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1/*
2 * MAX44000 Ambient and Infrared Proximity Sensor
3 *
4 * Copyright (c) 2016, Intel Corporation.
5 *
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
9 *
10 * Data sheet: https://datasheets.maximintegrated.com/en/ds/MAX44000.pdf
11 *
12 * 7-bit I2C slave address 0x4a
13 */
14
15#include <linux/module.h>
16#include <linux/init.h>
17#include <linux/i2c.h>
18#include <linux/regmap.h>
19#include <linux/util_macros.h>
20#include <linux/iio/iio.h>
21#include <linux/iio/sysfs.h>
22#include <linux/iio/buffer.h>
23#include <linux/iio/trigger_consumer.h>
24#include <linux/iio/triggered_buffer.h>
25#include <linux/acpi.h>
26
27#define MAX44000_DRV_NAME "max44000"
28
29/* Registers in datasheet order */
30#define MAX44000_REG_STATUS 0x00
31#define MAX44000_REG_CFG_MAIN 0x01
32#define MAX44000_REG_CFG_RX 0x02
33#define MAX44000_REG_CFG_TX 0x03
34#define MAX44000_REG_ALS_DATA_HI 0x04
35#define MAX44000_REG_ALS_DATA_LO 0x05
36#define MAX44000_REG_PRX_DATA 0x16
37#define MAX44000_REG_ALS_UPTHR_HI 0x06
38#define MAX44000_REG_ALS_UPTHR_LO 0x07
39#define MAX44000_REG_ALS_LOTHR_HI 0x08
40#define MAX44000_REG_ALS_LOTHR_LO 0x09
41#define MAX44000_REG_PST 0x0a
42#define MAX44000_REG_PRX_IND 0x0b
43#define MAX44000_REG_PRX_THR 0x0c
44#define MAX44000_REG_TRIM_GAIN_GREEN 0x0f
45#define MAX44000_REG_TRIM_GAIN_IR 0x10
46
47/* REG_CFG bits */
48#define MAX44000_CFG_ALSINTE 0x01
49#define MAX44000_CFG_PRXINTE 0x02
50#define MAX44000_CFG_MASK 0x1c
51#define MAX44000_CFG_MODE_SHUTDOWN 0x00
52#define MAX44000_CFG_MODE_ALS_GIR 0x04
53#define MAX44000_CFG_MODE_ALS_G 0x08
54#define MAX44000_CFG_MODE_ALS_IR 0x0c
55#define MAX44000_CFG_MODE_ALS_PRX 0x10
56#define MAX44000_CFG_MODE_PRX 0x14
57#define MAX44000_CFG_TRIM 0x20
58
59/*
60 * Upper 4 bits are not documented but start as 1 on powerup
61 * Setting them to 0 causes proximity to misbehave so set them to 1
62 */
63#define MAX44000_REG_CFG_RX_DEFAULT 0xf0
64
65/* REG_RX bits */
66#define MAX44000_CFG_RX_ALSTIM_MASK 0x0c
67#define MAX44000_CFG_RX_ALSTIM_SHIFT 2
68#define MAX44000_CFG_RX_ALSPGA_MASK 0x03
69#define MAX44000_CFG_RX_ALSPGA_SHIFT 0
70
71/* REG_TX bits */
72#define MAX44000_LED_CURRENT_MASK 0xf
73#define MAX44000_LED_CURRENT_MAX 11
74#define MAX44000_LED_CURRENT_DEFAULT 6
75
76#define MAX44000_ALSDATA_OVERFLOW 0x4000
77
78struct max44000_data {
79 struct mutex lock;
80 struct regmap *regmap;
81};
82
83/* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */
84#define MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 5
85
86/* Scale can be multiplied by up to 128x via ALSPGA for measurement gain */
87static const int max44000_alspga_shift[] = {0, 2, 4, 7};
88#define MAX44000_ALSPGA_MAX_SHIFT 7
89
90/*
91 * Scale can be multiplied by up to 64x via ALSTIM because of lost resolution
92 *
93 * This scaling factor is hidden from userspace and instead accounted for when
94 * reading raw values from the device.
95 *
96 * This makes it possible to cleanly expose ALSPGA as IIO_CHAN_INFO_SCALE and
97 * ALSTIM as IIO_CHAN_INFO_INT_TIME without the values affecting each other.
98 *
99 * Handling this internally is also required for buffer support because the
100 * channel's scan_type can't be modified dynamically.
101 */
102static const int max44000_alstim_shift[] = {0, 2, 4, 6};
103#define MAX44000_ALSTIM_SHIFT(alstim) (2 * (alstim))
104
105/* Available integration times with pretty manual alignment: */
106static const int max44000_int_time_avail_ns_array[] = {
107 100000000,
108 25000000,
109 6250000,
110 1562500,
111};
112static const char max44000_int_time_avail_str[] =
113 "0.100 "
114 "0.025 "
115 "0.00625 "
116 "0.0015625";
117
118/* Available scales (internal to ulux) with pretty manual alignment: */
119static const int max44000_scale_avail_ulux_array[] = {
120 31250,
121 125000,
122 500000,
123 4000000,
124};
125static const char max44000_scale_avail_str[] =
126 "0.03125 "
127 "0.125 "
128 "0.5 "
129 "4";
130
131#define MAX44000_SCAN_INDEX_ALS 0
132#define MAX44000_SCAN_INDEX_PRX 1
133
134static const struct iio_chan_spec max44000_channels[] = {
135 {
136 .type = IIO_LIGHT,
137 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
138 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
139 BIT(IIO_CHAN_INFO_INT_TIME),
140 .scan_index = MAX44000_SCAN_INDEX_ALS,
141 .scan_type = {
142 .sign = 'u',
143 .realbits = 14,
144 .storagebits = 16,
145 }
146 },
147 {
148 .type = IIO_PROXIMITY,
149 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
150 .scan_index = MAX44000_SCAN_INDEX_PRX,
151 .scan_type = {
152 .sign = 'u',
153 .realbits = 8,
154 .storagebits = 16,
155 }
156 },
157 IIO_CHAN_SOFT_TIMESTAMP(2),
158 {
159 .type = IIO_CURRENT,
160 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
161 BIT(IIO_CHAN_INFO_SCALE),
162 .extend_name = "led",
163 .output = 1,
164 .scan_index = -1,
165 },
166};
167
168static int max44000_read_alstim(struct max44000_data *data)
169{
170 unsigned int val;
171 int ret;
172
173 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
174 if (ret < 0)
175 return ret;
176 return (val & MAX44000_CFG_RX_ALSTIM_MASK) >> MAX44000_CFG_RX_ALSTIM_SHIFT;
177}
178
179static int max44000_write_alstim(struct max44000_data *data, int val)
180{
181 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
182 MAX44000_CFG_RX_ALSTIM_MASK,
183 val << MAX44000_CFG_RX_ALSTIM_SHIFT);
184}
185
186static int max44000_read_alspga(struct max44000_data *data)
187{
188 unsigned int val;
189 int ret;
190
191 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
192 if (ret < 0)
193 return ret;
194 return (val & MAX44000_CFG_RX_ALSPGA_MASK) >> MAX44000_CFG_RX_ALSPGA_SHIFT;
195}
196
197static int max44000_write_alspga(struct max44000_data *data, int val)
198{
199 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
200 MAX44000_CFG_RX_ALSPGA_MASK,
201 val << MAX44000_CFG_RX_ALSPGA_SHIFT);
202}
203
204static int max44000_read_alsval(struct max44000_data *data)
205{
206 u16 regval;
207 __be16 val;
208 int alstim, ret;
209
210 ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI,
211 &val, sizeof(val));
212 if (ret < 0)
213 return ret;
214 alstim = ret = max44000_read_alstim(data);
215 if (ret < 0)
216 return ret;
217
218 regval = be16_to_cpu(val);
219
220 /*
221 * Overflow is explained on datasheet page 17.
222 *
223 * It's a warning that either the G or IR channel has become saturated
224 * and that the value in the register is likely incorrect.
225 *
226 * The recommendation is to change the scale (ALSPGA).
227 * The driver just returns the max representable value.
228 */
229 if (regval & MAX44000_ALSDATA_OVERFLOW)
230 return 0x3FFF;
231
232 return regval << MAX44000_ALSTIM_SHIFT(alstim);
233}
234
235static int max44000_write_led_current_raw(struct max44000_data *data, int val)
236{
237 /* Maybe we should clamp the value instead? */
238 if (val < 0 || val > MAX44000_LED_CURRENT_MAX)
239 return -ERANGE;
240 if (val >= 8)
241 val += 4;
242 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX,
243 MAX44000_LED_CURRENT_MASK, val);
244}
245
246static int max44000_read_led_current_raw(struct max44000_data *data)
247{
248 unsigned int regval;
249 int ret;
250
251 ret = regmap_read(data->regmap, MAX44000_REG_CFG_TX, ®val);
252 if (ret < 0)
253 return ret;
254 regval &= MAX44000_LED_CURRENT_MASK;
255 if (regval >= 8)
256 regval -= 4;
257 return regval;
258}
259
260static int max44000_read_raw(struct iio_dev *indio_dev,
261 struct iio_chan_spec const *chan,
262 int *val, int *val2, long mask)
263{
264 struct max44000_data *data = iio_priv(indio_dev);
265 int alstim, alspga;
266 unsigned int regval;
267 int ret;
268
269 switch (mask) {
270 case IIO_CHAN_INFO_RAW:
271 switch (chan->type) {
272 case IIO_LIGHT:
273 mutex_lock(&data->lock);
274 ret = max44000_read_alsval(data);
275 mutex_unlock(&data->lock);
276 if (ret < 0)
277 return ret;
278 *val = ret;
279 return IIO_VAL_INT;
280
281 case IIO_PROXIMITY:
282 mutex_lock(&data->lock);
283 ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val);
284 mutex_unlock(&data->lock);
285 if (ret < 0)
286 return ret;
287 *val = regval;
288 return IIO_VAL_INT;
289
290 case IIO_CURRENT:
291 mutex_lock(&data->lock);
292 ret = max44000_read_led_current_raw(data);
293 mutex_unlock(&data->lock);
294 if (ret < 0)
295 return ret;
296 *val = ret;
297 return IIO_VAL_INT;
298
299 default:
300 return -EINVAL;
301 }
302
303 case IIO_CHAN_INFO_SCALE:
304 switch (chan->type) {
305 case IIO_CURRENT:
306 /* Output register is in 10s of miliamps */
307 *val = 10;
308 return IIO_VAL_INT;
309
310 case IIO_LIGHT:
311 mutex_lock(&data->lock);
312 alspga = ret = max44000_read_alspga(data);
313 mutex_unlock(&data->lock);
314 if (ret < 0)
315 return ret;
316
317 /* Avoid negative shifts */
318 *val = (1 << MAX44000_ALSPGA_MAX_SHIFT);
319 *val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2
320 + MAX44000_ALSPGA_MAX_SHIFT
321 - max44000_alspga_shift[alspga];
322 return IIO_VAL_FRACTIONAL_LOG2;
323
324 default:
325 return -EINVAL;
326 }
327
328 case IIO_CHAN_INFO_INT_TIME:
329 mutex_lock(&data->lock);
330 alstim = ret = max44000_read_alstim(data);
331 mutex_unlock(&data->lock);
332
333 if (ret < 0)
334 return ret;
335 *val = 0;
336 *val2 = max44000_int_time_avail_ns_array[alstim];
337 return IIO_VAL_INT_PLUS_NANO;
338
339 default:
340 return -EINVAL;
341 }
342}
343
344static int max44000_write_raw(struct iio_dev *indio_dev,
345 struct iio_chan_spec const *chan,
346 int val, int val2, long mask)
347{
348 struct max44000_data *data = iio_priv(indio_dev);
349 int ret;
350
351 if (mask == IIO_CHAN_INFO_RAW && chan->type == IIO_CURRENT) {
352 mutex_lock(&data->lock);
353 ret = max44000_write_led_current_raw(data, val);
354 mutex_unlock(&data->lock);
355 return ret;
356 } else if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) {
357 s64 valns = val * NSEC_PER_SEC + val2;
358 int alstim = find_closest_descending(valns,
359 max44000_int_time_avail_ns_array,
360 ARRAY_SIZE(max44000_int_time_avail_ns_array));
361 mutex_lock(&data->lock);
362 ret = max44000_write_alstim(data, alstim);
363 mutex_unlock(&data->lock);
364 return ret;
365 } else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) {
366 s64 valus = val * USEC_PER_SEC + val2;
367 int alspga = find_closest(valus,
368 max44000_scale_avail_ulux_array,
369 ARRAY_SIZE(max44000_scale_avail_ulux_array));
370 mutex_lock(&data->lock);
371 ret = max44000_write_alspga(data, alspga);
372 mutex_unlock(&data->lock);
373 return ret;
374 }
375
376 return -EINVAL;
377}
378
379static int max44000_write_raw_get_fmt(struct iio_dev *indio_dev,
380 struct iio_chan_spec const *chan,
381 long mask)
382{
383 if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT)
384 return IIO_VAL_INT_PLUS_NANO;
385 else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT)
386 return IIO_VAL_INT_PLUS_MICRO;
387 else
388 return IIO_VAL_INT;
389}
390
391static IIO_CONST_ATTR(illuminance_integration_time_available, max44000_int_time_avail_str);
392static IIO_CONST_ATTR(illuminance_scale_available, max44000_scale_avail_str);
393
394static struct attribute *max44000_attributes[] = {
395 &iio_const_attr_illuminance_integration_time_available.dev_attr.attr,
396 &iio_const_attr_illuminance_scale_available.dev_attr.attr,
397 NULL
398};
399
400static const struct attribute_group max44000_attribute_group = {
401 .attrs = max44000_attributes,
402};
403
404static const struct iio_info max44000_info = {
405 .read_raw = max44000_read_raw,
406 .write_raw = max44000_write_raw,
407 .write_raw_get_fmt = max44000_write_raw_get_fmt,
408 .attrs = &max44000_attribute_group,
409};
410
411static bool max44000_readable_reg(struct device *dev, unsigned int reg)
412{
413 switch (reg) {
414 case MAX44000_REG_STATUS:
415 case MAX44000_REG_CFG_MAIN:
416 case MAX44000_REG_CFG_RX:
417 case MAX44000_REG_CFG_TX:
418 case MAX44000_REG_ALS_DATA_HI:
419 case MAX44000_REG_ALS_DATA_LO:
420 case MAX44000_REG_PRX_DATA:
421 case MAX44000_REG_ALS_UPTHR_HI:
422 case MAX44000_REG_ALS_UPTHR_LO:
423 case MAX44000_REG_ALS_LOTHR_HI:
424 case MAX44000_REG_ALS_LOTHR_LO:
425 case MAX44000_REG_PST:
426 case MAX44000_REG_PRX_IND:
427 case MAX44000_REG_PRX_THR:
428 case MAX44000_REG_TRIM_GAIN_GREEN:
429 case MAX44000_REG_TRIM_GAIN_IR:
430 return true;
431 default:
432 return false;
433 }
434}
435
436static bool max44000_writeable_reg(struct device *dev, unsigned int reg)
437{
438 switch (reg) {
439 case MAX44000_REG_CFG_MAIN:
440 case MAX44000_REG_CFG_RX:
441 case MAX44000_REG_CFG_TX:
442 case MAX44000_REG_ALS_UPTHR_HI:
443 case MAX44000_REG_ALS_UPTHR_LO:
444 case MAX44000_REG_ALS_LOTHR_HI:
445 case MAX44000_REG_ALS_LOTHR_LO:
446 case MAX44000_REG_PST:
447 case MAX44000_REG_PRX_IND:
448 case MAX44000_REG_PRX_THR:
449 case MAX44000_REG_TRIM_GAIN_GREEN:
450 case MAX44000_REG_TRIM_GAIN_IR:
451 return true;
452 default:
453 return false;
454 }
455}
456
457static bool max44000_volatile_reg(struct device *dev, unsigned int reg)
458{
459 switch (reg) {
460 case MAX44000_REG_STATUS:
461 case MAX44000_REG_ALS_DATA_HI:
462 case MAX44000_REG_ALS_DATA_LO:
463 case MAX44000_REG_PRX_DATA:
464 return true;
465 default:
466 return false;
467 }
468}
469
470static bool max44000_precious_reg(struct device *dev, unsigned int reg)
471{
472 return reg == MAX44000_REG_STATUS;
473}
474
475static const struct regmap_config max44000_regmap_config = {
476 .reg_bits = 8,
477 .val_bits = 8,
478
479 .max_register = MAX44000_REG_PRX_DATA,
480 .readable_reg = max44000_readable_reg,
481 .writeable_reg = max44000_writeable_reg,
482 .volatile_reg = max44000_volatile_reg,
483 .precious_reg = max44000_precious_reg,
484
485 .use_single_rw = 1,
486 .cache_type = REGCACHE_RBTREE,
487};
488
489static irqreturn_t max44000_trigger_handler(int irq, void *p)
490{
491 struct iio_poll_func *pf = p;
492 struct iio_dev *indio_dev = pf->indio_dev;
493 struct max44000_data *data = iio_priv(indio_dev);
494 u16 buf[8]; /* 2x u16 + padding + 8 bytes timestamp */
495 int index = 0;
496 unsigned int regval;
497 int ret;
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 buf[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 buf[index] = regval;
511 }
512 mutex_unlock(&data->lock);
513
514 iio_push_to_buffers_with_timestamp(indio_dev, buf,
515 iio_get_time_ns(indio_dev));
516 iio_trigger_notify_done(indio_dev->trig);
517 return IRQ_HANDLED;
518
519out_unlock:
520 mutex_unlock(&data->lock);
521 iio_trigger_notify_done(indio_dev->trig);
522 return IRQ_HANDLED;
523}
524
525static int max44000_probe(struct i2c_client *client,
526 const struct i2c_device_id *id)
527{
528 struct max44000_data *data;
529 struct iio_dev *indio_dev;
530 int ret, reg;
531
532 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
533 if (!indio_dev)
534 return -ENOMEM;
535 data = iio_priv(indio_dev);
536 data->regmap = devm_regmap_init_i2c(client, &max44000_regmap_config);
537 if (IS_ERR(data->regmap)) {
538 dev_err(&client->dev, "regmap_init failed!\n");
539 return PTR_ERR(data->regmap);
540 }
541
542 i2c_set_clientdata(client, indio_dev);
543 mutex_init(&data->lock);
544 indio_dev->dev.parent = &client->dev;
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");