Patch "drm/mediatek: Keep dsi as LP00 before dcs cmds transfer" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/mediatek: Keep dsi as LP00 before dcs cmds transfer

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-mediatek-keep-dsi-as-lp00-before-dcs-cmds-transf.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7f86de396d1dab9dcb0538a562495d2c6afc5d70
Author: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
Date:   Fri May 20 10:00:06 2022 +0800

    drm/mediatek: Keep dsi as LP00 before dcs cmds transfer
    
    [ Upstream commit 39e8d062b03c3dc257d880d82bd55cdd9e185a3b ]
    
    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. The delay in lane_ready func is
    the reaction time of dsi_rx after pulling up the mipi signal.
    
    Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")
    
    Link: https://patchwork.kernel.org/project/linux-mediatek/patch/1653012007-11854-4-git-send-email-xinlei.lee@xxxxxxxxxxxx/
    Cc: <stable@xxxxxxxxxxxxxxx> # 5.10.x: 7f6335c6a258: drm/mediatek: Modify dsi funcs to atomic operations
    Cc: <stable@xxxxxxxxxxxxxxx> # 5.10.x: cde7e2e35c28: drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs
    Cc: <stable@xxxxxxxxxxxxxxx> # 5.10.x
    Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
    Signed-off-by: Xinlei Lee <xinlei.lee@xxxxxxxxxxxx>
    Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
    Reviewed-by: Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx>
    Signed-off-by: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index ab51656d5dae..ac14e598a14f 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;
@@ -649,18 +650,11 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
 	mtk_dsi_reset_engine(dsi);
 	mtk_dsi_phy_timconfig(dsi);
 
-	mtk_dsi_rxtx_control(dsi);
-	usleep_range(30, 100);
-	mtk_dsi_reset_dphy(dsi);
 	mtk_dsi_ps_control_vact(dsi);
 	mtk_dsi_set_vm_cmd(dsi);
 	mtk_dsi_config_vdo_timing(dsi);
 	mtk_dsi_set_interrupt_enable(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);
@@ -691,6 +685,23 @@ 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);
+		/* The reaction time after pulling up the mipi signal for dsi_rx */
+	}
 }
 
 static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
@@ -698,6 +709,7 @@ 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);
 
@@ -924,6 +936,8 @@ 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;