0) {
758 		dev_err(opt->dev, "failed to read register %02x\n",
759 				OPT3001_CONFIGURATION);
760 		return ret;
761 	}
762 
763 	reg = ret;
764 	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
765 
766 	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
767 			reg);
768 	if (ret < 0) {
769 		dev_err(opt->dev, "failed to write register %02x\n",
770 				OPT3001_CONFIGURATION);
771 		return ret;
772 	}
773 
774 	return 0;
775 }
776 
777 static const struct i2c_device_id opt3001_id[] = {
778 	{ "opt3001", 0 },
779 	{ } /* Terminating Entry */
780 };
781 MODULE_DEVICE_TABLE(i2c, opt3001_id);
782 
783 static const struct of_device_id opt3001_of_match[] = {
784 	{ .compatible = "ti,opt3001" },
785 	{ }
786 };
787 
788 static struct i2c_driver opt3001_driver = {
789 	.probe = opt3001_probe,
790 	.remove = opt3001_remove,
791 	.id_table = opt3001_id,
792 
793 	.driver = {
794 		.name = "opt3001",
795 		.of_match_table = of_match_ptr(opt3001_of_match),
796 		.owner = THIS_MODULE,
797 	},
798 };
799 
800 module_i2c_driver(opt3001_driver);
801 
802 MODULE_LICENSE("GPL v2");
803 MODULE_AUTHOR("Andreas Dannenberg <dannenberg@ti.com>");
804 MODULE_DESCRIPTION("Texas Instruments OPT3001 Light Sensor Driver");
805