1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * MAX44000 Ambient and Infrared Proximity Sensor
4 *
5 * Copyright (c) 2016, Intel Corporation.
6 *
7 * Data sheet: https://datasheets.maximintegrated.com/en/ds/MAX44000.pdf
8 *
9 * 7-bit I2C slave address 0x4a
10 */
11
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/i2c.h>
15 #include <linux/regmap.h>
16 #include <linux/util_macros.h>
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/trigger_consumer.h>
21 #include <linux/iio/triggered_buffer.h>
22
23 #define MAX44000_DRV_NAME "max44000"
24
25 /* Registers in datasheet order */
26 #define MAX44000_REG_STATUS 0x00
27 #define MAX44000_REG_CFG_MAIN 0x01
28 #define MAX44000_REG_CFG_RX 0x02
29 #define MAX44000_REG_CFG_TX 0x03
30 #define MAX44000_REG_ALS_DATA_HI 0x04
31 #define MAX44000_REG_ALS_DATA_LO 0x05
32 #define MAX44000_REG_PRX_DATA 0x16
33 #define MAX44000_REG_ALS_UPTHR_HI 0x06
34 #define MAX44000_REG_ALS_UPTHR_LO 0x07
35 #define MAX44000_REG_ALS_LOTHR_HI 0x08
36 #define MAX44000_REG_ALS_LOTHR_LO 0x09
37 #define MAX44000_REG_PST 0x0a
38 #define MAX44000_REG_PRX_IND 0x0b
39 #define MAX44000_REG_PRX_THR 0x0c
40 #define MAX44000_REG_TRIM_GAIN_GREEN 0x0f
41 #define MAX44000_REG_TRIM_GAIN_IR 0x10
42
43 /* REG_CFG bits */
44 #define MAX44000_CFG_ALSINTE 0x01
45 #define MAX44000_CFG_PRXINTE 0x02
46 #define MAX44000_CFG_MASK 0x1c
47 #define MAX44000_CFG_MODE_SHUTDOWN 0x00
48 #define MAX44000_CFG_MODE_ALS_GIR 0x04
49 #define MAX44000_CFG_MODE_ALS_G 0x08
50 #define MAX44000_CFG_MODE_ALS_IR 0x0c
51 #define MAX44000_CFG_MODE_ALS_PRX 0x10
52 #define MAX44000_CFG_MODE_PRX 0x14
53 #define MAX44000_CFG_TRIM 0x20
54
55 /*
56 * Upper 4 bits are not documented but start as 1 on powerup
57 * Setting them to 0 causes proximity to misbehave so set them to 1
58 */
59 #define MAX44000_REG_CFG_RX_DEFAULT 0xf0
60
61 /* REG_RX bits */
62 #define MAX44000_CFG_RX_ALSTIM_MASK 0x0c
63 #define MAX44000_CFG_RX_ALSTIM_SHIFT 2
64 #define MAX44000_CFG_RX_ALSPGA_MASK 0x03
65 #define MAX44000_CFG_RX_ALSPGA_SHIFT 0
66
67 /* REG_TX bits */
68 #define MAX44000_LED_CURRENT_MASK 0xf
69 #define MAX44000_LED_CURRENT_MAX 11
70 #define MAX44000_LED_CURRENT_DEFAULT 6
71
72 #define MAX44000_ALSDATA_OVERFLOW 0x4000
73
74 struct max44000_data {
75 struct mutex lock;
76 struct regmap *regmap;
77 };
78
79 /* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */
80 #define MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 5
81
82 /* Scale can be multiplied by up to 128x via ALSPGA for measurement gain */
83 static const int max44000_alspga_shift[] = {0, 2, 4, 7};
84 #define MAX44000_ALSPGA_MAX_SHIFT 7
85
86 /*
87 * Scale can be multiplied by up to 64x via ALSTIM because of lost resolution
88 *
89 * This scaling factor is hidden from userspace and instead accounted for when
90 * reading raw values from the device.
91 *
92 * This makes it possible to cleanly expose ALSPGA as IIO_CHAN_INFO_SCALE and
93 * ALSTIM as IIO_CHAN_INFO_INT_TIME without the values affecting each other.
94 *
95 * Handling this internally is also required for buffer support because the
96 * channel's scan_type can't be modified dynamically.
97 */
98 #define MAX44000_ALSTIM_SHIFT(alstim) (2 * (alstim))
99
100 /* Available integration times with pretty manual alignment: */
101 static const int max44000_int_time_avail_ns_array[] = {
102 100000000,
103 25000000,
104 6250000,
105 1562500,
106 };
107 static const char max44000_int_time_avail_str[] =
108 "0.100 "
109 "0.025 "
110 "0.00625 "
111 "0.0015625";
112
113 /* Available scales (internal to ulux) with pretty manual alignment: */
114 static const int max44000_scale_avail_ulux_array[] = {
115 31250,
116 125000,
117 500000,
118 4000000,
119 };
120 static const char max44000_scale_avail_str[] =
121 "0.03125 "
122 "0.125 "
123 "0.5 "
124 "4";
125
126 #define MAX44000_SCAN_INDEX_ALS 0
127 #define MAX44000_SCAN_INDEX_PRX 1
128
129 static const struct iio_chan_spec max44000_channels[] = {
130 {
131 .type = IIO_LIGHT,
132 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
133 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
134 BIT(IIO_CHAN_INFO_INT_TIME),
135 .scan_index = MAX44000_SCAN_INDEX_ALS,
136 .scan_type = {
137 .sign = 'u',
138 .realbits = 14,
139 .storagebits = 16,
140 }
141 },
142 {
143 .type = IIO_PROXIMITY,
144 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
145 .scan_index = MAX44000_SCAN_INDEX_PRX,
146 .scan_type = {
147 .sign = 'u',
148 .realbits = 8,
149 .storagebits = 16,
150 }
151 },
152 IIO_CHAN_SOFT_TIMESTAMP(2),
153 {
154 .type = IIO_CURRENT,
155 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
156 BIT(IIO_CHAN_INFO_SCALE),
157 .extend_name = "led",
158 .output = 1,
159 .scan_index = -1,
160 },
161 };
162
max44000_read_alstim(struct max44000_data * data)163 static int max44000_read_alstim(struct max44000_data *data)
164 {
165 unsigned int val;
166 int ret;
167
168 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
169 if (ret < 0)
170 return ret;
171 return (val & MAX44000_CFG_RX_ALSTIM_MASK) >> MAX44000_CFG_RX_ALSTIM_SHIFT;
172 }
173
max44000_write_alstim(struct max44000_data * data,int val)174 static int max44000_write_alstim(struct max44000_data *data, int val)
175 {
176 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
177 MAX44000_CFG_RX_ALSTIM_MASK,
178 val << MAX44000_CFG_RX_ALSTIM_SHIFT);
179 }
180
max44000_read_alspga(struct max44000_data * data)181 static int max44000_read_alspga(struct max44000_data *data)
182 {
183 unsigned int val;
184 int ret;
185
186 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
187 if (ret < 0)
188 return ret;
189 return (val & MAX44000_CFG_RX_ALSPGA_MASK) >> MAX44000_CFG_RX_ALSPGA_SHIFT;
190 }
191
max44000_write_alspga(struct max44000_data * data,int val)192 static int max44000_write_alspga(struct max44000_data *data, int val)
193 {
194 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
195 MAX44000_CFG_RX_ALSPGA_MASK,
196 val << MAX44000_CFG_RX_ALSPGA_SHIFT);
197 }
198
max44000_read_alsval(struct max44000_data * data)199 static int max44000_read_alsval(struct max44000_data *data)
200 {
201 u16 regval;
202 __be16 val;
203 int alstim, ret;
204
205 ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI,
206 &val, sizeof(val));
207 if (ret < 0)
208 return ret;
209 alstim = ret = max44000_read_alstim(data);
210 if (ret < 0)
211 return ret;
212
213 regval = be16_to_cpu(val);
214
215 /*
216 * Overflow is explained on datasheet page 17.
217 *
218 * It's a warning that either the G or IR channel has become saturated
219 * and that the value in the register is likely incorrect.
220 *
221 * The recommendation is to change the scale (ALSPGA).
222 * The driver just returns the max representable value.
223 */
224 if (regval & MAX44000_ALSDATA_OVERFLOW)
225 return 0x3FFF;
226
227 return regval << MAX44000_ALSTIM_SHIFT(alstim);
228 }
229
max44000_write_led_current_raw(struct max44000_data * data,int val)230 static int max44000_write_led_current_raw(struct max44000_data *data, int val)
231 {
232 /* Maybe we should clamp the value instead? */
233 if (val < 0 || val > MAX44000_LED_CURRENT_MAX)
234 return -ERANGE;
235 if (val >= 8)
236 val += 4;
237 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX,
238 MAX44000_LED_CURRENT_MASK, val);
239 }
240
max44000_read_led_current_raw(struct max44000_data * data)241 static int max44000_read_led_current_raw(struct max44000_data *data)
242 {
243 unsigned int regval;
244 int ret;
245
246 ret = regmap_read(data->regmap, MAX44000_REG_CFG_TX, ®val);
247 if (ret < 0)
248 return ret;
249 regval &= MAX44000_LED_CURRENT_MASK;
250 if (regval >= 8)
251 regval -= 4;
252 return regval;
253 }
254
max44000_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)255 static int max44000_read_raw(struct iio_dev *indio_dev,
256 struct iio_chan_spec const *chan,
257 int *val, int *val2, long mask)
258 {
259 struct max44000_data *data = iio_priv(indio_dev);
260 int alstim, alspga;
261 unsigned int regval;
262 int ret;
263
264 switch (mask) {
265 case IIO_CHAN_INFO_RAW:
266 switch (chan->type) {
267 case IIO_LIGHT:
268 mutex_lock(&data->lock);
269 ret = max44000_read_alsval(data);
270 mutex_unlock(&data->lock);
271 if (ret < 0)
272 return ret;
273 *val = ret;
274 return IIO_VAL_INT;
275
276 case IIO_PROXIMITY:
277 mutex_lock(&data->lock);
278 ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val);
279 mutex_unlock(&data->lock);
280 if (ret < 0)
281 return ret;
282 *val = regval;
283 return IIO_VAL_INT;
284
285 case IIO_CURRENT:
286 mutex_lock(&data->lock);
287 ret = max44000_read_led_current_raw(data);
288 mutex_unlock(&data->lock);
289 if (ret < 0)
290 return ret;
291 *val = ret;
292 return IIO_VAL_INT;
293
294 default:
295 return -EINVAL;
296 }
297
298 case IIO_CHAN_INFO_SCALE:
299 switch (chan->type) {
300 case IIO_CURRENT:
301 /* Output register is in 10s of miliamps */
302 *val = 10;
303 return IIO_VAL_INT;
304
305 case IIO_LIGHT:
306 mutex_lock(&data->lock);
307 alspga = ret = max44000_read_alspga(data);
308 mutex_unlock(&data->lock);
309 if (ret < 0)
310 return ret;
311
312 /* Avoid negative shifts */
313 *val = (1 << MAX44000_ALSPGA_MAX_SHIFT);
314 *val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2
315 + MAX44000_ALSPGA_MAX_SHIFT
316 - max44000_alspga_shift[alspga];
317 return IIO_VAL_FRACTIONAL_LOG2;
318
319 default:
320 return -EINVAL;
321 }
322
323 case IIO_CHAN_INFO_INT_TIME:
324 mutex_lock(&data->lock);
325 alstim = ret = max44000_read_alstim(data);
326 mutex_unlock(&data->lock);
327
328 if (ret < 0)
329 return ret;
330 *val = 0;
331 *val2 = max44000_int_time_avail_ns_array[alstim];
332 return IIO_VAL_INT_PLUS_NANO;
333
334 default:
335 return -EINVAL;
336 }
337 }
338
max44000_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)339 static int max44000_write_raw(struct iio_dev *indio_dev,
340 struct iio_chan_spec const *chan,
341 int val, int val2, long mask)
342 {
343 struct max44000_data *data = iio_priv(indio_dev);
344 int ret;
345
346 if (mask == IIO_CHAN_INFO_RAW && chan->type == IIO_CURRENT) {
347 mutex_lock(&data->lock);
348 ret = max44000_write_led_current_raw(data, val);
349 mutex_unlock(&data->lock);
350 return ret;
351 } else if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) {
352 s64 valns = val * NSEC_PER_SEC + val2;
353 int alstim = find_closest_descending(valns,
354 max44000_int_time_avail_ns_array,
355 ARRAY_SIZE(max44000_int_time_avail_ns_array));
356 mutex_lock(&data->lock);
357 ret = max44000_write_alstim(data, alstim);
358 mutex_unlock(&data->lock);
359 return ret;
360 } else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) {
361 s64 valus = val * USEC_PER_SEC + val2;
362 int alspga = find_closest(valus,
363 max44000_scale_avail_ulux_array,
364 ARRAY_SIZE(max44000_scale_avail_ulux_array));
365 mutex_lock(&data->lock);
366 ret = max44000_write_alspga(data, alspga);
367 mutex_unlock(&data->lock);
368 return ret;
369 }
370
371 return -EINVAL;
372 }
373
max44000_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)374 static int max44000_write_raw_get_fmt(struct iio_dev *indio_dev,
375 struct iio_chan_spec const *chan,
376 long mask)
377 {
378 if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT)
379 return IIO_VAL_INT_PLUS_NANO;
380 else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT)
381 return IIO_VAL_INT_PLUS_MICRO;
382 else
383 return IIO_VAL_INT;
384 }
385
386 static IIO_CONST_ATTR(illuminance_integration_time_available, max44000_int_time_avail_str);
387 static IIO_CONST_ATTR(illuminance_scale_available, max44000_scale_avail_str);
388
389 static struct attribute *max44000_attributes[] = {
390 &iio_const_attr_illuminance_integration_time_available.dev_attr.attr,
391 &iio_const_attr_illuminance_scale_available.dev_attr.attr,
392 NULL
393 };
394
395 static const struct attribute_group max44000_attribute_group = {
396 .attrs = max44000_attributes,
397 };
398
399 static const struct iio_info max44000_info = {
400 .read_raw = max44000_read_raw,
401 .write_raw = max44000_write_raw,
402 .write_raw_get_fmt = max44000_write_raw_get_fmt,
403 .attrs = &max44000_attribute_group,
404 };
405
max44000_readable_reg(struct device * dev,unsigned int reg)406 static bool max44000_readable_reg(struct device *dev, unsigned int reg)
407 {
408 switch (reg) {
409 case MAX44000_REG_STATUS:
410 case MAX44000_REG_CFG_MAIN:
411 case MAX44000_REG_CFG_RX:
412 case MAX44000_REG_CFG_TX:
413 case MAX44000_REG_ALS_DATA_HI:
414 case MAX44000_REG_ALS_DATA_LO:
415 case MAX44000_REG_PRX_DATA:
416 case MAX44000_REG_ALS_UPTHR_HI:
417 case MAX44000_REG_ALS_UPTHR_LO:
418 case MAX44000_REG_ALS_LOTHR_HI:
419 case MAX44000_REG_ALS_LOTHR_LO:
420 case MAX44000_REG_PST:
421 case MAX44000_REG_PRX_IND:
422 case MAX44000_REG_PRX_THR:
423 case MAX44000_REG_TRIM_GAIN_GREEN:
424 case MAX44000_REG_TRIM_GAIN_IR:
425 return true;
426 default:
427 return false;
428 }
429 }
430
max44000_writeable_reg(struct device * dev,unsigned int reg)431 static bool max44000_writeable_reg(struct device *dev, unsigned int reg)
432 {
433 switch (reg) {
434 case MAX44000_REG_CFG_MAIN:
435 case MAX44000_REG_CFG_RX:
436 case MAX44000_REG_CFG_TX:
437 case MAX44000_REG_ALS_UPTHR_HI:
438 case MAX44000_REG_ALS_UPTHR_LO:
439 case MAX44000_REG_ALS_LOTHR_HI:
440 case MAX44000_REG_ALS_LOTHR_LO:
441 case MAX44000_REG_PST:
442 case MAX44000_REG_PRX_IND:
443 case MAX44000_REG_PRX_THR:
444 case MAX44000_REG_TRIM_GAIN_GREEN:
445 case MAX44000_REG_TRIM_GAIN_IR:
446 return true;
447 default:
448 return false;
449 }
450 }
451
max44000_volatile_reg(struct device * dev,unsigned int reg)452 static bool max44000_volatile_reg(struct device *dev, unsigned int reg)
453 {
454 switch (reg) {
455 case MAX44000_REG_STATUS:
456 case MAX44000_REG_ALS_DATA_HI:
457 case MAX44000_REG_ALS_DATA_LO:
458 case MAX44000_REG_PRX_DATA:
459 return true;
460 default:
461 return false;
462 }
463 }
464
max44000_precious_reg(struct device * dev,unsigned int reg)465 static bool max44000_precious_reg(struct device *dev, unsigned int reg)
466 {
467 return reg == MAX44000_REG_STATUS;
468 }
469
470 static const struct regmap_config max44000_regmap_config = {
471 .reg_bits = 8,
472 .val_bits = 8,
473
474 .max_register = MAX44000_REG_PRX_DATA,
475 .readable_reg = max44000_readable_reg,
476 .writeable_reg = max44000_writeable_reg,
477 .volatile_reg = max44000_volatile_reg,
478 .precious_reg = max44000_precious_reg,
479
480 .use_single_read = true,
481 .use_single_write = true,
482 .cache_type = REGCACHE_RBTREE,
483 };
484
max44000_trigger_handler(int irq,void * p)485 static irqreturn_t max44000_trigger_handler(int irq, void *p)
486 {
487 struct iio_poll_func *pf = p;
488 struct iio_dev *indio_dev = pf->indio_dev;
489 struct max44000_data *data = iio_priv(indio_dev);
490 int index = 0;
491 unsigned int regval;
492 int ret;
493 struct {
494 u16 channels[2];
495 aligned_s64 ts;
496 } scan = { };
497
498
499 mutex_lock(&data->lock);
500 if (test_bit(MAX44000_SCAN_INDEX_ALS, indio_dev->active_scan_mask)) {
501 ret = max44000_read_alsval(data);
502 if (ret < 0)
503 goto out_unlock;
504 scan.channels[index++] = ret;
505 }
506 if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) {
507 ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val);
508 if (ret < 0)
509 goto out_unlock;
510 scan.channels[index] = regval;
511 }
512 mutex_unlock(&data->lock);
513
514 iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
515 iio_get_time_ns(indio_dev));
516 iio_trigger_notify_done(indio_dev->trig);
517 return IRQ_HANDLED;
518
519 out_unlock:
520 mutex_unlock(&data->lock);
521 iio_trigger_notify_done(indio_dev->trig);
522 return IRQ_HANDLED;
523 }
524
max44000_probe(struct i2c_client * client)525 static int max44000_probe(struct i2c_client *client)
526 {
527 struct max44000_data *data;
528 struct iio_dev *indio_dev;
529 int ret, reg;
530
531 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
532 if (!indio_dev)
533 return -ENOMEM;
534 data = iio_priv(indio_dev);
535 data->regmap = devm_regmap_init_i2c(client, &max44000_regmap_config);
536 if (IS_ERR(data->regmap)) {
537 dev_err(&client->dev, "regmap_init failed!\n");
538 return PTR_ERR(data->regmap);
539 }
540
541 mutex_init(&data->lock);
542 indio_dev->info = &max44000_info;
543 indio_dev->name = MAX44000_DRV_NAME;
544 indio_dev->channels = max44000_channels;
545 indio_dev->num_channels = ARRAY_SIZE(max44000_channels);
546
547 /*
548 * The device doesn't have a reset function so we just clear some
549 * important bits at probe time to ensure sane operation.
550 *
551 * Since we don't support interrupts/events the threshold values are
552 * not important. We also don't touch trim values.
553 */
554
555 /* Reset ALS scaling bits */
556 ret = regmap_write(data->regmap, MAX44000_REG_CFG_RX,
557 MAX44000_REG_CFG_RX_DEFAULT);
558 if (ret < 0) {
559 dev_err(&client->dev, "failed to write default CFG_RX: %d\n",
560 ret);
561 return ret;
562 }
563
564 /*
565 * By default the LED pulse used for the proximity sensor is disabled.
566 * Set a middle value so that we get some sort of valid data by default.
567 */
568 ret = max44000_write_led_current_raw(data, MAX44000_LED_CURRENT_DEFAULT);
569 if (ret < 0) {
570 dev_err(&client->dev, "failed to write init config: %d\n", ret);
571 return ret;
572 }
573
574 /* Reset CFG bits to ALS_PRX mode which allows easy reading of both values. */
575 reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX;
576 ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg);
577 if (ret < 0) {
578 dev_err(&client->dev, "failed to write init config: %d\n", ret);
579 return ret;
580 }
581
582 /* Read status at least once to clear any stale interrupt bits. */
583 ret = regmap_read(data->regmap, MAX44000_REG_STATUS, ®);
584 if (ret < 0) {
585 dev_err(&client->dev, "failed to read init status: %d\n", ret);
586 return ret;
587 }
588
589 ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
590 max44000_trigger_handler, NULL);
591 if (ret < 0) {
592 dev_err(&client->dev, "iio triggered buffer setup failed\n");
593 return ret;
594 }
595
596 return devm_iio_device_register(&client->dev, indio_dev);
597 }
598
599 static const struct i2c_device_id max44000_id[] = {
600 { .name = "max44000" },
601 { }
602 };
603 MODULE_DEVICE_TABLE(i2c, max44000_id);
604
605 static const struct acpi_device_id max44000_acpi_match[] = {
606 {"MAX44000", 0},
607 { }
608 };
609 MODULE_DEVICE_TABLE(acpi, max44000_acpi_match);
610
611 static struct i2c_driver max44000_driver = {
612 .driver = {
613 .name = MAX44000_DRV_NAME,
614 .acpi_match_table = max44000_acpi_match,
615 },
616 .probe = max44000_probe,
617 .id_table = max44000_id,
618 };
619
620 module_i2c_driver(max44000_driver);
621
622 MODULE_AUTHOR("Crestez Dan Leonard <leonard.crestez@intel.com>");
623 MODULE_DESCRIPTION("MAX44000 Ambient and Infrared Proximity Sensor");
624 MODULE_LICENSE("GPL v2");
625