xref: /linux/drivers/iio/light/vl6180.c (revision dd093fb0) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * vl6180.c - Support for STMicroelectronics VL6180 ALS, range and proximity
4  * sensor
5  *
6  * Copyright 2017 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
7  * Copyright 2017 Manivannan Sadhasivam <manivannanece23@gmail.com>
8  *
9  * IIO driver for VL6180 (7-bit I2C slave address 0x29)
10  *
11  * Range: 0 to 100mm
12  * ALS: < 1 Lux up to 100 kLux
13  * IR: 850nm
14  *
15  * TODO: irq, threshold events, continuous mode, hardware buffer
16  */
17 
18 #include <linux/module.h>
19 #include <linux/mod_devicetable.h>
20 #include <linux/i2c.h>
21 #include <linux/mutex.h>
22 #include <linux/err.h>
23 #include <linux/of.h>
24 #include <linux/delay.h>
25 #include <linux/util_macros.h>
26 
27 #include <linux/iio/iio.h>
28 #include <linux/iio/sysfs.h>
29 
30 #define VL6180_DRV_NAME "vl6180"
31 
32 /* Device identification register and value */
33 #define VL6180_MODEL_ID	0x000
34 #define VL6180_MODEL_ID_VAL 0xb4
35 
36 /* Configuration registers */
37 #define VL6180_INTR_CONFIG 0x014
38 #define VL6180_INTR_CLEAR 0x015
39 #define VL6180_OUT_OF_RESET 0x016
40 #define VL6180_HOLD 0x017
41 #define VL6180_RANGE_START 0x018
42 #define VL6180_ALS_START 0x038
43 #define VL6180_ALS_GAIN 0x03f
44 #define VL6180_ALS_IT 0x040
45 
46 /* Status registers */
47 #define VL6180_RANGE_STATUS 0x04d
48 #define VL6180_ALS_STATUS 0x04e
49 #define VL6180_INTR_STATUS 0x04f
50 
51 /* Result value registers */
52 #define VL6180_ALS_VALUE 0x050
53 #define VL6180_RANGE_VALUE 0x062
54 #define VL6180_RANGE_RATE 0x066
55 
56 /* bits of the RANGE_START and ALS_START register */
57 #define VL6180_MODE_CONT BIT(1) /* continuous mode */
58 #define VL6180_STARTSTOP BIT(0) /* start measurement, auto-reset */
59 
60 /* bits of the INTR_STATUS and INTR_CONFIG register */
61 #define VL6180_ALS_READY BIT(5)
62 #define VL6180_RANGE_READY BIT(2)
63 
64 /* bits of the INTR_CLEAR register */
65 #define VL6180_CLEAR_ERROR BIT(2)
66 #define VL6180_CLEAR_ALS BIT(1)
67 #define VL6180_CLEAR_RANGE BIT(0)
68 
69 /* bits of the HOLD register */
70 #define VL6180_HOLD_ON BIT(0)
71 
72 /* default value for the ALS_IT register */
73 #define VL6180_ALS_IT_100 0x63 /* 100 ms */
74 
75 /* values for the ALS_GAIN register */
76 #define VL6180_ALS_GAIN_1 0x46
77 #define VL6180_ALS_GAIN_1_25 0x45
78 #define VL6180_ALS_GAIN_1_67 0x44
79 #define VL6180_ALS_GAIN_2_5 0x43
80 #define VL6180_ALS_GAIN_5 0x42
81 #define VL6180_ALS_GAIN_10 0x41
82 #define VL6180_ALS_GAIN_20 0x40
83 #define VL6180_ALS_GAIN_40 0x47
84 
85 struct vl6180_data {
86 	struct i2c_client *client;
87 	struct mutex lock;
88 	unsigned int als_gain_milli;
89 	unsigned int als_it_ms;
90 };
91 
92 enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
93 
94 /**
95  * struct vl6180_chan_regs - Registers for accessing channels
96  * @drdy_mask:			Data ready bit in status register
97  * @start_reg:			Conversion start register
98  * @value_reg:			Result value register
99  * @word:			Register word length
100  */
101 struct vl6180_chan_regs {
102 	u8 drdy_mask;
103 	u16 start_reg, value_reg;
104 	bool word;
105 };
106 
107 static const struct vl6180_chan_regs vl6180_chan_regs_table[] = {
108 	[VL6180_ALS] = {
109 		.drdy_mask = VL6180_ALS_READY,
110 		.start_reg = VL6180_ALS_START,
111 		.value_reg = VL6180_ALS_VALUE,
112 		.word = true,
113 	},
114 	[VL6180_RANGE] = {
115 		.drdy_mask = VL6180_RANGE_READY,
116 		.start_reg = VL6180_RANGE_START,
117 		.value_reg = VL6180_RANGE_VALUE,
118 		.word = false,
119 	},
120 	[VL6180_PROX] = {
121 		.drdy_mask = VL6180_RANGE_READY,
122 		.start_reg = VL6180_RANGE_START,
123 		.value_reg = VL6180_RANGE_RATE,
124 		.word = true,
125 	},
126 };
127 
128 static int vl6180_read(struct i2c_client *client, u16 cmd, void *databuf,
129 		       u8 len)
130 {
131 	__be16 cmdbuf = cpu_to_be16(cmd);
132 	struct i2c_msg msgs[2] = {
133 		{ .addr = client->addr, .len = sizeof(cmdbuf), .buf = (u8 *) &cmdbuf },
134 		{ .addr = client->addr, .len = len, .buf = databuf,
135 		  .flags = I2C_M_RD } };
136 	int ret;
137 
138 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
139 	if (ret < 0)
140 		dev_err(&client->dev, "failed reading register 0x%04x\n", cmd);
141 
142 	return ret;
143 }
144 
145 static int vl6180_read_byte(struct i2c_client *client, u16 cmd)
146 {
147 	u8 data;
148 	int ret;
149 
150 	ret = vl6180_read(client, cmd, &data, sizeof(data));
151 	if (ret < 0)
152 		return ret;
153 
154 	return data;
155 }
156 
157 static int vl6180_read_word(struct i2c_client *client, u16 cmd)
158 {
159 	__be16 data;
160 	int ret;
161 
162 	ret = vl6180_read(client, cmd, &data, sizeof(data));
163 	if (ret < 0)
164 		return ret;
165 
166 	return be16_to_cpu(data);
167 }
168 
169 static int vl6180_write_byte(struct i2c_client *client, u16 cmd, u8 val)
170 {
171 	u8 buf[3];
172 	struct i2c_msg msgs[1] = {
173 		{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
174 	int ret;
175 
176 	buf[0] = cmd >> 8;
177 	buf[1] = cmd & 0xff;
178 	buf[2] = val;
179 
180 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
181 	if (ret < 0) {
182 		dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
183 		return ret;
184 	}
185 
186 	return 0;
187 }
188 
189 static int vl6180_write_word(struct i2c_client *client, u16 cmd, u16 val)
190 {
191 	__be16 buf[2];
192 	struct i2c_msg msgs[1] = {
193 		{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
194 	int ret;
195 
196 	buf[0] = cpu_to_be16(cmd);
197 	buf[1] = cpu_to_be16(val);
198 
199 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
200 	if (ret < 0) {
201 		dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
202 		return ret;
203 	}
204 
205 	return 0;
206 }
207 
208 static int vl6180_measure(struct vl6180_data *data, int addr)
209 {
210 	struct i2c_client *client = data->client;
211 	int tries = 20, ret;
212 	u16 value;
213 
214 	mutex_lock(&data->lock);
215 	/* Start single shot measurement */
216 	ret = vl6180_write_byte(client,
217 		vl6180_chan_regs_table[addr].start_reg, VL6180_STARTSTOP);
218 	if (ret < 0)
219 		goto fail;
220 
221 	while (tries--) {
222 		ret = vl6180_read_byte(client, VL6180_INTR_STATUS);
223 		if (ret < 0)
224 			goto fail;
225 
226 		if (ret & vl6180_chan_regs_table[addr].drdy_mask)
227 			break;
228 		msleep(20);
229 	}
230 
231 	if (tries < 0) {
232 		ret = -EIO;
233 		goto fail;
234 	}
235 
236 	/* Read result value from appropriate registers */
237 	ret = vl6180_chan_regs_table[addr].word ?
238 		vl6180_read_word(client, vl6180_chan_regs_table[addr].value_reg) :
239 		vl6180_read_byte(client, vl6180_chan_regs_table[addr].value_reg);
240 	if (ret < 0)
241 		goto fail;
242 	value = ret;
243 
244 	/* Clear the interrupt flag after data read */
245 	ret = vl6180_write_byte(client, VL6180_INTR_CLEAR,
246 		VL6180_CLEAR_ERROR | VL6180_CLEAR_ALS | VL6180_CLEAR_RANGE);
247 	if (ret < 0)
248 		goto fail;
249 
250 	ret = value;
251 
252 fail:
253 	mutex_unlock(&data->lock);
254 
255 	return ret;
256 }
257 
258 static const struct iio_chan_spec vl6180_channels[] = {
259 	{
260 		.type = IIO_LIGHT,
261 		.address = VL6180_ALS,
262 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
263 			BIT(IIO_CHAN_INFO_INT_TIME) |
264 			BIT(IIO_CHAN_INFO_SCALE) |
265 			BIT(IIO_CHAN_INFO_HARDWAREGAIN),
266 	}, {
267 		.type = IIO_DISTANCE,
268 		.address = VL6180_RANGE,
269 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
270 			BIT(IIO_CHAN_INFO_SCALE),
271 	}, {
272 		.type = IIO_PROXIMITY,
273 		.address = VL6180_PROX,
274 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
275 	}
276 };
277 
278 /*
279  * Available Ambient Light Sensor gain settings, 1/1000th, and
280  * corresponding setting for the VL6180_ALS_GAIN register
281  */
282 static const int vl6180_als_gain_tab[8] = {
283 	1000, 1250, 1670, 2500, 5000, 10000, 20000, 40000
284 };
285 static const u8 vl6180_als_gain_tab_bits[8] = {
286 	VL6180_ALS_GAIN_1,    VL6180_ALS_GAIN_1_25,
287 	VL6180_ALS_GAIN_1_67, VL6180_ALS_GAIN_2_5,
288 	VL6180_ALS_GAIN_5,    VL6180_ALS_GAIN_10,
289 	VL6180_ALS_GAIN_20,   VL6180_ALS_GAIN_40
290 };
291 
292 static int vl6180_read_raw(struct iio_dev *indio_dev,
293 				struct iio_chan_spec const *chan,
294 				int *val, int *val2, long mask)
295 {
296 	struct vl6180_data *data = iio_priv(indio_dev);
297 	int ret;
298 
299 	switch (mask) {
300 	case IIO_CHAN_INFO_RAW:
301 		ret = vl6180_measure(data, chan->address);
302 		if (ret < 0)
303 			return ret;
304 		*val = ret;
305 
306 		return IIO_VAL_INT;
307 	case IIO_CHAN_INFO_INT_TIME:
308 		*val = data->als_it_ms;
309 		*val2 = 1000;
310 
311 		return IIO_VAL_FRACTIONAL;
312 
313 	case IIO_CHAN_INFO_SCALE:
314 		switch (chan->type) {
315 		case IIO_LIGHT:
316 			/* one ALS count is 0.32 Lux @ gain 1, IT 100 ms */
317 			*val = 32000; /* 0.32 * 1000 * 100 */
318 			*val2 = data->als_gain_milli * data->als_it_ms;
319 
320 			return IIO_VAL_FRACTIONAL;
321 
322 		case IIO_DISTANCE:
323 			*val = 0; /* sensor reports mm, scale to meter */
324 			*val2 = 1000;
325 			break;
326 		default:
327 			return -EINVAL;
328 		}
329 
330 		return IIO_VAL_INT_PLUS_MICRO;
331 	case IIO_CHAN_INFO_HARDWAREGAIN:
332 		*val = data->als_gain_milli;
333 		*val2 = 1000;
334 
335 		return IIO_VAL_FRACTIONAL;
336 
337 	default:
338 		return -EINVAL;
339 	}
340 }
341 
342 static IIO_CONST_ATTR(als_gain_available, "1 1.25 1.67 2.5 5 10 20 40");
343 
344 static struct attribute *vl6180_attributes[] = {
345 	&iio_const_attr_als_gain_available.dev_attr.attr,
346 	NULL
347 };
348 
349 static const struct attribute_group vl6180_attribute_group = {
350 	.attrs = vl6180_attributes,
351 };
352 
353 /* HOLD is needed before updating any config registers */
354 static int vl6180_hold(struct vl6180_data *data, bool hold)
355 {
356 	return vl6180_write_byte(data->client, VL6180_HOLD,
357 		hold ? VL6180_HOLD_ON : 0);
358 }
359 
360 static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2)
361 {
362 	int i, ret, gain;
363 
364 	if (val < 1 || val > 40)
365 		return -EINVAL;
366 
367 	gain = (val * 1000000 + val2) / 1000;
368 	if (gain < 1 || gain > 40000)
369 		return -EINVAL;
370 
371 	i = find_closest(gain, vl6180_als_gain_tab,
372 			 ARRAY_SIZE(vl6180_als_gain_tab));
373 
374 	mutex_lock(&data->lock);
375 	ret = vl6180_hold(data, true);
376 	if (ret < 0)
377 		goto fail;
378 
379 	ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN,
380 				vl6180_als_gain_tab_bits[i]);
381 
382 	if (ret >= 0)
383 		data->als_gain_milli = vl6180_als_gain_tab[i];
384 
385 fail:
386 	vl6180_hold(data, false);
387 	mutex_unlock(&data->lock);
388 	return ret;
389 }
390 
391 static int vl6180_set_it(struct vl6180_data *data, int val, int val2)
392 {
393 	int ret, it_ms;
394 
395 	it_ms = DIV_ROUND_CLOSEST(val2, 1000); /* round to ms */
396 	if (val != 0 || it_ms < 1 || it_ms > 512)
397 		return -EINVAL;
398 
399 	mutex_lock(&data->lock);
400 	ret = vl6180_hold(data, true);
401 	if (ret < 0)
402 		goto fail;
403 
404 	ret = vl6180_write_word(data->client, VL6180_ALS_IT, it_ms - 1);
405 
406 	if (ret >= 0)
407 		data->als_it_ms = it_ms;
408 
409 fail:
410 	vl6180_hold(data, false);
411 	mutex_unlock(&data->lock);
412 
413 	return ret;
414 }
415 
416 static int vl6180_write_raw(struct iio_dev *indio_dev,
417 			     struct iio_chan_spec const *chan,
418 			     int val, int val2, long mask)
419 {
420 	struct vl6180_data *data = iio_priv(indio_dev);
421 
422 	switch (mask) {
423 	case IIO_CHAN_INFO_INT_TIME:
424 		return vl6180_set_it(data, val, val2);
425 
426 	case IIO_CHAN_INFO_HARDWAREGAIN:
427 		if (chan->type != IIO_LIGHT)
428 			return -EINVAL;
429 
430 		return vl6180_set_als_gain(data, val, val2);
431 	default:
432 		return -EINVAL;
433 	}
434 }
435 
436 static const struct iio_info vl6180_info = {
437 	.read_raw = vl6180_read_raw,
438 	.write_raw = vl6180_write_raw,
439 	.attrs = &vl6180_attribute_group,
440 };
441 
442 static int vl6180_init(struct vl6180_data *data)
443 {
444 	struct i2c_client *client = data->client;
445 	int ret;
446 
447 	ret = vl6180_read_byte(client, VL6180_MODEL_ID);
448 	if (ret < 0)
449 		return ret;
450 
451 	if (ret != VL6180_MODEL_ID_VAL) {
452 		dev_err(&client->dev, "invalid model ID %02x\n", ret);
453 		return -ENODEV;
454 	}
455 
456 	ret = vl6180_hold(data, true);
457 	if (ret < 0)
458 		return ret;
459 
460 	ret = vl6180_read_byte(client, VL6180_OUT_OF_RESET);
461 	if (ret < 0)
462 		return ret;
463 
464 	/*
465 	 * Detect false reset condition here. This bit is always set when the
466 	 * system comes out of reset.
467 	 */
468 	if (ret != 0x01)
469 		dev_info(&client->dev, "device is not fresh out of reset\n");
470 
471 	/* Enable ALS and Range ready interrupts */
472 	ret = vl6180_write_byte(client, VL6180_INTR_CONFIG,
473 				VL6180_ALS_READY | VL6180_RANGE_READY);
474 	if (ret < 0)
475 		return ret;
476 
477 	/* ALS integration time: 100ms */
478 	data->als_it_ms = 100;
479 	ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
480 	if (ret < 0)
481 		return ret;
482 
483 	/* ALS gain: 1 */
484 	data->als_gain_milli = 1000;
485 	ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1);
486 	if (ret < 0)
487 		return ret;
488 
489 	ret = vl6180_write_byte(client, VL6180_OUT_OF_RESET, 0x00);
490 	if (ret < 0)
491 		return ret;
492 
493 	return vl6180_hold(data, false);
494 }
495 
496 static int vl6180_probe(struct i2c_client *client)
497 {
498 	struct vl6180_data *data;
499 	struct iio_dev *indio_dev;
500 	int ret;
501 
502 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
503 	if (!indio_dev)
504 		return -ENOMEM;
505 
506 	data = iio_priv(indio_dev);
507 	i2c_set_clientdata(client, indio_dev);
508 	data->client = client;
509 	mutex_init(&data->lock);
510 
511 	indio_dev->info = &vl6180_info;
512 	indio_dev->channels = vl6180_channels;
513 	indio_dev->num_channels = ARRAY_SIZE(vl6180_channels);
514 	indio_dev->name = VL6180_DRV_NAME;
515 	indio_dev->modes = INDIO_DIRECT_MODE;
516 
517 	ret = vl6180_init(data);
518 	if (ret < 0)
519 		return ret;
520 
521 	return devm_iio_device_register(&client->dev, indio_dev);
522 }
523 
524 static const struct of_device_id vl6180_of_match[] = {
525 	{ .compatible = "st,vl6180", },
526 	{ },
527 };
528 MODULE_DEVICE_TABLE(of, vl6180_of_match);
529 
530 static const struct i2c_device_id vl6180_id[] = {
531 	{ "vl6180", 0 },
532 	{ }
533 };
534 MODULE_DEVICE_TABLE(i2c, vl6180_id);
535 
536 static struct i2c_driver vl6180_driver = {
537 	.driver = {
538 		.name   = VL6180_DRV_NAME,
539 		.of_match_table = vl6180_of_match,
540 	},
541 	.probe_new = vl6180_probe,
542 	.id_table = vl6180_id,
543 };
544 
545 module_i2c_driver(vl6180_driver);
546 
547 MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
548 MODULE_AUTHOR("Manivannan Sadhasivam <manivannanece23@gmail.com>");
549 MODULE_DESCRIPTION("STMicro VL6180 ALS, range and proximity sensor driver");
550 MODULE_LICENSE("GPL");
551