> ## Documentation Index > Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt > Use this file to discover all available pages before exploring further. # Locate and modify device trees Device tree source files for each Qualcomm® Linux board are present in arch/arm64/boot/dts/qcom/ and follow a two-tier SoC/board structure. The following provides the platform details, the corresponding device trees, and common customization patterns for platform bring-up. ## Device tree source location All Qualcomm® DTS and DTSI files are located in the kernel source tree under: ```text theme={null} arch/arm64/boot/dts/qcom/ ``` The file naming convention follows the same `--` pattern used by Yocto machine configurations. For the list of DTS files by target, see [Platform DTS files by target](#platform-dts-files-by-target) below. ## Locate platform DTS files for a target The `KERNEL_DEVICETREE` variable in `conf/machine/--.conf` selects which DTBs are built and packaged: ```text theme={null} KERNEL_DEVICETREE = " \ qcom/--.dtb \ " ``` **Table: Qualcomm device tree source — Dragonwing™ RB3 Gen 2** | Device tree source | Details | | :-----------------------------------------------------------------: | :-----------------------------------------------------------------------: | | `arch/arm64/boot/dts/qcom/sc7280.dtsi` | The QCS6490 SoC is derived from SC7280 SoC. | | `arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts` | Device tree source for the QCS6490 Dragonwing™ RB3 Gen 2 Development Kit. | | `arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-vision-mezzanine.dts` | QCS6490 Dragonwing™ RB3 Gen 2 vision Mezzanine Development Kit. | | `arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine.dts` | QCS6490 Dragonwing™ RB3 Gen 2 industrial Mezzanine Development Kit. | **Table: Qualcomm device tree source — Dragonwing™ IQ-9075** | Device tree source | Details | | :-------------------------------------------------------------------: | :------------------------------------------------------------------------: | | `arch/arm64/boot/dts/qcom/lemans.dtsi` | The Dragonwing™ IQ-9075 SoC is derived from Lemans. | | `arch/arm64/boot/dts/qcom/lemans-el2.dtso` | EL2 overlay applied to all IQ-9075 board variants for KVM environments. | | `arch/arm64/boot/dts/qcom/lemans-ride-common.dtsi` | Common DTSI for Qualcomm Linux development kits based on Lemans. | | `arch/arm64/boot/dts/qcom/qcs9100-ride.dts` and `qcs9100-ride-r3.dts` | Qualcomm Linux development kit for Dragonwing™ IQ-9100 ride. | | `arch/arm64/boot/dts/qcom/lemans-evk.dts` | Qualcomm Linux development kit for the Dragonwing™ IQ-9075 EVK. | **Table: Qualcomm device tree source — Dragonwing™ IQ-8275** | Device tree source | Details | | :-----------------------------------------: | :------------------------------------------------------------------------: | | `arch/arm64/boot/dts/qcom/qcs8300.dtsi` | The Dragonwing IQ-8275 SoC is derived from QCS8300 (Monaco). | | `arch/arm64/boot/dts/qcom/qcs8300-ride.dts` | Qualcomm Linux development kit for Dragonwing IQ-8300 ride. | | `arch/arm64/boot/dts/qcom/monaco-evk.dtb` | Qualcomm Linux development kit for the Dragonwing™ IQ-8275 EVK. | **Table: Qualcomm device tree source — Dragonwing™ IQ-615** | Device tree source | Details | | :----------------------------------------: | :-------------------------------------------------: | | `arch/arm64/boot/dts/qcom/qcs615.dtsi` | Base configuration file for Dragonwing IQ-615 SoC. | | `arch/arm64/boot/dts/qcom/qcs615-ride.dts` | Base configuration file for Dragonwing IQ-615 ride. | In kernel v6.19 and later, SoC DTSI names are updated to reflect actual SoC names: `sc7280.dtsi` → `kodiak.dtsi`, `qcs8300.dtsi` → `monaco.dtsi`, `qcs615.dtsi` → `talos.dtsi`. Device tree files suffixed with `el2` support Linux running at exception Level 2 (EL2) for KVM. Use EL2-specific DTBs only when Linux must operate as a KVM hypervisor. ## Common customization patterns Common customization with device trees are listed below. ### Enable or disable a peripheral node To enable a node that is declared but disabled in the SoC DTSI: ```dts theme={null} /* In your board DTS, override the status property */ &uart5 { status = "okay"; }; ``` To disable a node enabled by the SoC DTSI, mark it's status disabled: ```dts theme={null} &gpu { status = "disabled"; }; ``` ### Add a new peripheral To add a new device node or extend an existing bus node in the board DTS, follow corresponding device tree binding guidance. As an example add following for an i2c device: ```dts theme={null} &i2c2 { status = "okay"; sensor@48 { compatible = "ti,tmp102"; reg = <0x48>; }; }; ``` Always include the required `clock`, `pinctrl`, and `power-domain` references with the device node. Missing dependencies cause probe deferrals at boot. ### Add a new DTB to the kernel build To integrate a new platform device tree into the kernel build, add an entry to the Qualcomm `Makefile`: ```diff theme={null} diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile --- a/arch/arm64/boot/dts/qcom/Makefile +++ b/arch/arm64/boot/dts/qcom/Makefile +dtb-$(CONFIG_ARCH_QCOM) += qcs6490-my-board.dtb dtb-$(CONFIG_ARCH_QCOM) += qcs6490-rb3gen2.dtb ``` ### Include the DTB in the machine configuration Update `meta-qcom/conf/machine/qcs6490-rb3gen2-core-kit.conf` to include the new device tree blob: ```text theme={null} KERNEL_DEVICETREE = " \ qcom/qcs6490-rb3gen2.dtb \ qcom/qcs6490-my-board.dtb \ " ``` See `meta-qcom/conf/machine/*.conf` for the machine configuration files for all supported SoCs. ### Configure DTB boot selection By default (`QCOM_DTB_DEFAULT = "multi-dtb"`), the build produces a FIT image that contains all DTBs. At boot, UEFI selects the matching DTB by comparing the board's hardware compatible string with entries in `fit-dtb-compatible.inc`. For more information, see [Device tree architecture](./device-tree-architecture#fit-based-dtb-packaging). FIT-based selection doesn't work in following scenarios: * Your board's compatible string has no matching entry in `FIT_DTB_COMPATIBLE`. * You are bringing up a new board and the firmware metadata doesn't describe your compatible string in `qcom-metadata.dtb`. * You need to unconditionally force a specific DTB, regardless of what the firmware reports. In these cases, override `QCOM_DTB_DEFAULT` in your machine configuration file (for example, `meta-qcom/conf/machine/my-board.conf`): ```bitbake theme={null} QCOM_DTB_DEFAULT = "qcs6490-my-board" KERNEL_DEVICETREE = "qcs6490-my-board.dtb" ``` `qcs6490-my-board` is the DTB stem, which is the filename without the `.dtb` extension. Setting `QCOM_DTB_DEFAULT` to any value other than "multi-dtb" disables FIT image generation; the build produces only a single VFAT image for the specified DTB. After a successful build, the following DTB-related files appear under `build/tmp/deploy/images//`: **Table: Build artifacts when QCOM\_DTB\_DEFAULT is set** | File | Description | | --------------------------------- | ---------------------------------------------------------------------------------------- | | `dtb-qcs6490-my-board-image.vfat` | VFAT partition image containing `combined-dtb.dtb`. Written to the device DTB partition. | | `dtb.bin` | Inside the qcomflash tarball. Copy of the VFAT image flashed to the DTB partition. | To update only the DTB partition during iterative bring-up: ```bash theme={null} fastboot flash dtb_a dtb.bin fastboot reboot ``` UEFI selects `-my-board.dtb` from the FIT image on the next boot. For more information, see [The Devicetree Specification](https://www.devicetree.org/specifications/) and [Linux and the Devicetree](https://docs.kernel.org/devicetree/usage-model.html).