drm/exynos: Add DECON driver

This patch is based on exynos-drm-next branch of Inki Dae's tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos.git

DECON(Display and Enhancement Controller) is the new IP
in exynos7 SOC for generating video signals using pixel data.

DECON driver can be used to drive 2 different interfaces on Exynos7:
DECON-INT(video controller) and DECON-EXT(Mixer for HDMI)

The existing FIMD driver code was used as a template to create
DECON driver. Only DECON-INT is supported as of now, and
DECON-EXT support will be added later.

The current version of the driver supports video mode displays.

Changelog v2:
- Change config name, DRM_EXYNOS_DECON to DRM_EXYNOS7_DECON.

Signed-off-by: Akshu Agrawal <akshua@gmail.com>
Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
index 627aaa0..a5e7461 100644
--- a/drivers/gpu/drm/exynos/Kconfig
+++ b/drivers/gpu/drm/exynos/Kconfig
@@ -24,9 +24,16 @@
 	help
 	  Choose this option if you want to use Exynos FIMD for DRM.
 
+config DRM_EXYNOS7_DECON
+	bool "Exynos DRM DECON"
+	depends on DRM_EXYNOS
+	select FB_MODE_HELPERS
+	help
+	  Choose this option if you want to use Exynos DECON for DRM.
+
 config DRM_EXYNOS_DPI
 	bool "EXYNOS DRM parallel output support"
-	depends on DRM_EXYNOS_FIMD
+	depends on (DRM_EXYNOS_FIMD || DRM_EXYNOS7_DECON)
 	select DRM_PANEL
 	default n
 	help
@@ -34,7 +41,7 @@
 
 config DRM_EXYNOS_DSI
 	bool "EXYNOS DRM MIPI-DSI driver support"
-	depends on DRM_EXYNOS_FIMD
+	depends on (DRM_EXYNOS_FIMD || DRM_EXYNOS7_DECON)
 	select DRM_MIPI_DSI
 	select DRM_PANEL
 	default n
@@ -43,7 +50,7 @@
 
 config DRM_EXYNOS_DP
 	bool "EXYNOS DRM DP driver support"
-	depends on DRM_EXYNOS_FIMD && ARCH_EXYNOS && (DRM_PTN3460=n || DRM_PTN3460=y || DRM_PTN3460=DRM_EXYNOS)
+	depends on (DRM_EXYNOS_FIMD || DRM_EXYNOS7DECON) && ARCH_EXYNOS && (DRM_PTN3460=n || DRM_PTN3460=y || DRM_PTN3460=DRM_EXYNOS)
 	default DRM_EXYNOS
 	select DRM_PANEL
 	help