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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#include <linux/acpi.h>
23
24#define MAX44000_DRV_NAME "max44000"
25
26/* Registers in datasheet order */
27#define MAX44000_REG_STATUS 0x00
28#define MAX44000_REG_CFG_MAIN 0x01
29#define MAX44000_REG_CFG_RX 0x02
30#define MAX44000_REG_CFG_TX 0x03
31#define MAX44000_REG_ALS_DATA_HI 0x04
32#define MAX44000_REG_ALS_DATA_LO 0x05
33#define MAX44000_REG_PRX_DATA 0x16
34#define MAX44000_REG_ALS_UPTHR_HI 0x06
35#define MAX44000_REG_ALS_UPTHR_LO 0x07
36#define MAX44000_REG_ALS_LOTHR_HI 0x08
37#define MAX44000_REG_ALS_LOTHR_LO 0x09
38#define MAX44000_REG_PST 0x0a
39#define MAX44000_REG_PRX_IND 0x0b
40#define MAX44000_REG_PRX_THR 0x0c
41#define MAX44000_REG_TRIM_GAIN_GREEN 0x0f
42#define MAX44000_REG_TRIM_GAIN_IR 0x10
43
44/* REG_CFG bits */
45#define MAX44000_CFG_ALSINTE 0x01
46#define MAX44000_CFG_PRXINTE 0x02
47#define MAX44000_CFG_MASK 0x1c
48#define MAX44000_CFG_MODE_SHUTDOWN 0x00
49#define MAX44000_CFG_MODE_ALS_GIR 0x04
50#define MAX44000_CFG_MODE_ALS_G 0x08
51#define MAX44000_CFG_MODE_ALS_IR 0x0c
52#define MAX44000_CFG_MODE_ALS_PRX 0x10
53#define MAX44000_CFG_MODE_PRX 0x14
54#define MAX44000_CFG_TRIM 0x20
55
56/*
57 * Upper 4 bits are not documented but start as 1 on powerup
58 * Setting them to 0 causes proximity to misbehave so set them to 1
59 */
60#define MAX44000_REG_CFG_RX_DEFAULT 0xf0
61
62/* REG_RX bits */
63#define MAX44000_CFG_RX_ALSTIM_MASK 0x0c
64#define MAX44000_CFG_RX_ALSTIM_SHIFT 2
65#define MAX44000_CFG_RX_ALSPGA_MASK 0x03
66#define MAX44000_CFG_RX_ALSPGA_SHIFT 0
67
68/* REG_TX bits */
69#define MAX44000_LED_CURRENT_MASK 0xf
70#define MAX44000_LED_CURRENT_MAX 11
71#define MAX44000_LED_CURRENT_DEFAULT 6
72
73#define MAX44000_ALSDATA_OVERFLOW 0x4000
74
75struct max44000_data {
76 struct mutex lock;
77 struct regmap *regmap;
78 /* Ensure naturally aligned timestamp */
79 struct {
80 u16 channels[2];
81 s64 ts __aligned(8);
82 } scan;
83};
84
85/* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */
86#define MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 5
87
88/* Scale can be multiplied by up to 128x via ALSPGA for measurement gain */
89static const int max44000_alspga_shift[] = {0, 2, 4, 7};
90#define MAX44000_ALSPGA_MAX_SHIFT 7
91
92/*
93 * Scale can be multiplied by up to 64x via ALSTIM because of lost resolution
94 *
95 * This scaling factor is hidden from userspace and instead accounted for when
96 * reading raw values from the device.
97 *
98 * This makes it possible to cleanly expose ALSPGA as IIO_CHAN_INFO_SCALE and
99 * ALSTIM as IIO_CHAN_INFO_INT_TIME without the values affecting each other.
100 *
101 * Handling this internally is also required for buffer support because the
102 * channel's scan_type can't be modified dynamically.
103 */
104#define MAX44000_ALSTIM_SHIFT(alstim) (2 * (alstim))
105
106/* Available integration times with pretty manual alignment: */
107static const int max44000_int_time_avail_ns_array[] = {
108 100000000,
109 25000000,
110 6250000,
111 1562500,
112};
113static const char max44000_int_time_avail_str[] =
114 "0.100 "
115 "0.025 "
116 "0.00625 "
117 "0.0015625";
118
119/* Available scales (internal to ulux) with pretty manual alignment: */
120static const int max44000_scale_avail_ulux_array[] = {
121 31250,
122 125000,
123 500000,
124 4000000,
125};
126static const char max44000_scale_avail_str[] =
127 "0.03125 "
128 "0.125 "
129 "0.5 "
130 "4";
131
132#define MAX44000_SCAN_INDEX_ALS 0
133#define MAX44000_SCAN_INDEX_PRX 1
134
135static const struct iio_chan_spec max44000_channels[] = {
136 {
137 .type = IIO_LIGHT,
138 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
139 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
140 BIT(IIO_CHAN_INFO_INT_TIME),
141 .scan_index = MAX44000_SCAN_INDEX_ALS,
142 .scan_type = {
143 .sign = 'u',
144 .realbits = 14,
145 .storagebits = 16,
146 }
147 },
148 {
149 .type = IIO_PROXIMITY,
150 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
151 .scan_index = MAX44000_SCAN_INDEX_PRX,
152 .scan_type = {
153 .sign = 'u',
154 .realbits = 8,
155 .storagebits = 16,
156 }
157 },
158 IIO_CHAN_SOFT_TIMESTAMP(2),
159 {
160 .type = IIO_CURRENT,
161 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
162 BIT(IIO_CHAN_INFO_SCALE),
163 .extend_name = "led",
164 .output = 1,
165 .scan_index = -1,
166 },
167};
168
169static int max44000_read_alstim(struct max44000_data *data)
170{
171 unsigned int val;
172 int ret;
173
174 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
175 if (ret < 0)
176 return ret;
177 return (val & MAX44000_CFG_RX_ALSTIM_MASK) >> MAX44000_CFG_RX_ALSTIM_SHIFT;
178}
179
180static int max44000_write_alstim(struct max44000_data *data, int val)
181{
182 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
183 MAX44000_CFG_RX_ALSTIM_MASK,
184 val << MAX44000_CFG_RX_ALSTIM_SHIFT);
185}
186
187static int max44000_read_alspga(struct max44000_data *data)
188{
189 unsigned int val;
190 int ret;
191
192 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
193 if (ret < 0)
194 return ret;
195 return (val & MAX44000_CFG_RX_ALSPGA_MASK) >> MAX44000_CFG_RX_ALSPGA_SHIFT;
196}
197
198static int max44000_write_alspga(struct max44000_data *data, int val)
199{
200 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
201 MAX44000_CFG_RX_ALSPGA_MASK,
202 val << MAX44000_CFG_RX_ALSPGA_SHIFT);
203}
204
205static int max44000_read_alsval(struct max44000_data *data)
206{
207 u16 regval;
208 __be16 val;
209 int alstim, ret;
210
211 ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI,
212 &val, sizeof(val));
213 if (ret < 0)
214 return ret;
215 alstim = ret = max44000_read_alstim(data);
216 if (ret < 0)
217 return ret;
218
219 regval = be16_to_cpu(val);
220
221 /*
222 * Overflow is explained on datasheet page 17.
223 *
224 * It's a warning that either the G or IR channel has become saturated
225 * and that the value in the register is likely incorrect.
226 *
227 * The recommendation is to change the scale (ALSPGA).
228 * The driver just returns the max representable value.
229 */
230 if (regval & MAX44000_ALSDATA_OVERFLOW)
231 return 0x3FFF;
232
233 return regval << MAX44000_ALSTIM_SHIFT(alstim);
234}
235
236static int max44000_write_led_current_raw(struct max44000_data *data, int val)
237{
238 /* Maybe we should clamp the value instead? */
239 if (val < 0 || val > MAX44000_LED_CURRENT_MAX)
240 return -ERANGE;
241 if (val >= 8)
242 val += 4;
243 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX,
244 MAX44000_LED_CURRENT_MASK, val);
245}
246
247static int max44000_read_led_current_raw(struct max44000_data *data)
248{
249 unsigned int regval;
250 int ret;
251
252 ret = regmap_read(data->regmap, MAX44000_REG_CFG_TX, ®val);
253 if (ret < 0)
254 return ret;
255 regval &= MAX44000_LED_CURRENT_MASK;
256 if (regval >= 8)
257 regval -= 4;
258 return regval;
259}
260
261static int max44000_read_raw(struct iio_dev *indio_dev,
262 struct iio_chan_spec const *chan,
263 int *val, int *val2, long mask)
264{
265 struct max44000_data *data = iio_priv(indio_dev);
266 int alstim, alspga;
267 unsigned int regval;
268 int ret;
269
270 switch (mask) {
271 case IIO_CHAN_INFO_RAW:
272 switch (chan->type) {
273 case IIO_LIGHT:
274 mutex_lock(&data->lock);
275 ret = max44000_read_alsval(data);
276 mutex_unlock(&data->lock);
277 if (ret < 0)
278 return ret;
279 *val = ret;
280 return IIO_VAL_INT;
281
282 case IIO_PROXIMITY:
283 mutex_lock(&data->lock);
284 ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val);
285 mutex_unlock(&data->lock);
286 if (ret < 0)
287 return ret;
288 *val = regval;
289 return IIO_VAL_INT;
290
291 case IIO_CURRENT:
292 mutex_lock(&data->lock);
293 ret = max44000_read_led_current_raw(data);
294 mutex_unlock(&data->lock);
295 if (ret < 0)
296 return ret;
297 *val = ret;
298 return IIO_VAL_INT;
299
300 default:
301 return -EINVAL;
302 }
303
304 case IIO_CHAN_INFO_SCALE:
305 switch (chan->type) {
306 case IIO_CURRENT:
307 /* Output register is in 10s of miliamps */
308 *val = 10;
309 return IIO_VAL_INT;
310
311 case IIO_LIGHT:
312 mutex_lock(&data->lock);
313 alspga = ret = max44000_read_alspga(data);
314 mutex_unlock(&data->lock);
315 if (ret < 0)
316 return ret;
317
318 /* Avoid negative shifts */
319 *val = (1 << MAX44000_ALSPGA_MAX_SHIFT);
320 *val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2
321 + MAX44000_ALSPGA_MAX_SHIFT
322 - max44000_alspga_shift[alspga];
323 return IIO_VAL_FRACTIONAL_LOG2;
324
325 default:
326 return -EINVAL;
327 }
328
329 case IIO_CHAN_INFO_INT_TIME:
330 mutex_lock(&data->lock);
331 alstim = ret = max44000_read_alstim(data);
332 mutex_unlock(&data->lock);
333
334 if (ret < 0)
335 return ret;
336 *val = 0;
337 *val2 = max44000_int_time_avail_ns_array[alstim];
338 return IIO_VAL_INT_PLUS_NANO;
339
340 default:
341 return -EINVAL;
342 }
343}
344
345static int max44000_write_raw(struct iio_dev *indio_dev,
346 struct iio_chan_spec const *chan,
347 int val, int val2, long mask)
348{
349 struct max44000_data *data = iio_priv(indio_dev);
350 int ret;
351
352 if (mask == IIO_CHAN_INFO_RAW && chan->type == IIO_CURRENT) {
353 mutex_lock(&data->lock);
354 ret = max44000_write_led_current_raw(data, val);
355 mutex_unlock(&data->lock);
356 return ret;
357 } else if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) {
358 s64 valns = val * NSEC_PER_SEC + val2;
359 int alstim = find_closest_descending(valns,
360 max44000_int_time_avail_ns_array,
361 ARRAY_SIZE(max44000_int_time_avail_ns_array));
362 mutex_lock(&data->lock);
363 ret = max44000_write_alstim(data, alstim);
364 mutex_unlock(&data->lock);
365 return ret;
366 } else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) {
367 s64 valus = val * USEC_PER_SEC + val2;
368 int alspga = find_closest(valus,
369 max44000_scale_avail_ulux_array,
370 ARRAY_SIZE(max44000_scale_avail_ulux_array));
371 mutex_lock(&data->lock);
372 ret = max44000_write_alspga(data, alspga);
373 mutex_unlock(&data->lock);
374 return ret;
375 }
376
377 return -EINVAL;
378}
379
380static int max44000_write_raw_get_fmt(struct iio_dev *indio_dev,
381 struct iio_chan_spec const *chan,
382 long mask)
383{
384 if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT)
385 return IIO_VAL_INT_PLUS_NANO;
386 else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT)
387 return IIO_VAL_INT_PLUS_MICRO;
388 else
389 return IIO_VAL_INT;
390}
391
392static IIO_CONST_ATTR(illuminance_integration_time_available, max44000_int_time_avail_str);
393static IIO_CONST_ATTR(illuminance_scale_available, max44000_scale_avail_str);
394
395static struct attribute *max44000_attributes[] = {
396 &iio_const_attr_illuminance_integration_time_available.dev_attr.attr,
397 &iio_const_attr_illuminance_scale_available.dev_attr.attr,
398 NULL
399};
400
401static const struct attribute_group max44000_attribute_group = {
402 .attrs = max44000_attributes,
403};
404
405static const struct iio_info max44000_info = {
406 .read_raw = max44000_read_raw,
407 .write_raw = max44000_write_raw,
408 .write_raw_get_fmt = max44000_write_raw_get_fmt,
409 .attrs = &max44000_attribute_group,
410};
411
412static bool max44000_readable_reg(struct device *dev, unsigned int reg)
413{
414 switch (reg) {
415 case MAX44000_REG_STATUS:
416 case MAX44000_REG_CFG_MAIN:
417 case MAX44000_REG_CFG_RX:
418 case MAX44000_REG_CFG_TX:
419 case MAX44000_REG_ALS_DATA_HI:
420 case MAX44000_REG_ALS_DATA_LO:
421 case MAX44000_REG_PRX_DATA:
422 case MAX44000_REG_ALS_UPTHR_HI:
423 case MAX44000_REG_ALS_UPTHR_LO:
424 case MAX44000_REG_ALS_LOTHR_HI:
425 case MAX44000_REG_ALS_LOTHR_LO:
426 case MAX44000_REG_PST:
427 case MAX44000_REG_PRX_IND:
428 case MAX44000_REG_PRX_THR:
429 case MAX44000_REG_TRIM_GAIN_GREEN:
430 case MAX44000_REG_TRIM_GAIN_IR:
431 return true;
432 default:
433 return false;
434 }
435}
436
437static bool max44000_writeable_reg(struct device *dev, unsigned int reg)
438{
439 switch (reg) {
440 case MAX44000_REG_CFG_MAIN:
441 case MAX44000_REG_CFG_RX:
442 case MAX44000_REG_CFG_TX:
443 case MAX44000_REG_ALS_UPTHR_HI:
444 case MAX44000_REG_ALS_UPTHR_LO:
445 case MAX44000_REG_ALS_LOTHR_HI:
446 case MAX44000_REG_ALS_LOTHR_LO:
447 case MAX44000_REG_PST:
448 case MAX44000_REG_PRX_IND:
449 case MAX44000_REG_PRX_THR:
450 case MAX44000_REG_TRIM_GAIN_GREEN:
451 case MAX44000_REG_TRIM_GAIN_IR:
452 return true;
453 default:
454 return false;
455 }
456}
457
458static bool max44000_volatile_reg(struct device *dev, unsigned int reg)
459{
460 switch (reg) {
461 case MAX44000_REG_STATUS:
462 case MAX44000_REG_ALS_DATA_HI:
463 case MAX44000_REG_ALS_DATA_LO:
464 case MAX44000_REG_PRX_DATA:
465 return true;
466 default:
467 return false;
468 }
469}
470
471static bool max44000_precious_reg(struct device *dev, unsigned int reg)
472{
473 return reg == MAX44000_REG_STATUS;
474}
475
476static const struct regmap_config max44000_regmap_config = {
477 .reg_bits = 8,
478 .val_bits = 8,
479
480 .max_register = MAX44000_REG_PRX_DATA,
481 .readable_reg = max44000_readable_reg,
482 .writeable_reg = max44000_writeable_reg,
483 .volatile_reg = max44000_volatile_reg,
484 .precious_reg = max44000_precious_reg,
485
486 .use_single_read = true,
487 .use_single_write = true,
488 .cache_type = REGCACHE_RBTREE,
489};
490
491static irqreturn_t max44000_trigger_handler(int irq, void *p)
492{
493 struct iio_poll_func *pf = p;
494 struct iio_dev *indio_dev = pf->indio_dev;
495 struct max44000_data *data = iio_priv(indio_dev);
496 int index = 0;
497 unsigned int regval;
498 int ret;
499
500 mutex_lock(&data->lock);
501 if (test_bit(MAX44000_SCAN_INDEX_ALS, indio_dev->active_scan_mask)) {
502 ret = max44000_read_alsval(data);
503 if (ret < 0)
504 goto out_unlock;
505 data->scan.channels[index++] = ret;
506 }
507 if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) {
508 ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val);
509 if (ret < 0)
510 goto out_unlock;
511 data->scan.channels[index] = regval;
512 }
513 mutex_unlock(&data->lock);
514
515 iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
516 iio_get_time_ns(indio_dev));
517 iio_trigger_notify_done(indio_dev->trig);
518 return IRQ_HANDLED;
519
520out_unlock:
521 mutex_unlock(&data->lock);
522 iio_trigger_notify_done(indio_dev->trig);
523 return IRQ_HANDLED;
524}
525
526static int max44000_probe(struct i2c_client *client,
527 const struct i2c_device_id *id)
528{
529 struct max44000_data *data;
530 struct iio_dev *indio_dev;
531 int ret, reg;
532
533 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
534 if (!indio_dev)
535 return -ENOMEM;
536 data = iio_priv(indio_dev);
537 data->regmap = devm_regmap_init_i2c(client, &max44000_regmap_config);
538 if (IS_ERR(data->regmap)) {
539 dev_err(&client->dev, "regmap_init failed!\n");
540 return PTR_ERR(data->regmap);
541 }
542
543 i2c_set_clientdata(client, indio_dev);
544 mutex_init(&data->lock);
545 indio_dev->info = &max44000_info;
546 indio_dev->name = MAX44000_DRV_NAME;
547 indio_dev->channels = max44000_channels;
548 indio_dev->num_channels = ARRAY_SIZE(max44000_channels);
549
550 /*
551 * The device doesn't have a reset function so we just clear some
552 * important bits at probe time to ensure sane operation.
553 *
554 * Since we don't support interrupts/events the threshold values are
555 * not important. We also don't touch trim values.
556 */
557
558 /* Reset ALS scaling bits */
559 ret = regmap_write(data->regmap, MAX44000_REG_CFG_RX,
560 MAX44000_REG_CFG_RX_DEFAULT);
561 if (ret < 0) {
562 dev_err(&client->dev, "failed to write default CFG_RX: %d\n",
563 ret);
564 return ret;
565 }
566
567 /*
568 * By default the LED pulse used for the proximity sensor is disabled.
569 * Set a middle value so that we get some sort of valid data by default.
570 */
571 ret = max44000_write_led_current_raw(data, MAX44000_LED_CURRENT_DEFAULT);
572 if (ret < 0) {
573 dev_err(&client->dev, "failed to write init config: %d\n", ret);
574 return ret;
575 }
576
577 /* Reset CFG bits to ALS_PRX mode which allows easy reading of both values. */
578 reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX;
579 ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg);
580 if (ret < 0) {
581 dev_err(&client->dev, "failed to write init config: %d\n", ret);
582 return ret;
583 }
584
585 /* Read status at least once to clear any stale interrupt bits. */
586 ret = regmap_read(data->regmap, MAX44000_REG_STATUS, ®);
587 if (ret < 0) {
588 dev_err(&client->dev, "failed to read init status: %d\n", ret);
589 return ret;
590 }
591
592 ret = iio_triggered_buffer_setup(indio_dev, NULL, max44000_trigger_handler, NULL);
593 if (ret < 0) {
594 dev_err(&client->dev, "iio triggered buffer setup failed\n");
595 return ret;
596 }
597
598 return iio_device_register(indio_dev);
599}
600
601static int max44000_remove(struct i2c_client *client)
602{
603 struct iio_dev *indio_dev = i2c_get_clientdata(client);
604
605 iio_device_unregister(indio_dev);
606 iio_triggered_buffer_cleanup(indio_dev);
607
608 return 0;
609}
610
611static const struct i2c_device_id max44000_id[] = {
612 {"max44000", 0},
613 { }
614};
615MODULE_DEVICE_TABLE(i2c, max44000_id);
616
617#ifdef CONFIG_ACPI
618static const struct acpi_device_id max44000_acpi_match[] = {
619 {"MAX44000", 0},
620 { }
621};
622MODULE_DEVICE_TABLE(acpi, max44000_acpi_match);
623#endif
624
625static struct i2c_driver max44000_driver = {
626 .driver = {
627 .name = MAX44000_DRV_NAME,
628 .acpi_match_table = ACPI_PTR(max44000_acpi_match),
629 },
630 .probe = max44000_probe,
631 .remove = max44000_remove,
632 .id_table = max44000_id,
633};
634
635module_i2c_driver(max44000_driver);
636
637MODULE_AUTHOR("Crestez Dan Leonard <leonard.crestez@intel.com>");
638MODULE_DESCRIPTION("MAX44000 Ambient and Infrared Proximity Sensor");
639MODULE_LICENSE("GPL v2");