tomevault-io Zephyr Devicetree
The Devicetree (DT) is the source of truth for your hardware topology in Zephyr.
Core Workflows
1. Understanding Syntax & Nodes
Nodes, properties, and phandles form the hierarchy.
- Reference: dt_syntax.md
- Key Tools: Labels (
&label), Properties (reg,status,compatible).
2. Working with Bindings
Mapping hardware descriptions to driver schemas.
- Reference: dt_bindings.md
- Key Tools: YAML bindings, compatible strings,
pinctrl.
3. Application Overlays & HWMv2
Modifying board behavior for specific application needs.
- Reference: dt_overlays.md
- Key Tools:
.overlayfiles,zephyr,chosen, variant-specific overlays.
4. Advanced Hardware Modification
Deleting and redefining nodes/properties for product variants.
- Reference: dt_overlays.md
- Key Tools:
/delete-node/,/delete-property/.
Quick Start (Overlay)
/* app.overlay */
&i2c1 {
status = "okay";
};
&uart0 {
status = "disabled";
};
Tooling & Validation
west build -t rom_report: See how devicetree definitions impact memory.build/zephyr/zephyr.dts: Inspect the FINAL resolved devicetree after all overlays are applied.build/zephyr/include/generated/zephyr/devicetree_generated.h: Inspect generated DT macros consumed by C code.
Automation Tools
- overlay_include_check.py: Run basic sanity checks on
.overlayfiles.
Examples & Templates
- app_overlay_template.overlay: Starter overlay with common node status changes.
Validation Checklist
- Overlay compiles with no DTS syntax errors during
west build. - Expected node status/properties are present in
build/zephyr/zephyr.dts. - Expected DT macros exist in
build/zephyr/include/generated/zephyr/devicetree_generated.h. - Application runs with peripherals enabled/disabled exactly as described by the overlay.
Resources
- References:
dt_syntax.md: Core syntax and properties.dt_bindings.md: Binding definitions and compatible mapping.dt_overlays.md: Overlays, HWMv2, and deletion patterns.
- Scripts:
overlay_include_check.py: Overlay sanity checker.
- Assets:
app_overlay_template.overlay: Baseline overlay template.
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