8042: Add interface for handling off-matrix button changes

BUG=chrome-os-partner:24370
BRANCH=tot
TEST=Power key and keyboard work normally.

Signed-off-by: Dave Parker <dparker@chromium.org>
Orig-Change-Id: I291ff384ae2fc3e074132330713f0b0c2cc36a76
Reviewed-on: https://chromium-review.googlesource.com/184543
(cherry picked from commit c65f82a5b02cdecf5b62f71ef2e916795f808389)

Change-Id: I1cd02e824c97eb5909e7bff68c8ecefc89f52df0
Reviewed-on: https://chromium-review.googlesource.com/185242
Tested-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Commit-Queue: Randall Spangler <rspangler@chromium.org>

include/button.h

@@ -0,0 +1,24 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* Button API for Chrome EC */
+
+#ifndef __CROS_EC_BUTTON_H
+#define __CROS_EC_BUTTON_H
+
+#include "common.h"
+#include "gpio.h"
+
+#define BUTTON_FLAG_ACTIVE_HIGH (1 << 0)
+
+enum keyboard_button_type {
+	KEYBOARD_BUTTON_POWER = 0,
+	KEYBOARD_BUTTON_VOLUME_DOWN,
+	KEYBOARD_BUTTON_VOLUME_UP,
+
+	KEYBOARD_BUTTON_COUNT
+};
+
+#endif  /* __CROS_EC_BUTTON_H */

include/keyboard_protocol.h

@@ -9,6 +9,7 @@
 #define __CROS_EC_KEYBOARD_PROTOCOL_H
 
 #include "common.h"
+#include "button.h"
 
 /* Routines common to all protocols */
 
@@ -17,6 +18,15 @@
  */
 void keyboard_clear_buffer(void);
 
+/*
+ * Respond to button changes. Implemented by a host-specific
+ * handler.
+ *
+ * @param button	The button that changed.
+ * @param is_pressed	Whether the button is now pressed.
+ */
+void keyboard_update_button(enum keyboard_button_type button, int is_pressed);
+
 /* Protocol-specific includes */
 
 #ifdef CONFIG_KEYBOARD_PROTOCOL_8042