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

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Message-ID: <1644589818-13066-4-git-send-email-xinlei.lee@mediatek.com>
Date:   Fri, 11 Feb 2022 22:30:17 +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>
CC:     <dri-devel@...ts.freedesktop.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <rex-bc.chen@...iatek.com>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        Jitao Shi <jitao.shi@...iatek.com>,
        Xinlei Lee <xinlei.lee@...iatek.com>
Subject: [3/3] 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.
If dsi is not in cmd mode, then dsi will pull the mipi signal high in the mtk_output_dsi_enable function.

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 | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index e47c338..17a5270 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);
@@ -682,6 +676,8 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
 	mtk_dsi_reset_engine(dsi);
 	mtk_dsi_lane0_ulp_mode_enter(dsi);
 	mtk_dsi_clk_ulp_mode_enter(dsi);
+	/* set the lane number as 0 */
+	writel(0, dsi->regs + DSI_TXRX_CTRL);
 
 	mtk_dsi_disable(dsi);
 
@@ -689,6 +685,8 @@ 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_output_dsi_enable(struct mtk_dsi *dsi)
@@ -696,6 +694,16 @@ static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
 	if (dsi->enabled)
 		return;
 
+	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);
+	}
+
 	mtk_dsi_set_mode(dsi);
 	mtk_dsi_clk_hs_mode(dsi, 1);
 
@@ -907,6 +915,16 @@ 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;
 
+	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);
+	}
 	if (mtk_dsi_host_send_cmd(dsi, msg, irq_flag) < 0)
 		return -ETIME;
 
-- 
2.6.4