[PATCH v4 1/2] drm/mediatek: force hsa hbp hfp packets multiple of lanenum to avoid screen shift

From: Jitao Shi
Date: Sun Aug 01 2021 - 00:06:37 EST


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@xxxxxxxxxxxx>
---
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