dooly: update ALS lux equation

The previous equation in CL:2771482,
would cause lux = 0 on some ALS board in specific ambient light
, we worked with vendor and update the lux equation:
Lux = LuxScalar * (DGFn * ((C * Ccoefn) + (R * Rcoefn) +
(G * Gcoefn) + (B * Bcoefn)) / (Atime*Again))

Lux = MAX(0, Lux)

If (G+B)/C < 0.692 n=1
If (G+B)/C >= 0.692 and < 1.012 n=2
else n=3

LuxScalar = 1.00
Coeffs  n=1(Lo)  n=2(Med)    n=3(Hi)
Ccoef   0.009    0.202         -0.661
Rcoef   0.056    - 1.1         1.334
GCoef   2.735    8.692         1.095
BCoef   -1.903   -7.068        -1.821
DGF     799.797  801.347        795.574

BUG=b:184238881
BRANCH=puff
TEST=verify equation works as intended.

Signed-off-by: Zick Wei <zick.wei@quanta.corp-partner.google.com>
Change-Id: Ic9e41579c37544496f54a4faeb1a0d0aeea8f7c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2822388
Reviewed-by: Andrew McRae <amcrae@chromium.org>
Commit-Queue: Andrew McRae <amcrae@chromium.org>

1 files changed, 29 insertions, 39 deletions

diff --git a/board/dooly/board.c b/board/dooly/board.c
index 0cbf2938c0..241fa67a2a 100644
--- a/board/dooly/board.c
+++ b/board/dooly/board.c
@@ -187,65 +187,55 @@ DECLARE_DEFERRED(power_monitor);
 __override void tcs3400_translate_to_xyz(struct motion_sensor_t *s,
 				     int32_t *crgb_data, int32_t *xyz_data)
 {
-	int n, cur_gain, dgf;
+	int n, cur_gain;
 	fp_t n_interval;
-	fp_t integration_time_us;
+	int integration_time_us;
 	struct tcs_saturation_t *sat_p =
 				&(TCS3400_RGB_DRV_DATA(s+1)->saturation);
 
 	cur_gain = (1 << (2 * sat_p->again));
 
 	integration_time_us =
-		(tcs3400_get_integration_time(sat_p->atime));
+		tcs3400_get_integration_time(sat_p->atime);
 
 	/* n_interval = (G+B)/C, to use different coefficient*/
-	n_interval = INT_TO_FP(crgb_data[2]+crgb_data[3])/crgb_data[0];
-
-	dgf = 993; /* Device and Glass Factor */
+	if (crgb_data[0] != 0)
+		n_interval = INT_TO_FP(crgb_data[2]+crgb_data[3])/crgb_data[0];
+	else
+		n_interval = FLOAT_TO_FP(0.692); /* set default n = 2 */
 
-	if (n_interval < FLOAT_TO_FP(0.514))
+	if (n_interval < FLOAT_TO_FP(0.692))
 		n = 1;
-	else if (n_interval >= FLOAT_TO_FP(0.514) &&
-			 n_interval < FLOAT_TO_FP(0.66))
+	else if (n_interval >= FLOAT_TO_FP(0.692) &&
+			n_interval < FLOAT_TO_FP(1.012))
 		n = 2;
-	else if (n_interval >= FLOAT_TO_FP(0.66) &&
-			 n_interval < FLOAT_TO_FP(1.012))
-		n = 3;
 	else
-		n = 4;
+		n = 3;
 
 	switch (n) {
 	case 1:
-		xyz_data[1] = (fp_inter_t)(FP_TO_INT(dgf *
-		(crgb_data[0]*(fp_inter_t)FLOAT_TO_FP(3.8) +
-		 crgb_data[1]*(fp_inter_t)FLOAT_TO_FP(3.956) +
-		 crgb_data[2]*(fp_inter_t)FLOAT_TO_FP(-20.915) +
-		 crgb_data[3]*(fp_inter_t)FLOAT_TO_FP(3.281))))*1000 /
-		 (integration_time_us*cur_gain);
+		xyz_data[1] = FP_TO_INT(fp_mul(FLOAT_TO_FP(799.797),
+		(fp_mul(INT_TO_FP(crgb_data[0]), FLOAT_TO_FP(0.009)) +
+		fp_mul(INT_TO_FP(crgb_data[1]), FLOAT_TO_FP(0.056)) +
+		fp_mul(INT_TO_FP(crgb_data[2]), FLOAT_TO_FP(2.735)) +
+		fp_mul(INT_TO_FP(crgb_data[3]), FLOAT_TO_FP(-1.903))) /
+		(integration_time_us * cur_gain / 1000ULL)));
 	break;
 	case 2:
-		xyz_data[1] = (fp_inter_t)(FP_TO_INT(dgf *
-		(crgb_data[0]*(fp_inter_t)FLOAT_TO_FP(-17.436) +
-		 crgb_data[1]*(fp_inter_t)FLOAT_TO_FP(14.535) +
-		 crgb_data[2]*(fp_inter_t)FLOAT_TO_FP(32.07) +
-		 crgb_data[3]*(fp_inter_t)FLOAT_TO_FP(2.43))))*1000 /
-		 (integration_time_us*cur_gain);
+		xyz_data[1] = FP_TO_INT(fp_mul(FLOAT_TO_FP(801.347),
+		(fp_mul(INT_TO_FP(crgb_data[0]), FLOAT_TO_FP(0.202)) +
+		fp_mul(INT_TO_FP(crgb_data[1]), FLOAT_TO_FP(-1.1)) +
+		fp_mul(INT_TO_FP(crgb_data[2]), FLOAT_TO_FP(8.692)) +
+		fp_mul(INT_TO_FP(crgb_data[3]), FLOAT_TO_FP(-7.068))) /
+		(integration_time_us * cur_gain / 1000ULL)));
 	break;
 	case 3:
-		xyz_data[1] = (fp_inter_t)(FP_TO_INT(dgf *
-		(crgb_data[0]*(fp_inter_t)FLOAT_TO_FP(0.08) +
-		 crgb_data[1]*(fp_inter_t)FLOAT_TO_FP(-0.89) +
-		 crgb_data[2]*(fp_inter_t)FLOAT_TO_FP(7.096) +
-		 crgb_data[3]*(fp_inter_t)FLOAT_TO_FP(-5.603))))*1000 /
-		 (integration_time_us*cur_gain);
-	break;
-	case 4:
-		xyz_data[1] = (fp_inter_t)(FP_TO_INT(dgf *
-		(crgb_data[0]*(fp_inter_t)FLOAT_TO_FP(-0.686) +
-		 crgb_data[1]*(fp_inter_t)FLOAT_TO_FP(1.224) +
-		 crgb_data[2]*(fp_inter_t)FLOAT_TO_FP(4.043) +
-		 crgb_data[3]*(fp_inter_t)FLOAT_TO_FP(-4.584))))*1000 /
-		 (integration_time_us*cur_gain);
+		xyz_data[1] = FP_TO_INT(fp_mul(FLOAT_TO_FP(795.574),
+		(fp_mul(INT_TO_FP(crgb_data[0]), FLOAT_TO_FP(-0.661)) +
+		fp_mul(INT_TO_FP(crgb_data[1]), FLOAT_TO_FP(1.334)) +
+		fp_mul(INT_TO_FP(crgb_data[2]), FLOAT_TO_FP(1.095)) +
+		fp_mul(INT_TO_FP(crgb_data[3]), FLOAT_TO_FP(-1.821))) /
+		(integration_time_us * cur_gain / 1000ULL)));
 	break;
 	default:
 	break;