Convert motion sense calculations to fixed point.

Motion sense calculations do not require huge amounts of precision, so
fixed point is plenty accurate.  And fixed point works on Cortex-M0,
which lacks a FPU.

BUG=chrome-os-partner:36126
BRANCH=minnie (samus already works with the FPU, but could grab this if we
       want additional testing)
TEST=manual
    1. Boot system
    2. At EC console: accelinfo on 250
    3. Move lid through several different angles (30 degrees to max open) and
       see that it updates correctly and relatively smoothly.  A few degrees
       of angle jitter is normal.
    4. At several angles, rotate the chromebook around and see that the lid
       angle remains relatively stable.
    5. If the hinge is made normal to the ground (or within 15 degrees of
       vertical), the angle should read 500, since the acceleration vectors
       don't yield good results in that orientation (for either fixed or float
       math).
    And run 'make buildall -j', which tests arc_cos() and lid angle calculations

Change-Id: I70a0d08b8914629a3e21ae5578cbe8e50f29ad68
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/244116
Reviewed-by: Alec Berg <alecaberg@chromium.org>

1 files changed, 12 insertions, 12 deletions

diff --git a/board/samus/board.c b/board/samus/board.c
index 704b3102b8..9dfcd1a8b4 100644
--- a/board/samus/board.c
+++ b/board/samus/board.c
@@ -249,15 +249,15 @@ struct kxcj9_data g_kxcj9_data;
 /* Four Motion sensors */
 /* Matrix to rotate accelrator into standard reference frame */
 const matrix_3x3_t base_standard_ref = {
-	{-1,  0,  0},
-	{ 0, -1,  0},
-	{ 0,  0, -1}
+	{FLOAT_TO_FP(-1),  0,  0},
+	{ 0, FLOAT_TO_FP(-1),  0},
+	{ 0,  0, FLOAT_TO_FP(-1)}
 };
 
 const matrix_3x3_t lid_standard_ref = {
-	{ 0,  1,  0},
-	{-1,  0,  0},
-	{ 0,  0, -1}
+	{ 0,  FLOAT_TO_FP(1),  0},
+	{FLOAT_TO_FP(-1),  0,  0},
+	{ 0,  0, FLOAT_TO_FP(-1)}
 };
 
 struct motion_sensor_t motion_sensors[] = {
@@ -289,14 +289,14 @@ const unsigned int motion_sensor_count = ARRAY_SIZE(motion_sensors);
 const struct accel_orientation acc_orient = {
 	/* Hinge aligns with y axis. */
 	.rot_hinge_90 = {
-		{ 1,  0,  0},
-		{ 0,  1,  0},
-		{ 0,  0,  1}
+		{ FLOAT_TO_FP(1),  0,  0},
+		{ 0,  FLOAT_TO_FP(1),  0},
+		{ 0,  0,  FLOAT_TO_FP(1)}
 	},
 	.rot_hinge_180 = {
-		{ 1,  0,  0},
-		{ 0,  1,  0},
-		{ 0,  0,  1}
+		{ FLOAT_TO_FP(1),  0,  0},
+		{ 0,  FLOAT_TO_FP(1),  0},
+		{ 0,  0,  FLOAT_TO_FP(1)}
 	},
 	.hinge_axis = {0, 1, 0},
 };