drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.

This patch adds an initial DRM driver for the Mediatek MT8173 DISP
subsystem. It currently supports two fixed output streams from the
OVL0/OVL1 sources to the DSI0/DPI0 sinks, respectively.

Signed-off-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: YT Shen <yt.shen@mediatek.com>
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Signed-off-by: Mao Huang <littlecvr@chromium.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.h b/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
new file mode 100644
index 0000000..92c1175
--- /dev/null
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2015 MediaTek Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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 MTK_DRM_DDP_H
+#define MTK_DRM_DDP_H
+
+#include "mtk_drm_ddp_comp.h"
+
+struct regmap;
+struct device;
+struct mtk_disp_mutex;
+
+void mtk_ddp_add_comp_to_path(void __iomem *config_regs,
+			      enum mtk_ddp_comp_id cur,
+			      enum mtk_ddp_comp_id next);
+void mtk_ddp_remove_comp_from_path(void __iomem *config_regs,
+				   enum mtk_ddp_comp_id cur,
+				   enum mtk_ddp_comp_id next);
+
+struct mtk_disp_mutex *mtk_disp_mutex_get(struct device *dev, unsigned int id);
+int mtk_disp_mutex_prepare(struct mtk_disp_mutex *mutex);
+void mtk_disp_mutex_add_comp(struct mtk_disp_mutex *mutex,
+			     enum mtk_ddp_comp_id id);
+void mtk_disp_mutex_enable(struct mtk_disp_mutex *mutex);
+void mtk_disp_mutex_disable(struct mtk_disp_mutex *mutex);
+void mtk_disp_mutex_remove_comp(struct mtk_disp_mutex *mutex,
+				enum mtk_ddp_comp_id id);
+void mtk_disp_mutex_unprepare(struct mtk_disp_mutex *mutex);
+void mtk_disp_mutex_put(struct mtk_disp_mutex *mutex);
+
+#endif /* MTK_DRM_DDP_H */