tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Vishay VEML6075 UVA and UVB light sensor
4 *
5 * Copyright 2023 Javier Carrasco <javier.carrasco.cruz@gmail.com>
6 *
7 * 7-bit I2C slave, address 0x10
8 */
9
10#include <linux/bitfield.h>
11#include <linux/delay.h>
12#include <linux/err.h>
13#include <linux/i2c.h>
14#include <linux/module.h>
15#include <linux/mutex.h>
16#include <linux/regmap.h>
17#include <linux/units.h>
18
19#include <linux/iio/iio.h>
20
21#define VEML6075_CMD_CONF 0x00 /* configuration register */
22#define VEML6075_CMD_UVA 0x07 /* UVA channel */
23#define VEML6075_CMD_UVB 0x09 /* UVB channel */
24#define VEML6075_CMD_COMP1 0x0A /* visible light compensation */
25#define VEML6075_CMD_COMP2 0x0B /* infrarred light compensation */
26#define VEML6075_CMD_ID 0x0C /* device ID */
27
28#define VEML6075_CONF_IT GENMASK(6, 4) /* intregration time */
29#define VEML6075_CONF_HD BIT(3) /* dynamic setting */
30#define VEML6075_CONF_TRIG BIT(2) /* trigger */
31#define VEML6075_CONF_AF BIT(1) /* active force enable */
32#define VEML6075_CONF_SD BIT(0) /* shutdown */
33
34#define VEML6075_IT_50_MS 0x00
35#define VEML6075_IT_100_MS 0x01
36#define VEML6075_IT_200_MS 0x02
37#define VEML6075_IT_400_MS 0x03
38#define VEML6075_IT_800_MS 0x04
39
40#define VEML6075_AF_DISABLE 0x00
41#define VEML6075_AF_ENABLE 0x01
42
43#define VEML6075_SD_DISABLE 0x00
44#define VEML6075_SD_ENABLE 0x01
45
46/* Open-air coefficients and responsivity */
47#define VEML6075_A_COEF 2220
48#define VEML6075_B_COEF 1330
49#define VEML6075_C_COEF 2950
50#define VEML6075_D_COEF 1740
51#define VEML6075_UVA_RESP 1461
52#define VEML6075_UVB_RESP 2591
53
54static const int veml6075_it_ms[] = { 50, 100, 200, 400, 800 };
55
56struct veml6075_data {
57 struct i2c_client *client;
58 struct regmap *regmap;
59 /*
60 * prevent integration time modification and triggering
61 * measurements while a measurement is underway.
62 */
63 struct mutex lock;
64};
65
66/* channel number */
67enum veml6075_chan {
68 CH_UVA,
69 CH_UVB,
70};
71
72static const struct iio_chan_spec veml6075_channels[] = {
73 {
74 .type = IIO_INTENSITY,
75 .channel = CH_UVA,
76 .modified = 1,
77 .channel2 = IIO_MOD_LIGHT_UVA,
78 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
79 BIT(IIO_CHAN_INFO_SCALE),
80 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
81 .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
82 },
83 {
84 .type = IIO_INTENSITY,
85 .channel = CH_UVB,
86 .modified = 1,
87 .channel2 = IIO_MOD_LIGHT_UVB,
88 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
89 BIT(IIO_CHAN_INFO_SCALE),
90 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
91 .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
92 },
93 {
94 .type = IIO_UVINDEX,
95 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
96 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
97 .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
98 },
99};
100
101static int veml6075_request_measurement(struct veml6075_data *data)
102{
103 int ret, conf, int_time;
104
105 ret = regmap_read(data->regmap, VEML6075_CMD_CONF, &conf);
106 if (ret < 0)
107 return ret;
108
109 /* disable shutdown and trigger measurement */
110 ret = regmap_write(data->regmap, VEML6075_CMD_CONF,
111 (conf | VEML6075_CONF_TRIG) & ~VEML6075_CONF_SD);
112 if (ret < 0)
113 return ret;
114
115 /*
116 * A measurement requires between 1.30 and 1.40 times the integration
117 * time for all possible configurations. Using a 1.50 factor simplifies
118 * operations and ensures reliability under all circumstances.
119 */
120 int_time = veml6075_it_ms[FIELD_GET(VEML6075_CONF_IT, conf)];
121 msleep(int_time + (int_time / 2));
122
123 /* shutdown again, data registers are still accessible */
124 return regmap_update_bits(data->regmap, VEML6075_CMD_CONF,
125 VEML6075_CONF_SD, VEML6075_CONF_SD);
126}
127
128static int veml6075_uva_comp(int raw_uva, int comp1, int comp2)
129{
130 int comp1a_c, comp2a_c, uva_comp;
131
132 comp1a_c = (comp1 * VEML6075_A_COEF) / 1000U;
133 comp2a_c = (comp2 * VEML6075_B_COEF) / 1000U;
134 uva_comp = raw_uva - comp1a_c - comp2a_c;
135
136 return clamp_val(uva_comp, 0, U16_MAX);
137}
138
139static int veml6075_uvb_comp(int raw_uvb, int comp1, int comp2)
140{
141 int comp1b_c, comp2b_c, uvb_comp;
142
143 comp1b_c = (comp1 * VEML6075_C_COEF) / 1000U;
144 comp2b_c = (comp2 * VEML6075_D_COEF) / 1000U;
145 uvb_comp = raw_uvb - comp1b_c - comp2b_c;
146
147 return clamp_val(uvb_comp, 0, U16_MAX);
148}
149
150static int veml6075_read_comp(struct veml6075_data *data, int *c1, int *c2)
151{
152 int ret;
153
154 ret = regmap_read(data->regmap, VEML6075_CMD_COMP1, c1);
155 if (ret < 0)
156 return ret;
157
158 return regmap_read(data->regmap, VEML6075_CMD_COMP2, c2);
159}
160
161static int veml6075_read_uv_direct(struct veml6075_data *data, int chan,
162 int *val)
163{
164 int c1, c2, ret;
165
166 guard(mutex)(&data->lock);
167
168 ret = veml6075_request_measurement(data);
169 if (ret < 0)
170 return ret;
171
172 ret = veml6075_read_comp(data, &c1, &c2);
173 if (ret < 0)
174 return ret;
175
176 switch (chan) {
177 case CH_UVA:
178 ret = regmap_read(data->regmap, VEML6075_CMD_UVA, val);
179 if (ret < 0)
180 return ret;
181
182 *val = veml6075_uva_comp(*val, c1, c2);
183 return IIO_VAL_INT;
184 case CH_UVB:
185 ret = regmap_read(data->regmap, VEML6075_CMD_UVB, val);
186 if (ret < 0)
187 return ret;
188
189 *val = veml6075_uvb_comp(*val, c1, c2);
190 return IIO_VAL_INT;
191 default:
192 return -EINVAL;
193 }
194}
195
196static int veml6075_read_int_time_index(struct veml6075_data *data)
197{
198 int ret, conf;
199
200 ret = regmap_read(data->regmap, VEML6075_CMD_CONF, &conf);
201 if (ret < 0)
202 return ret;
203
204 return FIELD_GET(VEML6075_CONF_IT, conf);
205}
206
207static int veml6075_read_int_time_ms(struct veml6075_data *data, int *val)
208{
209 int int_index;
210
211 guard(mutex)(&data->lock);
212 int_index = veml6075_read_int_time_index(data);
213 if (int_index < 0)
214 return int_index;
215
216 *val = veml6075_it_ms[int_index];
217
218 return IIO_VAL_INT;
219}
220
221static int veml6075_get_uvi_micro(struct veml6075_data *data, int uva_comp,
222 int uvb_comp)
223{
224 int uvia_micro = uva_comp * VEML6075_UVA_RESP;
225 int uvib_micro = uvb_comp * VEML6075_UVB_RESP;
226 int int_index;
227
228 int_index = veml6075_read_int_time_index(data);
229 if (int_index < 0)
230 return int_index;
231
232 switch (int_index) {
233 case VEML6075_IT_50_MS:
234 return uvia_micro + uvib_micro;
235 case VEML6075_IT_100_MS:
236 case VEML6075_IT_200_MS:
237 case VEML6075_IT_400_MS:
238 case VEML6075_IT_800_MS:
239 return (uvia_micro + uvib_micro) / (2 << int_index);
240 default:
241 return -EINVAL;
242 }
243}
244
245static int veml6075_read_uvi(struct veml6075_data *data, int *val, int *val2)
246{
247 int ret, c1, c2, uva, uvb, uvi_micro;
248
249 guard(mutex)(&data->lock);
250
251 ret = veml6075_request_measurement(data);
252 if (ret < 0)
253 return ret;
254
255 ret = veml6075_read_comp(data, &c1, &c2);
256 if (ret < 0)
257 return ret;
258
259 ret = regmap_read(data->regmap, VEML6075_CMD_UVA, &uva);
260 if (ret < 0)
261 return ret;
262
263 ret = regmap_read(data->regmap, VEML6075_CMD_UVB, &uvb);
264 if (ret < 0)
265 return ret;
266
267 uvi_micro = veml6075_get_uvi_micro(data, veml6075_uva_comp(uva, c1, c2),
268 veml6075_uvb_comp(uvb, c1, c2));
269 if (uvi_micro < 0)
270 return uvi_micro;
271
272 *val = uvi_micro / MICRO;
273 *val2 = uvi_micro % MICRO;
274
275 return IIO_VAL_INT_PLUS_MICRO;
276}
277
278static int veml6075_read_responsivity(int chan, int *val, int *val2)
279{
280 /* scale = 1 / resp */
281 switch (chan) {
282 case CH_UVA:
283 /* resp = 0.93 c/uW/cm2: scale = 1.75268817 */
284 *val = 1;
285 *val2 = 75268817;
286 return IIO_VAL_INT_PLUS_NANO;
287 case CH_UVB:
288 /* resp = 2.1 c/uW/cm2: scale = 0.476190476 */
289 *val = 0;
290 *val2 = 476190476;
291 return IIO_VAL_INT_PLUS_NANO;
292 default:
293 return -EINVAL;
294 }
295}
296
297static int veml6075_read_avail(struct iio_dev *indio_dev,
298 struct iio_chan_spec const *chan,
299 const int **vals, int *type, int *length,
300 long mask)
301{
302 switch (mask) {
303 case IIO_CHAN_INFO_INT_TIME:
304 *length = ARRAY_SIZE(veml6075_it_ms);
305 *vals = veml6075_it_ms;
306 *type = IIO_VAL_INT;
307 return IIO_AVAIL_LIST;
308
309 default:
310 return -EINVAL;
311 }
312}
313
314static int veml6075_read_raw(struct iio_dev *indio_dev,
315 struct iio_chan_spec const *chan,
316 int *val, int *val2, long mask)
317{
318 struct veml6075_data *data = iio_priv(indio_dev);
319
320 switch (mask) {
321 case IIO_CHAN_INFO_RAW:
322 return veml6075_read_uv_direct(data, chan->channel, val);
323 case IIO_CHAN_INFO_PROCESSED:
324 return veml6075_read_uvi(data, val, val2);
325 case IIO_CHAN_INFO_INT_TIME:
326 return veml6075_read_int_time_ms(data, val);
327 case IIO_CHAN_INFO_SCALE:
328 return veml6075_read_responsivity(chan->channel, val, val2);
329 default:
330 return -EINVAL;
331 }
332}
333
334static int veml6075_write_int_time_ms(struct veml6075_data *data, int val)
335{
336 int i = ARRAY_SIZE(veml6075_it_ms);
337
338 guard(mutex)(&data->lock);
339
340 while (i-- > 0) {
341 if (val == veml6075_it_ms[i])
342 break;
343 }
344 if (i < 0)
345 return -EINVAL;
346
347 return regmap_update_bits(data->regmap, VEML6075_CMD_CONF,
348 VEML6075_CONF_IT,
349 FIELD_PREP(VEML6075_CONF_IT, i));
350}
351
352static int veml6075_write_raw(struct iio_dev *indio_dev,
353 struct iio_chan_spec const *chan,
354 int val, int val2, long mask)
355{
356 struct veml6075_data *data = iio_priv(indio_dev);
357
358 switch (mask) {
359 case IIO_CHAN_INFO_INT_TIME:
360 return veml6075_write_int_time_ms(data, val);
361 default:
362 return -EINVAL;
363 }
364}
365
366static const struct iio_info veml6075_info = {
367 .read_avail = veml6075_read_avail,
368 .read_raw = veml6075_read_raw,
369 .write_raw = veml6075_write_raw,
370};
371
372static bool veml6075_readable_reg(struct device *dev, unsigned int reg)
373{
374 switch (reg) {
375 case VEML6075_CMD_CONF:
376 case VEML6075_CMD_UVA:
377 case VEML6075_CMD_UVB:
378 case VEML6075_CMD_COMP1:
379 case VEML6075_CMD_COMP2:
380 case VEML6075_CMD_ID:
381 return true;
382 default:
383 return false;
384 }
385}
386
387static bool veml6075_writable_reg(struct device *dev, unsigned int reg)
388{
389 switch (reg) {
390 case VEML6075_CMD_CONF:
391 return true;
392 default:
393 return false;
394 }
395}
396
397static const struct regmap_config veml6075_regmap_config = {
398 .name = "veml6075",
399 .reg_bits = 8,
400 .val_bits = 16,
401 .max_register = VEML6075_CMD_ID,
402 .readable_reg = veml6075_readable_reg,
403 .writeable_reg = veml6075_writable_reg,
404 .val_format_endian = REGMAP_ENDIAN_LITTLE,
405};
406
407static int veml6075_probe(struct i2c_client *client)
408{
409 struct veml6075_data *data;
410 struct iio_dev *indio_dev;
411 struct regmap *regmap;
412 int config, ret;
413
414 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
415 if (!indio_dev)
416 return -ENOMEM;
417
418 regmap = devm_regmap_init_i2c(client, &veml6075_regmap_config);
419 if (IS_ERR(regmap))
420 return PTR_ERR(regmap);
421
422 data = iio_priv(indio_dev);
423 data->client = client;
424 data->regmap = regmap;
425
426 mutex_init(&data->lock);
427
428 indio_dev->name = "veml6075";
429 indio_dev->info = &veml6075_info;
430 indio_dev->channels = veml6075_channels;
431 indio_dev->num_channels = ARRAY_SIZE(veml6075_channels);
432 indio_dev->modes = INDIO_DIRECT_MODE;
433
434 ret = devm_regulator_get_enable(&client->dev, "vdd");
435 if (ret < 0)
436 return ret;
437
438 /* default: 100ms integration time, active force enable, shutdown */
439 config = FIELD_PREP(VEML6075_CONF_IT, VEML6075_IT_100_MS) |
440 FIELD_PREP(VEML6075_CONF_AF, VEML6075_AF_ENABLE) |
441 FIELD_PREP(VEML6075_CONF_SD, VEML6075_SD_ENABLE);
442 ret = regmap_write(data->regmap, VEML6075_CMD_CONF, config);
443 if (ret < 0)
444 return ret;
445
446 return devm_iio_device_register(&client->dev, indio_dev);
447}
448
449static const struct i2c_device_id veml6075_id[] = {
450 { "veml6075" },
451 { }
452};
453MODULE_DEVICE_TABLE(i2c, veml6075_id);
454
455static const struct of_device_id veml6075_of_match[] = {
456 { .compatible = "vishay,veml6075" },
457 {}
458};
459MODULE_DEVICE_TABLE(of, veml6075_of_match);
460
461static struct i2c_driver veml6075_driver = {
462 .driver = {
463 .name = "veml6075",
464 .of_match_table = veml6075_of_match,
465 },
466 .probe = veml6075_probe,
467 .id_table = veml6075_id,
468};
469
470module_i2c_driver(veml6075_driver);
471
472MODULE_AUTHOR("Javier Carrasco <javier.carrasco.cruz@gmail.com>");
473MODULE_DESCRIPTION("Vishay VEML6075 UVA and UVB light sensor driver");
474MODULE_LICENSE("GPL");