---
name: "fdtbus"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/fdtbus"
---

# fdtbus(4)

Flattened Device Tree bus driver

## NAME

**fdtbus** – Flattened Device Tree bus driver

## SYNOPSIS

**options FDT**

## DESCRIPTION

The **fdtbus** abstract bus driver is the primary connection and translation layer between [fdt(4)](/fdt/4.md) hardware resources description and FreeBSD native newbus device drivers framework. For an embedded system **fdtbus** represents peripherals typically found on a highly integrated chip (system-on-chip).

The **fdtbus** driver provides generic, common infrastructure for all [fdt(4)](/fdt/4.md) oriented device drivers, and its main responsibilities are the following:

- Creating newbus children that reflect [fdt(4)](/fdt/4.md) nodes in the flattened device tree.

- Managing SYS\_RES\_IRQ resources.

- Managing SYS\_RES\_MEMORY, SYS\_RES\_IOPORT resources.

## SEE ALSO

[fdt(4)](/fdt/4.md), [openfirm(4)](/openfirm/4.md), [simplebus(4)](/simplebus/4.md)

## STANDARDS

IEEE Std 1275: IEEE Standard for Boot (Initialization Configuration) Firmware: Core Requirements and Practices (*Open* *Firmware*).

Power.org Standard for Embedded Power Architecture Platform Requirements (*ePAPR*).

## HISTORY

The **fdtbus** support first appeared in FreeBSD 9.0.

## AUTHORS

The **fdtbus** support was developed by Semihalf under sponsorship from the FreeBSD Foundation. This manual page was written by Rafal Jaworowski.