PM: Add early suspend api.

include/linux/earlysuspend.h

@@ -0,0 +1,56 @@
+/* include/linux/earlysuspend.h
+ *
+ * Copyright (C) 2007-2008 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _LINUX_EARLYSUSPEND_H
+#define _LINUX_EARLYSUSPEND_H
+
+#ifdef CONFIG_HAS_EARLYSUSPEND
+#include <linux/list.h>
+#endif
+
+/* The early_suspend structure defines suspend and resume hooks to be called
+ * when the user visible sleep state of the system changes, and a level to
+ * control the order. They can be used to turn off the screen and input
+ * devices that are not used for wakeup.
+ * Suspend handlers are called in low to high level order, resume handlers are
+ * called in the opposite order. If, when calling register_early_suspend,
+ * the suspend handlers have already been called without a matching call to the
+ * resume handlers, the suspend handler will be called directly from
+ * register_early_suspend. This direct call can violate the normal level order.
+ */
+enum {
+	EARLY_SUSPEND_LEVEL_BLANK_SCREEN = 50,
+	EARLY_SUSPEND_LEVEL_STOP_DRAWING = 100,
+	EARLY_SUSPEND_LEVEL_DISABLE_FB = 150,
+};
+struct early_suspend {
+#ifdef CONFIG_HAS_EARLYSUSPEND
+	struct list_head link;
+	int level;
+	void (*suspend)(struct early_suspend *h);
+	void (*resume)(struct early_suspend *h);
+#endif
+};
+
+#ifdef CONFIG_HAS_EARLYSUSPEND
+void register_early_suspend(struct early_suspend *handler);
+void unregister_early_suspend(struct early_suspend *handler);
+#else
+#define register_early_suspend(handler) do { } while (0)
+#define unregister_early_suspend(handler) do { } while (0)
+#endif
+
+#endif
+