[PATCH v8 12/16] drm/mediatek: Support "Pre-multiplied" blending in Mixer

[Shawn Sung]

From: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>

Support "Pre-multiplied" alpha blending mode in Mixer.
Before this patch, only the coverage mode is supported.

Signed-off-by: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_ethdr.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index bcced62e455d..d01f65819816 100644
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -6,6 +6,7 @@
 #include <drm/drm_blend.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
+#include <drm/drm_blend.h>
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/of.h>
@@ -36,6 +37,7 @@
 #define MIX_SRC_L0_EN				BIT(0)
 #define MIX_L_SRC_CON(n)		(0x28 + 0x18 * (n))
 #define NON_PREMULTI_SOURCE			(2 << 12)
+#define PREMULTI_SOURCE				(3 << 12)
 #define MIX_L_SRC_SIZE(n)		(0x30 + 0x18 * (n))
 #define MIX_L_SRC_OFFSET(n)		(0x34 + 0x18 * (n))
 #define MIX_FUNC_DCM0			0x120
@@ -172,8 +174,12 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
 		return;
 	}
 
-	if (state->base.fb && state->base.fb->format->has_alpha)
-		alpha_con = MIXER_ALPHA_AEN | MIXER_ALPHA;
+	alpha_con |= MIXER_ALPHA_AEN | (state->base.alpha & MIXER_ALPHA);
+
+	if (state->base.pixel_blend_mode != DRM_MODE_BLEND_COVERAGE)
+		alpha_con |= PREMULTI_SOURCE;
+	else
+		alpha_con |= NON_PREMULTI_SOURCE;
 
 	if (state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE ||
 	    (state->base.fb && !state->base.fb->format->has_alpha)) {
@@ -191,8 +197,7 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
 	mtk_ddp_write(cmdq_pkt, pending->height << 16 | align_width, &mixer->cmdq_base,
 		      mixer->regs, MIX_L_SRC_SIZE(idx));
 	mtk_ddp_write(cmdq_pkt, offset, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_OFFSET(idx));
-	mtk_ddp_write_mask(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_CON(idx),
-			   0x1ff);
+	mtk_ddp_write(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_CON(idx));
 	mtk_ddp_write_mask(cmdq_pkt, BIT(idx), &mixer->cmdq_base, mixer->regs, MIX_SRC_CON,
 			   BIT(idx));
 }
-- 
2.18.0