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/bitfield.h>
12 #include <linux/cleanup.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/log2.h>
16 #include <linux/module.h>
17 #include <linux/regmap.h>
18
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/trigger_consumer.h>
23 #include <linux/iio/triggered_buffer.h>
24
25 #include <linux/unaligned.h>
26
27 #include "bme680.h"
28
29 /* 1st set of calibration data */
30 enum {
31 /* Temperature calib indexes */
32 T2_LSB = 0,
33 T3 = 2,
34 /* Pressure calib indexes */
35 P1_LSB = 4,
36 P2_LSB = 6,
37 P3 = 8,
38 P4_LSB = 10,
39 P5_LSB = 12,
40 P7 = 14,
41 P6 = 15,
42 P8_LSB = 18,
43 P9_LSB = 20,
44 P10 = 22,
45 };
46
47 /* 2nd set of calibration data */
48 enum {
49 /* Humidity calib indexes */
50 H2_MSB = 0,
51 H1_LSB = 1,
52 H3 = 3,
53 H4 = 4,
54 H5 = 5,
55 H6 = 6,
56 H7 = 7,
57 /* Stray T1 calib index */
58 T1_LSB = 8,
59 /* Gas heater calib indexes */
60 GH2_LSB = 10,
61 GH1 = 12,
62 GH3 = 13,
63 };
64
65 /* 3rd set of calibration data */
66 enum {
67 RES_HEAT_VAL = 0,
68 RES_HEAT_RANGE = 2,
69 RANGE_SW_ERR = 4,
70 };
71
72 struct bme680_calib {
73 u16 par_t1;
74 s16 par_t2;
75 s8 par_t3;
76 u16 par_p1;
77 s16 par_p2;
78 s8 par_p3;
79 s16 par_p4;
80 s16 par_p5;
81 s8 par_p6;
82 s8 par_p7;
83 s16 par_p8;
84 s16 par_p9;
85 u8 par_p10;
86 u16 par_h1;
87 u16 par_h2;
88 s8 par_h3;
89 s8 par_h4;
90 s8 par_h5;
91 u8 par_h6;
92 s8 par_h7;
93 s8 par_gh1;
94 s16 par_gh2;
95 s8 par_gh3;
96 u8 res_heat_range;
97 s8 res_heat_val;
98 s8 range_sw_err;
99 };
100
101 /* values of CTRL_MEAS register */
102 enum bme680_op_mode {
103 BME680_MODE_SLEEP = 0,
104 BME680_MODE_FORCED = 1,
105 };
106
107 enum bme680_scan {
108 BME680_TEMP,
109 BME680_PRESS,
110 BME680_HUMID,
111 BME680_GAS,
112 };
113
114 struct bme680_data {
115 struct regmap *regmap;
116 struct bme680_calib bme680;
117 struct mutex lock; /* Protect multiple serial R/W ops to device. */
118 u8 oversampling_temp;
119 u8 oversampling_press;
120 u8 oversampling_humid;
121 u8 preheat_curr_mA;
122 u16 heater_dur;
123 u16 heater_temp;
124
125 struct {
126 s32 chan[4];
127 aligned_s64 ts;
128 } scan;
129
130 union {
131 u8 buf[BME680_NUM_BULK_READ_REGS];
132 unsigned int check;
133 __be16 be16;
134 u8 bme680_cal_buf_1[BME680_CALIB_RANGE_1_LEN];
135 u8 bme680_cal_buf_2[BME680_CALIB_RANGE_2_LEN];
136 u8 bme680_cal_buf_3[BME680_CALIB_RANGE_3_LEN];
137 };
138 };
139
140 static const struct regmap_range bme680_volatile_ranges[] = {
141 regmap_reg_range(BME680_REG_MEAS_STAT_0, BME680_REG_GAS_R_LSB),
142 regmap_reg_range(BME680_REG_STATUS, BME680_REG_STATUS),
143 regmap_reg_range(BME680_T2_LSB_REG, BME680_GH3_REG),
144 };
145
146 static const struct regmap_access_table bme680_volatile_table = {
147 .yes_ranges = bme680_volatile_ranges,
148 .n_yes_ranges = ARRAY_SIZE(bme680_volatile_ranges),
149 };
150
151 const struct regmap_config bme680_regmap_config = {
152 .reg_bits = 8,
153 .val_bits = 8,
154 .max_register = 0xef,
155 .volatile_table = &bme680_volatile_table,
156 .cache_type = REGCACHE_RBTREE,
157 };
158 EXPORT_SYMBOL_NS(bme680_regmap_config, "IIO_BME680");
159
160 static const struct iio_chan_spec bme680_channels[] = {
161 {
162 .type = IIO_TEMP,
163 /* PROCESSED maintained for ABI backwards compatibility */
164 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
165 BIT(IIO_CHAN_INFO_RAW) |
166 BIT(IIO_CHAN_INFO_SCALE) |
167 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
168 .scan_index = 0,
169 .scan_type = {
170 .sign = 's',
171 .realbits = 16,
172 .storagebits = 16,
173 .endianness = IIO_CPU,
174 },
175 },
176 {
177 .type = IIO_PRESSURE,
178 /* PROCESSED maintained for ABI backwards compatibility */
179 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
180 BIT(IIO_CHAN_INFO_RAW) |
181 BIT(IIO_CHAN_INFO_SCALE) |
182 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
183 .scan_index = 1,
184 .scan_type = {
185 .sign = 'u',
186 .realbits = 32,
187 .storagebits = 32,
188 .endianness = IIO_CPU,
189 },
190 },
191 {
192 .type = IIO_HUMIDITYRELATIVE,
193 /* PROCESSED maintained for ABI backwards compatibility */
194 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
195 BIT(IIO_CHAN_INFO_RAW) |
196 BIT(IIO_CHAN_INFO_SCALE) |
197 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
198 .scan_index = 2,
199 .scan_type = {
200 .sign = 'u',
201 .realbits = 32,
202 .storagebits = 32,
203 .endianness = IIO_CPU,
204 },
205 },
206 {
207 .type = IIO_RESISTANCE,
208 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
209 .scan_index = 3,
210 .scan_type = {
211 .sign = 'u',
212 .realbits = 32,
213 .storagebits = 32,
214 .endianness = IIO_CPU,
215 },
216 },
217 IIO_CHAN_SOFT_TIMESTAMP(4),
218 {
219 .type = IIO_CURRENT,
220 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
221 .output = 1,
222 .scan_index = -1,
223 },
224 };
225
bme680_read_calib(struct bme680_data * data,struct bme680_calib * calib)226 static int bme680_read_calib(struct bme680_data *data,
227 struct bme680_calib *calib)
228 {
229 struct device *dev = regmap_get_device(data->regmap);
230 unsigned int tmp_msb, tmp_lsb;
231 int ret;
232
233 ret = regmap_bulk_read(data->regmap, BME680_T2_LSB_REG,
234 data->bme680_cal_buf_1,
235 sizeof(data->bme680_cal_buf_1));
236 if (ret < 0) {
237 dev_err(dev, "failed to read 1st set of calib data;\n");
238 return ret;
239 }
240
241 calib->par_t2 = get_unaligned_le16(&data->bme680_cal_buf_1[T2_LSB]);
242 calib->par_t3 = data->bme680_cal_buf_1[T3];
243 calib->par_p1 = get_unaligned_le16(&data->bme680_cal_buf_1[P1_LSB]);
244 calib->par_p2 = get_unaligned_le16(&data->bme680_cal_buf_1[P2_LSB]);
245 calib->par_p3 = data->bme680_cal_buf_1[P3];
246 calib->par_p4 = get_unaligned_le16(&data->bme680_cal_buf_1[P4_LSB]);
247 calib->par_p5 = get_unaligned_le16(&data->bme680_cal_buf_1[P5_LSB]);
248 calib->par_p7 = data->bme680_cal_buf_1[P7];
249 calib->par_p6 = data->bme680_cal_buf_1[P6];
250 calib->par_p8 = get_unaligned_le16(&data->bme680_cal_buf_1[P8_LSB]);
251 calib->par_p9 = get_unaligned_le16(&data->bme680_cal_buf_1[P9_LSB]);
252 calib->par_p10 = data->bme680_cal_buf_1[P10];
253
254 ret = regmap_bulk_read(data->regmap, BME680_H2_MSB_REG,
255 data->bme680_cal_buf_2,
256 sizeof(data->bme680_cal_buf_2));
257 if (ret < 0) {
258 dev_err(dev, "failed to read 2nd set of calib data;\n");
259 return ret;
260 }
261
262 tmp_lsb = data->bme680_cal_buf_2[H1_LSB];
263 tmp_msb = data->bme680_cal_buf_2[H1_LSB + 1];
264 calib->par_h1 = (tmp_msb << BME680_HUM_REG_SHIFT_VAL) |
265 (tmp_lsb & BME680_BIT_H1_DATA_MASK);
266
267 tmp_msb = data->bme680_cal_buf_2[H2_MSB];
268 tmp_lsb = data->bme680_cal_buf_2[H2_MSB + 1];
269 calib->par_h2 = (tmp_msb << BME680_HUM_REG_SHIFT_VAL) |
270 (tmp_lsb >> BME680_HUM_REG_SHIFT_VAL);
271
272 calib->par_h3 = data->bme680_cal_buf_2[H3];
273 calib->par_h4 = data->bme680_cal_buf_2[H4];
274 calib->par_h5 = data->bme680_cal_buf_2[H5];
275 calib->par_h6 = data->bme680_cal_buf_2[H6];
276 calib->par_h7 = data->bme680_cal_buf_2[H7];
277 calib->par_t1 = get_unaligned_le16(&data->bme680_cal_buf_2[T1_LSB]);
278 calib->par_gh2 = get_unaligned_le16(&data->bme680_cal_buf_2[GH2_LSB]);
279 calib->par_gh1 = data->bme680_cal_buf_2[GH1];
280 calib->par_gh3 = data->bme680_cal_buf_2[GH3];
281
282 ret = regmap_bulk_read(data->regmap, BME680_REG_RES_HEAT_VAL,
283 data->bme680_cal_buf_3,
284 sizeof(data->bme680_cal_buf_3));
285 if (ret < 0) {
286 dev_err(dev, "failed to read 3rd set of calib data;\n");
287 return ret;
288 }
289
290 calib->res_heat_val = data->bme680_cal_buf_3[RES_HEAT_VAL];
291
292 calib->res_heat_range = FIELD_GET(BME680_RHRANGE_MASK,
293 data->bme680_cal_buf_3[RES_HEAT_RANGE]);
294
295 calib->range_sw_err = FIELD_GET(BME680_RSERROR_MASK,
296 data->bme680_cal_buf_3[RANGE_SW_ERR]);
297
298 return 0;
299 }
300
bme680_read_temp_adc(struct bme680_data * data,u32 * adc_temp)301 static int bme680_read_temp_adc(struct bme680_data *data, u32 *adc_temp)
302 {
303 struct device *dev = regmap_get_device(data->regmap);
304 u32 value_temp;
305 int ret;
306
307 ret = regmap_bulk_read(data->regmap, BME680_REG_TEMP_MSB,
308 data->buf, BME680_TEMP_NUM_BYTES);
309 if (ret < 0) {
310 dev_err(dev, "failed to read temperature\n");
311 return ret;
312 }
313
314 value_temp = FIELD_GET(BME680_MEAS_TRIM_MASK,
315 get_unaligned_be24(data->buf));
316 if (value_temp == BME680_MEAS_SKIPPED) {
317 /* reading was skipped */
318 dev_err(dev, "reading temperature skipped\n");
319 return -EINVAL;
320 }
321 *adc_temp = value_temp;
322
323 return 0;
324 }
325
326 /*
327 * Taken from Bosch BME680 API:
328 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L876
329 *
330 * Returns temperature measurement in DegC, resolutions is 0.01 DegC. Therefore,
331 * output value of "3233" represents 32.33 DegC.
332 */
bme680_calc_t_fine(struct bme680_data * data,u32 adc_temp)333 static s32 bme680_calc_t_fine(struct bme680_data *data, u32 adc_temp)
334 {
335 struct bme680_calib *calib = &data->bme680;
336 s64 var1, var2, var3;
337
338 /* If the calibration is invalid, attempt to reload it */
339 if (!calib->par_t2)
340 bme680_read_calib(data, calib);
341
342 var1 = ((s32)adc_temp >> 3) - ((s32)calib->par_t1 << 1);
343 var2 = (var1 * calib->par_t2) >> 11;
344 var3 = ((var1 >> 1) * (var1 >> 1)) >> 12;
345 var3 = (var3 * ((s32)calib->par_t3 << 4)) >> 14;
346 return var2 + var3; /* t_fine = var2 + var3 */
347 }
348
bme680_get_t_fine(struct bme680_data * data,s32 * t_fine)349 static int bme680_get_t_fine(struct bme680_data *data, s32 *t_fine)
350 {
351 u32 adc_temp;
352 int ret;
353
354 ret = bme680_read_temp_adc(data, &adc_temp);
355 if (ret)
356 return ret;
357
358 *t_fine = bme680_calc_t_fine(data, adc_temp);
359
360 return 0;
361 }
362
bme680_compensate_temp(struct bme680_data * data,u32 adc_temp)363 static s16 bme680_compensate_temp(struct bme680_data *data,
364 u32 adc_temp)
365 {
366 return (bme680_calc_t_fine(data, adc_temp) * 5 + 128) / 256;
367 }
368
bme680_read_press_adc(struct bme680_data * data,u32 * adc_press)369 static int bme680_read_press_adc(struct bme680_data *data, u32 *adc_press)
370 {
371 struct device *dev = regmap_get_device(data->regmap);
372 u32 value_press;
373 int ret;
374
375 ret = regmap_bulk_read(data->regmap, BME680_REG_PRESS_MSB,
376 data->buf, BME680_PRESS_NUM_BYTES);
377 if (ret < 0) {
378 dev_err(dev, "failed to read pressure\n");
379 return ret;
380 }
381
382 value_press = FIELD_GET(BME680_MEAS_TRIM_MASK,
383 get_unaligned_be24(data->buf));
384 if (value_press == BME680_MEAS_SKIPPED) {
385 /* reading was skipped */
386 dev_err(dev, "reading pressure skipped\n");
387 return -EINVAL;
388 }
389 *adc_press = value_press;
390
391 return 0;
392 }
393
394 /*
395 * Taken from Bosch BME680 API:
396 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L896
397 *
398 * Returns pressure measurement in Pa. Output value of "97356" represents
399 * 97356 Pa = 973.56 hPa.
400 */
bme680_compensate_press(struct bme680_data * data,u32 adc_press,s32 t_fine)401 static u32 bme680_compensate_press(struct bme680_data *data,
402 u32 adc_press, s32 t_fine)
403 {
404 struct bme680_calib *calib = &data->bme680;
405 s32 var1, var2, var3, press_comp;
406
407 var1 = (t_fine >> 1) - 64000;
408 var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) * calib->par_p6) >> 2;
409 var2 = var2 + (var1 * calib->par_p5 << 1);
410 var2 = (var2 >> 2) + ((s32)calib->par_p4 << 16);
411 var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
412 ((s32)calib->par_p3 << 5)) >> 3) +
413 ((calib->par_p2 * var1) >> 1);
414 var1 = var1 >> 18;
415 var1 = ((32768 + var1) * calib->par_p1) >> 15;
416 press_comp = 1048576 - adc_press;
417 press_comp = ((press_comp - (var2 >> 12)) * 3125);
418
419 if (press_comp >= BME680_MAX_OVERFLOW_VAL)
420 press_comp = ((press_comp / (u32)var1) << 1);
421 else
422 press_comp = ((press_comp << 1) / (u32)var1);
423
424 var1 = (calib->par_p9 * (((press_comp >> 3) *
425 (press_comp >> 3)) >> 13)) >> 12;
426 var2 = ((press_comp >> 2) * calib->par_p8) >> 13;
427 var3 = ((press_comp >> 8) * (press_comp >> 8) *
428 (press_comp >> 8) * calib->par_p10) >> 17;
429
430 press_comp += (var1 + var2 + var3 + ((s32)calib->par_p7 << 7)) >> 4;
431
432 return press_comp;
433 }
434
bme680_read_humid_adc(struct bme680_data * data,u32 * adc_humidity)435 static int bme680_read_humid_adc(struct bme680_data *data, u32 *adc_humidity)
436 {
437 struct device *dev = regmap_get_device(data->regmap);
438 u32 value_humidity;
439 int ret;
440
441 ret = regmap_bulk_read(data->regmap, BME680_REG_HUMIDITY_MSB,
442 &data->be16, BME680_HUMID_NUM_BYTES);
443 if (ret < 0) {
444 dev_err(dev, "failed to read humidity\n");
445 return ret;
446 }
447
448 value_humidity = be16_to_cpu(data->be16);
449 if (value_humidity == BME680_MEAS_SKIPPED) {
450 /* reading was skipped */
451 dev_err(dev, "reading humidity skipped\n");
452 return -EINVAL;
453 }
454 *adc_humidity = value_humidity;
455
456 return 0;
457 }
458
459 /*
460 * Taken from Bosch BME680 API:
461 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L937
462 *
463 * Returns humidity measurement in percent, resolution is 0.001 percent. Output
464 * value of "43215" represents 43.215 %rH.
465 */
bme680_compensate_humid(struct bme680_data * data,u16 adc_humid,s32 t_fine)466 static u32 bme680_compensate_humid(struct bme680_data *data,
467 u16 adc_humid, s32 t_fine)
468 {
469 struct bme680_calib *calib = &data->bme680;
470 s32 var1, var2, var3, var4, var5, var6, temp_scaled, calc_hum;
471
472 temp_scaled = (t_fine * 5 + 128) >> 8;
473 var1 = (adc_humid - (((s32)calib->par_h1 * 16))) -
474 (((temp_scaled * calib->par_h3) / 100) >> 1);
475 var2 = (calib->par_h2 *
476 (((temp_scaled * calib->par_h4) / 100) +
477 (((temp_scaled * ((temp_scaled * calib->par_h5) / 100))
478 >> 6) / 100) + (1 << 14))) >> 10;
479 var3 = var1 * var2;
480 var4 = (s32)calib->par_h6 << 7;
481 var4 = (var4 + ((temp_scaled * calib->par_h7) / 100)) >> 4;
482 var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
483 var6 = (var4 * var5) >> 1;
484 calc_hum = (((var3 + var6) >> 10) * 1000) >> 12;
485
486 calc_hum = clamp(calc_hum, 0, 100000); /* clamp between 0-100 %rH */
487
488 return calc_hum;
489 }
490
491 /*
492 * Taken from Bosch BME680 API:
493 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L973
494 *
495 * Returns gas measurement in Ohm. Output value of "82986" represent 82986 ohms.
496 */
bme680_compensate_gas(struct bme680_data * data,u16 gas_res_adc,u8 gas_range)497 static u32 bme680_compensate_gas(struct bme680_data *data, u16 gas_res_adc,
498 u8 gas_range)
499 {
500 struct bme680_calib *calib = &data->bme680;
501 s64 var1;
502 u64 var2;
503 s64 var3;
504 u32 calc_gas_res;
505
506 /* Look up table for the possible gas range values */
507 static const u32 lookup_table[16] = {
508 2147483647u, 2147483647u, 2147483647u, 2147483647u,
509 2147483647u, 2126008810u, 2147483647u, 2130303777u,
510 2147483647u, 2147483647u, 2143188679u, 2136746228u,
511 2147483647u, 2126008810u, 2147483647u, 2147483647u
512 };
513
514 var1 = ((1340LL + (5 * calib->range_sw_err)) *
515 (lookup_table[gas_range])) >> 16;
516 var2 = ((gas_res_adc << 15) - 16777216) + var1;
517 var3 = ((125000 << (15 - gas_range)) * var1) >> 9;
518 var3 += (var2 >> 1);
519 calc_gas_res = div64_s64(var3, (s64)var2);
520
521 return calc_gas_res;
522 }
523
524 /*
525 * Taken from Bosch BME680 API:
526 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L1002
527 */
bme680_calc_heater_res(struct bme680_data * data,u16 temp)528 static u8 bme680_calc_heater_res(struct bme680_data *data, u16 temp)
529 {
530 struct bme680_calib *calib = &data->bme680;
531 s32 var1, var2, var3, var4, var5, heatr_res_x100;
532 u8 heatr_res;
533
534 if (temp > 400) /* Cap temperature */
535 temp = 400;
536
537 var1 = (((s32)BME680_AMB_TEMP * calib->par_gh3) / 1000) * 256;
538 var2 = (calib->par_gh1 + 784) * (((((calib->par_gh2 + 154009) *
539 temp * 5) / 100)
540 + 3276800) / 10);
541 var3 = var1 + (var2 / 2);
542 var4 = (var3 / (calib->res_heat_range + 4));
543 var5 = 131 * calib->res_heat_val + 65536;
544 heatr_res_x100 = ((var4 / var5) - 250) * 34;
545 heatr_res = DIV_ROUND_CLOSEST(heatr_res_x100, 100);
546
547 return heatr_res;
548 }
549
550 /*
551 * Taken from Bosch BME680 API:
552 * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L1188
553 */
bme680_calc_heater_dur(u16 dur)554 static u8 bme680_calc_heater_dur(u16 dur)
555 {
556 u8 durval, factor = 0;
557
558 if (dur >= 0xfc0) {
559 durval = 0xff; /* Max duration */
560 } else {
561 while (dur > 0x3F) {
562 dur = dur / 4;
563 factor += 1;
564 }
565 durval = dur + (factor * 64);
566 }
567
568 return durval;
569 }
570
571 /* Taken from datasheet, section 5.3.3 */
bme680_calc_heater_preheat_current(u8 curr)572 static u8 bme680_calc_heater_preheat_current(u8 curr)
573 {
574 return 8 * curr - 1;
575 }
576
bme680_set_mode(struct bme680_data * data,enum bme680_op_mode mode)577 static int bme680_set_mode(struct bme680_data *data, enum bme680_op_mode mode)
578 {
579 struct device *dev = regmap_get_device(data->regmap);
580 int ret;
581
582 ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS,
583 BME680_MODE_MASK, mode);
584 if (ret < 0) {
585 dev_err(dev, "failed to set ctrl_meas register\n");
586 return ret;
587 }
588
589 return ret;
590 }
591
bme680_oversampling_to_reg(u8 val)592 static u8 bme680_oversampling_to_reg(u8 val)
593 {
594 return ilog2(val) + 1;
595 }
596
597 /*
598 * Taken from Bosch BME680 API:
599 * https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L490
600 */
bme680_wait_for_eoc(struct bme680_data * data)601 static int bme680_wait_for_eoc(struct bme680_data *data)
602 {
603 struct device *dev = regmap_get_device(data->regmap);
604 int ret;
605 /*
606 * (Sum of oversampling ratios * time per oversampling) +
607 * TPH measurement + gas measurement + wait transition from forced mode
608 * + heater duration
609 */
610 int wait_eoc_us = ((data->oversampling_temp + data->oversampling_press +
611 data->oversampling_humid) * 1936) + (477 * 4) +
612 (477 * 5) + 1000 + (data->heater_dur * 1000);
613
614 fsleep(wait_eoc_us);
615
616 ret = regmap_read(data->regmap, BME680_REG_MEAS_STAT_0, &data->check);
617 if (ret) {
618 dev_err(dev, "failed to read measurement status register.\n");
619 return ret;
620 }
621 if (data->check & BME680_MEAS_BIT) {
622 dev_err(dev, "Device measurement cycle incomplete.\n");
623 return -EBUSY;
624 }
625 if (!(data->check & BME680_NEW_DATA_BIT)) {
626 dev_err(dev, "No new data available from the device.\n");
627 return -ENODATA;
628 }
629
630 return 0;
631 }
632
bme680_chip_config(struct bme680_data * data)633 static int bme680_chip_config(struct bme680_data *data)
634 {
635 struct device *dev = regmap_get_device(data->regmap);
636 int ret;
637 u8 osrs;
638
639 osrs = FIELD_PREP(BME680_OSRS_HUMIDITY_MASK,
640 bme680_oversampling_to_reg(data->oversampling_humid));
641 /*
642 * Highly recommended to set oversampling of humidity before
643 * temperature/pressure oversampling.
644 */
645 ret = regmap_update_bits(data->regmap, BME680_REG_CTRL_HUMIDITY,
646 BME680_OSRS_HUMIDITY_MASK, osrs);
647 if (ret < 0) {
648 dev_err(dev, "failed to write ctrl_hum register\n");
649 return ret;
650 }
651
652 /* IIR filter settings */
653 ret = regmap_update_bits(data->regmap, BME680_REG_CONFIG,
654 BME680_FILTER_MASK, BME680_FILTER_COEFF_VAL);
655 if (ret < 0) {
656 dev_err(dev, "failed to write config register\n");
657 return ret;
658 }
659
660 osrs = FIELD_PREP(BME680_OSRS_TEMP_MASK,
661 bme680_oversampling_to_reg(data->oversampling_temp)) |
662 FIELD_PREP(BME680_OSRS_PRESS_MASK,
663 bme680_oversampling_to_reg(data->oversampling_press));
664 ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS,
665 BME680_OSRS_TEMP_MASK | BME680_OSRS_PRESS_MASK,
666 osrs);
667 if (ret < 0) {
668 dev_err(dev, "failed to write ctrl_meas register\n");
669 return ret;
670 }
671
672 return 0;
673 }
674
bme680_preheat_curr_config(struct bme680_data * data,u8 val)675 static int bme680_preheat_curr_config(struct bme680_data *data, u8 val)
676 {
677 struct device *dev = regmap_get_device(data->regmap);
678 u8 heatr_curr;
679 int ret;
680
681 heatr_curr = bme680_calc_heater_preheat_current(val);
682 ret = regmap_write(data->regmap, BME680_REG_IDAC_HEAT_0, heatr_curr);
683 if (ret < 0)
684 dev_err(dev, "failed to write idac_heat_0 register\n");
685
686 return ret;
687 }
688
bme680_gas_config(struct bme680_data * data)689 static int bme680_gas_config(struct bme680_data *data)
690 {
691 struct device *dev = regmap_get_device(data->regmap);
692 int ret;
693 u8 heatr_res, heatr_dur;
694
695 ret = bme680_set_mode(data, BME680_MODE_SLEEP);
696 if (ret < 0)
697 return ret;
698
699 heatr_res = bme680_calc_heater_res(data, data->heater_temp);
700
701 /* set target heater temperature */
702 ret = regmap_write(data->regmap, BME680_REG_RES_HEAT_0, heatr_res);
703 if (ret < 0) {
704 dev_err(dev, "failed to write res_heat_0 register\n");
705 return ret;
706 }
707
708 heatr_dur = bme680_calc_heater_dur(data->heater_dur);
709
710 /* set target heating duration */
711 ret = regmap_write(data->regmap, BME680_REG_GAS_WAIT_0, heatr_dur);
712 if (ret < 0) {
713 dev_err(dev, "failed to write gas_wait_0 register\n");
714 return ret;
715 }
716
717 ret = bme680_preheat_curr_config(data, data->preheat_curr_mA);
718 if (ret)
719 return ret;
720
721 /* Enable the gas sensor and select heater profile set-point 0 */
722 ret = regmap_update_bits(data->regmap, BME680_REG_CTRL_GAS_1,
723 BME680_RUN_GAS_MASK | BME680_NB_CONV_MASK,
724 FIELD_PREP(BME680_RUN_GAS_MASK, 1) |
725 FIELD_PREP(BME680_NB_CONV_MASK, 0));
726 if (ret < 0)
727 dev_err(dev, "failed to write ctrl_gas_1 register\n");
728
729 return ret;
730 }
731
bme680_read_temp(struct bme680_data * data,s16 * comp_temp)732 static int bme680_read_temp(struct bme680_data *data, s16 *comp_temp)
733 {
734 int ret;
735 u32 adc_temp;
736
737 ret = bme680_read_temp_adc(data, &adc_temp);
738 if (ret)
739 return ret;
740
741 *comp_temp = bme680_compensate_temp(data, adc_temp);
742 return 0;
743 }
744
bme680_read_press(struct bme680_data * data,u32 * comp_press)745 static int bme680_read_press(struct bme680_data *data, u32 *comp_press)
746 {
747 int ret;
748 u32 adc_press;
749 s32 t_fine;
750
751 ret = bme680_get_t_fine(data, &t_fine);
752 if (ret)
753 return ret;
754
755 ret = bme680_read_press_adc(data, &adc_press);
756 if (ret)
757 return ret;
758
759 *comp_press = bme680_compensate_press(data, adc_press, t_fine);
760 return 0;
761 }
762
bme680_read_humid(struct bme680_data * data,u32 * comp_humidity)763 static int bme680_read_humid(struct bme680_data *data, u32 *comp_humidity)
764 {
765 int ret;
766 u32 adc_humidity;
767 s32 t_fine;
768
769 ret = bme680_get_t_fine(data, &t_fine);
770 if (ret)
771 return ret;
772
773 ret = bme680_read_humid_adc(data, &adc_humidity);
774 if (ret)
775 return ret;
776
777 *comp_humidity = bme680_compensate_humid(data, adc_humidity, t_fine);
778 return 0;
779 }
780
bme680_read_gas(struct bme680_data * data,int * comp_gas_res)781 static int bme680_read_gas(struct bme680_data *data, int *comp_gas_res)
782 {
783 struct device *dev = regmap_get_device(data->regmap);
784 int ret;
785 u16 adc_gas_res, gas_regs_val;
786 u8 gas_range;
787
788 ret = regmap_read(data->regmap, BME680_REG_MEAS_STAT_0, &data->check);
789 if (data->check & BME680_GAS_MEAS_BIT) {
790 dev_err(dev, "gas measurement incomplete\n");
791 return -EBUSY;
792 }
793
794 ret = regmap_bulk_read(data->regmap, BME680_REG_GAS_MSB,
795 &data->be16, BME680_GAS_NUM_BYTES);
796 if (ret < 0) {
797 dev_err(dev, "failed to read gas resistance\n");
798 return ret;
799 }
800
801 gas_regs_val = be16_to_cpu(data->be16);
802 adc_gas_res = FIELD_GET(BME680_ADC_GAS_RES, gas_regs_val);
803
804 /*
805 * occurs if either the gas heating duration was insuffient
806 * to reach the target heater temperature or the target
807 * heater temperature was too high for the heater sink to
808 * reach.
809 */
810 if ((gas_regs_val & BME680_GAS_STAB_BIT) == 0) {
811 dev_err(dev, "heater failed to reach the target temperature\n");
812 return -EINVAL;
813 }
814
815 gas_range = FIELD_GET(BME680_GAS_RANGE_MASK, gas_regs_val);
816 *comp_gas_res = bme680_compensate_gas(data, adc_gas_res, gas_range);
817 return 0;
818 }
819
bme680_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)820 static int bme680_read_raw(struct iio_dev *indio_dev,
821 struct iio_chan_spec const *chan,
822 int *val, int *val2, long mask)
823 {
824 struct bme680_data *data = iio_priv(indio_dev);
825 int chan_val, ret;
826 s16 temp_chan_val;
827
828 guard(mutex)(&data->lock);
829
830 ret = bme680_set_mode(data, BME680_MODE_FORCED);
831 if (ret < 0)
832 return ret;
833
834 ret = bme680_wait_for_eoc(data);
835 if (ret)
836 return ret;
837
838 switch (mask) {
839 case IIO_CHAN_INFO_PROCESSED:
840 switch (chan->type) {
841 case IIO_TEMP:
842 ret = bme680_read_temp(data, &temp_chan_val);
843 if (ret)
844 return ret;
845
846 *val = temp_chan_val * 10;
847 return IIO_VAL_INT;
848 case IIO_PRESSURE:
849 ret = bme680_read_press(data, &chan_val);
850 if (ret)
851 return ret;
852
853 *val = chan_val;
854 *val2 = 1000;
855 return IIO_VAL_FRACTIONAL;
856 case IIO_HUMIDITYRELATIVE:
857 ret = bme680_read_humid(data, &chan_val);
858 if (ret)
859 return ret;
860
861 *val = chan_val;
862 *val2 = 1000;
863 return IIO_VAL_FRACTIONAL;
864 case IIO_RESISTANCE:
865 ret = bme680_read_gas(data, &chan_val);
866 if (ret)
867 return ret;
868
869 *val = chan_val;
870 return IIO_VAL_INT;
871 default:
872 return -EINVAL;
873 }
874 case IIO_CHAN_INFO_RAW:
875 switch (chan->type) {
876 case IIO_TEMP:
877 ret = bme680_read_temp(data, (s16 *)&chan_val);
878 if (ret)
879 return ret;
880
881 *val = chan_val;
882 return IIO_VAL_INT;
883 case IIO_PRESSURE:
884 ret = bme680_read_press(data, &chan_val);
885 if (ret)
886 return ret;
887
888 *val = chan_val;
889 return IIO_VAL_INT;
890 case IIO_HUMIDITYRELATIVE:
891 ret = bme680_read_humid(data, &chan_val);
892 if (ret)
893 return ret;
894
895 *val = chan_val;
896 return IIO_VAL_INT;
897 default:
898 return -EINVAL;
899 }
900 case IIO_CHAN_INFO_SCALE:
901 switch (chan->type) {
902 case IIO_TEMP:
903 *val = 10;
904 return IIO_VAL_INT;
905 case IIO_PRESSURE:
906 *val = 1;
907 *val2 = 1000;
908 return IIO_VAL_FRACTIONAL;
909 case IIO_HUMIDITYRELATIVE:
910 *val = 1;
911 *val2 = 1000;
912 return IIO_VAL_FRACTIONAL;
913 default:
914 return -EINVAL;
915 }
916 case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
917 switch (chan->type) {
918 case IIO_TEMP:
919 *val = data->oversampling_temp;
920 return IIO_VAL_INT;
921 case IIO_PRESSURE:
922 *val = data->oversampling_press;
923 return IIO_VAL_INT;
924 case IIO_HUMIDITYRELATIVE:
925 *val = data->oversampling_humid;
926 return IIO_VAL_INT;
927 default:
928 return -EINVAL;
929 }
930 default:
931 return -EINVAL;
932 }
933 }
934
bme680_is_valid_oversampling(int rate)935 static bool bme680_is_valid_oversampling(int rate)
936 {
937 return (rate > 0 && rate <= 16 && is_power_of_2(rate));
938 }
939
bme680_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)940 static int bme680_write_raw(struct iio_dev *indio_dev,
941 struct iio_chan_spec const *chan,
942 int val, int val2, long mask)
943 {
944 struct bme680_data *data = iio_priv(indio_dev);
945
946 guard(mutex)(&data->lock);
947
948 if (val2 != 0)
949 return -EINVAL;
950
951 switch (mask) {
952 case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
953 {
954 if (!bme680_is_valid_oversampling(val))
955 return -EINVAL;
956
957 switch (chan->type) {
958 case IIO_TEMP:
959 data->oversampling_temp = val;
960 break;
961 case IIO_PRESSURE:
962 data->oversampling_press = val;
963 break;
964 case IIO_HUMIDITYRELATIVE:
965 data->oversampling_humid = val;
966 break;
967 default:
968 return -EINVAL;
969 }
970
971 return bme680_chip_config(data);
972 }
973 case IIO_CHAN_INFO_PROCESSED:
974 {
975 switch (chan->type) {
976 case IIO_CURRENT:
977 return bme680_preheat_curr_config(data, (u8)val);
978 default:
979 return -EINVAL;
980 }
981 }
982 default:
983 return -EINVAL;
984 }
985 }
986
987 static const char bme680_oversampling_ratio_show[] = "1 2 4 8 16";
988
989 static IIO_CONST_ATTR(oversampling_ratio_available,
990 bme680_oversampling_ratio_show);
991
992 static struct attribute *bme680_attributes[] = {
993 &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
994 NULL,
995 };
996
997 static const struct attribute_group bme680_attribute_group = {
998 .attrs = bme680_attributes,
999 };
1000
1001 static const struct iio_info bme680_info = {
1002 .read_raw = &bme680_read_raw,
1003 .write_raw = &bme680_write_raw,
1004 .attrs = &bme680_attribute_group,
1005 };
1006
1007 static const unsigned long bme680_avail_scan_masks[] = {
1008 BIT(BME680_GAS) | BIT(BME680_HUMID) | BIT(BME680_PRESS) | BIT(BME680_TEMP),
1009 0
1010 };
1011
bme680_trigger_handler(int irq,void * p)1012 static irqreturn_t bme680_trigger_handler(int irq, void *p)
1013 {
1014 struct iio_poll_func *pf = p;
1015 struct iio_dev *indio_dev = pf->indio_dev;
1016 struct bme680_data *data = iio_priv(indio_dev);
1017 struct device *dev = regmap_get_device(data->regmap);
1018 u32 adc_temp, adc_press, adc_humid;
1019 u16 adc_gas_res, gas_regs_val;
1020 u8 gas_range;
1021 s32 t_fine;
1022 int ret;
1023
1024 guard(mutex)(&data->lock);
1025
1026 ret = bme680_set_mode(data, BME680_MODE_FORCED);
1027 if (ret < 0)
1028 goto out;
1029
1030 ret = bme680_wait_for_eoc(data);
1031 if (ret)
1032 goto out;
1033
1034 ret = regmap_bulk_read(data->regmap, BME680_REG_MEAS_STAT_0,
1035 data->buf, sizeof(data->buf));
1036 if (ret) {
1037 dev_err(dev, "failed to burst read sensor data\n");
1038 goto out;
1039 }
1040 if (data->buf[0] & BME680_GAS_MEAS_BIT) {
1041 dev_err(dev, "gas measurement incomplete\n");
1042 goto out;
1043 }
1044
1045 /* Temperature calculations */
1046 adc_temp = FIELD_GET(BME680_MEAS_TRIM_MASK, get_unaligned_be24(&data->buf[5]));
1047 if (adc_temp == BME680_MEAS_SKIPPED) {
1048 dev_err(dev, "reading temperature skipped\n");
1049 goto out;
1050 }
1051 data->scan.chan[0] = bme680_compensate_temp(data, adc_temp);
1052 t_fine = bme680_calc_t_fine(data, adc_temp);
1053
1054 /* Pressure calculations */
1055 adc_press = FIELD_GET(BME680_MEAS_TRIM_MASK, get_unaligned_be24(&data->buf[2]));
1056 if (adc_press == BME680_MEAS_SKIPPED) {
1057 dev_err(dev, "reading pressure skipped\n");
1058 goto out;
1059 }
1060 data->scan.chan[1] = bme680_compensate_press(data, adc_press, t_fine);
1061
1062 /* Humidity calculations */
1063 adc_humid = get_unaligned_be16(&data->buf[8]);
1064 if (adc_humid == BME680_MEAS_SKIPPED) {
1065 dev_err(dev, "reading humidity skipped\n");
1066 goto out;
1067 }
1068 data->scan.chan[2] = bme680_compensate_humid(data, adc_humid, t_fine);
1069
1070 /* Gas calculations */
1071 gas_regs_val = get_unaligned_be16(&data->buf[13]);
1072 adc_gas_res = FIELD_GET(BME680_ADC_GAS_RES, gas_regs_val);
1073 if ((gas_regs_val & BME680_GAS_STAB_BIT) == 0) {
1074 dev_err(dev, "heater failed to reach the target temperature\n");
1075 goto out;
1076 }
1077 gas_range = FIELD_GET(BME680_GAS_RANGE_MASK, gas_regs_val);
1078 data->scan.chan[3] = bme680_compensate_gas(data, adc_gas_res, gas_range);
1079
1080 iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
1081 iio_get_time_ns(indio_dev));
1082 out:
1083 iio_trigger_notify_done(indio_dev->trig);
1084 return IRQ_HANDLED;
1085 }
1086
bme680_core_probe(struct device * dev,struct regmap * regmap,const char * name)1087 int bme680_core_probe(struct device *dev, struct regmap *regmap,
1088 const char *name)
1089 {
1090 struct iio_dev *indio_dev;
1091 struct bme680_data *data;
1092 int ret;
1093
1094 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
1095 if (!indio_dev)
1096 return -ENOMEM;
1097
1098 data = iio_priv(indio_dev);
1099 mutex_init(&data->lock);
1100 dev_set_drvdata(dev, indio_dev);
1101 data->regmap = regmap;
1102 indio_dev->name = name;
1103 indio_dev->channels = bme680_channels;
1104 indio_dev->num_channels = ARRAY_SIZE(bme680_channels);
1105 indio_dev->available_scan_masks = bme680_avail_scan_masks;
1106 indio_dev->info = &bme680_info;
1107 indio_dev->modes = INDIO_DIRECT_MODE;
1108
1109 /* default values for the sensor */
1110 data->oversampling_humid = 2; /* 2X oversampling rate */
1111 data->oversampling_press = 4; /* 4X oversampling rate */
1112 data->oversampling_temp = 8; /* 8X oversampling rate */
1113 data->heater_temp = 320; /* degree Celsius */
1114 data->heater_dur = 150; /* milliseconds */
1115 data->preheat_curr_mA = 0;
1116
1117 ret = regmap_write(regmap, BME680_REG_SOFT_RESET, BME680_CMD_SOFTRESET);
1118 if (ret < 0)
1119 return dev_err_probe(dev, ret, "Failed to reset chip\n");
1120
1121 fsleep(BME680_STARTUP_TIME_US);
1122
1123 ret = regmap_read(regmap, BME680_REG_CHIP_ID, &data->check);
1124 if (ret < 0)
1125 return dev_err_probe(dev, ret, "Error reading chip ID\n");
1126
1127 if (data->check != BME680_CHIP_ID_VAL) {
1128 dev_err(dev, "Wrong chip ID, got %x expected %x\n",
1129 data->check, BME680_CHIP_ID_VAL);
1130 return -ENODEV;
1131 }
1132
1133 ret = bme680_read_calib(data, &data->bme680);
1134 if (ret < 0) {
1135 return dev_err_probe(dev, ret,
1136 "failed to read calibration coefficients at probe\n");
1137 }
1138
1139 ret = bme680_chip_config(data);
1140 if (ret < 0)
1141 return dev_err_probe(dev, ret,
1142 "failed to set chip_config data\n");
1143
1144 ret = bme680_gas_config(data);
1145 if (ret < 0)
1146 return dev_err_probe(dev, ret,
1147 "failed to set gas config data\n");
1148
1149 ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
1150 iio_pollfunc_store_time,
1151 bme680_trigger_handler,
1152 NULL);
1153 if (ret)
1154 return dev_err_probe(dev, ret,
1155 "iio triggered buffer setup failed\n");
1156
1157 return devm_iio_device_register(dev, indio_dev);
1158 }
1159 EXPORT_SYMBOL_NS_GPL(bme680_core_probe, "IIO_BME680");
1160
1161 MODULE_AUTHOR("Himanshu Jha <himanshujha199640@gmail.com>");
1162 MODULE_DESCRIPTION("Bosch BME680 Driver");
1163 MODULE_LICENSE("GPL v2");
1164