linux-kernel - [v8, PATCH 2/3] drm/mediatek: implement the DSI hs packets aligned

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Message-ID: <20220112153639.12343-3-rex-bc.chen@mediatek.com>
Date:   Wed, 12 Jan 2022 23:36:38 +0800
From:   Rex-BC Chen <rex-bc.chen@...iatek.com>
To:     <chunkuang.hu@...nel.org>, <matthias.bgg@...il.com>,
        <narmstrong@...libre.com>, <robert.foss@...aro.org>,
        <andrzej.hajda@...el.com>, <daniel@...ll.ch>, <airlied@...ux.ie>,
        <p.zabel@...gutronix.de>
CC:     <xji@...logixsemi.com>, <jitao.shi@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        Rex-BC Chen <rex-bc.chen@...iatek.com>
Subject: [v8, PATCH 2/3] drm/mediatek: implement the DSI hs packets aligned

Some DSI RX devices require the packets on all lanes aligned at the end.
Otherwise, there will be some issues of shift or scroll for screen.

Signed-off-by: Jitao Shi <jitao.shi@...iatek.com>
Reviewed-by: Chun-Kuang Hu <chunkuang.hu@...nel.org>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..2f3ff9b595a4 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -195,6 +195,8 @@ struct mtk_dsi {
 	struct clk *hs_clk;
 
 	u32 data_rate;
+	/* force dsi line end without dsi_null data */
+	bool hs_packet_end_aligned;
 
 	unsigned long mode_flags;
 	enum mipi_dsi_pixel_format format;
@@ -500,6 +502,13 @@ 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->hs_packet_end_aligned) {
+		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);
@@ -794,6 +803,7 @@ static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
 	dsi->lanes = device->lanes;
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
+	dsi->hs_packet_end_aligned = device->hs_packet_end_aligned;
 
 	return 0;
 }
-- 
2.18.0