drm/exynos: add crtc disable function

The crtc disable is used to turn off private plane for crtc.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_crtc.c

@@ -173,6 +173,16 @@ static void exynos_drm_crtc_load_lut(struct drm_crtc *crtc)
 	/* drm framework doesn't check NULL */
 }
 
+static void exynos_drm_crtc_disable(struct drm_crtc *crtc)
+{
+	struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
+
+	DRM_DEBUG_KMS("%s\n", __FILE__);
+
+	exynos_plane_dpms(exynos_crtc->plane, DRM_MODE_DPMS_OFF);
+	exynos_drm_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
+}
+
 static struct drm_crtc_helper_funcs exynos_crtc_helper_funcs = {
 	.dpms		= exynos_drm_crtc_dpms,
 	.prepare	= exynos_drm_crtc_prepare,
@@ -181,6 +191,7 @@ static struct drm_crtc_helper_funcs exynos_crtc_helper_funcs = {
 	.mode_set	= exynos_drm_crtc_mode_set,
 	.mode_set_base	= exynos_drm_crtc_mode_set_base,
 	.load_lut	= exynos_drm_crtc_load_lut,
+	.disable	= exynos_drm_crtc_disable,
 };
 
 static int exynos_drm_crtc_page_flip(struct drm_crtc *crtc,