xref: /linux/drivers/iio/light/ltrf216a.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * LTRF216A Ambient Light Sensor
4  *
5  * Copyright (C) 2022 Collabora, Ltd.
6  * Author: Shreeya Patel <shreeya.patel@collabora.com>
7  *
8  * Copyright (C) 2021 Lite-On Technology Corp (Singapore)
9  * Author: Shi Zhigang <Zhigang.Shi@liteon.com>
10  *
11  * IIO driver for LTRF216A (7-bit I2C slave address 0x53).
12  */
13 
14 #include <linux/bitfield.h>
15 #include <linux/bits.h>
16 #include <linux/delay.h>
17 #include <linux/i2c.h>
18 #include <linux/init.h>
19 #include <linux/iopoll.h>
20 #include <linux/mod_devicetable.h>
21 #include <linux/module.h>
22 #include <linux/mutex.h>
23 #include <linux/pm.h>
24 #include <linux/pm_runtime.h>
25 #include <linux/regmap.h>
26 
27 #include <linux/iio/iio.h>
28 
29 #include <linux/unaligned.h>
30 
31 #define LTRF216A_ALS_RESET_MASK		BIT(4)
32 #define LTRF216A_ALS_DATA_STATUS	BIT(3)
33 #define LTRF216A_ALS_ENABLE_MASK	BIT(1)
34 #define LTRF216A_MAIN_CTRL		0x00
35 #define LTRF216A_ALS_MEAS_RES		0x04
36 #define LTRF216A_ALS_GAIN		0x05
37 #define LTRF216A_PART_ID		0x06
38 #define LTRF216A_MAIN_STATUS		0x07
39 #define LTRF216A_ALS_CLEAR_DATA_0	0x0a
40 #define LTRF216A_ALS_CLEAR_DATA_1	0x0b
41 #define LTRF216A_ALS_CLEAR_DATA_2	0x0c
42 #define LTRF216A_ALS_DATA_0		0x0d
43 #define LTRF216A_ALS_DATA_1		0x0e
44 #define LTRF216A_ALS_DATA_2		0x0f
45 #define LTRF216A_INT_CFG		0x19
46 #define LTRF216A_INT_PST		0x1a
47 #define LTRF216A_ALS_THRES_UP_0		0x21
48 #define LTRF216A_ALS_THRES_UP_1		0x22
49 #define LTRF216A_ALS_THRES_UP_2		0x23
50 #define LTRF216A_ALS_THRES_LOW_0	0x24
51 #define LTRF216A_ALS_THRES_LOW_1	0x25
52 #define LTRF216A_ALS_THRES_LOW_2	0x26
53 #define LTRF216A_ALS_READ_DATA_DELAY_US	20000
54 
55 static const int ltrf216a_int_time_available[][2] = {
56 	{ 0, 400000 },
57 	{ 0, 200000 },
58 	{ 0, 100000 },
59 	{ 0,  50000 },
60 	{ 0,  25000 },
61 };
62 
63 static const int ltrf216a_int_time_reg[][2] = {
64 	{ 400, 0x03 },
65 	{ 200, 0x13 },
66 	{ 100, 0x22 },
67 	{  50, 0x31 },
68 	{  25, 0x40 },
69 };
70 
71 struct ltr_chip_info {
72 	/* Chip contains CLEAR_DATA_0/1/2 registers at offset 0xa..0xc */
73 	bool		has_clear_data;
74 	/* Lux calculation multiplier for ALS data */
75 	int		lux_multiplier;
76 };
77 
78 /*
79  * Window Factor is needed when the device is under Window glass
80  * with coated tinted ink. This is to compensate for the light loss
81  * due to the lower transmission rate of the window glass and helps
82  * in calculating lux.
83  */
84 #define LTRF216A_WIN_FAC	1
85 
86 struct ltrf216a_data {
87 	struct regmap *regmap;
88 	struct i2c_client *client;
89 	const struct ltr_chip_info *info;
90 	u32 int_time;
91 	u16 int_time_fac;
92 	u8 als_gain_fac;
93 	/*
94 	 * Protects regmap accesses and makes sure integration time
95 	 * remains constant during the measurement of lux.
96 	 */
97 	struct mutex lock;
98 };
99 
100 static const struct iio_chan_spec ltrf216a_channels[] = {
101 	{
102 		.type = IIO_LIGHT,
103 		.info_mask_separate =
104 			BIT(IIO_CHAN_INFO_RAW) |
105 			BIT(IIO_CHAN_INFO_PROCESSED) |
106 			BIT(IIO_CHAN_INFO_INT_TIME),
107 		.info_mask_separate_available =
108 			BIT(IIO_CHAN_INFO_INT_TIME),
109 	},
110 };
111 
112 static void ltrf216a_reset(struct iio_dev *indio_dev)
113 {
114 	struct ltrf216a_data *data = iio_priv(indio_dev);
115 
116 	/* reset sensor, chip fails to respond to this, so ignore any errors */
117 	regmap_write(data->regmap, LTRF216A_MAIN_CTRL, LTRF216A_ALS_RESET_MASK);
118 
119 	/* reset time */
120 	usleep_range(1000, 2000);
121 }
122 
123 static int ltrf216a_enable(struct iio_dev *indio_dev)
124 {
125 	struct ltrf216a_data *data = iio_priv(indio_dev);
126 	struct device *dev = &data->client->dev;
127 	int ret;
128 
129 	/* enable sensor */
130 	ret = regmap_set_bits(data->regmap,
131 			      LTRF216A_MAIN_CTRL, LTRF216A_ALS_ENABLE_MASK);
132 	if (ret) {
133 		dev_err(dev, "failed to enable sensor: %d\n", ret);
134 		return ret;
135 	}
136 
137 	/* sleep for one integration cycle after enabling the device */
138 	msleep(ltrf216a_int_time_reg[0][0]);
139 
140 	return 0;
141 }
142 
143 static int ltrf216a_disable(struct iio_dev *indio_dev)
144 {
145 	struct ltrf216a_data *data = iio_priv(indio_dev);
146 	struct device *dev = &data->client->dev;
147 	int ret;
148 
149 	ret = regmap_write(data->regmap, LTRF216A_MAIN_CTRL, 0);
150 	if (ret)
151 		dev_err(dev, "failed to disable sensor: %d\n", ret);
152 
153 	return ret;
154 }
155 
156 static void ltrf216a_cleanup(void *data)
157 {
158 	struct iio_dev *indio_dev = data;
159 
160 	ltrf216a_disable(indio_dev);
161 }
162 
163 static int ltrf216a_set_int_time(struct ltrf216a_data *data, int itime)
164 {
165 	struct device *dev = &data->client->dev;
166 	unsigned int i;
167 	u8 reg_val;
168 	int ret;
169 
170 	for (i = 0; i < ARRAY_SIZE(ltrf216a_int_time_available); i++) {
171 		if (ltrf216a_int_time_available[i][1] == itime)
172 			break;
173 	}
174 	if (i == ARRAY_SIZE(ltrf216a_int_time_available))
175 		return -EINVAL;
176 
177 	reg_val = ltrf216a_int_time_reg[i][1];
178 
179 	ret = regmap_write(data->regmap, LTRF216A_ALS_MEAS_RES, reg_val);
180 	if (ret) {
181 		dev_err(dev, "failed to set integration time: %d\n", ret);
182 		return ret;
183 	}
184 
185 	data->int_time_fac = ltrf216a_int_time_reg[i][0];
186 	data->int_time = itime;
187 
188 	return 0;
189 }
190 
191 static int ltrf216a_get_int_time(struct ltrf216a_data *data,
192 				 int *val, int *val2)
193 {
194 	*val = 0;
195 	*val2 = data->int_time;
196 	return IIO_VAL_INT_PLUS_MICRO;
197 }
198 
199 static int ltrf216a_set_power_state(struct ltrf216a_data *data, bool on)
200 {
201 	struct device *dev = &data->client->dev;
202 	int ret = 0;
203 
204 	if (on) {
205 		ret = pm_runtime_resume_and_get(dev);
206 		if (ret) {
207 			dev_err(dev, "failed to resume runtime PM: %d\n", ret);
208 			return ret;
209 		}
210 	} else {
211 		pm_runtime_mark_last_busy(dev);
212 		pm_runtime_put_autosuspend(dev);
213 	}
214 
215 	return ret;
216 }
217 
218 static int ltrf216a_read_data(struct ltrf216a_data *data, u8 addr)
219 {
220 	struct device *dev = &data->client->dev;
221 	int ret, val;
222 	u8 buf[3];
223 
224 	ret = regmap_read_poll_timeout(data->regmap, LTRF216A_MAIN_STATUS,
225 				       val, val & LTRF216A_ALS_DATA_STATUS,
226 				       LTRF216A_ALS_READ_DATA_DELAY_US,
227 				       LTRF216A_ALS_READ_DATA_DELAY_US * 50);
228 	if (ret) {
229 		dev_err(dev, "failed to wait for measurement data: %d\n", ret);
230 		return ret;
231 	}
232 
233 	ret = regmap_bulk_read(data->regmap, addr, buf, sizeof(buf));
234 	if (ret) {
235 		dev_err(dev, "failed to read measurement data: %d\n", ret);
236 		return ret;
237 	}
238 
239 	return get_unaligned_le24(&buf[0]);
240 }
241 
242 static int ltrf216a_get_lux(struct ltrf216a_data *data)
243 {
244 	int ret, greendata;
245 	u64 lux;
246 
247 	ret = ltrf216a_set_power_state(data, true);
248 	if (ret)
249 		return ret;
250 
251 	greendata = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
252 	if (greendata < 0)
253 		return greendata;
254 
255 	ltrf216a_set_power_state(data, false);
256 
257 	lux = greendata * data->info->lux_multiplier * LTRF216A_WIN_FAC;
258 
259 	return lux;
260 }
261 
262 static int ltrf216a_read_raw(struct iio_dev *indio_dev,
263 			     struct iio_chan_spec const *chan, int *val,
264 			     int *val2, long mask)
265 {
266 	struct ltrf216a_data *data = iio_priv(indio_dev);
267 	int ret;
268 
269 	switch (mask) {
270 	case IIO_CHAN_INFO_RAW:
271 		ret = ltrf216a_set_power_state(data, true);
272 		if (ret)
273 			return ret;
274 		mutex_lock(&data->lock);
275 		ret = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
276 		mutex_unlock(&data->lock);
277 		ltrf216a_set_power_state(data, false);
278 		if (ret < 0)
279 			return ret;
280 		*val = ret;
281 		return IIO_VAL_INT;
282 	case IIO_CHAN_INFO_PROCESSED:
283 		mutex_lock(&data->lock);
284 		ret = ltrf216a_get_lux(data);
285 		mutex_unlock(&data->lock);
286 		if (ret < 0)
287 			return ret;
288 		*val = ret;
289 		*val2 = data->als_gain_fac * data->int_time_fac;
290 		return IIO_VAL_FRACTIONAL;
291 	case IIO_CHAN_INFO_INT_TIME:
292 		mutex_lock(&data->lock);
293 		ret = ltrf216a_get_int_time(data, val, val2);
294 		mutex_unlock(&data->lock);
295 		return ret;
296 	default:
297 		return -EINVAL;
298 	}
299 }
300 
301 static int ltrf216a_write_raw(struct iio_dev *indio_dev,
302 			      struct iio_chan_spec const *chan, int val,
303 			      int val2, long mask)
304 {
305 	struct ltrf216a_data *data = iio_priv(indio_dev);
306 	int ret;
307 
308 	switch (mask) {
309 	case IIO_CHAN_INFO_INT_TIME:
310 		if (val != 0)
311 			return -EINVAL;
312 		mutex_lock(&data->lock);
313 		ret = ltrf216a_set_int_time(data, val2);
314 		mutex_unlock(&data->lock);
315 		return ret;
316 	default:
317 		return -EINVAL;
318 	}
319 }
320 
321 static int ltrf216a_read_available(struct iio_dev *indio_dev,
322 				   struct iio_chan_spec const *chan,
323 				   const int **vals, int *type, int *length,
324 				   long mask)
325 {
326 	switch (mask) {
327 	case IIO_CHAN_INFO_INT_TIME:
328 		*length = ARRAY_SIZE(ltrf216a_int_time_available) * 2;
329 		*vals = (const int *)ltrf216a_int_time_available;
330 		*type = IIO_VAL_INT_PLUS_MICRO;
331 		return IIO_AVAIL_LIST;
332 	default:
333 		return -EINVAL;
334 	}
335 }
336 
337 static const struct iio_info ltrf216a_info = {
338 	.read_raw = ltrf216a_read_raw,
339 	.write_raw = ltrf216a_write_raw,
340 	.read_avail = ltrf216a_read_available,
341 };
342 
343 static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
344 {
345 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
346 	struct ltrf216a_data *data = iio_priv(indio_dev);
347 
348 	switch (reg) {
349 	case LTRF216A_MAIN_CTRL:
350 	case LTRF216A_ALS_MEAS_RES:
351 	case LTRF216A_ALS_GAIN:
352 	case LTRF216A_PART_ID:
353 	case LTRF216A_MAIN_STATUS:
354 	case LTRF216A_ALS_DATA_0:
355 	case LTRF216A_ALS_DATA_1:
356 	case LTRF216A_ALS_DATA_2:
357 	case LTRF216A_INT_CFG:
358 	case LTRF216A_INT_PST:
359 	case LTRF216A_ALS_THRES_UP_0:
360 	case LTRF216A_ALS_THRES_UP_1:
361 	case LTRF216A_ALS_THRES_UP_2:
362 	case LTRF216A_ALS_THRES_LOW_0:
363 	case LTRF216A_ALS_THRES_LOW_1:
364 	case LTRF216A_ALS_THRES_LOW_2:
365 		return true;
366 	case LTRF216A_ALS_CLEAR_DATA_0:
367 	case LTRF216A_ALS_CLEAR_DATA_1:
368 	case LTRF216A_ALS_CLEAR_DATA_2:
369 		return data->info->has_clear_data;
370 	default:
371 		return false;
372 	}
373 }
374 
375 static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
376 {
377 	switch (reg) {
378 	case LTRF216A_MAIN_CTRL:
379 	case LTRF216A_ALS_MEAS_RES:
380 	case LTRF216A_ALS_GAIN:
381 	case LTRF216A_INT_CFG:
382 	case LTRF216A_INT_PST:
383 	case LTRF216A_ALS_THRES_UP_0:
384 	case LTRF216A_ALS_THRES_UP_1:
385 	case LTRF216A_ALS_THRES_UP_2:
386 	case LTRF216A_ALS_THRES_LOW_0:
387 	case LTRF216A_ALS_THRES_LOW_1:
388 	case LTRF216A_ALS_THRES_LOW_2:
389 		return true;
390 	default:
391 		return false;
392 	}
393 }
394 
395 static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
396 {
397 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
398 	struct ltrf216a_data *data = iio_priv(indio_dev);
399 
400 	switch (reg) {
401 	case LTRF216A_MAIN_STATUS:
402 	case LTRF216A_ALS_DATA_0:
403 	case LTRF216A_ALS_DATA_1:
404 	case LTRF216A_ALS_DATA_2:
405 		return true;
406 	/*
407 	 * If these registers are not present on a chip (like LTR-308),
408 	 * the missing registers are not considered volatile.
409 	 */
410 	case LTRF216A_ALS_CLEAR_DATA_0:
411 	case LTRF216A_ALS_CLEAR_DATA_1:
412 	case LTRF216A_ALS_CLEAR_DATA_2:
413 		return data->info->has_clear_data;
414 	default:
415 		return false;
416 	}
417 }
418 
419 static bool ltrf216a_precious_reg(struct device *dev, unsigned int reg)
420 {
421 	return reg == LTRF216A_MAIN_STATUS;
422 }
423 
424 static const struct regmap_config ltrf216a_regmap_config = {
425 	.name = "ltrf216a",
426 	.reg_bits = 8,
427 	.val_bits = 8,
428 	.cache_type = REGCACHE_RBTREE,
429 	.max_register = LTRF216A_ALS_THRES_LOW_2,
430 	.readable_reg = ltrf216a_readable_reg,
431 	.writeable_reg = ltrf216a_writable_reg,
432 	.volatile_reg = ltrf216a_volatile_reg,
433 	.precious_reg = ltrf216a_precious_reg,
434 	.disable_locking = true,
435 };
436 
437 static int ltrf216a_probe(struct i2c_client *client)
438 {
439 	struct ltrf216a_data *data;
440 	struct iio_dev *indio_dev;
441 	int ret;
442 
443 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
444 	if (!indio_dev)
445 		return -ENOMEM;
446 
447 	data = iio_priv(indio_dev);
448 
449 	data->regmap = devm_regmap_init_i2c(client, &ltrf216a_regmap_config);
450 	if (IS_ERR(data->regmap))
451 		return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
452 				     "regmap initialization failed\n");
453 
454 	i2c_set_clientdata(client, indio_dev);
455 	data->client = client;
456 	data->info = i2c_get_match_data(client);
457 
458 	mutex_init(&data->lock);
459 
460 	indio_dev->info = &ltrf216a_info;
461 	indio_dev->name = "ltrf216a";
462 	indio_dev->channels = ltrf216a_channels;
463 	indio_dev->num_channels = ARRAY_SIZE(ltrf216a_channels);
464 	indio_dev->modes = INDIO_DIRECT_MODE;
465 
466 	ret = pm_runtime_set_active(&client->dev);
467 	if (ret)
468 		return ret;
469 
470 	/* reset sensor, chip fails to respond to this, so ignore any errors */
471 	ltrf216a_reset(indio_dev);
472 
473 	ret = regmap_reinit_cache(data->regmap, &ltrf216a_regmap_config);
474 	if (ret)
475 		return dev_err_probe(&client->dev, ret,
476 				     "failed to reinit regmap cache\n");
477 
478 	ret = ltrf216a_enable(indio_dev);
479 	if (ret)
480 		return ret;
481 
482 	ret = devm_add_action_or_reset(&client->dev, ltrf216a_cleanup,
483 				       indio_dev);
484 	if (ret)
485 		return ret;
486 
487 	ret = devm_pm_runtime_enable(&client->dev);
488 	if (ret)
489 		return dev_err_probe(&client->dev, ret,
490 				     "failed to enable runtime PM\n");
491 
492 	pm_runtime_set_autosuspend_delay(&client->dev, 1000);
493 	pm_runtime_use_autosuspend(&client->dev);
494 
495 	data->int_time = 100000;
496 	data->int_time_fac = 100;
497 	data->als_gain_fac = 3;
498 
499 	return devm_iio_device_register(&client->dev, indio_dev);
500 }
501 
502 static int ltrf216a_runtime_suspend(struct device *dev)
503 {
504 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
505 	struct ltrf216a_data *data = iio_priv(indio_dev);
506 	int ret;
507 
508 	ret = ltrf216a_disable(indio_dev);
509 	if (ret)
510 		return ret;
511 
512 	regcache_cache_only(data->regmap, true);
513 
514 	return 0;
515 }
516 
517 static int ltrf216a_runtime_resume(struct device *dev)
518 {
519 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
520 	struct ltrf216a_data *data = iio_priv(indio_dev);
521 	int ret;
522 
523 	regcache_cache_only(data->regmap, false);
524 	regcache_mark_dirty(data->regmap);
525 	ret = regcache_sync(data->regmap);
526 	if (ret)
527 		goto cache_only;
528 
529 	ret = ltrf216a_enable(indio_dev);
530 	if (ret)
531 		goto cache_only;
532 
533 	return 0;
534 
535 cache_only:
536 	regcache_cache_only(data->regmap, true);
537 
538 	return ret;
539 }
540 
541 static DEFINE_RUNTIME_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_runtime_suspend,
542 				 ltrf216a_runtime_resume, NULL);
543 
544 static const struct ltr_chip_info ltr308_chip_info = {
545 	.has_clear_data		= false,
546 	.lux_multiplier		= 60,
547 };
548 
549 static const struct ltr_chip_info ltrf216a_chip_info = {
550 	.has_clear_data		= true,
551 	.lux_multiplier		= 45,
552 };
553 
554 static const struct i2c_device_id ltrf216a_id[] = {
555 	{ "ltr308", .driver_data = (kernel_ulong_t)&ltr308_chip_info },
556 	{ "ltrf216a", .driver_data = (kernel_ulong_t)&ltrf216a_chip_info },
557 	{}
558 };
559 MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
560 
561 static const struct of_device_id ltrf216a_of_match[] = {
562 	{ .compatible = "liteon,ltr308", .data = &ltr308_chip_info },
563 	{ .compatible = "liteon,ltrf216a", .data = &ltrf216a_chip_info },
564 	{ .compatible = "ltr,ltrf216a", .data = &ltrf216a_chip_info },
565 	{}
566 };
567 MODULE_DEVICE_TABLE(of, ltrf216a_of_match);
568 
569 static struct i2c_driver ltrf216a_driver = {
570 	.driver = {
571 		.name = "ltrf216a",
572 		.pm = pm_ptr(&ltrf216a_pm_ops),
573 		.of_match_table = ltrf216a_of_match,
574 	},
575 	.probe = ltrf216a_probe,
576 	.id_table = ltrf216a_id,
577 };
578 module_i2c_driver(ltrf216a_driver);
579 
580 MODULE_AUTHOR("Shreeya Patel <shreeya.patel@collabora.com>");
581 MODULE_AUTHOR("Shi Zhigang <Zhigang.Shi@liteon.com>");
582 MODULE_DESCRIPTION("LTRF216A ambient light sensor driver");
583 MODULE_LICENSE("GPL");
584