1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * BU27034 ROHM Ambient Light Sensor 4 * 5 * Copyright (c) 2023, ROHM Semiconductor. 6 * https://fscdn.rohm.com/en/products/databook/datasheet/ic/sensor/light/bu27034nuc-e.pdf 7 */ 8 9 #include <linux/bitfield.h> 10 #include <linux/bits.h> 11 #include <linux/device.h> 12 #include <linux/i2c.h> 13 #include <linux/module.h> 14 #include <linux/property.h> 15 #include <linux/regmap.h> 16 #include <linux/regulator/consumer.h> 17 #include <linux/units.h> 18 19 #include <linux/iio/buffer.h> 20 #include <linux/iio/iio.h> 21 #include <linux/iio/iio-gts-helper.h> 22 #include <linux/iio/kfifo_buf.h> 23 24 #define BU27034_REG_SYSTEM_CONTROL 0x40 25 #define BU27034_MASK_SW_RESET BIT(7) 26 #define BU27034_MASK_PART_ID GENMASK(5, 0) 27 #define BU27034_ID 0x19 28 #define BU27034_REG_MODE_CONTROL1 0x41 29 #define BU27034_MASK_MEAS_MODE GENMASK(2, 0) 30 31 #define BU27034_REG_MODE_CONTROL2 0x42 32 #define BU27034_MASK_D01_GAIN GENMASK(7, 3) 33 #define BU27034_MASK_D2_GAIN_HI GENMASK(7, 6) 34 #define BU27034_MASK_D2_GAIN_LO GENMASK(2, 0) 35 36 #define BU27034_REG_MODE_CONTROL3 0x43 37 #define BU27034_REG_MODE_CONTROL4 0x44 38 #define BU27034_MASK_MEAS_EN BIT(0) 39 #define BU27034_MASK_VALID BIT(7) 40 #define BU27034_REG_DATA0_LO 0x50 41 #define BU27034_REG_DATA1_LO 0x52 42 #define BU27034_REG_DATA2_LO 0x54 43 #define BU27034_REG_DATA2_HI 0x55 44 #define BU27034_REG_MANUFACTURER_ID 0x92 45 #define BU27034_REG_MAX BU27034_REG_MANUFACTURER_ID 46 47 /* 48 * The BU27034 does not have interrupt to trigger the data read when a 49 * measurement has finished. Hence we poll the VALID bit in a thread. We will 50 * try to wake the thread BU27034_MEAS_WAIT_PREMATURE_MS milliseconds before 51 * the expected sampling time to prevent the drifting. 52 * 53 * If we constantly wake up a bit too late we would eventually skip a sample. 54 * And because the sleep can't wake up _exactly_ at given time this would be 55 * inevitable even if the sensor clock would be perfectly phase-locked to CPU 56 * clock - which we can't say is the case. 57 * 58 * This is still fragile. No matter how big advance do we have, we will still 59 * risk of losing a sample because things can in a rainy-day scenario be 60 * delayed a lot. Yet, more we reserve the time for polling, more we also lose 61 * the performance by spending cycles polling the register. So, selecting this 62 * value is a balancing dance between severity of wasting CPU time and severity 63 * of losing samples. 64 * 65 * In most cases losing the samples is not _that_ crucial because light levels 66 * tend to change slowly. 67 * 68 * Other option that was pointed to me would be always sleeping 1/2 of the 69 * measurement time, checking the VALID bit and just sleeping again if the bit 70 * was not set. That should be pretty tolerant against missing samples due to 71 * the scheduling delays while also not wasting much of cycles for polling. 72 * Downside is that the time-stamps would be very inaccurate as the wake-up 73 * would not really be tied to the sensor toggling the valid bit. This would also 74 * result 'jumps' in the time-stamps when the delay drifted so that wake-up was 75 * performed during the consecutive wake-ups (Or, when sensor and CPU clocks 76 * were very different and scheduling the wake-ups was very close to given 77 * timeout - and when the time-outs were very close to the actual sensor 78 * sampling, Eg. once in a blue moon, two consecutive time-outs would occur 79 * without having a sample ready). 80 */ 81 #define BU27034_MEAS_WAIT_PREMATURE_MS 5 82 #define BU27034_DATA_WAIT_TIME_US 1000 83 #define BU27034_TOTAL_DATA_WAIT_TIME_US (BU27034_MEAS_WAIT_PREMATURE_MS * 1000) 84 85 #define BU27034_RETRY_LIMIT 18 86 87 enum { 88 BU27034_CHAN_ALS, 89 BU27034_CHAN_DATA0, 90 BU27034_CHAN_DATA1, 91 BU27034_CHAN_DATA2, 92 BU27034_NUM_CHANS 93 }; 94 95 static const unsigned long bu27034_scan_masks[] = { 96 GENMASK(BU27034_CHAN_DATA2, BU27034_CHAN_ALS), 0 97 }; 98 99 /* 100 * Available scales with gain 1x - 4096x, timings 55, 100, 200, 400 mS 101 * Time impacts to gain: 1x, 2x, 4x, 8x. 102 * 103 * => Max total gain is HWGAIN * gain by integration time (8 * 4096) = 32768 104 * 105 * Using NANO precision for scale we must use scale 64x corresponding gain 1x 106 * to avoid precision loss. (32x would result scale 976 562.5(nanos). 107 */ 108 #define BU27034_SCALE_1X 64 109 110 /* See the data sheet for the "Gain Setting" table */ 111 #define BU27034_GSEL_1X 0x00 /* 00000 */ 112 #define BU27034_GSEL_4X 0x08 /* 01000 */ 113 #define BU27034_GSEL_16X 0x0a /* 01010 */ 114 #define BU27034_GSEL_32X 0x0b /* 01011 */ 115 #define BU27034_GSEL_64X 0x0c /* 01100 */ 116 #define BU27034_GSEL_256X 0x18 /* 11000 */ 117 #define BU27034_GSEL_512X 0x19 /* 11001 */ 118 #define BU27034_GSEL_1024X 0x1a /* 11010 */ 119 #define BU27034_GSEL_2048X 0x1b /* 11011 */ 120 #define BU27034_GSEL_4096X 0x1c /* 11100 */ 121 122 /* Available gain settings */ 123 static const struct iio_gain_sel_pair bu27034_gains[] = { 124 GAIN_SCALE_GAIN(1, BU27034_GSEL_1X), 125 GAIN_SCALE_GAIN(4, BU27034_GSEL_4X), 126 GAIN_SCALE_GAIN(16, BU27034_GSEL_16X), 127 GAIN_SCALE_GAIN(32, BU27034_GSEL_32X), 128 GAIN_SCALE_GAIN(64, BU27034_GSEL_64X), 129 GAIN_SCALE_GAIN(256, BU27034_GSEL_256X), 130 GAIN_SCALE_GAIN(512, BU27034_GSEL_512X), 131 GAIN_SCALE_GAIN(1024, BU27034_GSEL_1024X), 132 GAIN_SCALE_GAIN(2048, BU27034_GSEL_2048X), 133 GAIN_SCALE_GAIN(4096, BU27034_GSEL_4096X), 134 }; 135 136 /* 137 * The IC has 5 modes for sampling time. 5 mS mode is exceptional as it limits 138 * the data collection to data0-channel only and cuts the supported range to 139 * 10 bit. It is not supported by the driver. 140 * 141 * "normal" modes are 55, 100, 200 and 400 mS modes - which do have direct 142 * multiplying impact to the register values (similar to gain). 143 * 144 * This means that if meas-mode is changed for example from 400 => 200, 145 * the scale is doubled. Eg, time impact to total gain is x1, x2, x4, x8. 146 */ 147 #define BU27034_MEAS_MODE_100MS 0 148 #define BU27034_MEAS_MODE_55MS 1 149 #define BU27034_MEAS_MODE_200MS 2 150 #define BU27034_MEAS_MODE_400MS 4 151 152 static const struct iio_itime_sel_mul bu27034_itimes[] = { 153 GAIN_SCALE_ITIME_US(400000, BU27034_MEAS_MODE_400MS, 8), 154 GAIN_SCALE_ITIME_US(200000, BU27034_MEAS_MODE_200MS, 4), 155 GAIN_SCALE_ITIME_US(100000, BU27034_MEAS_MODE_100MS, 2), 156 GAIN_SCALE_ITIME_US(55000, BU27034_MEAS_MODE_55MS, 1), 157 }; 158 159 #define BU27034_CHAN_DATA(_name, _ch2) \ 160 { \ 161 .type = IIO_INTENSITY, \ 162 .channel = BU27034_CHAN_##_name, \ 163 .channel2 = (_ch2), \ 164 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 165 BIT(IIO_CHAN_INFO_SCALE), \ 166 .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), \ 167 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \ 168 .info_mask_shared_by_all_available = \ 169 BIT(IIO_CHAN_INFO_INT_TIME), \ 170 .address = BU27034_REG_##_name##_LO, \ 171 .scan_index = BU27034_CHAN_##_name, \ 172 .scan_type = { \ 173 .sign = 'u', \ 174 .realbits = 16, \ 175 .storagebits = 16, \ 176 .endianness = IIO_LE, \ 177 }, \ 178 .indexed = 1, \ 179 } 180 181 static const struct iio_chan_spec bu27034_channels[] = { 182 { 183 .type = IIO_LIGHT, 184 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 185 BIT(IIO_CHAN_INFO_SCALE), 186 .channel = BU27034_CHAN_ALS, 187 .scan_index = BU27034_CHAN_ALS, 188 .scan_type = { 189 .sign = 'u', 190 .realbits = 32, 191 .storagebits = 32, 192 .endianness = IIO_CPU, 193 }, 194 }, 195 /* 196 * The BU27034 DATA0 and DATA1 channels are both on the visible light 197 * area (mostly). The data0 sensitivity peaks at 500nm, DATA1 at 600nm. 198 * These wave lengths are pretty much on the border of colours making 199 * these a poor candidates for R/G/B standardization. Hence they're both 200 * marked as clear channels 201 */ 202 BU27034_CHAN_DATA(DATA0, IIO_MOD_LIGHT_CLEAR), 203 BU27034_CHAN_DATA(DATA1, IIO_MOD_LIGHT_CLEAR), 204 BU27034_CHAN_DATA(DATA2, IIO_MOD_LIGHT_IR), 205 IIO_CHAN_SOFT_TIMESTAMP(4), 206 }; 207 208 struct bu27034_data { 209 struct regmap *regmap; 210 struct device *dev; 211 /* 212 * Protect gain and time during scale adjustment and data reading. 213 * Protect measurement enabling/disabling. 214 */ 215 struct mutex mutex; 216 struct iio_gts gts; 217 struct task_struct *task; 218 __le16 raw[3]; 219 struct { 220 u32 mlux; 221 __le16 channels[3]; 222 s64 ts __aligned(8); 223 } scan; 224 }; 225 226 struct bu27034_result { 227 u16 ch0; 228 u16 ch1; 229 u16 ch2; 230 }; 231 232 static const struct regmap_range bu27034_volatile_ranges[] = { 233 { 234 .range_min = BU27034_REG_SYSTEM_CONTROL, 235 .range_max = BU27034_REG_SYSTEM_CONTROL, 236 }, { 237 .range_min = BU27034_REG_MODE_CONTROL4, 238 .range_max = BU27034_REG_MODE_CONTROL4, 239 }, { 240 .range_min = BU27034_REG_DATA0_LO, 241 .range_max = BU27034_REG_DATA2_HI, 242 }, 243 }; 244 245 static const struct regmap_access_table bu27034_volatile_regs = { 246 .yes_ranges = &bu27034_volatile_ranges[0], 247 .n_yes_ranges = ARRAY_SIZE(bu27034_volatile_ranges), 248 }; 249 250 static const struct regmap_range bu27034_read_only_ranges[] = { 251 { 252 .range_min = BU27034_REG_DATA0_LO, 253 .range_max = BU27034_REG_DATA2_HI, 254 }, { 255 .range_min = BU27034_REG_MANUFACTURER_ID, 256 .range_max = BU27034_REG_MANUFACTURER_ID, 257 } 258 }; 259 260 static const struct regmap_access_table bu27034_ro_regs = { 261 .no_ranges = &bu27034_read_only_ranges[0], 262 .n_no_ranges = ARRAY_SIZE(bu27034_read_only_ranges), 263 }; 264 265 static const struct regmap_config bu27034_regmap = { 266 .reg_bits = 8, 267 .val_bits = 8, 268 .max_register = BU27034_REG_MAX, 269 .cache_type = REGCACHE_RBTREE, 270 .volatile_table = &bu27034_volatile_regs, 271 .wr_table = &bu27034_ro_regs, 272 }; 273 274 struct bu27034_gain_check { 275 int old_gain; 276 int new_gain; 277 int chan; 278 }; 279 280 static int bu27034_get_gain_sel(struct bu27034_data *data, int chan) 281 { 282 int ret, val; 283 284 switch (chan) { 285 case BU27034_CHAN_DATA0: 286 case BU27034_CHAN_DATA1: 287 { 288 int reg[] = { 289 [BU27034_CHAN_DATA0] = BU27034_REG_MODE_CONTROL2, 290 [BU27034_CHAN_DATA1] = BU27034_REG_MODE_CONTROL3, 291 }; 292 ret = regmap_read(data->regmap, reg[chan], &val); 293 if (ret) 294 return ret; 295 296 return FIELD_GET(BU27034_MASK_D01_GAIN, val); 297 } 298 case BU27034_CHAN_DATA2: 299 { 300 int d2_lo_bits = fls(BU27034_MASK_D2_GAIN_LO); 301 302 ret = regmap_read(data->regmap, BU27034_REG_MODE_CONTROL2, &val); 303 if (ret) 304 return ret; 305 306 /* 307 * The data2 channel gain is composed by 5 non continuous bits 308 * [7:6], [2:0]. Thus when we combine the 5-bit 'selector' 309 * from register value we must right shift the high bits by 3. 310 */ 311 return FIELD_GET(BU27034_MASK_D2_GAIN_HI, val) << d2_lo_bits | 312 FIELD_GET(BU27034_MASK_D2_GAIN_LO, val); 313 } 314 default: 315 return -EINVAL; 316 } 317 } 318 319 static int bu27034_get_gain(struct bu27034_data *data, int chan, int *gain) 320 { 321 int ret, sel; 322 323 ret = bu27034_get_gain_sel(data, chan); 324 if (ret < 0) 325 return ret; 326 327 sel = ret; 328 329 ret = iio_gts_find_gain_by_sel(&data->gts, sel); 330 if (ret < 0) { 331 dev_err(data->dev, "chan %u: unknown gain value 0x%x\n", chan, 332 sel); 333 334 return ret; 335 } 336 337 *gain = ret; 338 339 return 0; 340 } 341 342 static int bu27034_get_int_time(struct bu27034_data *data) 343 { 344 int ret, sel; 345 346 ret = regmap_read(data->regmap, BU27034_REG_MODE_CONTROL1, &sel); 347 if (ret) 348 return ret; 349 350 return iio_gts_find_int_time_by_sel(&data->gts, 351 sel & BU27034_MASK_MEAS_MODE); 352 } 353 354 static int _bu27034_get_scale(struct bu27034_data *data, int channel, int *val, 355 int *val2) 356 { 357 int gain, ret; 358 359 ret = bu27034_get_gain(data, channel, &gain); 360 if (ret) 361 return ret; 362 363 ret = bu27034_get_int_time(data); 364 if (ret < 0) 365 return ret; 366 367 return iio_gts_get_scale(&data->gts, gain, ret, val, val2); 368 } 369 370 static int bu27034_get_scale(struct bu27034_data *data, int channel, int *val, 371 int *val2) 372 { 373 int ret; 374 375 if (channel == BU27034_CHAN_ALS) { 376 *val = 0; 377 *val2 = 1000; 378 return IIO_VAL_INT_PLUS_MICRO; 379 } 380 381 mutex_lock(&data->mutex); 382 ret = _bu27034_get_scale(data, channel, val, val2); 383 mutex_unlock(&data->mutex); 384 if (ret) 385 return ret; 386 387 return IIO_VAL_INT_PLUS_NANO; 388 } 389 390 /* Caller should hold the lock to protect lux reading */ 391 static int bu27034_write_gain_sel(struct bu27034_data *data, int chan, int sel) 392 { 393 static const int reg[] = { 394 [BU27034_CHAN_DATA0] = BU27034_REG_MODE_CONTROL2, 395 [BU27034_CHAN_DATA1] = BU27034_REG_MODE_CONTROL3, 396 }; 397 int mask, val; 398 399 if (chan != BU27034_CHAN_DATA0 && chan != BU27034_CHAN_DATA1) 400 return -EINVAL; 401 402 val = FIELD_PREP(BU27034_MASK_D01_GAIN, sel); 403 404 mask = BU27034_MASK_D01_GAIN; 405 406 if (chan == BU27034_CHAN_DATA0) { 407 /* 408 * We keep the same gain for channel 2 as we set for channel 0 409 * We can't allow them to be individually controlled because 410 * setting one will impact also the other. Also, if we don't 411 * always update both gains we may result unsupported bit 412 * combinations. 413 * 414 * This is not nice but this is yet another place where the 415 * user space must be prepared to surprizes. Namely, see chan 2 416 * gain changed when chan 0 gain is changed. 417 * 418 * This is not fatal for most users though. I don't expect the 419 * channel 2 to be used in any generic cases - the intensity 420 * values provided by the sensor for IR area are not openly 421 * documented. Also, channel 2 is not used for visible light. 422 * 423 * So, if there is application which is written to utilize the 424 * channel 2 - then it is probably specifically targeted to this 425 * sensor and knows how to utilize those values. It is safe to 426 * hope such user can also cope with the gain changes. 427 */ 428 mask |= BU27034_MASK_D2_GAIN_LO; 429 430 /* 431 * The D2 gain bits are directly the lowest bits of selector. 432 * Just do add those bits to the value 433 */ 434 val |= sel & BU27034_MASK_D2_GAIN_LO; 435 } 436 437 return regmap_update_bits(data->regmap, reg[chan], mask, val); 438 } 439 440 static int bu27034_set_gain(struct bu27034_data *data, int chan, int gain) 441 { 442 int ret; 443 444 /* 445 * We don't allow setting channel 2 gain as it messes up the 446 * gain for channel 0 - which shares the high bits 447 */ 448 if (chan != BU27034_CHAN_DATA0 && chan != BU27034_CHAN_DATA1) 449 return -EINVAL; 450 451 ret = iio_gts_find_sel_by_gain(&data->gts, gain); 452 if (ret < 0) 453 return ret; 454 455 return bu27034_write_gain_sel(data, chan, ret); 456 } 457 458 /* Caller should hold the lock to protect data->int_time */ 459 static int bu27034_set_int_time(struct bu27034_data *data, int time) 460 { 461 int ret; 462 463 ret = iio_gts_find_sel_by_int_time(&data->gts, time); 464 if (ret < 0) 465 return ret; 466 467 return regmap_update_bits(data->regmap, BU27034_REG_MODE_CONTROL1, 468 BU27034_MASK_MEAS_MODE, ret); 469 } 470 471 /* 472 * We try to change the time in such way that the scale is maintained for 473 * given channels by adjusting gain so that it compensates the time change. 474 */ 475 static int bu27034_try_set_int_time(struct bu27034_data *data, int time_us) 476 { 477 struct bu27034_gain_check gains[] = { 478 { .chan = BU27034_CHAN_DATA0 }, 479 { .chan = BU27034_CHAN_DATA1 }, 480 }; 481 int numg = ARRAY_SIZE(gains); 482 int ret, int_time_old, i; 483 484 mutex_lock(&data->mutex); 485 ret = bu27034_get_int_time(data); 486 if (ret < 0) 487 goto unlock_out; 488 489 int_time_old = ret; 490 491 if (!iio_gts_valid_time(&data->gts, time_us)) { 492 dev_err(data->dev, "Unsupported integration time %u\n", 493 time_us); 494 ret = -EINVAL; 495 496 goto unlock_out; 497 } 498 499 if (time_us == int_time_old) { 500 ret = 0; 501 goto unlock_out; 502 } 503 504 for (i = 0; i < numg; i++) { 505 ret = bu27034_get_gain(data, gains[i].chan, &gains[i].old_gain); 506 if (ret) 507 goto unlock_out; 508 509 ret = iio_gts_find_new_gain_by_old_gain_time(&data->gts, 510 gains[i].old_gain, 511 int_time_old, time_us, 512 &gains[i].new_gain); 513 if (ret) { 514 int scale1, scale2; 515 bool ok; 516 517 _bu27034_get_scale(data, gains[i].chan, &scale1, &scale2); 518 dev_dbg(data->dev, 519 "chan %u, can't support time %u with scale %u %u\n", 520 gains[i].chan, time_us, scale1, scale2); 521 522 if (gains[i].new_gain < 0) 523 goto unlock_out; 524 525 /* 526 * If caller requests for integration time change and we 527 * can't support the scale - then the caller should be 528 * prepared to 'pick up the pieces and deal with the 529 * fact that the scale changed'. 530 */ 531 ret = iio_find_closest_gain_low(&data->gts, 532 gains[i].new_gain, &ok); 533 534 if (!ok) 535 dev_dbg(data->dev, 536 "optimal gain out of range for chan %u\n", 537 gains[i].chan); 538 539 if (ret < 0) { 540 dev_dbg(data->dev, 541 "Total gain increase. Risk of saturation"); 542 ret = iio_gts_get_min_gain(&data->gts); 543 if (ret < 0) 544 goto unlock_out; 545 } 546 dev_dbg(data->dev, "chan %u scale changed\n", 547 gains[i].chan); 548 gains[i].new_gain = ret; 549 dev_dbg(data->dev, "chan %u new gain %u\n", 550 gains[i].chan, gains[i].new_gain); 551 } 552 } 553 554 for (i = 0; i < numg; i++) { 555 ret = bu27034_set_gain(data, gains[i].chan, gains[i].new_gain); 556 if (ret) 557 goto unlock_out; 558 } 559 560 ret = bu27034_set_int_time(data, time_us); 561 562 unlock_out: 563 mutex_unlock(&data->mutex); 564 565 return ret; 566 } 567 568 static int bu27034_set_scale(struct bu27034_data *data, int chan, 569 int val, int val2) 570 { 571 int ret, time_sel, gain_sel, i; 572 bool found = false; 573 574 if (chan == BU27034_CHAN_DATA2) 575 return -EINVAL; 576 577 if (chan == BU27034_CHAN_ALS) { 578 if (val == 0 && val2 == 1000) 579 return 0; 580 581 return -EINVAL; 582 } 583 584 mutex_lock(&data->mutex); 585 ret = regmap_read(data->regmap, BU27034_REG_MODE_CONTROL1, &time_sel); 586 if (ret) 587 goto unlock_out; 588 589 ret = iio_gts_find_gain_sel_for_scale_using_time(&data->gts, time_sel, 590 val, val2 * 1000, &gain_sel); 591 if (ret) { 592 /* 593 * Could not support scale with given time. Need to change time. 594 * We still want to maintain the scale for all channels 595 */ 596 struct bu27034_gain_check gain; 597 int new_time_sel; 598 599 /* 600 * Populate information for the other channel which should also 601 * maintain the scale. (Due to the HW limitations the chan2 602 * gets the same gain as chan0, so we only need to explicitly 603 * set the chan 0 and 1). 604 */ 605 if (chan == BU27034_CHAN_DATA0) 606 gain.chan = BU27034_CHAN_DATA1; 607 else if (chan == BU27034_CHAN_DATA1) 608 gain.chan = BU27034_CHAN_DATA0; 609 610 ret = bu27034_get_gain(data, gain.chan, &gain.old_gain); 611 if (ret) 612 goto unlock_out; 613 614 /* 615 * Iterate through all the times to see if we find one which 616 * can support requested scale for requested channel, while 617 * maintaining the scale for other channels 618 */ 619 for (i = 0; i < data->gts.num_itime; i++) { 620 new_time_sel = data->gts.itime_table[i].sel; 621 622 if (new_time_sel == time_sel) 623 continue; 624 625 /* Can we provide requested scale with this time? */ 626 ret = iio_gts_find_gain_sel_for_scale_using_time( 627 &data->gts, new_time_sel, val, val2 * 1000, 628 &gain_sel); 629 if (ret) 630 continue; 631 632 /* Can the other channel(s) maintain scale? */ 633 ret = iio_gts_find_new_gain_sel_by_old_gain_time( 634 &data->gts, gain.old_gain, time_sel, 635 new_time_sel, &gain.new_gain); 636 if (!ret) { 637 /* Yes - we found suitable time */ 638 found = true; 639 break; 640 } 641 } 642 if (!found) { 643 dev_dbg(data->dev, 644 "Can't set scale maintaining other channels\n"); 645 ret = -EINVAL; 646 647 goto unlock_out; 648 } 649 650 ret = bu27034_set_gain(data, gain.chan, gain.new_gain); 651 if (ret) 652 goto unlock_out; 653 654 ret = regmap_update_bits(data->regmap, BU27034_REG_MODE_CONTROL1, 655 BU27034_MASK_MEAS_MODE, new_time_sel); 656 if (ret) 657 goto unlock_out; 658 } 659 660 ret = bu27034_write_gain_sel(data, chan, gain_sel); 661 unlock_out: 662 mutex_unlock(&data->mutex); 663 664 return ret; 665 } 666 667 /* 668 * for (D1/D0 < 0.87): 669 * lx = 0.004521097 * D1 - 0.002663996 * D0 + 670 * 0.00012213 * D1 * D1 / D0 671 * 672 * => 115.7400832 * ch1 / gain1 / mt - 673 * 68.1982976 * ch0 / gain0 / mt + 674 * 0.00012213 * 25600 * (ch1 / gain1 / mt) * 25600 * 675 * (ch1 /gain1 / mt) / (25600 * ch0 / gain0 / mt) 676 * 677 * A = 0.00012213 * 25600 * (ch1 /gain1 / mt) * 25600 * 678 * (ch1 /gain1 / mt) / (25600 * ch0 / gain0 / mt) 679 * => 0.00012213 * 25600 * (ch1 /gain1 / mt) * 680 * (ch1 /gain1 / mt) / (ch0 / gain0 / mt) 681 * => 0.00012213 * 25600 * (ch1 / gain1) * (ch1 /gain1 / mt) / 682 * (ch0 / gain0) 683 * => 0.00012213 * 25600 * (ch1 / gain1) * (ch1 /gain1 / mt) * 684 * gain0 / ch0 685 * => 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / mt /ch0 686 * 687 * lx = (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0) / 688 * mt + A 689 * => (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0) / 690 * mt + 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / mt / 691 * ch0 692 * 693 * => (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0 + 694 * 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / ch0) / 695 * mt 696 * 697 * For (0.87 <= D1/D0 < 1.00) 698 * lx = (0.001331* D0 + 0.0000354 * D1) * ((D1/D0 – 0.87) * (0.385) + 1) 699 * => (0.001331 * 256 * 100 * ch0 / gain0 / mt + 0.0000354 * 256 * 700 * 100 * ch1 / gain1 / mt) * ((D1/D0 - 0.87) * (0.385) + 1) 701 * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) * 702 * ((D1/D0 - 0.87) * (0.385) + 1) 703 * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) * 704 * (0.385 * D1/D0 - 0.66505) 705 * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) * 706 * (0.385 * 256 * 100 * ch1 / gain1 / mt / (256 * 100 * ch0 / gain0 / mt) - 0.66505) 707 * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) * 708 * (9856 * ch1 / gain1 / mt / (25600 * ch0 / gain0 / mt) + 0.66505) 709 * => 13.118336 * ch1 / (gain1 * mt) 710 * + 22.66064768 * ch0 / (gain0 * mt) 711 * + 8931.90144 * ch1 * ch1 * gain0 / 712 * (25600 * ch0 * gain1 * gain1 * mt) 713 * + 0.602694912 * ch1 / (gain1 * mt) 714 * 715 * => [0.3489024 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) 716 * + 22.66064768 * ch0 / gain0 717 * + 13.721030912 * ch1 / gain1 718 * ] / mt 719 * 720 * For (D1/D0 >= 1.00) 721 * 722 * lx = (0.001331* D0 + 0.0000354 * D1) * ((D1/D0 – 2.0) * (-0.05) + 1) 723 * => (0.001331* D0 + 0.0000354 * D1) * (-0.05D1/D0 + 1.1) 724 * => (0.001331 * 256 * 100 * ch0 / gain0 / mt + 0.0000354 * 256 * 725 * 100 * ch1 / gain1 / mt) * (-0.05D1/D0 + 1.1) 726 * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) * 727 * (-0.05 * 256 * 100 * ch1 / gain1 / mt / (256 * 100 * ch0 / gain0 / mt) + 1.1) 728 * => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) * 729 * (-1280 * ch1 / (gain1 * mt * 25600 * ch0 / gain0 / mt) + 1.1) 730 * => (34.0736 * ch0 * -1280 * ch1 * gain0 * mt /( gain0 * mt * gain1 * mt * 25600 * ch0) 731 * + 34.0736 * 1.1 * ch0 / (gain0 * mt) 732 * + 0.90624 * ch1 * -1280 * ch1 *gain0 * mt / (gain1 * mt *gain1 * mt * 25600 * ch0) 733 * + 1.1 * 0.90624 * ch1 / (gain1 * mt) 734 * => -43614.208 * ch1 / (gain1 * mt * 25600) 735 * + 37.48096 ch0 / (gain0 * mt) 736 * - 1159.9872 * ch1 * ch1 * gain0 / (gain1 * gain1 * mt * 25600 * ch0) 737 * + 0.996864 ch1 / (gain1 * mt) 738 * => [ 739 * - 0.045312 * ch1 * ch1 * gain0 / (gain1 * gain1 * ch0) 740 * - 0.706816 * ch1 / gain1 741 * + 37.48096 ch0 /gain0 742 * ] * mt 743 * 744 * 745 * So, the first case (D1/D0 < 0.87) can be computed to a form: 746 * 747 * lx = (3.126528 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) + 748 * 115.7400832 * ch1 / gain1 + 749 * -68.1982976 * ch0 / gain0 750 * / mt 751 * 752 * Second case (0.87 <= D1/D0 < 1.00) goes to form: 753 * 754 * => [0.3489024 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) + 755 * 13.721030912 * ch1 / gain1 + 756 * 22.66064768 * ch0 / gain0 757 * ] / mt 758 * 759 * Third case (D1/D0 >= 1.00) goes to form: 760 * => [-0.045312 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) + 761 * -0.706816 * ch1 / gain1 + 762 * 37.48096 ch0 /(gain0 763 * ] / mt 764 * 765 * This can be unified to format: 766 * lx = [ 767 * A * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) + 768 * B * ch1 / gain1 + 769 * C * ch0 / gain0 770 * ] / mt 771 * 772 * For case 1: 773 * A = 3.126528, 774 * B = 115.7400832 775 * C = -68.1982976 776 * 777 * For case 2: 778 * A = 0.3489024 779 * B = 13.721030912 780 * C = 22.66064768 781 * 782 * For case 3: 783 * A = -0.045312 784 * B = -0.706816 785 * C = 37.48096 786 */ 787 788 struct bu27034_lx_coeff { 789 unsigned int A; 790 unsigned int B; 791 unsigned int C; 792 /* Indicate which of the coefficients above are negative */ 793 bool is_neg[3]; 794 }; 795 796 static inline u64 gain_mul_div_helper(u64 val, unsigned int gain, 797 unsigned int div) 798 { 799 /* 800 * Max gain for a channel is 4096. The max u64 (0xffffffffffffffffULL) 801 * divided by 4096 is 0xFFFFFFFFFFFFF (GENMASK_ULL(51, 0)) (floored). 802 * Thus, the 0xFFFFFFFFFFFFF is the largest value we can safely multiply 803 * with the gain, no matter what gain is set. 804 * 805 * So, multiplication with max gain may overflow if val is greater than 806 * 0xFFFFFFFFFFFFF (52 bits set).. 807 * 808 * If this is the case we divide first. 809 */ 810 if (val < GENMASK_ULL(51, 0)) { 811 val *= gain; 812 do_div(val, div); 813 } else { 814 do_div(val, div); 815 val *= gain; 816 } 817 818 return val; 819 } 820 821 static u64 bu27034_fixp_calc_t1_64bit(unsigned int coeff, unsigned int ch0, 822 unsigned int ch1, unsigned int gain0, 823 unsigned int gain1) 824 { 825 unsigned int helper; 826 u64 helper64; 827 828 helper64 = (u64)coeff * (u64)ch1 * (u64)ch1; 829 830 helper = gain1 * gain1; 831 if (helper > ch0) { 832 do_div(helper64, helper); 833 834 return gain_mul_div_helper(helper64, gain0, ch0); 835 } 836 837 do_div(helper64, ch0); 838 839 return gain_mul_div_helper(helper64, gain0, helper); 840 841 } 842 843 static u64 bu27034_fixp_calc_t1(unsigned int coeff, unsigned int ch0, 844 unsigned int ch1, unsigned int gain0, 845 unsigned int gain1) 846 { 847 unsigned int helper, tmp; 848 849 /* 850 * Here we could overflow even the 64bit value. Hence we 851 * multiply with gain0 only after the divisions - even though 852 * it may result loss of accuracy 853 */ 854 helper = coeff * ch1 * ch1; 855 tmp = helper * gain0; 856 857 helper = ch1 * ch1; 858 859 if (check_mul_overflow(helper, coeff, &helper)) 860 return bu27034_fixp_calc_t1_64bit(coeff, ch0, ch1, gain0, gain1); 861 862 if (check_mul_overflow(helper, gain0, &tmp)) 863 return bu27034_fixp_calc_t1_64bit(coeff, ch0, ch1, gain0, gain1); 864 865 return tmp / (gain1 * gain1) / ch0; 866 867 } 868 869 static u64 bu27034_fixp_calc_t23(unsigned int coeff, unsigned int ch, 870 unsigned int gain) 871 { 872 unsigned int helper; 873 u64 helper64; 874 875 if (!check_mul_overflow(coeff, ch, &helper)) 876 return helper / gain; 877 878 helper64 = (u64)coeff * (u64)ch; 879 do_div(helper64, gain); 880 881 return helper64; 882 } 883 884 static int bu27034_fixp_calc_lx(unsigned int ch0, unsigned int ch1, 885 unsigned int gain0, unsigned int gain1, 886 unsigned int meastime, int coeff_idx) 887 { 888 static const struct bu27034_lx_coeff coeff[] = { 889 { 890 .A = 31265280, /* 3.126528 */ 891 .B = 1157400832, /*115.7400832 */ 892 .C = 681982976, /* -68.1982976 */ 893 .is_neg = {false, false, true}, 894 }, { 895 .A = 3489024, /* 0.3489024 */ 896 .B = 137210309, /* 13.721030912 */ 897 .C = 226606476, /* 22.66064768 */ 898 /* All terms positive */ 899 }, { 900 .A = 453120, /* -0.045312 */ 901 .B = 7068160, /* -0.706816 */ 902 .C = 374809600, /* 37.48096 */ 903 .is_neg = {true, true, false}, 904 } 905 }; 906 const struct bu27034_lx_coeff *c = &coeff[coeff_idx]; 907 u64 res = 0, terms[3]; 908 int i; 909 910 if (coeff_idx >= ARRAY_SIZE(coeff)) 911 return -EINVAL; 912 913 terms[0] = bu27034_fixp_calc_t1(c->A, ch0, ch1, gain0, gain1); 914 terms[1] = bu27034_fixp_calc_t23(c->B, ch1, gain1); 915 terms[2] = bu27034_fixp_calc_t23(c->C, ch0, gain0); 916 917 /* First, add positive terms */ 918 for (i = 0; i < 3; i++) 919 if (!c->is_neg[i]) 920 res += terms[i]; 921 922 /* No positive term => zero lux */ 923 if (!res) 924 return 0; 925 926 /* Then, subtract negative terms (if any) */ 927 for (i = 0; i < 3; i++) 928 if (c->is_neg[i]) { 929 /* 930 * If the negative term is greater than positive - then 931 * the darkness has taken over and we are all doomed! Eh, 932 * I mean, then we can just return 0 lx and go out 933 */ 934 if (terms[i] >= res) 935 return 0; 936 937 res -= terms[i]; 938 } 939 940 meastime *= 10; 941 do_div(res, meastime); 942 943 return (int) res; 944 } 945 946 static bool bu27034_has_valid_sample(struct bu27034_data *data) 947 { 948 int ret, val; 949 950 ret = regmap_read(data->regmap, BU27034_REG_MODE_CONTROL4, &val); 951 if (ret) { 952 dev_err(data->dev, "Read failed %d\n", ret); 953 954 return false; 955 } 956 957 return val & BU27034_MASK_VALID; 958 } 959 960 /* 961 * Reading the register where VALID bit is clears this bit. (So does changing 962 * any gain / integration time configuration registers) The bit gets 963 * set when we have acquired new data. We use this bit to indicate data 964 * validity. 965 */ 966 static void bu27034_invalidate_read_data(struct bu27034_data *data) 967 { 968 bu27034_has_valid_sample(data); 969 } 970 971 static int bu27034_read_result(struct bu27034_data *data, int chan, int *res) 972 { 973 int reg[] = { 974 [BU27034_CHAN_DATA0] = BU27034_REG_DATA0_LO, 975 [BU27034_CHAN_DATA1] = BU27034_REG_DATA1_LO, 976 [BU27034_CHAN_DATA2] = BU27034_REG_DATA2_LO, 977 }; 978 int valid, ret; 979 __le16 val; 980 981 ret = regmap_read_poll_timeout(data->regmap, BU27034_REG_MODE_CONTROL4, 982 valid, (valid & BU27034_MASK_VALID), 983 BU27034_DATA_WAIT_TIME_US, 0); 984 if (ret) 985 return ret; 986 987 ret = regmap_bulk_read(data->regmap, reg[chan], &val, sizeof(val)); 988 if (ret) 989 return ret; 990 991 *res = le16_to_cpu(val); 992 993 return 0; 994 } 995 996 static int bu27034_get_result_unlocked(struct bu27034_data *data, __le16 *res, 997 int size) 998 { 999 int ret = 0, retry_cnt = 0; 1000 1001 retry: 1002 /* Get new value from sensor if data is ready */ 1003 if (bu27034_has_valid_sample(data)) { 1004 ret = regmap_bulk_read(data->regmap, BU27034_REG_DATA0_LO, 1005 res, size); 1006 if (ret) 1007 return ret; 1008 1009 bu27034_invalidate_read_data(data); 1010 } else { 1011 /* No new data in sensor. Wait and retry */ 1012 retry_cnt++; 1013 1014 if (retry_cnt > BU27034_RETRY_LIMIT) { 1015 dev_err(data->dev, "No data from sensor\n"); 1016 1017 return -ETIMEDOUT; 1018 } 1019 1020 msleep(25); 1021 1022 goto retry; 1023 } 1024 1025 return ret; 1026 } 1027 1028 static int bu27034_meas_set(struct bu27034_data *data, bool en) 1029 { 1030 if (en) 1031 return regmap_set_bits(data->regmap, BU27034_REG_MODE_CONTROL4, 1032 BU27034_MASK_MEAS_EN); 1033 1034 return regmap_clear_bits(data->regmap, BU27034_REG_MODE_CONTROL4, 1035 BU27034_MASK_MEAS_EN); 1036 } 1037 1038 static int bu27034_get_single_result(struct bu27034_data *data, int chan, 1039 int *val) 1040 { 1041 int ret; 1042 1043 if (chan < BU27034_CHAN_DATA0 || chan > BU27034_CHAN_DATA2) 1044 return -EINVAL; 1045 1046 ret = bu27034_meas_set(data, true); 1047 if (ret) 1048 return ret; 1049 1050 ret = bu27034_get_int_time(data); 1051 if (ret < 0) 1052 return ret; 1053 1054 msleep(ret / 1000); 1055 1056 return bu27034_read_result(data, chan, val); 1057 } 1058 1059 /* 1060 * The formula given by vendor for computing luxes out of data0 and data1 1061 * (in open air) is as follows: 1062 * 1063 * Let's mark: 1064 * D0 = data0/ch0_gain/meas_time_ms * 25600 1065 * D1 = data1/ch1_gain/meas_time_ms * 25600 1066 * 1067 * Then: 1068 * if (D1/D0 < 0.87) 1069 * lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 0.87) * 3.45 + 1) 1070 * else if (D1/D0 < 1) 1071 * lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 0.87) * 0.385 + 1) 1072 * else 1073 * lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 2) * -0.05 + 1) 1074 * 1075 * We use it here. Users who have for example some colored lens 1076 * need to modify the calculation but I hope this gives a starting point for 1077 * those working with such devices. 1078 */ 1079 1080 static int bu27034_calc_mlux(struct bu27034_data *data, __le16 *res, int *val) 1081 { 1082 unsigned int gain0, gain1, meastime; 1083 unsigned int d1_d0_ratio_scaled; 1084 u16 ch0, ch1; 1085 u64 helper64; 1086 int ret; 1087 1088 /* 1089 * We return 0 lux if calculation fails. This should be reasonably 1090 * easy to spot from the buffers especially if raw-data channels show 1091 * valid values 1092 */ 1093 *val = 0; 1094 1095 ch0 = max_t(u16, 1, le16_to_cpu(res[0])); 1096 ch1 = max_t(u16, 1, le16_to_cpu(res[1])); 1097 1098 ret = bu27034_get_gain(data, BU27034_CHAN_DATA0, &gain0); 1099 if (ret) 1100 return ret; 1101 1102 ret = bu27034_get_gain(data, BU27034_CHAN_DATA1, &gain1); 1103 if (ret) 1104 return ret; 1105 1106 ret = bu27034_get_int_time(data); 1107 if (ret < 0) 1108 return ret; 1109 1110 meastime = ret; 1111 1112 d1_d0_ratio_scaled = (unsigned int)ch1 * (unsigned int)gain0 * 100; 1113 helper64 = (u64)ch1 * (u64)gain0 * 100LLU; 1114 1115 if (helper64 != d1_d0_ratio_scaled) { 1116 unsigned int div = (unsigned int)ch0 * gain1; 1117 1118 do_div(helper64, div); 1119 d1_d0_ratio_scaled = helper64; 1120 } else { 1121 d1_d0_ratio_scaled /= ch0 * gain1; 1122 } 1123 1124 if (d1_d0_ratio_scaled < 87) 1125 ret = bu27034_fixp_calc_lx(ch0, ch1, gain0, gain1, meastime, 0); 1126 else if (d1_d0_ratio_scaled < 100) 1127 ret = bu27034_fixp_calc_lx(ch0, ch1, gain0, gain1, meastime, 1); 1128 else 1129 ret = bu27034_fixp_calc_lx(ch0, ch1, gain0, gain1, meastime, 2); 1130 1131 if (ret < 0) 1132 return ret; 1133 1134 *val = ret; 1135 1136 return 0; 1137 1138 } 1139 1140 static int bu27034_get_mlux(struct bu27034_data *data, int chan, int *val) 1141 { 1142 __le16 res[3]; 1143 int ret; 1144 1145 ret = bu27034_meas_set(data, true); 1146 if (ret) 1147 return ret; 1148 1149 ret = bu27034_get_result_unlocked(data, &res[0], sizeof(res)); 1150 if (ret) 1151 return ret; 1152 1153 ret = bu27034_calc_mlux(data, res, val); 1154 if (ret) 1155 return ret; 1156 1157 ret = bu27034_meas_set(data, false); 1158 if (ret) 1159 dev_err(data->dev, "failed to disable measurement\n"); 1160 1161 return 0; 1162 } 1163 1164 static int bu27034_read_raw(struct iio_dev *idev, 1165 struct iio_chan_spec const *chan, 1166 int *val, int *val2, long mask) 1167 { 1168 struct bu27034_data *data = iio_priv(idev); 1169 int ret; 1170 1171 switch (mask) { 1172 case IIO_CHAN_INFO_INT_TIME: 1173 *val = 0; 1174 *val2 = bu27034_get_int_time(data); 1175 if (*val2 < 0) 1176 return *val2; 1177 1178 return IIO_VAL_INT_PLUS_MICRO; 1179 1180 case IIO_CHAN_INFO_SCALE: 1181 return bu27034_get_scale(data, chan->channel, val, val2); 1182 1183 case IIO_CHAN_INFO_RAW: 1184 { 1185 int (*result_get)(struct bu27034_data *data, int chan, int *val); 1186 1187 if (chan->type == IIO_INTENSITY) 1188 result_get = bu27034_get_single_result; 1189 else if (chan->type == IIO_LIGHT) 1190 result_get = bu27034_get_mlux; 1191 else 1192 return -EINVAL; 1193 1194 /* Don't mess with measurement enabling while buffering */ 1195 ret = iio_device_claim_direct_mode(idev); 1196 if (ret) 1197 return ret; 1198 1199 mutex_lock(&data->mutex); 1200 /* 1201 * Reading one channel at a time is inefficient but we 1202 * don't care here. Buffered version should be used if 1203 * performance is an issue. 1204 */ 1205 ret = result_get(data, chan->channel, val); 1206 1207 mutex_unlock(&data->mutex); 1208 iio_device_release_direct_mode(idev); 1209 1210 if (ret) 1211 return ret; 1212 1213 return IIO_VAL_INT; 1214 } 1215 default: 1216 return -EINVAL; 1217 } 1218 } 1219 1220 static int bu27034_write_raw(struct iio_dev *idev, 1221 struct iio_chan_spec const *chan, 1222 int val, int val2, long mask) 1223 { 1224 struct bu27034_data *data = iio_priv(idev); 1225 int ret; 1226 1227 ret = iio_device_claim_direct_mode(idev); 1228 if (ret) 1229 return ret; 1230 1231 switch (mask) { 1232 case IIO_CHAN_INFO_SCALE: 1233 ret = bu27034_set_scale(data, chan->channel, val, val2); 1234 break; 1235 case IIO_CHAN_INFO_INT_TIME: 1236 if (!val) 1237 ret = bu27034_try_set_int_time(data, val2); 1238 else 1239 ret = -EINVAL; 1240 break; 1241 default: 1242 ret = -EINVAL; 1243 break; 1244 } 1245 1246 iio_device_release_direct_mode(idev); 1247 1248 return ret; 1249 } 1250 1251 static int bu27034_read_avail(struct iio_dev *idev, 1252 struct iio_chan_spec const *chan, const int **vals, 1253 int *type, int *length, long mask) 1254 { 1255 struct bu27034_data *data = iio_priv(idev); 1256 1257 switch (mask) { 1258 case IIO_CHAN_INFO_INT_TIME: 1259 return iio_gts_avail_times(&data->gts, vals, type, length); 1260 case IIO_CHAN_INFO_SCALE: 1261 return iio_gts_all_avail_scales(&data->gts, vals, type, length); 1262 default: 1263 return -EINVAL; 1264 } 1265 } 1266 1267 static const struct iio_info bu27034_info = { 1268 .read_raw = &bu27034_read_raw, 1269 .write_raw = &bu27034_write_raw, 1270 .read_avail = &bu27034_read_avail, 1271 }; 1272 1273 static int bu27034_chip_init(struct bu27034_data *data) 1274 { 1275 int ret, sel; 1276 1277 /* Reset */ 1278 ret = regmap_write_bits(data->regmap, BU27034_REG_SYSTEM_CONTROL, 1279 BU27034_MASK_SW_RESET, BU27034_MASK_SW_RESET); 1280 if (ret) 1281 return dev_err_probe(data->dev, ret, "Sensor reset failed\n"); 1282 1283 msleep(1); 1284 1285 ret = regmap_reinit_cache(data->regmap, &bu27034_regmap); 1286 if (ret) { 1287 dev_err(data->dev, "Failed to reinit reg cache\n"); 1288 return ret; 1289 } 1290 1291 /* 1292 * Read integration time here to ensure it is in regmap cache. We do 1293 * this to speed-up the int-time acquisition in the start of the buffer 1294 * handling thread where longer delays could make it more likely we end 1295 * up skipping a sample, and where the longer delays make timestamps 1296 * less accurate. 1297 */ 1298 ret = regmap_read(data->regmap, BU27034_REG_MODE_CONTROL1, &sel); 1299 if (ret) 1300 dev_err(data->dev, "reading integration time failed\n"); 1301 1302 return 0; 1303 } 1304 1305 static int bu27034_wait_for_data(struct bu27034_data *data) 1306 { 1307 int ret, val; 1308 1309 ret = regmap_read_poll_timeout(data->regmap, BU27034_REG_MODE_CONTROL4, 1310 val, val & BU27034_MASK_VALID, 1311 BU27034_DATA_WAIT_TIME_US, 1312 BU27034_TOTAL_DATA_WAIT_TIME_US); 1313 if (ret) { 1314 dev_err(data->dev, "data polling %s\n", 1315 !(val & BU27034_MASK_VALID) ? "timeout" : "fail"); 1316 1317 return ret; 1318 } 1319 1320 ret = regmap_bulk_read(data->regmap, BU27034_REG_DATA0_LO, 1321 &data->scan.channels[0], 1322 sizeof(data->scan.channels)); 1323 if (ret) 1324 return ret; 1325 1326 bu27034_invalidate_read_data(data); 1327 1328 return 0; 1329 } 1330 1331 static int bu27034_buffer_thread(void *arg) 1332 { 1333 struct iio_dev *idev = arg; 1334 struct bu27034_data *data; 1335 int wait_ms; 1336 1337 data = iio_priv(idev); 1338 1339 wait_ms = bu27034_get_int_time(data); 1340 wait_ms /= 1000; 1341 1342 wait_ms -= BU27034_MEAS_WAIT_PREMATURE_MS; 1343 1344 while (!kthread_should_stop()) { 1345 int ret; 1346 int64_t tstamp; 1347 1348 msleep(wait_ms); 1349 ret = bu27034_wait_for_data(data); 1350 if (ret) 1351 continue; 1352 1353 tstamp = iio_get_time_ns(idev); 1354 1355 if (test_bit(BU27034_CHAN_ALS, idev->active_scan_mask)) { 1356 int mlux; 1357 1358 ret = bu27034_calc_mlux(data, &data->scan.channels[0], 1359 &mlux); 1360 if (ret) 1361 dev_err(data->dev, "failed to calculate lux\n"); 1362 1363 /* 1364 * The maximum Milli lux value we get with gain 1x time 1365 * 55mS data ch0 = 0xffff ch1 = 0xffff fits in 26 bits 1366 * so there should be no problem returning int from 1367 * computations and casting it to u32 1368 */ 1369 data->scan.mlux = (u32)mlux; 1370 } 1371 iio_push_to_buffers_with_timestamp(idev, &data->scan, tstamp); 1372 } 1373 1374 return 0; 1375 } 1376 1377 static int bu27034_buffer_enable(struct iio_dev *idev) 1378 { 1379 struct bu27034_data *data = iio_priv(idev); 1380 struct task_struct *task; 1381 int ret; 1382 1383 mutex_lock(&data->mutex); 1384 ret = bu27034_meas_set(data, true); 1385 if (ret) 1386 goto unlock_out; 1387 1388 task = kthread_run(bu27034_buffer_thread, idev, 1389 "bu27034-buffering-%u", 1390 iio_device_id(idev)); 1391 if (IS_ERR(task)) { 1392 ret = PTR_ERR(task); 1393 goto unlock_out; 1394 } 1395 1396 data->task = task; 1397 1398 unlock_out: 1399 mutex_unlock(&data->mutex); 1400 1401 return ret; 1402 } 1403 1404 static int bu27034_buffer_disable(struct iio_dev *idev) 1405 { 1406 struct bu27034_data *data = iio_priv(idev); 1407 int ret; 1408 1409 mutex_lock(&data->mutex); 1410 if (data->task) { 1411 kthread_stop(data->task); 1412 data->task = NULL; 1413 } 1414 1415 ret = bu27034_meas_set(data, false); 1416 mutex_unlock(&data->mutex); 1417 1418 return ret; 1419 } 1420 1421 static const struct iio_buffer_setup_ops bu27034_buffer_ops = { 1422 .postenable = &bu27034_buffer_enable, 1423 .predisable = &bu27034_buffer_disable, 1424 }; 1425 1426 static int bu27034_probe(struct i2c_client *i2c) 1427 { 1428 struct device *dev = &i2c->dev; 1429 struct bu27034_data *data; 1430 struct regmap *regmap; 1431 struct iio_dev *idev; 1432 unsigned int part_id, reg; 1433 int ret; 1434 1435 regmap = devm_regmap_init_i2c(i2c, &bu27034_regmap); 1436 if (IS_ERR(regmap)) 1437 return dev_err_probe(dev, PTR_ERR(regmap), 1438 "Failed to initialize Regmap\n"); 1439 1440 idev = devm_iio_device_alloc(dev, sizeof(*data)); 1441 if (!idev) 1442 return -ENOMEM; 1443 1444 ret = devm_regulator_get_enable(dev, "vdd"); 1445 if (ret) 1446 return dev_err_probe(dev, ret, "Failed to get regulator\n"); 1447 1448 data = iio_priv(idev); 1449 1450 ret = regmap_read(regmap, BU27034_REG_SYSTEM_CONTROL, ®); 1451 if (ret) 1452 return dev_err_probe(dev, ret, "Failed to access sensor\n"); 1453 1454 part_id = FIELD_GET(BU27034_MASK_PART_ID, reg); 1455 1456 if (part_id != BU27034_ID) 1457 dev_warn(dev, "unknown device 0x%x\n", part_id); 1458 1459 ret = devm_iio_init_iio_gts(dev, BU27034_SCALE_1X, 0, bu27034_gains, 1460 ARRAY_SIZE(bu27034_gains), bu27034_itimes, 1461 ARRAY_SIZE(bu27034_itimes), &data->gts); 1462 if (ret) 1463 return ret; 1464 1465 mutex_init(&data->mutex); 1466 data->regmap = regmap; 1467 data->dev = dev; 1468 1469 idev->channels = bu27034_channels; 1470 idev->num_channels = ARRAY_SIZE(bu27034_channels); 1471 idev->name = "bu27034"; 1472 idev->info = &bu27034_info; 1473 1474 idev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE; 1475 idev->available_scan_masks = bu27034_scan_masks; 1476 1477 ret = bu27034_chip_init(data); 1478 if (ret) 1479 return ret; 1480 1481 ret = devm_iio_kfifo_buffer_setup(dev, idev, &bu27034_buffer_ops); 1482 if (ret) 1483 return dev_err_probe(dev, ret, "buffer setup failed\n"); 1484 1485 ret = devm_iio_device_register(dev, idev); 1486 if (ret < 0) 1487 return dev_err_probe(dev, ret, 1488 "Unable to register iio device\n"); 1489 1490 return ret; 1491 } 1492 1493 static const struct of_device_id bu27034_of_match[] = { 1494 { .compatible = "rohm,bu27034" }, 1495 { } 1496 }; 1497 MODULE_DEVICE_TABLE(of, bu27034_of_match); 1498 1499 static struct i2c_driver bu27034_i2c_driver = { 1500 .driver = { 1501 .name = "bu27034-als", 1502 .of_match_table = bu27034_of_match, 1503 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 1504 }, 1505 .probe = bu27034_probe, 1506 }; 1507 module_i2c_driver(bu27034_i2c_driver); 1508 1509 MODULE_LICENSE("GPL"); 1510 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>"); 1511 MODULE_DESCRIPTION("ROHM BU27034 ambient light sensor driver"); 1512 MODULE_IMPORT_NS(IIO_GTS_HELPER); 1513