[PATCH 3/3] drm: rcar-du: Add DRM blend mode support

[Takanari Hayama]

R-Car DU supports different blend modes via VSP1. Add DRM blend mode
supports to make it configurable.

As drm_plane_create_blend_mode_property() creates the blend mode
property with the default value of DRM_MODE_BLEND_PREMULTI, it changes
the default blending behavior on R-Car DU. The rcar-du's blend mode was
same as DRM_MODE_BLEND_COVERAGE, i.e., pixel color values have not been
pre-multitplied.

Signed-off-by: Takanari Hayama <taki at igel.co.jp>
---
 drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
index 8eb9b2b097ae..283327046aa5 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
@@ -170,6 +170,18 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
 	format = rcar_du_format_info(state->format->fourcc);
 	cfg.pixelformat = format->v4l2;
 
+	switch (state->state.pixel_blend_mode) {
+	case DRM_MODE_BLEND_PREMULTI:
+		cfg.blend_mode = VSP1_DU_BLEND_MODE_PREMULTI;
+		break;
+	case DRM_MODE_BLEND_COVERAGE:
+		cfg.blend_mode = VSP1_DU_BLEND_MODE_COVERAGE;
+		break;
+	case DRM_MODE_BLEND_PIXEL_NONE:
+		cfg.blend_mode = VSP1_DU_BLEND_MODE_PIXEL_NONE;
+		break;
+	}
+
 	vsp1_du_atomic_update(plane->vsp->vsp, crtc->vsp_pipe,
 			      plane->index, &cfg);
 }
@@ -444,6 +456,11 @@ int rcar_du_vsp_init(struct rcar_du_vsp *vsp, struct device_node *np,
 						       num_planes - 1);
 		}
 
+		drm_plane_create_blend_mode_property(&plane->plane,
+					BIT(DRM_MODE_BLEND_PIXEL_NONE) |
+					BIT(DRM_MODE_BLEND_PREMULTI) |
+					BIT(DRM_MODE_BLEND_COVERAGE));
+
 		vsp->num_planes++;
 	}
 
-- 
2.25.1