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 <asm/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 /*
72 * Window Factor is needed when the device is under Window glass
73 * with coated tinted ink. This is to compensate for the light loss
74 * due to the lower transmission rate of the window glass and helps
75 * in calculating lux.
76 */
77 #define LTRF216A_WIN_FAC 1
78
79 struct ltrf216a_data {
80 struct regmap *regmap;
81 struct i2c_client *client;
82 u32 int_time;
83 u16 int_time_fac;
84 u8 als_gain_fac;
85 /*
86 * Protects regmap accesses and makes sure integration time
87 * remains constant during the measurement of lux.
88 */
89 struct mutex lock;
90 };
91
92 static const struct iio_chan_spec ltrf216a_channels[] = {
93 {
94 .type = IIO_LIGHT,
95 .info_mask_separate =
96 BIT(IIO_CHAN_INFO_RAW) |
97 BIT(IIO_CHAN_INFO_PROCESSED) |
98 BIT(IIO_CHAN_INFO_INT_TIME),
99 .info_mask_separate_available =
100 BIT(IIO_CHAN_INFO_INT_TIME),
101 },
102 };
103
ltrf216a_reset(struct iio_dev * indio_dev)104 static void ltrf216a_reset(struct iio_dev *indio_dev)
105 {
106 struct ltrf216a_data *data = iio_priv(indio_dev);
107
108 /* reset sensor, chip fails to respond to this, so ignore any errors */
109 regmap_write(data->regmap, LTRF216A_MAIN_CTRL, LTRF216A_ALS_RESET_MASK);
110
111 /* reset time */
112 usleep_range(1000, 2000);
113 }
114
ltrf216a_enable(struct iio_dev * indio_dev)115 static int ltrf216a_enable(struct iio_dev *indio_dev)
116 {
117 struct ltrf216a_data *data = iio_priv(indio_dev);
118 struct device *dev = &data->client->dev;
119 int ret;
120
121 /* enable sensor */
122 ret = regmap_set_bits(data->regmap,
123 LTRF216A_MAIN_CTRL, LTRF216A_ALS_ENABLE_MASK);
124 if (ret) {
125 dev_err(dev, "failed to enable sensor: %d\n", ret);
126 return ret;
127 }
128
129 /* sleep for one integration cycle after enabling the device */
130 msleep(ltrf216a_int_time_reg[0][0]);
131
132 return 0;
133 }
134
ltrf216a_disable(struct iio_dev * indio_dev)135 static int ltrf216a_disable(struct iio_dev *indio_dev)
136 {
137 struct ltrf216a_data *data = iio_priv(indio_dev);
138 struct device *dev = &data->client->dev;
139 int ret;
140
141 ret = regmap_write(data->regmap, LTRF216A_MAIN_CTRL, 0);
142 if (ret)
143 dev_err(dev, "failed to disable sensor: %d\n", ret);
144
145 return ret;
146 }
147
ltrf216a_cleanup(void * data)148 static void ltrf216a_cleanup(void *data)
149 {
150 struct iio_dev *indio_dev = data;
151
152 ltrf216a_disable(indio_dev);
153 }
154
ltrf216a_set_int_time(struct ltrf216a_data * data,int itime)155 static int ltrf216a_set_int_time(struct ltrf216a_data *data, int itime)
156 {
157 struct device *dev = &data->client->dev;
158 unsigned int i;
159 u8 reg_val;
160 int ret;
161
162 for (i = 0; i < ARRAY_SIZE(ltrf216a_int_time_available); i++) {
163 if (ltrf216a_int_time_available[i][1] == itime)
164 break;
165 }
166 if (i == ARRAY_SIZE(ltrf216a_int_time_available))
167 return -EINVAL;
168
169 reg_val = ltrf216a_int_time_reg[i][1];
170
171 ret = regmap_write(data->regmap, LTRF216A_ALS_MEAS_RES, reg_val);
172 if (ret) {
173 dev_err(dev, "failed to set integration time: %d\n", ret);
174 return ret;
175 }
176
177 data->int_time_fac = ltrf216a_int_time_reg[i][0];
178 data->int_time = itime;
179
180 return 0;
181 }
182
ltrf216a_get_int_time(struct ltrf216a_data * data,int * val,int * val2)183 static int ltrf216a_get_int_time(struct ltrf216a_data *data,
184 int *val, int *val2)
185 {
186 *val = 0;
187 *val2 = data->int_time;
188 return IIO_VAL_INT_PLUS_MICRO;
189 }
190
ltrf216a_set_power_state(struct ltrf216a_data * data,bool on)191 static int ltrf216a_set_power_state(struct ltrf216a_data *data, bool on)
192 {
193 struct device *dev = &data->client->dev;
194 int ret = 0;
195
196 if (on) {
197 ret = pm_runtime_resume_and_get(dev);
198 if (ret) {
199 dev_err(dev, "failed to resume runtime PM: %d\n", ret);
200 return ret;
201 }
202 } else {
203 pm_runtime_mark_last_busy(dev);
204 pm_runtime_put_autosuspend(dev);
205 }
206
207 return ret;
208 }
209
ltrf216a_read_data(struct ltrf216a_data * data,u8 addr)210 static int ltrf216a_read_data(struct ltrf216a_data *data, u8 addr)
211 {
212 struct device *dev = &data->client->dev;
213 int ret, val;
214 u8 buf[3];
215
216 ret = regmap_read_poll_timeout(data->regmap, LTRF216A_MAIN_STATUS,
217 val, val & LTRF216A_ALS_DATA_STATUS,
218 LTRF216A_ALS_READ_DATA_DELAY_US,
219 LTRF216A_ALS_READ_DATA_DELAY_US * 50);
220 if (ret) {
221 dev_err(dev, "failed to wait for measurement data: %d\n", ret);
222 return ret;
223 }
224
225 ret = regmap_bulk_read(data->regmap, addr, buf, sizeof(buf));
226 if (ret) {
227 dev_err(dev, "failed to read measurement data: %d\n", ret);
228 return ret;
229 }
230
231 return get_unaligned_le24(&buf[0]);
232 }
233
ltrf216a_get_lux(struct ltrf216a_data * data)234 static int ltrf216a_get_lux(struct ltrf216a_data *data)
235 {
236 int ret, greendata;
237 u64 lux, div;
238
239 ret = ltrf216a_set_power_state(data, true);
240 if (ret)
241 return ret;
242
243 greendata = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
244 if (greendata < 0)
245 return greendata;
246
247 ltrf216a_set_power_state(data, false);
248
249 lux = greendata * 45 * LTRF216A_WIN_FAC * 100;
250 div = data->als_gain_fac * data->int_time_fac * 100;
251
252 return div_u64(lux, div);
253 }
254
ltrf216a_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)255 static int ltrf216a_read_raw(struct iio_dev *indio_dev,
256 struct iio_chan_spec const *chan, int *val,
257 int *val2, long mask)
258 {
259 struct ltrf216a_data *data = iio_priv(indio_dev);
260 int ret;
261
262 switch (mask) {
263 case IIO_CHAN_INFO_RAW:
264 ret = ltrf216a_set_power_state(data, true);
265 if (ret)
266 return ret;
267 mutex_lock(&data->lock);
268 ret = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
269 mutex_unlock(&data->lock);
270 ltrf216a_set_power_state(data, false);
271 if (ret < 0)
272 return ret;
273 *val = ret;
274 return IIO_VAL_INT;
275 case IIO_CHAN_INFO_PROCESSED:
276 mutex_lock(&data->lock);
277 ret = ltrf216a_get_lux(data);
278 mutex_unlock(&data->lock);
279 if (ret < 0)
280 return ret;
281 *val = ret;
282 return IIO_VAL_INT;
283 case IIO_CHAN_INFO_INT_TIME:
284 mutex_lock(&data->lock);
285 ret = ltrf216a_get_int_time(data, val, val2);
286 mutex_unlock(&data->lock);
287 return ret;
288 default:
289 return -EINVAL;
290 }
291 }
292
ltrf216a_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)293 static int ltrf216a_write_raw(struct iio_dev *indio_dev,
294 struct iio_chan_spec const *chan, int val,
295 int val2, long mask)
296 {
297 struct ltrf216a_data *data = iio_priv(indio_dev);
298 int ret;
299
300 switch (mask) {
301 case IIO_CHAN_INFO_INT_TIME:
302 if (val != 0)
303 return -EINVAL;
304 mutex_lock(&data->lock);
305 ret = ltrf216a_set_int_time(data, val2);
306 mutex_unlock(&data->lock);
307 return ret;
308 default:
309 return -EINVAL;
310 }
311 }
312
ltrf216a_read_available(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)313 static int ltrf216a_read_available(struct iio_dev *indio_dev,
314 struct iio_chan_spec const *chan,
315 const int **vals, int *type, int *length,
316 long mask)
317 {
318 switch (mask) {
319 case IIO_CHAN_INFO_INT_TIME:
320 *length = ARRAY_SIZE(ltrf216a_int_time_available) * 2;
321 *vals = (const int *)ltrf216a_int_time_available;
322 *type = IIO_VAL_INT_PLUS_MICRO;
323 return IIO_AVAIL_LIST;
324 default:
325 return -EINVAL;
326 }
327 }
328
329 static const struct iio_info ltrf216a_info = {
330 .read_raw = ltrf216a_read_raw,
331 .write_raw = ltrf216a_write_raw,
332 .read_avail = ltrf216a_read_available,
333 };
334
ltrf216a_readable_reg(struct device * dev,unsigned int reg)335 static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
336 {
337 switch (reg) {
338 case LTRF216A_MAIN_CTRL:
339 case LTRF216A_ALS_MEAS_RES:
340 case LTRF216A_ALS_GAIN:
341 case LTRF216A_PART_ID:
342 case LTRF216A_MAIN_STATUS:
343 case LTRF216A_ALS_CLEAR_DATA_0:
344 case LTRF216A_ALS_CLEAR_DATA_1:
345 case LTRF216A_ALS_CLEAR_DATA_2:
346 case LTRF216A_ALS_DATA_0:
347 case LTRF216A_ALS_DATA_1:
348 case LTRF216A_ALS_DATA_2:
349 case LTRF216A_INT_CFG:
350 case LTRF216A_INT_PST:
351 case LTRF216A_ALS_THRES_UP_0:
352 case LTRF216A_ALS_THRES_UP_1:
353 case LTRF216A_ALS_THRES_UP_2:
354 case LTRF216A_ALS_THRES_LOW_0:
355 case LTRF216A_ALS_THRES_LOW_1:
356 case LTRF216A_ALS_THRES_LOW_2:
357 return true;
358 default:
359 return false;
360 }
361 }
362
ltrf216a_writable_reg(struct device * dev,unsigned int reg)363 static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
364 {
365 switch (reg) {
366 case LTRF216A_MAIN_CTRL:
367 case LTRF216A_ALS_MEAS_RES:
368 case LTRF216A_ALS_GAIN:
369 case LTRF216A_INT_CFG:
370 case LTRF216A_INT_PST:
371 case LTRF216A_ALS_THRES_UP_0:
372 case LTRF216A_ALS_THRES_UP_1:
373 case LTRF216A_ALS_THRES_UP_2:
374 case LTRF216A_ALS_THRES_LOW_0:
375 case LTRF216A_ALS_THRES_LOW_1:
376 case LTRF216A_ALS_THRES_LOW_2:
377 return true;
378 default:
379 return false;
380 }
381 }
382
ltrf216a_volatile_reg(struct device * dev,unsigned int reg)383 static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
384 {
385 switch (reg) {
386 case LTRF216A_MAIN_STATUS:
387 case LTRF216A_ALS_CLEAR_DATA_0:
388 case LTRF216A_ALS_CLEAR_DATA_1:
389 case LTRF216A_ALS_CLEAR_DATA_2:
390 case LTRF216A_ALS_DATA_0:
391 case LTRF216A_ALS_DATA_1:
392 case LTRF216A_ALS_DATA_2:
393 return true;
394 default:
395 return false;
396 }
397 }
398
ltrf216a_precious_reg(struct device * dev,unsigned int reg)399 static bool ltrf216a_precious_reg(struct device *dev, unsigned int reg)
400 {
401 return reg == LTRF216A_MAIN_STATUS;
402 }
403
404 static const struct regmap_config ltrf216a_regmap_config = {
405 .name = "ltrf216a",
406 .reg_bits = 8,
407 .val_bits = 8,
408 .cache_type = REGCACHE_RBTREE,
409 .max_register = LTRF216A_ALS_THRES_LOW_2,
410 .readable_reg = ltrf216a_readable_reg,
411 .writeable_reg = ltrf216a_writable_reg,
412 .volatile_reg = ltrf216a_volatile_reg,
413 .precious_reg = ltrf216a_precious_reg,
414 .disable_locking = true,
415 };
416
ltrf216a_probe(struct i2c_client * client)417 static int ltrf216a_probe(struct i2c_client *client)
418 {
419 struct ltrf216a_data *data;
420 struct iio_dev *indio_dev;
421 int ret;
422
423 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
424 if (!indio_dev)
425 return -ENOMEM;
426
427 data = iio_priv(indio_dev);
428
429 data->regmap = devm_regmap_init_i2c(client, <rf216a_regmap_config);
430 if (IS_ERR(data->regmap))
431 return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
432 "regmap initialization failed\n");
433
434 i2c_set_clientdata(client, indio_dev);
435 data->client = client;
436
437 mutex_init(&data->lock);
438
439 indio_dev->info = <rf216a_info;
440 indio_dev->name = "ltrf216a";
441 indio_dev->channels = ltrf216a_channels;
442 indio_dev->num_channels = ARRAY_SIZE(ltrf216a_channels);
443 indio_dev->modes = INDIO_DIRECT_MODE;
444
445 ret = pm_runtime_set_active(&client->dev);
446 if (ret)
447 return ret;
448
449 /* reset sensor, chip fails to respond to this, so ignore any errors */
450 ltrf216a_reset(indio_dev);
451
452 ret = regmap_reinit_cache(data->regmap, <rf216a_regmap_config);
453 if (ret)
454 return dev_err_probe(&client->dev, ret,
455 "failed to reinit regmap cache\n");
456
457 ret = ltrf216a_enable(indio_dev);
458 if (ret)
459 return ret;
460
461 ret = devm_add_action_or_reset(&client->dev, ltrf216a_cleanup,
462 indio_dev);
463 if (ret)
464 return ret;
465
466 ret = devm_pm_runtime_enable(&client->dev);
467 if (ret)
468 return dev_err_probe(&client->dev, ret,
469 "failed to enable runtime PM\n");
470
471 pm_runtime_set_autosuspend_delay(&client->dev, 1000);
472 pm_runtime_use_autosuspend(&client->dev);
473
474 data->int_time = 100000;
475 data->int_time_fac = 100;
476 data->als_gain_fac = 3;
477
478 return devm_iio_device_register(&client->dev, indio_dev);
479 }
480
ltrf216a_runtime_suspend(struct device * dev)481 static int ltrf216a_runtime_suspend(struct device *dev)
482 {
483 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
484 struct ltrf216a_data *data = iio_priv(indio_dev);
485 int ret;
486
487 ret = ltrf216a_disable(indio_dev);
488 if (ret)
489 return ret;
490
491 regcache_cache_only(data->regmap, true);
492
493 return 0;
494 }
495
ltrf216a_runtime_resume(struct device * dev)496 static int ltrf216a_runtime_resume(struct device *dev)
497 {
498 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
499 struct ltrf216a_data *data = iio_priv(indio_dev);
500 int ret;
501
502 regcache_cache_only(data->regmap, false);
503 regcache_mark_dirty(data->regmap);
504 ret = regcache_sync(data->regmap);
505 if (ret)
506 goto cache_only;
507
508 ret = ltrf216a_enable(indio_dev);
509 if (ret)
510 goto cache_only;
511
512 return 0;
513
514 cache_only:
515 regcache_cache_only(data->regmap, true);
516
517 return ret;
518 }
519
520 static DEFINE_RUNTIME_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_runtime_suspend,
521 ltrf216a_runtime_resume, NULL);
522
523 static const struct i2c_device_id ltrf216a_id[] = {
524 { "ltrf216a" },
525 {}
526 };
527 MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
528
529 static const struct of_device_id ltrf216a_of_match[] = {
530 { .compatible = "liteon,ltrf216a" },
531 { .compatible = "ltr,ltrf216a" },
532 {}
533 };
534 MODULE_DEVICE_TABLE(of, ltrf216a_of_match);
535
536 static struct i2c_driver ltrf216a_driver = {
537 .driver = {
538 .name = "ltrf216a",
539 .pm = pm_ptr(<rf216a_pm_ops),
540 .of_match_table = ltrf216a_of_match,
541 },
542 .probe = ltrf216a_probe,
543 .id_table = ltrf216a_id,
544 };
545 module_i2c_driver(ltrf216a_driver);
546
547 MODULE_AUTHOR("Shreeya Patel <shreeya.patel@collabora.com>");
548 MODULE_AUTHOR("Shi Zhigang <Zhigang.Shi@liteon.com>");
549 MODULE_DESCRIPTION("LTRF216A ambient light sensor driver");
550 MODULE_LICENSE("GPL");
551