drm/mediatek: Add display merge mute/unmute support for MT8195

Add merge mute/unmute setting for MT8195.
MT8195 Vdosys1 merge1~merge4 support HW mute function.
Signed-off-by: Nancy.Lin <nancy.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220620091930.27797-7-nancy.lin@mediatek.com/Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

drivers/gpu/drm/mediatek/mtk_disp_merge.c

@@ -58,12 +58,15 @@
 #define FLD_PREULTRA_TH_LOW			GENMASK(15, 0)
 #define FLD_PREULTRA_TH_HIGH			GENMASK(31, 16)
 
+#define DISP_REG_MERGE_MUTE_0		0xf00
+
 struct mtk_disp_merge {
 	void __iomem			*regs;
 	struct clk			*clk;
 	struct clk			*async_clk;
 	struct cmdq_client_reg		cmdq_reg;
 	bool				fifo_en;
+	bool				mute_support;
 };
 
 void mtk_merge_start(struct device *dev)
@@ -80,6 +83,10 @@ void mtk_merge_start_cmdq(struct device *dev, struct cmdq_pkt *cmdq_pkt)
 {
 	struct mtk_disp_merge *priv = dev_get_drvdata(dev);
 
+	if (priv->mute_support)
+		mtk_ddp_write(cmdq_pkt, 0x0, &priv->cmdq_reg, priv->regs,
+			      DISP_REG_MERGE_MUTE_0);
+
 	mtk_ddp_write(cmdq_pkt, 1, &priv->cmdq_reg, priv->regs,
 		      DISP_REG_MERGE_CTRL);
 }
@@ -88,6 +95,10 @@ void mtk_merge_stop_cmdq(struct device *dev, struct cmdq_pkt *cmdq_pkt)
 {
 	struct mtk_disp_merge *priv = dev_get_drvdata(dev);
 
+	if (priv->mute_support)
+		mtk_ddp_write(cmdq_pkt, 0x1, &priv->cmdq_reg, priv->regs,
+			      DISP_REG_MERGE_MUTE_0);
+
 	mtk_ddp_write(cmdq_pkt, 0, &priv->cmdq_reg, priv->regs,
 		      DISP_REG_MERGE_CTRL);
 }
@@ -262,6 +273,8 @@ static int mtk_disp_merge_probe(struct platform_device *pdev)
 	priv->fifo_en = of_property_read_bool(dev->of_node,
 					      "mediatek,merge-fifo-en");
 
+	priv->mute_support = of_property_read_bool(dev->of_node,
+						   "mediatek,merge-mute");
 	platform_set_drvdata(pdev, priv);
 
 	ret = component_add(dev, &mtk_disp_merge_component_ops);