tabletmode: ignore lid angle if hall sensor active

If the 360 degree hall sensor is active, then we should remain in tablet
mode even if the lid angle says we are 1 degree since an angle of 360
could wrap around to 1 degree.

Also ensure that tablet mode always gets initialized to the correct state
at startup (by setting initial value to -1)

BRANCH=R75
BUG=b:131785573,b:132178305
TEST=NB_MODE# on arcada does not flutter when the device is at 360
degrees with CL stack.

Change-Id: I962a9c23205766080a65d741c6c425452d9de608
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1597189
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1625785

3 files changed, 42 insertions, 15 deletions

diff --git a/common/tablet_mode.c b/common/tablet_mode.c
index da2de38ad3..652756b665 100644
--- a/common/tablet_mode.c
+++ b/common/tablet_mode.c
@@ -14,14 +14,21 @@
 #define CPRINTS(format, args...) cprints(CC_MOTION_LID, format, ## args)
 #define CPRINTF(format, args...) cprintf(CC_MOTION_LID, format, ## args)
 
-/* 1: in tablet mode. 0: otherwise */
-static int tablet_mode = 1;
+/* 1: in tablet mode; 0: notebook mode; -1: uninitialized  */
+static int tablet_mode = -1;
 
+/* 1: hall sensor is reporting 360 degrees. */
+static int hall_sensor_at_360;
+
+/*
+ * 1: all calls to tablet_set_mode are ignored and tablet_mode if forced to 0
+ * 0: all calls to tablet_set_mode are honored
+ */
 static int disabled;
 
 int tablet_get_mode(void)
 {
-	return tablet_mode;
+	return !!tablet_mode;
 }
 
 void tablet_set_mode(int mode)
@@ -34,15 +41,20 @@ void tablet_set_mode(int mode)
 		return;
 	}
 
+	if (hall_sensor_at_360 && !mode) {
+		CPRINTS("Ignoring tablet mode exit while hall sensor active.");
+		return;
+	}
+
 	tablet_mode = mode;
 	CPRINTS("tablet mode %sabled", mode ? "en" : "dis");
 	hook_notify(HOOK_TABLET_MODE_CHANGE);
 
+#ifdef CONFIG_HOSTCMD_EVENTS
 	/*
 	 * When tablet mode changes, send an event to ACPI to retrieve
 	 * tablet mode value and send an event to the kernel.
 	 */
-#ifdef CONFIG_HOSTCMD_EVENTS
 	host_set_single_event(EC_HOST_EVENT_MODE_CHANGE);
 #endif
 }
@@ -54,7 +66,9 @@ void tablet_set_mode(int mode)
 #endif
 static void hall_sensor_interrupt_debounce(void)
 {
-	int flipped_360_mode = !gpio_get_level(HALL_SENSOR_GPIO_L);
+	hall_sensor_at_360 = IS_ENABLED(CONFIG_HALL_SENSOR_CUSTOM)
+				     ? board_sensor_at_360()
+				     : !gpio_get_level(HALL_SENSOR_GPIO_L);
 
 	/*
 	 * 1. Peripherals are disabled only when lid reaches 360 position (It's
@@ -69,15 +83,11 @@ static void hall_sensor_interrupt_debounce(void)
 	 * driver to clear it when lid goes into laptop zone.
 	 */
 
-#ifdef CONFIG_LID_ANGLE
-	if (flipped_360_mode)
-#endif /* CONFIG_LID_ANGLE */
-		tablet_set_mode(flipped_360_mode);
+	if (!IS_ENABLED(CONFIG_LID_ANGLE) || hall_sensor_at_360)
+		tablet_set_mode(hall_sensor_at_360);
 
-#ifdef CONFIG_LID_ANGLE_UPDATE
-	if (flipped_360_mode)
+	if (IS_ENABLED(CONFIG_LID_ANGLE_UPDATE) && hall_sensor_at_360)
 		lid_angle_peripheral_enable(0);
-#endif /* CONFIG_LID_ANGLE_UPDATE */
 }
 DECLARE_DEFERRED(hall_sensor_interrupt_debounce);
 
@@ -87,7 +97,7 @@ DECLARE_DEFERRED(hall_sensor_interrupt_debounce);
 void hall_sensor_isr(enum gpio_signal signal)
 {
 	hook_call_deferred(&hall_sensor_interrupt_debounce_data,
-				HALL_SENSOR_DEBOUNCE_US);
+			   HALL_SENSOR_DEBOUNCE_US);
 }
 
 static void hall_sensor_init(void)
@@ -97,8 +107,10 @@ static void hall_sensor_init(void)
 		return;
 
 	gpio_enable_interrupt(HALL_SENSOR_GPIO_L);
-	/* Ensure tablet mode is initialized according to the hardware state
-	 * so that the cached state reflects reality. */
+	/*
+	 * Ensure tablet mode is initialized according to the hardware state
+	 * so that the cached state reflects reality.
+	 */
 	hall_sensor_interrupt_debounce();
 }
 DECLARE_HOOK(HOOK_INIT, hall_sensor_init, HOOK_PRIO_DEFAULT);
diff --git a/include/config.h b/include/config.h
index e6d5f9fb82..e010636952 100644
--- a/include/config.h
+++ b/include/config.h
@@ -3067,6 +3067,12 @@
 #undef CONFIG_HALL_SENSOR
 
 /*
+ * Board provides board_sensor_at_360 method instead of HALL_SENSOR_GPIO_L as
+ * the means for determining the state of the 360 hall sensor.
+ */
+#undef CONFIG_HALL_SENSOR_CUSTOM
+
+/*
  * Add a virtual switch to indicate when detachable device has
  * base attached.
  */
diff --git a/include/tablet_mode.h b/include/tablet_mode.h
index 5edfb52f20..e4444aca1b 100644
--- a/include/tablet_mode.h
+++ b/include/tablet_mode.h
@@ -28,4 +28,13 @@ void hall_sensor_isr(enum gpio_signal signal);
  */
 void hall_sensor_disable(void);
 
+/*
+ * This must be defined when CONFIG_HALL_SENSOR_CUSTOM is defined. This allows
+ * a board to override the default behavior that determines if the 360 sensor is
+ * active: !gpio_get_level(HALL_SENSOR_GPIO_L).
+ *
+ * Returns 1 if the 360 sensor is active; otherwise 0.
+ */
+int board_sensor_at_360(void);
+
 #endif