From 6a46566628b1c399e117e5c08df4afae3c44df9f Mon Sep 17 00:00:00 2001 From: Xinlei Lee Date: Tue, 10 Jan 2023 13:54:51 +0800 Subject: [PATCH] drm/mediatek: dsi: Reduce the time of dsi from LP11 to sending cmd [ Upstream commit 91aeaed2c1147e3b1157dc084d23f190856a6c23 ] According to Figure 16 Turnaround Procedure on page 36 in [1], you can see the status of LP-00 -> LP10 -> LP11. This state can correspond to the state of DSI from LP00 -> LP11 in mtk_dsi_lane_ready function in mtk_dsi.c. LP-00 -> LP10 -> LP11 takes about 2*TLPX time (refer to [1] page 51 to see that TLPX is 50ns) The delay at the end of the mtk_dsi_lane_ready function should be greater than the 2*TLPX specified by the DSI spec, and less than the time specified by the DSI_RX (generally 6ms to 40ms), to avoid problems caused by the RX specification [1]:mipi_D-PHY_specification_v1-1 Fixes: 39e8d062b03c ("drm/mediatek: Keep dsi as LP00 before dcs cmds transfer") Signed-off-by: Xinlei Lee Acked-by: Sam Ravnborg Reviewed-by: AngeloGioacchino Del Regno Link: https://patchwork.kernel.org/project/linux-mediatek/patch/1673330093-6771-2-git-send-email-xinlei.lee@mediatek.com/ Signed-off-by: Chun-Kuang Hu Signed-off-by: Sasha Levin --- drivers/gpu/drm/mediatek/mtk_dsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c index 3b7d130..9e1363c 100644 --- a/drivers/gpu/drm/mediatek/mtk_dsi.c +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c @@ -721,7 +721,7 @@ static void mtk_dsi_lane_ready(struct mtk_dsi *dsi) mtk_dsi_clk_ulp_mode_leave(dsi); mtk_dsi_lane0_ulp_mode_leave(dsi); mtk_dsi_clk_hs_mode(dsi, 0); - msleep(20); + usleep_range(1000, 3000); /* The reaction time after pulling up the mipi signal for dsi_rx */ } } -- 2.7.4