tablet_mode: Define common interrupt handler for tablet switch

This patch adds an interrupt handler for a tablet switch and an init
hook to enable the interrupt.

The handler does the typical tasks for convertible devices: 1. sets
tablet mode then 2. disables peripherals if tablet mode is on.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>

BUG=b:77298177
BRANCH=none
TEST=buildall. Verify on Nami.

Change-Id: If7fb5ea15f388d2b6084d800d2bc05efafd1945e
Reviewed-on: https://chromium-review.googlesource.com/1043057
Commit-Ready: Daisuke Nojiri <dnojiri@chromium.org>
Tested-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

1 files changed, 51 insertions, 5 deletions

diff --git a/common/tablet_mode.c b/common/tablet_mode.c
index 4a9a0b2364..d73140c4bf 100644
--- a/common/tablet_mode.c
+++ b/common/tablet_mode.c
@@ -3,9 +3,17 @@
  * found in the LICENSE file.
  */
 
+#include "console.h"
+#include "gpio.h"
 #include "hooks.h"
+#include "lid_angle.h"
+#include "tablet_mode.h"
+#include "timer.h"
 
-/* Return 1 if in tablet mode, 0 otherwise */
+#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;
 
 int tablet_get_mode(void)
@@ -15,9 +23,47 @@ int tablet_get_mode(void)
 
 void tablet_set_mode(int mode)
 {
-	if (tablet_mode != mode) {
-		tablet_mode = mode;
-		hook_notify(HOOK_TABLET_MODE_CHANGE);
-	}
+	if (tablet_mode == mode)
+		return;
+
+	tablet_mode = mode;
+	CPRINTS("tablet mode %sabled\n", mode ? "en" : "dis");
+	hook_notify(HOOK_TABLET_MODE_CHANGE);
+}
+
+/* This ifdef can be removed once we clean up past projects which do own init */
+#ifdef CONFIG_TABLET_SWITCH
+#ifndef TABLET_MODE_GPIO_L
+#error  TABLET_MODE_GPIO_L must be defined
+#endif
+static void tablet_mode_debounce(void)
+{
+	/* We won't reach here on boards without a dedicated tablet switch */
+	tablet_set_mode(!gpio_get_level(TABLET_MODE_GPIO_L));
+
+	/* Then, we disable peripherals only when the lid reaches 360 position.
+	 * (It's probably already disabled by motion_sense_task.)
+	 * We deliberately do not enable peripherals when the lid is leaving
+	 * 360 position. Instead, we let motion_sense_task enable it once it
+	 * reaches laptop zone (180 or less). */
+	if (tablet_mode)
+		lid_angle_peripheral_enable(0);
+}
+DECLARE_DEFERRED(tablet_mode_debounce);
+
+#define TABLET_DEBOUNCE_US    (30 * MSEC)  /* Debounce time for tablet switch */
+
+void tablet_mode_isr(enum gpio_signal signal)
+{
+	hook_call_deferred(&tablet_mode_debounce_data, TABLET_DEBOUNCE_US);
 }
 
+static void tablet_mode_init(void)
+{
+	gpio_enable_interrupt(TABLET_MODE_GPIO_L);
+	/* Ensure tablet mode is initialized according to the hardware state
+	 * so that the cached state reflects reality. */
+	tablet_mode_debounce();
+}
+DECLARE_HOOK(HOOK_INIT, tablet_mode_init, HOOK_PRIO_DEFAULT);
+#endif