linux-kernel - [PATCH v4,3/4] drm/mediatek: keep dsi as LP00 before dcs cmds transfer

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Date:   Mon, 11 Apr 2022 10:31:47 +0800
From:   <xinlei.lee@...iatek.com>
To:     <chunkuang.hu@...nel.org>, <p.zabel@...gutronix.de>,
        <airlied@...ux.ie>, <daniel@...ll.ch>, <matthias.bgg@...il.com>,
        <rex-bc.chen@...iatek.com>
CC:     <dri-devel@...ts.freedesktop.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <jitao.shi@...iatek.com>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        Xinlei Lee <xinlei.lee@...iatek.com>
Subject: [PATCH v4,3/4] drm/mediatek: keep dsi as LP00 before dcs cmds transfer

From: Jitao Shi <jitao.shi@...iatek.com>

To comply with the panel sequence, hold the mipi signal to LP00 before the dcs cmds transmission,
and pull the mipi signal high from LP00 to LP11 until the start of the dcs cmds transmission.
The normal panel timing is :
(1) pp1800 DC pull up
(2) avdd & avee AC pull high
(3) lcm_reset pull high -> pull low -> pull high
(4) Pull MIPI signal high (LP11) -> initial code -> send video data(HS mode)
The power-off sequence is reversed.
If dsi is not in cmd mode, then dsi will pull the mipi signal high in the mtk_output_dsi_enable function.

Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")

Signed-off-by: Jitao Shi <jitao.shi@...iatek.com>
Signed-off-by: Xinlei Lee <xinlei.lee@...iatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index cf76c53a1af6..9ad6f08c8bfe 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -203,6 +203,7 @@ struct mtk_dsi {
 	struct mtk_phy_timing phy_timing;
 	int refcount;
 	bool enabled;
+	bool lanes_ready;
 	u32 irq_data;
 	wait_queue_head_t irq_wait_queue;
 	const struct mtk_dsi_driver_data *driver_data;
@@ -654,13 +655,6 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
 	mtk_dsi_config_vdo_timing(dsi);
 	mtk_dsi_set_interrupt_enable(dsi);
 
-	mtk_dsi_rxtx_control(dsi);
-	usleep_range(30, 100);
-	mtk_dsi_reset_dphy(dsi);
-	mtk_dsi_clk_ulp_mode_leave(dsi);
-	mtk_dsi_lane0_ulp_mode_leave(dsi);
-	mtk_dsi_clk_hs_mode(dsi, 0);
-
 	return 0;
 err_disable_engine_clk:
 	clk_disable_unprepare(dsi->engine_clk);
@@ -689,6 +683,23 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
 	clk_disable_unprepare(dsi->digital_clk);
 
 	phy_power_off(dsi->phy);
+
+	dsi->lanes_ready = false;
+}
+
+static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
+{
+	if (!dsi->lanes_ready) {
+		dsi->lanes_ready = true;
+		mtk_dsi_rxtx_control(dsi);
+		usleep_range(30, 100);
+		mtk_dsi_reset_dphy(dsi);
+		mtk_dsi_clk_ulp_mode_leave(dsi);
+		mtk_dsi_lane0_ulp_mode_leave(dsi);
+		mtk_dsi_clk_hs_mode(dsi, 0);
+		msleep(20);
+	} else
+		DRM_DEBUG("The dsi_lane is ready\n");
 }
 
 static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
@@ -696,6 +707,7 @@ static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
 	if (dsi->enabled)
 		return;
 
+	mtk_dsi_lane_ready(dsi);
 	mtk_dsi_set_mode(dsi);
 	mtk_dsi_clk_hs_mode(dsi, 1);
 
@@ -1001,6 +1013,8 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 	if (MTK_DSI_HOST_IS_READ(msg->type))
 		irq_flag |= LPRX_RD_RDY_INT_FLAG;
 
+	mtk_dsi_lane_ready(dsi);
+
 	ret = mtk_dsi_host_send_cmd(dsi, msg, irq_flag);
 	if (ret)
 		goto restore_dsi_mode;
-- 
2.18.0