Do you reference to the l4t-documentation-28.1 ??
The file should be “tegra186-quill-camera-modules.dtsi” not tegra18x-quill-cv-camera-modules.dtsi
Using Main Platform Device Tree File
Register your new device by updating main platform DTSI file to include your new device DTSI file. Because Tegra uses Plugin Manager by default, you must first unregister Plugin Manager support, then add your device information to the main device tree DTSI file.
Prerequisites
• You have obtained the kernel source files. For more information, see Synchronizing the Kernel in the Development Guide for the release.
To register a device using main-platform device tree files
1. Locate and edit the following file:
• TX1:
hardware/nvidia/platform/t210/jetson/kernel-dts/tegra210-jetson-cv-base-p25970-2180-a00.dts
• TX2:
hardware/nvidia/platform/t18x/quill/kernel-dts/tegra186-quill-p3310-1000-a00-00-base.dtsi
2. In the DTSI, remove the following line:
• TX1:
#include "jetson-plugin-manager/tegra210-jetson-cv-camera-plugin-manager.dtsi"
• TX2:
#include <t18x-common-plugin-manager/tegra186-quill-camera-plugin-manager.dtsi"
3. Locate and edit the following file:
TX1:
hardware/nvidia/platform/t210/jetson/kernel-dts/tegra210-jetson-cv-base-p2597-2180-a00.dts
TX2:
hardware/nvidia/platform/t18x/quill/kernel-dts/tegra186-quill-p3310-1000-a00-00-base.dts
4. In the DTS file, replace the following line:
• TX1:
#include "jetson-platforms/tegra210-jetson-cv-camera-modules.dtsi"
• TX2:
#include <t18x-common-platforms/tegra186-quill-camera-modules.dtsi>
With an #include statement specifying the DTSI file for your new device.