1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * lv0104cs.c: LV0104CS Ambient Light Sensor Driver |
4 | * |
5 | * Copyright (C) 2018 |
6 | * Author: Jeff LaBundy <jeff@labundy.com> |
7 | * |
8 | * 7-bit I2C slave address: 0x13 |
9 | * |
10 | * Link to data sheet: https://www.onsemi.com/pub/Collateral/LV0104CS-D.PDF |
11 | */ |
12 | |
13 | #include <linux/kernel.h> |
14 | #include <linux/module.h> |
15 | #include <linux/i2c.h> |
16 | #include <linux/err.h> |
17 | #include <linux/mutex.h> |
18 | #include <linux/delay.h> |
19 | #include <linux/iio/iio.h> |
20 | #include <linux/iio/sysfs.h> |
21 | |
22 | #define LV0104CS_REGVAL_MEASURE 0xE0 |
23 | #define LV0104CS_REGVAL_SLEEP 0x00 |
24 | |
25 | #define LV0104CS_SCALE_0_25X 0 |
26 | #define LV0104CS_SCALE_1X 1 |
27 | #define LV0104CS_SCALE_2X 2 |
28 | #define LV0104CS_SCALE_8X 3 |
29 | #define LV0104CS_SCALE_SHIFT 3 |
30 | |
31 | #define LV0104CS_INTEG_12_5MS 0 |
32 | #define LV0104CS_INTEG_100MS 1 |
33 | #define LV0104CS_INTEG_200MS 2 |
34 | #define LV0104CS_INTEG_SHIFT 1 |
35 | |
36 | #define LV0104CS_CALIBSCALE_UNITY 31 |
37 | |
38 | struct lv0104cs_private { |
39 | struct i2c_client *client; |
40 | struct mutex lock; |
41 | u8 calibscale; |
42 | u8 scale; |
43 | u8 int_time; |
44 | }; |
45 | |
46 | struct lv0104cs_mapping { |
47 | int val; |
48 | int val2; |
49 | u8 regval; |
50 | }; |
51 | |
52 | static const struct lv0104cs_mapping lv0104cs_calibscales[] = { |
53 | { 0, 666666, 0x81 }, |
54 | { 0, 800000, 0x82 }, |
55 | { 0, 857142, 0x83 }, |
56 | { 0, 888888, 0x84 }, |
57 | { 0, 909090, 0x85 }, |
58 | { 0, 923076, 0x86 }, |
59 | { 0, 933333, 0x87 }, |
60 | { 0, 941176, 0x88 }, |
61 | { 0, 947368, 0x89 }, |
62 | { 0, 952380, 0x8A }, |
63 | { 0, 956521, 0x8B }, |
64 | { 0, 960000, 0x8C }, |
65 | { 0, 962962, 0x8D }, |
66 | { 0, 965517, 0x8E }, |
67 | { 0, 967741, 0x8F }, |
68 | { 0, 969696, 0x90 }, |
69 | { 0, 971428, 0x91 }, |
70 | { 0, 972972, 0x92 }, |
71 | { 0, 974358, 0x93 }, |
72 | { 0, 975609, 0x94 }, |
73 | { 0, 976744, 0x95 }, |
74 | { 0, 977777, 0x96 }, |
75 | { 0, 978723, 0x97 }, |
76 | { 0, 979591, 0x98 }, |
77 | { 0, 980392, 0x99 }, |
78 | { 0, 981132, 0x9A }, |
79 | { 0, 981818, 0x9B }, |
80 | { 0, 982456, 0x9C }, |
81 | { 0, 983050, 0x9D }, |
82 | { 0, 983606, 0x9E }, |
83 | { 0, 984126, 0x9F }, |
84 | { 1, 0, 0x80 }, |
85 | { 1, 16129, 0xBF }, |
86 | { 1, 16666, 0xBE }, |
87 | { 1, 17241, 0xBD }, |
88 | { 1, 17857, 0xBC }, |
89 | { 1, 18518, 0xBB }, |
90 | { 1, 19230, 0xBA }, |
91 | { 1, 20000, 0xB9 }, |
92 | { 1, 20833, 0xB8 }, |
93 | { 1, 21739, 0xB7 }, |
94 | { 1, 22727, 0xB6 }, |
95 | { 1, 23809, 0xB5 }, |
96 | { 1, 24999, 0xB4 }, |
97 | { 1, 26315, 0xB3 }, |
98 | { 1, 27777, 0xB2 }, |
99 | { 1, 29411, 0xB1 }, |
100 | { 1, 31250, 0xB0 }, |
101 | { 1, 33333, 0xAF }, |
102 | { 1, 35714, 0xAE }, |
103 | { 1, 38461, 0xAD }, |
104 | { 1, 41666, 0xAC }, |
105 | { 1, 45454, 0xAB }, |
106 | { 1, 50000, 0xAA }, |
107 | { 1, 55555, 0xA9 }, |
108 | { 1, 62500, 0xA8 }, |
109 | { 1, 71428, 0xA7 }, |
110 | { 1, 83333, 0xA6 }, |
111 | { 1, 100000, 0xA5 }, |
112 | { 1, 125000, 0xA4 }, |
113 | { 1, 166666, 0xA3 }, |
114 | { 1, 250000, 0xA2 }, |
115 | { 1, 500000, 0xA1 }, |
116 | }; |
117 | |
118 | static const struct lv0104cs_mapping lv0104cs_scales[] = { |
119 | { 0, 250000, LV0104CS_SCALE_0_25X << LV0104CS_SCALE_SHIFT }, |
120 | { 1, 0, LV0104CS_SCALE_1X << LV0104CS_SCALE_SHIFT }, |
121 | { 2, 0, LV0104CS_SCALE_2X << LV0104CS_SCALE_SHIFT }, |
122 | { 8, 0, LV0104CS_SCALE_8X << LV0104CS_SCALE_SHIFT }, |
123 | }; |
124 | |
125 | static const struct lv0104cs_mapping lv0104cs_int_times[] = { |
126 | { 0, 12500, LV0104CS_INTEG_12_5MS << LV0104CS_INTEG_SHIFT }, |
127 | { 0, 100000, LV0104CS_INTEG_100MS << LV0104CS_INTEG_SHIFT }, |
128 | { 0, 200000, LV0104CS_INTEG_200MS << LV0104CS_INTEG_SHIFT }, |
129 | }; |
130 | |
131 | static int lv0104cs_write_reg(struct i2c_client *client, u8 regval) |
132 | { |
133 | int ret; |
134 | |
135 | ret = i2c_master_send(client, buf: (char *)®val, count: sizeof(regval)); |
136 | if (ret < 0) |
137 | return ret; |
138 | if (ret != sizeof(regval)) |
139 | return -EIO; |
140 | |
141 | return 0; |
142 | } |
143 | |
144 | static int lv0104cs_read_adc(struct i2c_client *client, u16 *adc_output) |
145 | { |
146 | __be16 regval; |
147 | int ret; |
148 | |
149 | ret = i2c_master_recv(client, buf: (char *)®val, count: sizeof(regval)); |
150 | if (ret < 0) |
151 | return ret; |
152 | if (ret != sizeof(regval)) |
153 | return -EIO; |
154 | |
155 | *adc_output = be16_to_cpu(regval); |
156 | |
157 | return 0; |
158 | } |
159 | |
160 | static int lv0104cs_get_lux(struct lv0104cs_private *lv0104cs, |
161 | int *val, int *val2) |
162 | { |
163 | u8 regval = LV0104CS_REGVAL_MEASURE; |
164 | u16 adc_output; |
165 | int ret; |
166 | |
167 | regval |= lv0104cs_scales[lv0104cs->scale].regval; |
168 | regval |= lv0104cs_int_times[lv0104cs->int_time].regval; |
169 | ret = lv0104cs_write_reg(client: lv0104cs->client, regval); |
170 | if (ret) |
171 | return ret; |
172 | |
173 | /* wait for integration time to pass (with margin) */ |
174 | switch (lv0104cs->int_time) { |
175 | case LV0104CS_INTEG_12_5MS: |
176 | msleep(msecs: 50); |
177 | break; |
178 | |
179 | case LV0104CS_INTEG_100MS: |
180 | msleep(msecs: 150); |
181 | break; |
182 | |
183 | case LV0104CS_INTEG_200MS: |
184 | msleep(msecs: 250); |
185 | break; |
186 | |
187 | default: |
188 | return -EINVAL; |
189 | } |
190 | |
191 | ret = lv0104cs_read_adc(client: lv0104cs->client, adc_output: &adc_output); |
192 | if (ret) |
193 | return ret; |
194 | |
195 | ret = lv0104cs_write_reg(client: lv0104cs->client, LV0104CS_REGVAL_SLEEP); |
196 | if (ret) |
197 | return ret; |
198 | |
199 | /* convert ADC output to lux */ |
200 | switch (lv0104cs->scale) { |
201 | case LV0104CS_SCALE_0_25X: |
202 | *val = adc_output * 4; |
203 | *val2 = 0; |
204 | return 0; |
205 | |
206 | case LV0104CS_SCALE_1X: |
207 | *val = adc_output; |
208 | *val2 = 0; |
209 | return 0; |
210 | |
211 | case LV0104CS_SCALE_2X: |
212 | *val = adc_output / 2; |
213 | *val2 = (adc_output % 2) * 500000; |
214 | return 0; |
215 | |
216 | case LV0104CS_SCALE_8X: |
217 | *val = adc_output / 8; |
218 | *val2 = (adc_output % 8) * 125000; |
219 | return 0; |
220 | |
221 | default: |
222 | return -EINVAL; |
223 | } |
224 | } |
225 | |
226 | static int lv0104cs_read_raw(struct iio_dev *indio_dev, |
227 | struct iio_chan_spec const *chan, |
228 | int *val, int *val2, long mask) |
229 | { |
230 | struct lv0104cs_private *lv0104cs = iio_priv(indio_dev); |
231 | int ret; |
232 | |
233 | if (chan->type != IIO_LIGHT) |
234 | return -EINVAL; |
235 | |
236 | mutex_lock(&lv0104cs->lock); |
237 | |
238 | switch (mask) { |
239 | case IIO_CHAN_INFO_PROCESSED: |
240 | ret = lv0104cs_get_lux(lv0104cs, val, val2); |
241 | if (ret) |
242 | goto err_mutex; |
243 | ret = IIO_VAL_INT_PLUS_MICRO; |
244 | break; |
245 | |
246 | case IIO_CHAN_INFO_CALIBSCALE: |
247 | *val = lv0104cs_calibscales[lv0104cs->calibscale].val; |
248 | *val2 = lv0104cs_calibscales[lv0104cs->calibscale].val2; |
249 | ret = IIO_VAL_INT_PLUS_MICRO; |
250 | break; |
251 | |
252 | case IIO_CHAN_INFO_SCALE: |
253 | *val = lv0104cs_scales[lv0104cs->scale].val; |
254 | *val2 = lv0104cs_scales[lv0104cs->scale].val2; |
255 | ret = IIO_VAL_INT_PLUS_MICRO; |
256 | break; |
257 | |
258 | case IIO_CHAN_INFO_INT_TIME: |
259 | *val = lv0104cs_int_times[lv0104cs->int_time].val; |
260 | *val2 = lv0104cs_int_times[lv0104cs->int_time].val2; |
261 | ret = IIO_VAL_INT_PLUS_MICRO; |
262 | break; |
263 | |
264 | default: |
265 | ret = -EINVAL; |
266 | } |
267 | |
268 | err_mutex: |
269 | mutex_unlock(lock: &lv0104cs->lock); |
270 | |
271 | return ret; |
272 | } |
273 | |
274 | static int lv0104cs_set_calibscale(struct lv0104cs_private *lv0104cs, |
275 | int val, int val2) |
276 | { |
277 | int calibscale = val * 1000000 + val2; |
278 | int floor, ceil, mid; |
279 | int ret, i, index; |
280 | |
281 | /* round to nearest quantized calibscale (sensitivity) */ |
282 | for (i = 0; i < ARRAY_SIZE(lv0104cs_calibscales) - 1; i++) { |
283 | floor = lv0104cs_calibscales[i].val * 1000000 |
284 | + lv0104cs_calibscales[i].val2; |
285 | ceil = lv0104cs_calibscales[i + 1].val * 1000000 |
286 | + lv0104cs_calibscales[i + 1].val2; |
287 | mid = (floor + ceil) / 2; |
288 | |
289 | /* round down */ |
290 | if (calibscale >= floor && calibscale < mid) { |
291 | index = i; |
292 | break; |
293 | } |
294 | |
295 | /* round up */ |
296 | if (calibscale >= mid && calibscale <= ceil) { |
297 | index = i + 1; |
298 | break; |
299 | } |
300 | } |
301 | |
302 | if (i == ARRAY_SIZE(lv0104cs_calibscales) - 1) |
303 | return -EINVAL; |
304 | |
305 | mutex_lock(&lv0104cs->lock); |
306 | |
307 | /* set calibscale (sensitivity) */ |
308 | ret = lv0104cs_write_reg(client: lv0104cs->client, |
309 | regval: lv0104cs_calibscales[index].regval); |
310 | if (ret) |
311 | goto err_mutex; |
312 | |
313 | lv0104cs->calibscale = index; |
314 | |
315 | err_mutex: |
316 | mutex_unlock(lock: &lv0104cs->lock); |
317 | |
318 | return ret; |
319 | } |
320 | |
321 | static int lv0104cs_set_scale(struct lv0104cs_private *lv0104cs, |
322 | int val, int val2) |
323 | { |
324 | int i; |
325 | |
326 | /* hard matching */ |
327 | for (i = 0; i < ARRAY_SIZE(lv0104cs_scales); i++) { |
328 | if (val != lv0104cs_scales[i].val) |
329 | continue; |
330 | |
331 | if (val2 == lv0104cs_scales[i].val2) |
332 | break; |
333 | } |
334 | |
335 | if (i == ARRAY_SIZE(lv0104cs_scales)) |
336 | return -EINVAL; |
337 | |
338 | mutex_lock(&lv0104cs->lock); |
339 | lv0104cs->scale = i; |
340 | mutex_unlock(lock: &lv0104cs->lock); |
341 | |
342 | return 0; |
343 | } |
344 | |
345 | static int lv0104cs_set_int_time(struct lv0104cs_private *lv0104cs, |
346 | int val, int val2) |
347 | { |
348 | int i; |
349 | |
350 | /* hard matching */ |
351 | for (i = 0; i < ARRAY_SIZE(lv0104cs_int_times); i++) { |
352 | if (val != lv0104cs_int_times[i].val) |
353 | continue; |
354 | |
355 | if (val2 == lv0104cs_int_times[i].val2) |
356 | break; |
357 | } |
358 | |
359 | if (i == ARRAY_SIZE(lv0104cs_int_times)) |
360 | return -EINVAL; |
361 | |
362 | mutex_lock(&lv0104cs->lock); |
363 | lv0104cs->int_time = i; |
364 | mutex_unlock(lock: &lv0104cs->lock); |
365 | |
366 | return 0; |
367 | } |
368 | |
369 | static int lv0104cs_write_raw(struct iio_dev *indio_dev, |
370 | struct iio_chan_spec const *chan, |
371 | int val, int val2, long mask) |
372 | { |
373 | struct lv0104cs_private *lv0104cs = iio_priv(indio_dev); |
374 | |
375 | if (chan->type != IIO_LIGHT) |
376 | return -EINVAL; |
377 | |
378 | switch (mask) { |
379 | case IIO_CHAN_INFO_CALIBSCALE: |
380 | return lv0104cs_set_calibscale(lv0104cs, val, val2); |
381 | |
382 | case IIO_CHAN_INFO_SCALE: |
383 | return lv0104cs_set_scale(lv0104cs, val, val2); |
384 | |
385 | case IIO_CHAN_INFO_INT_TIME: |
386 | return lv0104cs_set_int_time(lv0104cs, val, val2); |
387 | |
388 | default: |
389 | return -EINVAL; |
390 | } |
391 | } |
392 | |
393 | static ssize_t lv0104cs_show_calibscale_avail(struct device *dev, |
394 | struct device_attribute *attr, char *buf) |
395 | { |
396 | ssize_t len = 0; |
397 | int i; |
398 | |
399 | for (i = 0; i < ARRAY_SIZE(lv0104cs_calibscales); i++) { |
400 | len += scnprintf(buf: buf + len, PAGE_SIZE - len, fmt: "%d.%06d " , |
401 | lv0104cs_calibscales[i].val, |
402 | lv0104cs_calibscales[i].val2); |
403 | } |
404 | |
405 | buf[len - 1] = '\n'; |
406 | |
407 | return len; |
408 | } |
409 | |
410 | static ssize_t lv0104cs_show_scale_avail(struct device *dev, |
411 | struct device_attribute *attr, char *buf) |
412 | { |
413 | ssize_t len = 0; |
414 | int i; |
415 | |
416 | for (i = 0; i < ARRAY_SIZE(lv0104cs_scales); i++) { |
417 | len += scnprintf(buf: buf + len, PAGE_SIZE - len, fmt: "%d.%06d " , |
418 | lv0104cs_scales[i].val, |
419 | lv0104cs_scales[i].val2); |
420 | } |
421 | |
422 | buf[len - 1] = '\n'; |
423 | |
424 | return len; |
425 | } |
426 | |
427 | static ssize_t lv0104cs_show_int_time_avail(struct device *dev, |
428 | struct device_attribute *attr, char *buf) |
429 | { |
430 | ssize_t len = 0; |
431 | int i; |
432 | |
433 | for (i = 0; i < ARRAY_SIZE(lv0104cs_int_times); i++) { |
434 | len += scnprintf(buf: buf + len, PAGE_SIZE - len, fmt: "%d.%06d " , |
435 | lv0104cs_int_times[i].val, |
436 | lv0104cs_int_times[i].val2); |
437 | } |
438 | |
439 | buf[len - 1] = '\n'; |
440 | |
441 | return len; |
442 | } |
443 | |
444 | static IIO_DEVICE_ATTR(calibscale_available, 0444, |
445 | lv0104cs_show_calibscale_avail, NULL, 0); |
446 | static IIO_DEVICE_ATTR(scale_available, 0444, |
447 | lv0104cs_show_scale_avail, NULL, 0); |
448 | static IIO_DEV_ATTR_INT_TIME_AVAIL(lv0104cs_show_int_time_avail); |
449 | |
450 | static struct attribute *lv0104cs_attributes[] = { |
451 | &iio_dev_attr_calibscale_available.dev_attr.attr, |
452 | &iio_dev_attr_scale_available.dev_attr.attr, |
453 | &iio_dev_attr_integration_time_available.dev_attr.attr, |
454 | NULL |
455 | }; |
456 | |
457 | static const struct attribute_group lv0104cs_attribute_group = { |
458 | .attrs = lv0104cs_attributes, |
459 | }; |
460 | |
461 | static const struct iio_info lv0104cs_info = { |
462 | .attrs = &lv0104cs_attribute_group, |
463 | .read_raw = &lv0104cs_read_raw, |
464 | .write_raw = &lv0104cs_write_raw, |
465 | }; |
466 | |
467 | static const struct iio_chan_spec lv0104cs_channels[] = { |
468 | { |
469 | .type = IIO_LIGHT, |
470 | .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | |
471 | BIT(IIO_CHAN_INFO_CALIBSCALE) | |
472 | BIT(IIO_CHAN_INFO_SCALE) | |
473 | BIT(IIO_CHAN_INFO_INT_TIME), |
474 | }, |
475 | }; |
476 | |
477 | static int lv0104cs_probe(struct i2c_client *client) |
478 | { |
479 | struct iio_dev *indio_dev; |
480 | struct lv0104cs_private *lv0104cs; |
481 | int ret; |
482 | |
483 | indio_dev = devm_iio_device_alloc(parent: &client->dev, sizeof_priv: sizeof(*lv0104cs)); |
484 | if (!indio_dev) |
485 | return -ENOMEM; |
486 | |
487 | lv0104cs = iio_priv(indio_dev); |
488 | |
489 | i2c_set_clientdata(client, data: lv0104cs); |
490 | lv0104cs->client = client; |
491 | |
492 | mutex_init(&lv0104cs->lock); |
493 | |
494 | lv0104cs->calibscale = LV0104CS_CALIBSCALE_UNITY; |
495 | lv0104cs->scale = LV0104CS_SCALE_1X; |
496 | lv0104cs->int_time = LV0104CS_INTEG_200MS; |
497 | |
498 | ret = lv0104cs_write_reg(client: lv0104cs->client, |
499 | regval: lv0104cs_calibscales[LV0104CS_CALIBSCALE_UNITY].regval); |
500 | if (ret) |
501 | return ret; |
502 | |
503 | indio_dev->modes = INDIO_DIRECT_MODE; |
504 | indio_dev->channels = lv0104cs_channels; |
505 | indio_dev->num_channels = ARRAY_SIZE(lv0104cs_channels); |
506 | indio_dev->name = client->name; |
507 | indio_dev->info = &lv0104cs_info; |
508 | |
509 | return devm_iio_device_register(&client->dev, indio_dev); |
510 | } |
511 | |
512 | static const struct i2c_device_id lv0104cs_id[] = { |
513 | { "lv0104cs" , 0 }, |
514 | { } |
515 | }; |
516 | MODULE_DEVICE_TABLE(i2c, lv0104cs_id); |
517 | |
518 | static struct i2c_driver lv0104cs_i2c_driver = { |
519 | .driver = { |
520 | .name = "lv0104cs" , |
521 | }, |
522 | .id_table = lv0104cs_id, |
523 | .probe = lv0104cs_probe, |
524 | }; |
525 | module_i2c_driver(lv0104cs_i2c_driver); |
526 | |
527 | MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>" ); |
528 | MODULE_DESCRIPTION("LV0104CS Ambient Light Sensor Driver" ); |
529 | MODULE_LICENSE("GPL" ); |
530 | |