[PATCH v13 6/8] drm/mediatek: enable dither function

[Hsin-Yi Wang]

From: Yongqiang Niu <yongqiang.niu at mediatek.com>

Enable dither function to improve the display quality for dither
supported bpc 4, 6, 8. For not supported bpc, use relay mode.

Signed-off-by: Yongqiang Niu <yongqiang.niu at mediatek.com>
Signed-off-by: Hsin-Yi Wang <hsinyi at chromium.org>
---
 drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
index ac2cb25620357..5761dd15eedf2 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
@@ -53,6 +53,7 @@
 #define DITHER_EN				BIT(0)
 #define DISP_DITHER_CFG				0x0020
 #define DITHER_RELAY_MODE			BIT(0)
+#define DITHER_ENGINE_EN			BIT(1)
 #define DISP_DITHER_SIZE			0x0030
 
 #define LUT_10BIT_MASK				0x03ff
@@ -314,9 +315,17 @@ static void mtk_dither_config(struct device *dev, unsigned int w,
 			      unsigned int bpc, struct cmdq_pkt *cmdq_pkt)
 {
 	struct mtk_ddp_comp_dev *priv = dev_get_drvdata(dev);
-
-	mtk_ddp_write(cmdq_pkt, h << 16 | w, &priv->cmdq_reg, priv->regs, DISP_DITHER_SIZE);
-	mtk_ddp_write(cmdq_pkt, DITHER_RELAY_MODE, &priv->cmdq_reg, priv->regs, DISP_DITHER_CFG);
+	bool valid_bpc = (bpc == 4 || bpc == 6 || bpc == 8);
+
+	mtk_ddp_write(cmdq_pkt, h << 16 | w, &priv->cmdq_reg, priv->regs,
+		      DISP_DITHER_SIZE);
+	if (valid_bpc)
+		mtk_dither_set_common(priv->regs, &priv->cmdq_reg, bpc,
+				      DISP_DITHER_CFG, DITHER_ENGINE_EN,
+				      cmdq_pkt);
+	else
+		mtk_ddp_write(cmdq_pkt, DITHER_RELAY_MODE, &priv->cmdq_reg,
+			      priv->regs, DISP_DITHER_CFG);
 }
 
 static void mtk_dither_start(struct device *dev)
-- 
2.30.0.365.g02bc693789-goog