shrambo,
For your first question, yes, two sors can use the same source.
To bring up the DSI panel, you have to rebuild your dtb file. Please check the config you use to flash. For example, p2371-2180.config uses tegra210-jetson-cv-base-p2597-2180-a00.dtb.
Please look into the kernel source. We have devicetree example for DSI panel: kernel/arch/arm/boot/dts/panel-s-wuxga-8-0.dtsi.
To know the meaning of each parameter: Please refer to kernel/Documentation/devicetree/bindings/video/nvidia,tegra210-dsi.txt