drm/mediatek: dsi: Correct calculation formula of PHY Timing

This patch correct calculation formula of PHY timing.
The spec define HS-PREPARE should be from 40ns+4*UI(44ns) to
85ns+6*UI(91ns). But current duration is 88ns and is near the boundary.
So this patch make the duration to 64ns so it is near the safe range.

Signed-off-by: Shuijing Li <shuijing.li@mediatek.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20240412031208.30688-1-shuijing.li@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 67239606adbfc7d137885ac7cdedc1d7e0f1d3e0..c255559cc56eddf0ba01088e83d499501f5bb9c8 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -242,22 +242,23 @@ static void mtk_dsi_phy_timconfig(struct mtk_dsi *dsi)
        u32 data_rate_mhz = DIV_ROUND_UP(dsi->data_rate, HZ_PER_MHZ);
        struct mtk_phy_timing *timing = &dsi->phy_timing;
 
-       timing->lpx = (60 * data_rate_mhz / (8 * 1000)) + 1;
-       timing->da_hs_prepare = (80 * data_rate_mhz + 4 * 1000) / 8000;
-       timing->da_hs_zero = (170 * data_rate_mhz + 10 * 1000) / 8000 + 1 -
+       timing->lpx = (80 * data_rate_mhz / (8 * 1000)) + 1;
+       timing->da_hs_prepare = (59 * data_rate_mhz + 4 * 1000) / 8000 + 1;
+       timing->da_hs_zero = (163 * data_rate_mhz + 11 * 1000) / 8000 + 1 -
                             timing->da_hs_prepare;
-       timing->da_hs_trail = timing->da_hs_prepare + 1;
-
-       timing->ta_go = 4 * timing->lpx - 2;
-       timing->ta_sure = timing->lpx + 2;
-       timing->ta_get = 4 * timing->lpx;
-       timing->da_hs_exit = 2 * timing->lpx + 1;
-
-       timing->clk_hs_prepare = 70 * data_rate_mhz / (8 * 1000);
-       timing->clk_hs_post = timing->clk_hs_prepare + 8;
-       timing->clk_hs_trail = timing->clk_hs_prepare;
-       timing->clk_hs_zero = timing->clk_hs_trail * 4;
-       timing->clk_hs_exit = 2 * timing->clk_hs_trail;
+       timing->da_hs_trail = (78 * data_rate_mhz + 7 * 1000) / 8000 + 1;
+
+       timing->ta_go = 4 * timing->lpx;
+       timing->ta_sure = 3 * timing->lpx / 2;
+       timing->ta_get = 5 * timing->lpx;
+       timing->da_hs_exit = (118 * data_rate_mhz / (8 * 1000)) + 1;
+
+       timing->clk_hs_prepare = (57 * data_rate_mhz / (8 * 1000)) + 1;
+       timing->clk_hs_post = (65 * data_rate_mhz + 53 * 1000) / 8000 + 1;
+       timing->clk_hs_trail = (78 * data_rate_mhz + 7 * 1000) / 8000 + 1;
+       timing->clk_hs_zero = (330 * data_rate_mhz / (8 * 1000)) + 1 -
+                             timing->clk_hs_prepare;
+       timing->clk_hs_exit = (118 * data_rate_mhz / (8 * 1000)) + 1;
 
        timcon0 = FIELD_PREP(LPX, timing->lpx) |
                  FIELD_PREP(HS_PREP, timing->da_hs_prepare) |