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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
bu27034: ROHM BU27034ANUC correct lux calculation
The ROHM BU27034NUC was cancelled and BU27034ANUC is replacing this
sensor. The lux computation based on the data from a BU27034ANUC is
different from the computation for the data from an old BU27034NUC.
Fix the lux computation.
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://patch.msgid.link/b7bea76b54b28eb354dc523771a0e0a8b6f26095.1720176341.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
authored by
Matti Vaittinen
and committed by
Jonathan Cameron
eb13959e
bb105981
+31
-126
+31
-126
drivers/iio/light/rohm-bu27034.c
+31
-126
drivers/iio/light/rohm-bu27034.c
···
573
573
}
574
574
575
575
/*
576
-
* for (D1/D0 < 0.87):
577
-
* lx = 0.004521097 * D1 - 0.002663996 * D0 +
578
-
* 0.00012213 * D1 * D1 / D0
576
+
* for (D1/D0 < 1.5):
577
+
* lx = (0.001193 * D0 + (-0.0000747) * D1) * ((D1/D0 – 1.5) * (0.25) + 1)
579
578
*
580
-
* => 115.7400832 * ch1 / gain1 / mt -
581
-
* 68.1982976 * ch0 / gain0 / mt +
582
-
* 0.00012213 * 25600 * (ch1 / gain1 / mt) * 25600 *
583
-
* (ch1 /gain1 / mt) / (25600 * ch0 / gain0 / mt)
579
+
* => -0.000745625 * D0 + 0.0002515625 * D1 + -0.000018675 * D1 * D1 / D0
584
580
*
585
-
* A = 0.00012213 * 25600 * (ch1 /gain1 / mt) * 25600 *
586
-
* (ch1 /gain1 / mt) / (25600 * ch0 / gain0 / mt)
587
-
* => 0.00012213 * 25600 * (ch1 /gain1 / mt) *
588
-
* (ch1 /gain1 / mt) / (ch0 / gain0 / mt)
589
-
* => 0.00012213 * 25600 * (ch1 / gain1) * (ch1 /gain1 / mt) /
590
-
* (ch0 / gain0)
591
-
* => 0.00012213 * 25600 * (ch1 / gain1) * (ch1 /gain1 / mt) *
592
-
* gain0 / ch0
593
-
* => 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / mt /ch0
581
+
* => (6.44 * ch1 / gain1 + 19.088 * ch0 / gain0 -
582
+
* 0.47808 * ch1 * ch1 * gain0 / gain1 / gain1 / ch0) /
583
+
* mt
594
584
*
595
-
* lx = (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0) /
596
-
* mt + A
597
-
* => (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0) /
598
-
* mt + 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / mt /
599
-
* ch0
585
+
* Else
586
+
* lx = 0.001193 * D0 - 0.0000747 * D1
600
587
*
601
-
* => (115.7400832 * ch1 / gain1 - 68.1982976 * ch0 / gain0 +
602
-
* 3.126528 * ch1 * ch1 * gain0 / gain1 / gain1 / ch0) /
603
-
* mt
604
-
*
605
-
* For (0.87 <= D1/D0 < 1.00)
606
-
* lx = (0.001331* D0 + 0.0000354 * D1) * ((D1/D0 – 0.87) * (0.385) + 1)
607
-
* => (0.001331 * 256 * 100 * ch0 / gain0 / mt + 0.0000354 * 256 *
608
-
* 100 * ch1 / gain1 / mt) * ((D1/D0 - 0.87) * (0.385) + 1)
609
-
* => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
610
-
* ((D1/D0 - 0.87) * (0.385) + 1)
611
-
* => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
612
-
* (0.385 * D1/D0 - 0.66505)
613
-
* => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
614
-
* (0.385 * 256 * 100 * ch1 / gain1 / mt / (256 * 100 * ch0 / gain0 / mt) - 0.66505)
615
-
* => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
616
-
* (9856 * ch1 / gain1 / mt / (25600 * ch0 / gain0 / mt) + 0.66505)
617
-
* => 13.118336 * ch1 / (gain1 * mt)
618
-
* + 22.66064768 * ch0 / (gain0 * mt)
619
-
* + 8931.90144 * ch1 * ch1 * gain0 /
620
-
* (25600 * ch0 * gain1 * gain1 * mt)
621
-
* + 0.602694912 * ch1 / (gain1 * mt)
622
-
*
623
-
* => [0.3489024 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1)
624
-
* + 22.66064768 * ch0 / gain0
625
-
* + 13.721030912 * ch1 / gain1
626
-
* ] / mt
627
-
*
628
-
* For (D1/D0 >= 1.00)
629
-
*
630
-
* lx = (0.001331* D0 + 0.0000354 * D1) * ((D1/D0 – 2.0) * (-0.05) + 1)
631
-
* => (0.001331* D0 + 0.0000354 * D1) * (-0.05D1/D0 + 1.1)
632
-
* => (0.001331 * 256 * 100 * ch0 / gain0 / mt + 0.0000354 * 256 *
633
-
* 100 * ch1 / gain1 / mt) * (-0.05D1/D0 + 1.1)
634
-
* => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
635
-
* (-0.05 * 256 * 100 * ch1 / gain1 / mt / (256 * 100 * ch0 / gain0 / mt) + 1.1)
636
-
* => (34.0736 * ch0 / gain0 / mt + 0.90624 * ch1 / gain1 / mt) *
637
-
* (-1280 * ch1 / (gain1 * mt * 25600 * ch0 / gain0 / mt) + 1.1)
638
-
* => (34.0736 * ch0 * -1280 * ch1 * gain0 * mt /( gain0 * mt * gain1 * mt * 25600 * ch0)
639
-
* + 34.0736 * 1.1 * ch0 / (gain0 * mt)
640
-
* + 0.90624 * ch1 * -1280 * ch1 *gain0 * mt / (gain1 * mt *gain1 * mt * 25600 * ch0)
641
-
* + 1.1 * 0.90624 * ch1 / (gain1 * mt)
642
-
* => -43614.208 * ch1 / (gain1 * mt * 25600)
643
-
* + 37.48096 ch0 / (gain0 * mt)
644
-
* - 1159.9872 * ch1 * ch1 * gain0 / (gain1 * gain1 * mt * 25600 * ch0)
645
-
* + 0.996864 ch1 / (gain1 * mt)
646
-
* => [
647
-
* - 0.045312 * ch1 * ch1 * gain0 / (gain1 * gain1 * ch0)
648
-
* - 0.706816 * ch1 / gain1
649
-
* + 37.48096 ch0 /gain0
650
-
* ] * mt
651
-
*
652
-
*
653
-
* So, the first case (D1/D0 < 0.87) can be computed to a form:
654
-
*
655
-
* lx = (3.126528 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) +
656
-
* 115.7400832 * ch1 / gain1 +
657
-
* -68.1982976 * ch0 / gain0
658
-
* / mt
659
-
*
660
-
* Second case (0.87 <= D1/D0 < 1.00) goes to form:
661
-
*
662
-
* => [0.3489024 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) +
663
-
* 13.721030912 * ch1 / gain1 +
664
-
* 22.66064768 * ch0 / gain0
665
-
* ] / mt
666
-
*
667
-
* Third case (D1/D0 >= 1.00) goes to form:
668
-
* => [-0.045312 * ch1 * ch1 * gain0 / (ch0 * gain1 * gain1) +
669
-
* -0.706816 * ch1 / gain1 +
670
-
* 37.48096 ch0 /(gain0
671
-
* ] / mt
588
+
* => (1.91232 * ch1 / gain1 + 30.5408 * ch0 / gain0 +
589
+
* [0 * ch1 * ch1 * gain0 / gain1 / gain1 / ch0] ) /
590
+
* mt
672
591
*
673
592
* This can be unified to format:
674
593
* lx = [
···
597
678
* ] / mt
598
679
*
599
680
* For case 1:
600
-
* A = 3.126528,
601
-
* B = 115.7400832
602
-
* C = -68.1982976
681
+
* A = -0.47808,
682
+
* B = 6.44,
683
+
* C = 19.088
603
684
*
604
685
* For case 2:
605
-
* A = 0.3489024
606
-
* B = 13.721030912
607
-
* C = 22.66064768
608
-
*
609
-
* For case 3:
610
-
* A = -0.045312
611
-
* B = -0.706816
612
-
* C = 37.48096
686
+
* A = 0
687
+
* B = 1.91232
688
+
* C = 30.5408
613
689
*/
614
690
615
691
struct bu27034_lx_coeff {
···
709
795
{
710
796
static const struct bu27034_lx_coeff coeff[] = {
711
797
{
712
-
.A = 31265280, /* 3.126528 */
713
-
.B = 1157400832, /*115.7400832 */
714
-
.C = 681982976, /* -68.1982976 */
715
-
.is_neg = {false, false, true},
798
+
.A = 4780800, /* -0.47808 */
799
+
.B = 64400000, /* 6.44 */
800
+
.C = 190880000, /* 19.088 */
801
+
.is_neg = { true, false, false },
716
802
}, {
717
-
.A = 3489024, /* 0.3489024 */
718
-
.B = 137210309, /* 13.721030912 */
719
-
.C = 226606476, /* 22.66064768 */
803
+
.A = 0, /* 0 */
804
+
.B = 19123200, /* 1.91232 */
805
+
.C = 305408000, /* 30.5408 */
720
806
/* All terms positive */
721
-
}, {
722
-
.A = 453120, /* -0.045312 */
723
-
.B = 7068160, /* -0.706816 */
724
-
.C = 374809600, /* 37.48096 */
725
-
.is_neg = {true, true, false},
726
-
}
807
+
},
727
808
};
728
809
const struct bu27034_lx_coeff *c = &coeff[coeff_idx];
729
810
u64 res = 0, terms[3];
···
881
972
* D1 = data1/ch1_gain/meas_time_ms * 25600
882
973
*
883
974
* Then:
884
-
* if (D1/D0 < 0.87)
885
-
* lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 0.87) * 3.45 + 1)
886
-
* else if (D1/D0 < 1)
887
-
* lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 0.87) * 0.385 + 1)
888
-
* else
889
-
* lx = (0.001331 * D0 + 0.0000354 * D1) * ((D1 / D0 - 2) * -0.05 + 1)
975
+
* If (D1/D0 < 1.5)
976
+
* lx = (0.001193 * D0 + (-0.0000747) * D1) * ((D1 / D0 – 1.5) * 0.25 + 1)
977
+
* Else
978
+
* lx = (0.001193 * D0 + (-0.0000747) * D1)
890
979
*
891
980
* We use it here. Users who have for example some colored lens
892
981
* need to modify the calculation but I hope this gives a starting point for
···
935
1028
d1_d0_ratio_scaled /= ch0 * gain1;
936
1029
}
937
1030
938
-
if (d1_d0_ratio_scaled < 87)
1031
+
if (d1_d0_ratio_scaled < 150)
939
1032
ret = bu27034_fixp_calc_lx(ch0, ch1, gain0, gain1, meastime, 0);
940
-
else if (d1_d0_ratio_scaled < 100)
941
-
ret = bu27034_fixp_calc_lx(ch0, ch1, gain0, gain1, meastime, 1);
942
1033
else
943
-
ret = bu27034_fixp_calc_lx(ch0, ch1, gain0, gain1, meastime, 2);
1034
+
ret = bu27034_fixp_calc_lx(ch0, ch1, gain0, gain1, meastime, 1);
944
1035
945
1036
if (ret < 0)
946
1037
return ret;