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;
 		}