1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Bosch BME680 - Temperature, Pressure, Humidity & Gas Sensor
4 *
5 * Copyright (C) 2017 - 2018 Bosch Sensortec GmbH
6 * Copyright (C) 2018 Himanshu Jha <himanshujha199640@gmail.com>
7 *
8 * Datasheet:
9 * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BME680-DS001-00.pdf
10 */
11 #include <linux/acpi.h>
12 #include <linux/bitfield.h>
13 #include <linux/device.h>
14 #include <linux/module.h>
15 #include <linux/log2.h>
16 #include <linux/regmap.h>
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19
20 #include "bme680.h"
21
22 struct bme680_calib {
23 u16 par_t1;
24 s16 par_t2;
25 s8 par_t3;
26 u16 par_p1;
27 s16 par_p2;
28 s8 par_p3;
29 s16 par_p4;
30 s16 par_p5;
31 s8 par_p6;
32 s8 par_p7;
33 s16 par_p8;
34 s16 par_p9;
35 u8 par_p10;
36 u16 par_h1;
37 u16 par_h2;
38 s8 par_h3;
39 s8 par_h4;
40 s8 par_h5;
41 s8 par_h6;
42 s8 par_h7;
43 s8 par_gh1;
44 s16 par_gh2;
45 s8 par_gh3;
46 u8 res_heat_range;
47 s8 res_heat_val;
48 s8 range_sw_err;
49 };
50
51 struct bme680_data {
52 struct regmap *regmap;
53 struct bme680_calib bme680;
54 u8 oversampling_temp;
55 u8 oversampling_press;
56 u8 oversampling_humid;
57 u16 heater_dur;
58 u16 heater_temp;
59 /*
60 * Carryover value from temperature conversion, used in pressure
61 * and humidity compensation calculations.
62 */
63 s32 t_fine;
64 };
65
66 static const struct regmap_range bme680_volatile_ranges[] = {
67 regmap_reg_range(BME680_REG_MEAS_STAT_0, BME680_REG_GAS_R_LSB),
68 regmap_reg_range(BME680_REG_STATUS, BME680_REG_STATUS),
69 regmap_reg_range(BME680_T2_LSB_REG, BME680_GH3_REG),
70 };
71
72 static const struct regmap_access_table bme680_volatile_table = {
73 .yes_ranges = bme680_volatile_ranges,
74 .n_yes_ranges = ARRAY_SIZE(bme680_volatile_ranges),
75 };
76
77 const struct regmap_config bme680_regmap_config = {
78 .reg_bits = 8,
79 .val_bits = 8,
80 .max_register = 0xef,
81 .volatile_table = &bme680_volatile_table,
82 .cache_type = REGCACHE_RBTREE,
83 };
84 EXPORT_SYMBOL(bme680_regmap_config);
85
86 static const struct iio_chan_spec bme680_channels[] = {
87 {
88 .type = IIO_TEMP,
89 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
90 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
91 },
92 {
93 .type = IIO_PRESSURE,
94 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
95 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
96 },
97 {
98 .type = IIO_HUMIDITYRELATIVE,
99 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
100 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
101 },
102 {
103 .type = IIO_RESISTANCE,
104 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
105 },
106 };
107
bme680_read_calib(struct bme680_data * data,struct bme680_calib * calib)108 static int bme680_read_calib(struct bme680_data *data,
109 struct bme680_calib *calib)
110 {
111 struct device *dev = regmap_get_device(data->regmap);
112 unsigned int tmp, tmp_msb, tmp_lsb;
113 int ret;
114 __le16 buf;
115
116 /* Temperature related coefficients */
117 ret = regmap_bulk_read(data->regmap, BME680_T1_LSB_REG,
118 &buf, sizeof(buf));
119 if (ret < 0) {
120 dev_err(dev, "failed to read BME680_T1_LSB_REG\n");
121 return ret;
122 }
123 calib->par_t1 = le16_to_cpu(buf);
124
125 ret = regmap_bulk_read(data->regmap, BME680_T2_LSB_REG,
126 &buf, sizeof(buf));
127 if (ret < 0) {
128 dev_err(dev, "failed to read BME680_T2_LSB_REG\n");
129 return ret;
130 }
131 calib->par_t2 = le16_to_cpu(buf);
132
133 ret = regmap_read(data->regmap, BME680_T3_REG, &tmp);
134 if (ret < 0) {
135 dev_err(dev, "failed to read BME680_T3_REG\n");
136 return ret;
137 }
138 calib->par_t3 = tmp;
139
140 /* Pressure related coefficients */
141 ret = regmap_bulk_read(data->regmap, BME680_P1_LSB_REG,
142 &buf, sizeof(buf));
143 if (ret < 0) {
144 dev_err(dev, "failed to read BME680_P1_LSB_REG\n");
145 return ret;
146 }
147 calib->par_p1 = le16_to_cpu(buf);
148
149 ret = regmap_bulk_read(data->regmap, BME680_P2_LSB_REG,
150 &buf, sizeof(buf));
151 if (ret < 0) {
152 dev_err(dev, "failed to read BME680_P2_LSB_REG\n");
153 return ret;
154 }
155 calib->par_p2 = le16_to_cpu(buf);
156
157 ret = regmap_read(data->regmap, BME680_P3_REG, &tmp);
158 if (ret < 0) {
159 dev_err(dev, "failed to read BME680_P3_REG\n");
160 return ret;
161 }
162 calib->par_p3 = tmp;
163
164 ret = regmap_bulk_read(data->regmap, BME680_P4_LSB_REG,
165 &buf, sizeof(buf));
166 if (ret < 0) {
167 dev_err(dev, "failed to read BME680_P4_LSB_REG\n");
168 return ret;
169 }
170 calib->par_p4 = le16_to_cpu(buf);
171
172 ret = regmap_bulk_read(data->regmap, BME680_P5_LSB_REG,
173 &buf, sizeof(buf));
174 if (ret < 0) {
175 dev_err(dev, "failed to read BME680_P5_LSB_REG\n");
176 return ret;
177 }
178 calib->par_p5 = le16_to_cpu(buf);
179
180 ret = regmap_read(data->regmap, BME680_P6_REG, &tmp);
181 if (ret < 0) {
182 dev_err(dev, "failed to read BME680_P6_REG\n");
183 return ret;
184 }
185 calib->par_p6 = tmp;
186
187 ret = regmap_read(data->regmap, BME680_P7_REG, &tmp);
188 if (ret < 0) {
189 dev_err(dev, "failed to read BME680_P7_REG\n");
190 return ret;
191 }
192 calib->par_p7 = tmp;
193
194 ret = regmap_bulk_read(data->regmap, BME680_P8_LSB_REG,
195 &buf, sizeof(buf));
196 if (ret < 0) {
197 dev_err(dev, "failed to read BME680_P8_LSB_REG\n");
198 return ret;
199 }
200 calib->par_p8 = le16_to_cpu(buf);
201
202 ret = regmap_bulk_read(data->regmap, BME680_P9_LSB_REG,
203 &buf, sizeof(buf));
204 if (ret < 0) {
205 dev_err(dev, "failed to read BME680_P9_LSB_REG\n");
206 return ret;
207 }
208 calib->par_p9 = le16_to_cpu(buf);
209
210 ret = regmap_read(data->regmap, BME680_P10_REG, &tmp);
211 if (ret < 0) {
212 dev_err(dev, "failed to read BME680_P10_REG\n");
213 return ret;
214 }
215 calib->par_p10 = tmp;
216
217 /* Humidity related coefficients */
218 ret = regmap_read(data->regmap, BME680_H1_MSB_REG, &tmp_msb);
219 if (ret < 0) {
220 dev_err(dev, "failed to read BME680_H1_MSB_REG\n");
221 return ret;
222 }
223 ret = regmap_read(data->regmap, BME680_H1_LSB_REG, &tmp_lsb);
224 if (ret < 0) {
225 dev_err(dev, "failed to read BME680_H1_LSB_REG\n");
226 return ret;
227 }
228 calib->par_h1 = (tmp_msb << BME680_HUM_REG_SHIFT_VAL) |
229 (tmp_lsb & BME680_BIT_H1_DATA_MASK);
230
231 ret = regmap_read(data->regmap, BME680_H2_MSB_REG, &tmp_msb);
232 if (ret < 0) {
233 dev_err(dev, "failed to read BME680_H2_MSB_REG\n");
234 return ret;
235 }
236 ret = regmap_read(data->regmap, BME680_H2_LSB_REG, &tmp_lsb);
237 if (ret < 0) {
238 dev_err(dev, "failed to read BME680_H2_LSB_REG\n");
239 return ret;
240 }
241 calib->par_h2 = (tmp_msb << BME680_HUM_REG_SHIFT_VAL) |
242 (tmp_lsb >> BME680_HUM_REG_SHIFT_VAL);
243
244 ret = regmap_read(data->regmap, BME680_H3_REG, &tmp);
245 if (ret < 0) {
246 dev_err(dev, "failed to read BME680_H3_REG\n");
247 return ret;
248 }
249 calib->par_h3 = tmp;
250
251 ret = regmap_read(data->regmap, BME680_H4_REG, &tmp);
252 if (ret < 0) {
253 dev_err(dev, "failed to read BME680_H4_REG\n");
254 return ret;
255 }
256 calib->par_h4 = tmp;
257
258 ret = regmap_read(data->regmap, BME680_H5_REG, &tmp);
259 if (ret < 0) {
260 dev_err(dev, "failed to read BME680_H5_REG\n");
261 return ret;
262 }
263 calib->par_h5 = tmp;
264
265 ret = regmap_read(data->regmap, BME680_H6_REG, &tmp);
266 if (ret < 0) {
267 dev_err(dev, "failed to read BME680_H6_REG\n");
268 return ret;
269 }
270 calib->par_h6 = tmp;
271
272 ret = regmap_read(data->regmap, BME680_H7_REG, &tmp);
273 if (ret < 0) {
274 dev_err(dev, "failed to read BME680_H7_REG\n");
275 return ret;
276 }
277 calib->par_h7 = tmp;
278
279 /* Gas heater related coefficients */
280 ret = regmap_read(data->regmap, BME680_GH1_REG, &tmp);
281 if (ret < 0) {
282 dev_err(dev, "failed to read BME680_GH1_REG\n");
283 return ret;
284 }
285 calib->par_gh1 = tmp;
286
287 ret = regmap_bulk_read(data->regmap, BME680_GH2_LSB_REG,
288 &buf, sizeof(buf));
289 if (ret < 0) {
290 dev_err(dev, "failed to read BME680_GH2_LSB_REG\n");
291 return ret;
292 }
293 calib->par_gh2 = le16_to_cpu(buf);
294
295 ret = regmap_read(data->regmap, BME680_GH3_REG, &tmp);
296 if (ret < 0) {
297 dev_err(dev, "failed to read BME680_GH3_REG\n");
298 return ret;
299 }
300 calib->par_gh3 = tmp;
301
302 /* Other coefficients */
303 ret = regmap_read(data->regmap, BME680_REG_RES_HEAT_RANGE, &tmp);
304 if (ret < 0) {
305 dev_err(dev, "failed to read resistance heat range\n");
306 return ret;
307 }
308 calib->res_heat_range = FIELD_GET(BME680_RHRANGE_MASK, tmp);
309
310 ret = regmap_read(data->regmap, BME680_REG_RES_HEAT_VAL, &tmp);
311 if (ret < 0) {
312 dev_err(dev, "failed to read resistance heat value\n");
313 return ret;
314 }
315 calib->res_heat_val = tmp;
316
317 ret = regmap_read(data->regmap, BME680_REG_RANGE_SW_ERR, &tmp);
318 if (ret < 0) {
319 dev_err(dev, "failed to read range software error\n");
320 return ret;
321 }
322 calib->range_sw_err = FIELD_GET(BME680_RSERROR_MASK, tmp);
323
324 return 0;
325 }
326
327 /*
328 * Taken from Bosch BME680 API:
329 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L876
330 *
331 * Returns temperature measurement in DegC, resolutions is 0.01 DegC. Therefore,
332 * output value of "3233" represents 32.33 DegC.
333 */
bme680_compensate_temp(struct bme680_data * data,s32 adc_temp)334 static s16 bme680_compensate_temp(struct bme680_data *data,
335 s32 adc_temp)
336 {
337 struct bme680_calib *calib = &data->bme680;
338 s64 var1, var2, var3;
339 s16 calc_temp;
340
341 /* If the calibration is invalid, attempt to reload it */
342 if (!calib->par_t2)
343 bme680_read_calib(data, calib);
344
345 var1 = (adc_temp >> 3) - (calib->par_t1 << 1);
346 var2 = (var1 * calib->par_t2) >> 11;
347 var3 = ((var1 >> 1) * (var1 >> 1)) >> 12;
348 var3 = (var3 * (calib->par_t3 << 4)) >> 14;
349 data->t_fine = var2 + var3;
350 calc_temp = (data->t_fine * 5 + 128) >> 8;
351
352 return calc_temp;
353 }
354
355 /*
356 * Taken from Bosch BME680 API:
357 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L896
358 *
359 * Returns pressure measurement in Pa. Output value of "97356" represents
360 * 97356 Pa = 973.56 hPa.
361 */
bme680_compensate_press(struct bme680_data * data,u32 adc_press)362 static u32 bme680_compensate_press(struct bme680_data *data,
363 u32 adc_press)
364 {
365 struct bme680_calib *calib = &data->bme680;
366 s32 var1, var2, var3, press_comp;
367
368 var1 = (data->t_fine >> 1) - 64000;
369 var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) * calib->par_p6) >> 2;
370 var2 = var2 + (var1 * calib->par_p5 << 1);
371 var2 = (var2 >> 2) + (calib->par_p4 << 16);
372 var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
373 (calib->par_p3 << 5)) >> 3) +
374 ((calib->par_p2 * var1) >> 1);
375 var1 = var1 >> 18;
376 var1 = ((32768 + var1) * calib->par_p1) >> 15;
377 press_comp = 1048576 - adc_press;
378 press_comp = ((press_comp - (var2 >> 12)) * 3125);
379
380 if (press_comp >= BME680_MAX_OVERFLOW_VAL)
381 press_comp = ((press_comp / (u32)var1) << 1);
382 else
383 press_comp = ((press_comp << 1) / (u32)var1);
384
385 var1 = (calib->par_p9 * (((press_comp >> 3) *
386 (press_comp >> 3)) >> 13)) >> 12;
387 var2 = ((press_comp >> 2) * calib->par_p8) >> 13;
388 var3 = ((press_comp >> 8) * (press_comp >> 8) *
389 (press_comp >> 8) * calib->par_p10) >> 17;
390
391 press_comp += (var1 + var2 + var3 + (calib->par_p7 << 7)) >> 4;
392
393 return press_comp;
394 }
395
396 /*
397 * Taken from Bosch BME680 API:
398 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L937
399 *
400 * Returns humidity measurement in percent, resolution is 0.001 percent. Output
401 * value of "43215" represents 43.215 %rH.
402 */
bme680_compensate_humid(struct bme680_data * data,u16 adc_humid)403 static u32 bme680_compensate_humid(struct bme680_data *data,
404 u16 adc_humid)
405 {
406 struct bme680_calib *calib = &data->bme680;
407 s32 var1, var2, var3, var4, var5, var6, temp_scaled, calc_hum;
408
409 temp_scaled = (data->t_fine * 5 + 128) >> 8;
410 var1 = (adc_humid - ((s32) ((s32) calib->par_h1 * 16))) -
411 (((temp_scaled * (s32) calib->par_h3) / 100) >> 1);
412 var2 = ((s32) calib->par_h2 *
413 (((temp_scaled * calib->par_h4) / 100) +
414 (((temp_scaled * ((temp_scaled * calib->par_h5) / 100))
415 >> 6) / 100) + (1 << 14))) >> 10;
416 var3 = var1 * var2;
417 var4 = calib->par_h6 << 7;
418 var4 = (var4 + ((temp_scaled * calib->par_h7) / 100)) >> 4;
419 var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
420 var6 = (var4 * var5) >> 1;
421 calc_hum = (((var3 + var6) >> 10) * 1000) >> 12;
422
423 calc_hum = clamp(calc_hum, 0, 100000); /* clamp between 0-100 %rH */
424
425 return calc_hum;
426 }
427
428 /*
429 * Taken from Bosch BME680 API:
430 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L973
431 *
432 * Returns gas measurement in Ohm. Output value of "82986" represent 82986 ohms.
433 */
bme680_compensate_gas(struct bme680_data * data,u16 gas_res_adc,u8 gas_range)434 static u32 bme680_compensate_gas(struct bme680_data *data, u16 gas_res_adc,
435 u8 gas_range)
436 {
437 struct bme680_calib *calib = &data->bme680;
438 s64 var1;
439 u64 var2;
440 s64 var3;
441 u32 calc_gas_res;
442
443 /* Look up table for the possible gas range values */
444 const u32 lookupTable[16] = {2147483647u, 2147483647u,
445 2147483647u, 2147483647u, 2147483647u,
446 2126008810u, 2147483647u, 2130303777u,
447 2147483647u, 2147483647u, 2143188679u,
448 2136746228u, 2147483647u, 2126008810u,
449 2147483647u, 2147483647u};
450
451 var1 = ((1340 + (5 * (s64) calib->range_sw_err)) *
452 ((s64) lookupTable[gas_range])) >> 16;
453 var2 = ((gas_res_adc << 15) - 16777216) + var1;
454 var3 = ((125000 << (15 - gas_range)) * var1) >> 9;
455 var3 += (var2 >> 1);
456 calc_gas_res = div64_s64(var3, (s64) var2);
457
458 return calc_gas_res;
459 }
460
461 /*
462 * Taken from Bosch BME680 API:
463 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L1002
464 */
bme680_calc_heater_res(struct bme680_data * data,u16 temp)465 static u8 bme680_calc_heater_res(struct bme680_data *data, u16 temp)
466 {
467 struct bme680_calib *calib = &data->bme680;
468 s32 var1, var2, var3, var4, var5, heatr_res_x100;
469 u8 heatr_res;
470
471 if (temp > 400) /* Cap temperature */
472 temp = 400;
473
474 var1 = (((s32) BME680_AMB_TEMP * calib->par_gh3) / 1000) * 256;
475 var2 = (calib->par_gh1 + 784) * (((((calib->par_gh2 + 154009) *
476 temp * 5) / 100)
477 + 3276800) / 10);
478 var3 = var1 + (var2 / 2);
479 var4 = (var3 / (calib->res_heat_range + 4));
480 var5 = 131 * calib->res_heat_val + 65536;
481 heatr_res_x100 = ((var4 / var5) - 250) * 34;
482 heatr_res = (heatr_res_x100 + 50) / 100;
483
484 return heatr_res;
485 }
486
487 /*
488 * Taken from Bosch BME680 API:
489 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L1188
490 */
bme680_calc_heater_dur(u16 dur)491 static u8 bme680_calc_heater_dur(u16 dur)
492 {
493 u8 durval, factor = 0;
494
495 if (dur >= 0xfc0) {
496 durval = 0xff; /* Max duration */
497 } else {
498 while (dur > 0x3F) {
499 dur = dur / 4;
500 factor += 1;
501 }
502 durval = dur + (factor * 64);
503 }
504
505 return durval;
506 }
507
bme680_set_mode(struct bme680_data * data,bool mode)508 static int bme680_set_mode(struct bme680_data *data, bool mode)
509 {
510 struct device *dev = regmap_get_device(data->regmap);
511 int ret;
512
513 if (mode) {
514 ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS,
515 BME680_MODE_MASK, BME680_MODE_FORCED);
516 if (ret < 0)
517 dev_err(dev, "failed to set forced mode\n");
518
519 } else {
520 ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS,
521 BME680_MODE_MASK, BME680_MODE_SLEEP);
522 if (ret < 0)
523 dev_err(dev, "failed to set sleep mode\n");
524
525 }
526
527 return ret;
528 }
529
bme680_oversampling_to_reg(u8 val)530 static u8 bme680_oversampling_to_reg(u8 val)
531 {
532 return ilog2(val) + 1;
533 }
534
bme680_chip_config(struct bme680_data * data)535 static int bme680_chip_config(struct bme680_data *data)
536 {
537 struct device *dev = regmap_get_device(data->regmap);
538 int ret;
539 u8 osrs;
540
541 osrs = FIELD_PREP(
542 BME680_OSRS_HUMIDITY_MASK,
543 bme680_oversampling_to_reg(data->oversampling_humid));
544 /*
545 * Highly recommended to set oversampling of humidity before
546 * temperature/pressure oversampling.
547 */
548 ret = regmap_update_bits(data->regmap, BME680_REG_CTRL_HUMIDITY,
549 BME680_OSRS_HUMIDITY_MASK, osrs);
550 if (ret < 0) {
551 dev_err(dev, "failed to write ctrl_hum register\n");
552 return ret;
553 }
554
555 /* IIR filter settings */
556 ret = regmap_update_bits(data->regmap, BME680_REG_CONFIG,
557 BME680_FILTER_MASK,
558 BME680_FILTER_COEFF_VAL);
559 if (ret < 0) {
560 dev_err(dev, "failed to write config register\n");
561 return ret;
562 }
563
564 osrs = FIELD_PREP(BME680_OSRS_TEMP_MASK,
565 bme680_oversampling_to_reg(data->oversampling_temp)) |
566 FIELD_PREP(BME680_OSRS_PRESS_MASK,
567 bme680_oversampling_to_reg(data->oversampling_press));
568 ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS,
569 BME680_OSRS_TEMP_MASK | BME680_OSRS_PRESS_MASK,
570 osrs);
571 if (ret < 0)
572 dev_err(dev, "failed to write ctrl_meas register\n");
573
574 return ret;
575 }
576
bme680_gas_config(struct bme680_data * data)577 static int bme680_gas_config(struct bme680_data *data)
578 {
579 struct device *dev = regmap_get_device(data->regmap);
580 int ret;
581 u8 heatr_res, heatr_dur;
582
583 heatr_res = bme680_calc_heater_res(data, data->heater_temp);
584
585 /* set target heater temperature */
586 ret = regmap_write(data->regmap, BME680_REG_RES_HEAT_0, heatr_res);
587 if (ret < 0) {
588 dev_err(dev, "failed to write res_heat_0 register\n");
589 return ret;
590 }
591
592 heatr_dur = bme680_calc_heater_dur(data->heater_dur);
593
594 /* set target heating duration */
595 ret = regmap_write(data->regmap, BME680_REG_GAS_WAIT_0, heatr_dur);
596 if (ret < 0) {
597 dev_err(dev, "failed to write gas_wait_0 register\n");
598 return ret;
599 }
600
601 /* Enable the gas sensor and select heater profile set-point 0 */
602 ret = regmap_update_bits(data->regmap, BME680_REG_CTRL_GAS_1,
603 BME680_RUN_GAS_MASK | BME680_NB_CONV_MASK,
604 FIELD_PREP(BME680_RUN_GAS_MASK, 1) |
605 FIELD_PREP(BME680_NB_CONV_MASK, 0));
606 if (ret < 0)
607 dev_err(dev, "failed to write ctrl_gas_1 register\n");
608
609 return ret;
610 }
611
bme680_read_temp(struct bme680_data * data,int * val)612 static int bme680_read_temp(struct bme680_data *data, int *val)
613 {
614 struct device *dev = regmap_get_device(data->regmap);
615 int ret;
616 __be32 tmp = 0;
617 s32 adc_temp;
618 s16 comp_temp;
619
620 /* set forced mode to trigger measurement */
621 ret = bme680_set_mode(data, true);
622 if (ret < 0)
623 return ret;
624
625 ret = regmap_bulk_read(data->regmap, BME680_REG_TEMP_MSB,
626 &tmp, 3);
627 if (ret < 0) {
628 dev_err(dev, "failed to read temperature\n");
629 return ret;
630 }
631
632 adc_temp = be32_to_cpu(tmp) >> 12;
633 if (adc_temp == BME680_MEAS_SKIPPED) {
634 /* reading was skipped */
635 dev_err(dev, "reading temperature skipped\n");
636 return -EINVAL;
637 }
638 comp_temp = bme680_compensate_temp(data, adc_temp);
639 /*
640 * val might be NULL if we're called by the read_press/read_humid
641 * routine which is callled to get t_fine value used in
642 * compensate_press/compensate_humid to get compensated
643 * pressure/humidity readings.
644 */
645 if (val) {
646 *val = comp_temp * 10; /* Centidegrees to millidegrees */
647 return IIO_VAL_INT;
648 }
649
650 return ret;
651 }
652
bme680_read_press(struct bme680_data * data,int * val,int * val2)653 static int bme680_read_press(struct bme680_data *data,
654 int *val, int *val2)
655 {
656 struct device *dev = regmap_get_device(data->regmap);
657 int ret;
658 __be32 tmp = 0;
659 s32 adc_press;
660
661 /* Read and compensate temperature to get a reading of t_fine */
662 ret = bme680_read_temp(data, NULL);
663 if (ret < 0)
664 return ret;
665
666 ret = regmap_bulk_read(data->regmap, BME680_REG_PRESS_MSB,
667 &tmp, 3);
668 if (ret < 0) {
669 dev_err(dev, "failed to read pressure\n");
670 return ret;
671 }
672
673 adc_press = be32_to_cpu(tmp) >> 12;
674 if (adc_press == BME680_MEAS_SKIPPED) {
675 /* reading was skipped */
676 dev_err(dev, "reading pressure skipped\n");
677 return -EINVAL;
678 }
679
680 *val = bme680_compensate_press(data, adc_press);
681 *val2 = 100;
682 return IIO_VAL_FRACTIONAL;
683 }
684
bme680_read_humid(struct bme680_data * data,int * val,int * val2)685 static int bme680_read_humid(struct bme680_data *data,
686 int *val, int *val2)
687 {
688 struct device *dev = regmap_get_device(data->regmap);
689 int ret;
690 __be16 tmp = 0;
691 s32 adc_humidity;
692 u32 comp_humidity;
693
694 /* Read and compensate temperature to get a reading of t_fine */
695 ret = bme680_read_temp(data, NULL);
696 if (ret < 0)
697 return ret;
698
699 ret = regmap_bulk_read(data->regmap, BM6880_REG_HUMIDITY_MSB,
700 &tmp, sizeof(tmp));
701 if (ret < 0) {
702 dev_err(dev, "failed to read humidity\n");
703 return ret;
704 }
705
706 adc_humidity = be16_to_cpu(tmp);
707 if (adc_humidity == BME680_MEAS_SKIPPED) {
708 /* reading was skipped */
709 dev_err(dev, "reading humidity skipped\n");
710 return -EINVAL;
711 }
712 comp_humidity = bme680_compensate_humid(data, adc_humidity);
713
714 *val = comp_humidity;
715 *val2 = 1000;
716 return IIO_VAL_FRACTIONAL;
717 }
718
bme680_read_gas(struct bme680_data * data,int * val)719 static int bme680_read_gas(struct bme680_data *data,
720 int *val)
721 {
722 struct device *dev = regmap_get_device(data->regmap);
723 int ret;
724 __be16 tmp = 0;
725 unsigned int check;
726 u16 adc_gas_res;
727 u8 gas_range;
728
729 /* Set heater settings */
730 ret = bme680_gas_config(data);
731 if (ret < 0) {
732 dev_err(dev, "failed to set gas config\n");
733 return ret;
734 }
735
736 /* set forced mode to trigger measurement */
737 ret = bme680_set_mode(data, true);
738 if (ret < 0)
739 return ret;
740
741 ret = regmap_read(data->regmap, BME680_REG_MEAS_STAT_0, &check);
742 if (check & BME680_GAS_MEAS_BIT) {
743 dev_err(dev, "gas measurement incomplete\n");
744 return -EBUSY;
745 }
746
747 ret = regmap_read(data->regmap, BME680_REG_GAS_R_LSB, &check);
748 if (ret < 0) {
749 dev_err(dev, "failed to read gas_r_lsb register\n");
750 return ret;
751 }
752
753 /*
754 * occurs if either the gas heating duration was insuffient
755 * to reach the target heater temperature or the target
756 * heater temperature was too high for the heater sink to
757 * reach.
758 */
759 if ((check & BME680_GAS_STAB_BIT) == 0) {
760 dev_err(dev, "heater failed to reach the target temperature\n");
761 return -EINVAL;
762 }
763
764 ret = regmap_bulk_read(data->regmap, BME680_REG_GAS_MSB,
765 &tmp, sizeof(tmp));
766 if (ret < 0) {
767 dev_err(dev, "failed to read gas resistance\n");
768 return ret;
769 }
770
771 gas_range = check & BME680_GAS_RANGE_MASK;
772 adc_gas_res = be16_to_cpu(tmp) >> BME680_ADC_GAS_RES_SHIFT;
773
774 *val = bme680_compensate_gas(data, adc_gas_res, gas_range);
775 return IIO_VAL_INT;
776 }
777
bme680_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)778 static int bme680_read_raw(struct iio_dev *indio_dev,
779 struct iio_chan_spec const *chan,
780 int *val, int *val2, long mask)
781 {
782 struct bme680_data *data = iio_priv(indio_dev);
783
784 switch (mask) {
785 case IIO_CHAN_INFO_PROCESSED:
786 switch (chan->type) {
787 case IIO_TEMP:
788 return bme680_read_temp(data, val);
789 case IIO_PRESSURE:
790 return bme680_read_press(data, val, val2);
791 case IIO_HUMIDITYRELATIVE:
792 return bme680_read_humid(data, val, val2);
793 case IIO_RESISTANCE:
794 return bme680_read_gas(data, val);
795 default:
796 return -EINVAL;
797 }
798 case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
799 switch (chan->type) {
800 case IIO_TEMP:
801 *val = data->oversampling_temp;
802 return IIO_VAL_INT;
803 case IIO_PRESSURE:
804 *val = data->oversampling_press;
805 return IIO_VAL_INT;
806 case IIO_HUMIDITYRELATIVE:
807 *val = data->oversampling_humid;
808 return IIO_VAL_INT;
809 default:
810 return -EINVAL;
811 }
812 default:
813 return -EINVAL;
814 }
815 }
816
bme680_is_valid_oversampling(int rate)817 static bool bme680_is_valid_oversampling(int rate)
818 {
819 return (rate > 0 && rate <= 16 && is_power_of_2(rate));
820 }
821
bme680_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)822 static int bme680_write_raw(struct iio_dev *indio_dev,
823 struct iio_chan_spec const *chan,
824 int val, int val2, long mask)
825 {
826 struct bme680_data *data = iio_priv(indio_dev);
827
828 if (val2 != 0)
829 return -EINVAL;
830
831 switch (mask) {
832 case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
833 {
834 if (!bme680_is_valid_oversampling(val))
835 return -EINVAL;
836
837 switch (chan->type) {
838 case IIO_TEMP:
839 data->oversampling_temp = val;
840 break;
841 case IIO_PRESSURE:
842 data->oversampling_press = val;
843 break;
844 case IIO_HUMIDITYRELATIVE:
845 data->oversampling_humid = val;
846 break;
847 default:
848 return -EINVAL;
849 }
850
851 return bme680_chip_config(data);
852 }
853 default:
854 return -EINVAL;
855 }
856 }
857
858 static const char bme680_oversampling_ratio_show[] = "1 2 4 8 16";
859
860 static IIO_CONST_ATTR(oversampling_ratio_available,
861 bme680_oversampling_ratio_show);
862
863 static struct attribute *bme680_attributes[] = {
864 &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
865 NULL,
866 };
867
868 static const struct attribute_group bme680_attribute_group = {
869 .attrs = bme680_attributes,
870 };
871
872 static const struct iio_info bme680_info = {
873 .read_raw = &bme680_read_raw,
874 .write_raw = &bme680_write_raw,
875 .attrs = &bme680_attribute_group,
876 };
877
bme680_match_acpi_device(struct device * dev)878 static const char *bme680_match_acpi_device(struct device *dev)
879 {
880 const struct acpi_device_id *id;
881
882 id = acpi_match_device(dev->driver->acpi_match_table, dev);
883 if (!id)
884 return NULL;
885
886 return dev_name(dev);
887 }
888
bme680_core_probe(struct device * dev,struct regmap * regmap,const char * name)889 int bme680_core_probe(struct device *dev, struct regmap *regmap,
890 const char *name)
891 {
892 struct iio_dev *indio_dev;
893 struct bme680_data *data;
894 unsigned int val;
895 int ret;
896
897 ret = regmap_write(regmap, BME680_REG_SOFT_RESET,
898 BME680_CMD_SOFTRESET);
899 if (ret < 0) {
900 dev_err(dev, "Failed to reset chip\n");
901 return ret;
902 }
903
904 ret = regmap_read(regmap, BME680_REG_CHIP_ID, &val);
905 if (ret < 0) {
906 dev_err(dev, "Error reading chip ID\n");
907 return ret;
908 }
909
910 if (val != BME680_CHIP_ID_VAL) {
911 dev_err(dev, "Wrong chip ID, got %x expected %x\n",
912 val, BME680_CHIP_ID_VAL);
913 return -ENODEV;
914 }
915
916 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
917 if (!indio_dev)
918 return -ENOMEM;
919
920 if (!name && ACPI_HANDLE(dev))
921 name = bme680_match_acpi_device(dev);
922
923 data = iio_priv(indio_dev);
924 dev_set_drvdata(dev, indio_dev);
925 data->regmap = regmap;
926 indio_dev->name = name;
927 indio_dev->channels = bme680_channels;
928 indio_dev->num_channels = ARRAY_SIZE(bme680_channels);
929 indio_dev->info = &bme680_info;
930 indio_dev->modes = INDIO_DIRECT_MODE;
931
932 /* default values for the sensor */
933 data->oversampling_humid = 2; /* 2X oversampling rate */
934 data->oversampling_press = 4; /* 4X oversampling rate */
935 data->oversampling_temp = 8; /* 8X oversampling rate */
936 data->heater_temp = 320; /* degree Celsius */
937 data->heater_dur = 150; /* milliseconds */
938
939 ret = bme680_chip_config(data);
940 if (ret < 0) {
941 dev_err(dev, "failed to set chip_config data\n");
942 return ret;
943 }
944
945 ret = bme680_gas_config(data);
946 if (ret < 0) {
947 dev_err(dev, "failed to set gas config data\n");
948 return ret;
949 }
950
951 ret = bme680_read_calib(data, &data->bme680);
952 if (ret < 0) {
953 dev_err(dev,
954 "failed to read calibration coefficients at probe\n");
955 return ret;
956 }
957
958 return devm_iio_device_register(dev, indio_dev);
959 }
960 EXPORT_SYMBOL_GPL(bme680_core_probe);
961
962 MODULE_AUTHOR("Himanshu Jha <himanshujha199640@gmail.com>");
963 MODULE_DESCRIPTION("Bosch BME680 Driver");
964 MODULE_LICENSE("GPL v2");
965