tablet_mode: ensure that tablet mode is always initialized

The board init should ensure that tablet_mode is always set so the rest
of the subsystems can rely on this. We assume notebook mode if we don't
have any input from the GSR 360 hall sensor. That matches the default up
in AP firmware as well.

BRANCH=none
BUG=b:141494453,chromium:1010343
BUG=b:160981170
TEST=put arcada at 200 degrees and see that tablet mode it initialized
correctly.

Change-Id: I4e23d3ba149f9add84f9667a5af676803cf50da5
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1845779
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2294633
Tested-by: Marco Chen <marcochen@chromium.org>
Reviewed-by: Marco Chen <marcochen@chromium.org>
Commit-Queue: Marco Chen <marcochen@chromium.org>

1 files changed, 53 insertions, 34 deletions

diff --git a/common/tablet_mode.c b/common/tablet_mode.c
index ab954cff0a..7f5d28b50d 100644
--- a/common/tablet_mode.c
+++ b/common/tablet_mode.c
@@ -8,60 +8,73 @@
 #include "hooks.h"
 #include "host_command.h"
 #include "lid_angle.h"
+#include "stdbool.h"
 #include "tablet_mode.h"
 #include "timer.h"
 
 #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: notebook mode; -1: uninitialized  */
-static int tablet_mode = -1;
-static int forced_tablet_mode = -1;
+/*
+ * Other code modules assume that notebook mode (i.e. tablet_mode = false) at
+ * startup
+ */
+static bool tablet_mode;
+
+/*
+ * Console command can force the value of tablet_mode. If tablet_mode_force is
+ * true, the all external set call for tablet_mode are ignored.
+ */
+static bool tablet_mode_forced;
 
-static int disabled;
+/*
+ * True: all calls to tablet_set_mode are ignored and tablet_mode if forced to 0
+ * False: all calls to tablet_set_mode are honored
+ */
+static bool disabled;
 
 int tablet_get_mode(void)
 {
-	if (forced_tablet_mode != -1)
-		return !!forced_tablet_mode;
-	return !!tablet_mode;
+	return tablet_mode;
 }
 
-void tablet_set_mode(int mode)
+static void notify_tablet_mode_change(void)
 {
-	if (tablet_mode == mode)
-		return;
+	CPRINTS("tablet mode %sabled", tablet_mode ? "en" : "dis");
+	hook_notify(HOOK_TABLET_MODE_CHANGE);
 
-	if (disabled) {
-		CPRINTS("Tablet mode set while disabled (ignoring)!");
-		return;
-	}
+	/*
+	 * When tablet mode changes, send an event to ACPI to retrieve
+	 * tablet mode value and send an event to the kernel.
+	 */
+	if (IS_ENABLED(CONFIG_HOSTCMD_EVENTS))
+		host_set_single_event(EC_HOST_EVENT_MODE_CHANGE);
 
-	tablet_mode = mode;
+}
 
-	if (forced_tablet_mode != -1)
+void tablet_set_mode(int mode)
+{
+	/* If tablet_mode is forced via a console command, ignore set. */
+	if (tablet_mode_forced)
 		return;
 
-	CPRINTS("tablet mode %sabled", mode ? "en" : "dis");
-	hook_notify(HOOK_TABLET_MODE_CHANGE);
-}
+	if (tablet_mode == !!mode)
+		return;
 
-static void tabletmode_force_state(int mode)
-{
-	if (forced_tablet_mode == mode)
+	if (disabled) {
+		CPRINTS("Tablet mode set while disabled (ignoring)!");
 		return;
+	}
 
-	forced_tablet_mode = mode;
+	tablet_mode = !!mode;
 
 	hook_notify(HOOK_TABLET_MODE_CHANGE);
-	if (IS_ENABLED(CONFIG_HOSTCMD_EVENTS))
-		host_set_single_event(EC_HOST_EVENT_MODE_CHANGE);
 }
 
 void tablet_disable(void)
 {
-	tablet_mode = 0;
-	disabled = 1;
+	tablet_mode = false;
+	disabled = true;
 }
 
 /* This ifdef can be removed once we clean up past projects which do own init */
@@ -133,14 +146,20 @@ static int command_settabletmode(int argc, char **argv)
 {
 	if (argc != 2)
 		return EC_ERROR_PARAM_COUNT;
-	if (argv[1][0] == 'o' && argv[1][1] == 'n')
-		tabletmode_force_state(1);
-	else if (argv[1][0] == 'o' && argv[1][1] == 'f')
-		tabletmode_force_state(0);
-	else if (argv[1][0] == 'r')
-		tabletmode_force_state(-1);
-	else
+
+	if (argv[1][0] == 'o' && argv[1][1] == 'n') {
+		tablet_mode = true;
+		tablet_mode_forced = true;
+	} else if (argv[1][0] == 'o' && argv[1][1] == 'f') {
+		tablet_mode = false;
+		tablet_mode_forced = true;
+	} else if (argv[1][0] == 'r') {
+		tablet_mode_forced = false;
+	} else {
 		return EC_ERROR_PARAM1;
+	}
+
+	notify_tablet_mode_change();
 	return EC_SUCCESS;
 }
 DECLARE_CONSOLE_COMMAND(tabletmode, command_settabletmode,