[PATCH v3 1/2] drm/mediatek: force hsa hbp hfp packets multiple of lanenum to avoid screen shift

From: Jitao Shi <jitao.shi@mediatek.com>
To: Chun-Kuang Hu <chunkuang.hu@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
	<dri-devel@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>
Cc: <linux-mediatek@lists.infradead.org>,
	<linux-arm-kernel@lists.infradead.org>, <ck.hu@mediatek.com>,
	<stonea168@163.com>, <huijuan.xie@mediatek.com>,
	<rex-bc.chen@mediatek.com>, <shuijing.li@mediatek.com>,
	<robh+dt@kernel.org>, <devicetree@vger.kernel.org>,
	Jitao Shi <jitao.shi@mediatek.com>
Subject: [PATCH v3 1/2] drm/mediatek: force hsa hbp hfp packets multiple of lanenum to avoid screen shift
Date: Mon, 26 Jul 2021 10:11:03 +0800	[thread overview]
Message-ID: <20210726021104.80007-1-jitao.shi@mediatek.com> (raw)

The bridge chip ANX7625 requires the packets on lanes aligned at the end,
or ANX7625 will shift the screen.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index ae403c67cbd9..4735e0092ffe 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -194,6 +194,8 @@ struct mtk_dsi {
 	struct clk *hs_clk;
 
 	u32 data_rate;
+	/* force dsi line end without dsi_null data */
+	bool force_dsi_end_without_null;
 
 	unsigned long mode_flags;
 	enum mipi_dsi_pixel_format format;
@@ -499,6 +501,13 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
 		DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");
 	}
 
+	if (dsi->force_dsi_end_without_null) {
+		horizontal_sync_active_byte = roundup(horizontal_sync_active_byte, dsi->lanes) - 2;
+		horizontal_frontporch_byte = roundup(horizontal_frontporch_byte, dsi->lanes) - 2;
+		horizontal_backporch_byte = roundup(horizontal_backporch_byte, dsi->lanes) - 2;
+		horizontal_backporch_byte -= (vm->hactive * dsi_tmp_buf_bpp + 2) % dsi->lanes;
+	}
+
 	writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
 	writel(horizontal_backporch_byte, dsi->regs + DSI_HBP_WC);
 	writel(horizontal_frontporch_byte, dsi->regs + DSI_HFP_WC);
@@ -1095,6 +1104,10 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->bridge.of_node = dev->of_node;
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 
+	if (dsi->next_bridge)
+		dsi->force_dsi_end_without_null = of_property_read_bool(dsi->next_bridge->of_node,
+									"force_dsi_end_without_null");
+
 	drm_bridge_add(&dsi->bridge);
 
 	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
-- 
2.25.1
