accel: Add host cmd for setting lid angle threshold for disabling keyboard wake

Added a sub-command to the motionsense host command (0x2b) for getting/setting
the lid angle at which the keyboard is disabled as a wake source in S3. The
value can be anywhere from 0 to 360 degrees, default set to 180. Note, this
only takes affect for boards that have CONFIG_LID_ANGLE_KEY_SCAN defined.
Modified ectool motionsense command to use new host sub-command.

Also modified the lid angle measurement in the EC to be in the range [0, 360],
instead of [-180, 180], and changed casting of lid angle as an int to round
to nearest.

BUG=none
BRANCH=rambi
TEST=Tested on a glimmer:
Using default keyboard disable lid angle of 180, made sure that when lid
angle is past 180, key presses do not wake system, and when lid angle is
less than 180, key presses do wake up system.

Used ectool motionsense kb_wake to set the keyboard disable lid angle to 0.
Made sure that keyboard never wakes up the system. Set keyboard disable lid
angle to 360 and made sure that the keyboard always wakes up the system.

Change-Id: I437164c6e38c29169ef6e20e86c9cf2a1c78f86e
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/193663
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/194172

1 files changed, 90 insertions, 2 deletions

diff --git a/common/lid_angle.c b/common/lid_angle.c
index e7a3139ebb..02f72f1991 100644
--- a/common/lid_angle.c
+++ b/common/lid_angle.c
@@ -25,6 +25,94 @@
  */
 #define KEY_SCAN_LID_ANGLE_BUFFER_SIZE 4
 
+/*
+ * Define two variables to determine if keyboard scanning should be enabled
+ * or disabled in S3 based on the current lid angle. Note, the lid angle is
+ * bound to [0, 360]. Here are two angles, defined such that we segregate the
+ * lid angle space into two regions. The first region is the region in which
+ * we enable keyboard scanning in S3 and is when the lid angle CCW of the
+ * small_angle and CW of the large_angle. The second region is the region in
+ * which we disable keyboard scanning in S3 and is when the lid angle is CCW
+ * of the large_angle and CW of the small_angle.
+ *
+ * Note, the most sensical values are small_angle = 0 and large_angle = 180,
+ * but, the angle measurement is not perfect, and we know that if the angle is
+ * near 0 and the lid isn't closed, then the lid must be near 360. So, the
+ * small_angle is set to a small positive value to make sure we don't swap modes
+ * when the lid is open all the way but is measuring a small positive value.
+ */
+static int kb_wake_large_angle = 180;
+static const int kb_wake_small_angle = 13;
+
+/* Define hysteresis value to add stability to the keyboard scanning flag. */
+#define KB_DIS_HYSTERESIS_DEG  2
+
+/* Define max and min values for kb_wake_large_angle. */
+#define KB_DIS_MIN_LARGE_ANGLE 0
+#define KB_DIS_MAX_LARGE_ANGLE 360
+
+/**
+ * Determine if given angle is in region to accept keyboard presses.
+ *
+ * @param ang Some lid angle in degrees [0, 360]
+ *
+ * @return true/false
+ */
+static int lid_in_range_to_accept_keys(float ang)
+{
+	/*
+	 * If the keyboard wake large angle is min or max, then this
+	 * function should return false or true respectively, independent of
+	 * input angle.
+	 */
+	if (kb_wake_large_angle == KB_DIS_MIN_LARGE_ANGLE)
+		return 0;
+	else if (kb_wake_large_angle == KB_DIS_MAX_LARGE_ANGLE)
+		return 1;
+
+	return  (ang >= (kb_wake_small_angle + KB_DIS_HYSTERESIS_DEG)) &&
+		(ang <= (kb_wake_large_angle - KB_DIS_HYSTERESIS_DEG));
+}
+
+/**
+ * Determine if given angle is in region to ignore keyboard presses.
+ *
+ * @param ang Some lid angle in degrees [0, 360]
+ *
+ * @return true/false
+ */
+static int lid_in_range_to_ignore_keys(float ang)
+{
+	/*
+	 * If the keyboard wake large angle is min or max, then this
+	 * function should return true or false respectively, independent of
+	 * input angle.
+	 */
+	if (kb_wake_large_angle == KB_DIS_MIN_LARGE_ANGLE)
+		return 1;
+	else if (kb_wake_large_angle == KB_DIS_MAX_LARGE_ANGLE)
+		return 0;
+
+	return  (ang <= (kb_wake_small_angle - KB_DIS_HYSTERESIS_DEG)) ||
+		(ang >= (kb_wake_large_angle + KB_DIS_HYSTERESIS_DEG));
+}
+
+
+int lid_angle_get_kb_wake_angle(void)
+{
+	return kb_wake_large_angle;
+}
+
+void lid_angle_set_kb_wake_angle(int ang)
+{
+	if (ang < KB_DIS_MIN_LARGE_ANGLE)
+		ang = KB_DIS_MIN_LARGE_ANGLE;
+	else if (ang > KB_DIS_MAX_LARGE_ANGLE)
+		ang = KB_DIS_MAX_LARGE_ANGLE;
+
+	kb_wake_large_angle = ang;
+}
+
 void lidangle_keyscan_update(float lid_ang)
 {
 	static float lidangle_buffer[KEY_SCAN_LID_ANGLE_BUFFER_SIZE];
@@ -60,9 +148,9 @@ void lidangle_keyscan_update(float lid_ang)
 			 * in range of one of the conditions in order to change
 			 * to the corresponding key scanning state.
 			 */
-			if (!LID_IN_RANGE_TO_ACCEPT_KEYS(lidangle_buffer[i]))
+			if (!lid_in_range_to_accept_keys(lidangle_buffer[i]))
 				keys_accept = 0;
-			if (!LID_IN_RANGE_TO_IGNORE_KEYS(lidangle_buffer[i]))
+			if (!lid_in_range_to_ignore_keys(lidangle_buffer[i]))
 				keys_ignore = 0;
 		}