mipi屏调试时序问题

mipi屏的时序大同小异，一般都跟以下差不多：

 

 

屏参配置如下：

&dsi0 {status = "disabled";//rockchip,lane-rate = <1000>;dsi0_panel: panel@0 {status = "okay";compatible = "simple-panel-dsi";reg = <0>;backlight = <&backlight>;reset-delay-ms = <60>;enable-delay-ms = <60>;prepare-delay-ms = <60>;unprepare-delay-ms = <60>;disable-delay-ms = <60>;dsi,flags = <(MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET)>;dsi,format = <MIPI_DSI_FMT_RGB888>;dsi,lanes  = <4>;panel-init-sequence = [39 00 04 FF 98 81 03。。。。15 00 01 3505 78 01 1105 14 01 29];disp_timings0: display-timings {native-mode = <&dsi0_timing0>;dsi0_timing0: timing0 {clock-frequency = <69000000>;hactive = <720>;vactive = <1280>;hfront-porch = <32>;hsync-len = <6>;hback-porch = <120>;vfront-porch = <8>;vsync-len = <4>;vback-porch = <18>;hsync-active = <0>;vsync-active = <0>;de-active = <0>;pixelclk-active = <1>;};};ports {#address-cells = <1>;#size-cells = <0>;port@0 {reg = <0>;panel_in_dsi: endpoint {remote-endpoint = <&dsi_out_panel>;};};};};ports {#address-cells = <1>;#size-cells = <0>;port@1 {reg = <1>;dsi_out_panel: endpoint {remote-endpoint = <&panel_in_dsi>;};};};};

&dsi0 {status = "okay";
};&dsi0_in_vp1 {status = "disabled";
};&dsi0_in_vp0 {status = "okay";
};&dsi0_panel {power-supply = <&vcc3v3_lcd0_n>;backlight = <&backlight>;init-delay-ms = <30>;reset-gpios =<&gpio0 RK_PD4 GPIO_ACTIVE_LOW>;pinctrl-names = "default";pinctrl-0 = <&lcd_rst>;
};&route_dsi0 {status = "okay";connect = <&vp0_out_dsi0>;
};

点屏过程，各个方面都核对过，供电和reset也都有，但屏没亮。把信号都拉出来量 ：

黄色通道是reset，蓝色是mipi信号

 可以发现，mipi发送指令的时候，跟reset信号是重叠的，应该是这里的问题。解决办法是延迟一下mipi信号的发送。添加30ms的延迟：

init-delay-ms = <30>;

再量信号：

 此时屏也正常顺利电量。

 

屏点不亮的时候，重点排查：

1.核对原理图，软件配置的mipi通道是否和原理图一致（rk3568有dsi0和dsi1两组通道）

2.确认1.8v和3.3.v供电是否正常

3.reset动作是否正常

4.根据屏的规格书，填写屏参

5、核对mipi初始化指令是否正确

6、同时把供电、reset信号，mipi信号(D0信号)拉出来，看是否符合时序要求