Flattened Device Tree Python Module

Common errors

• FileNotFoundError: [Errno 2] No such file or directory: 'dtc'

  cause You are attempting to parse a DTS string using `FDT.from_dts()`, but the `dtc` (Device Tree Compiler) utility is not installed or not found in your system's PATH.
  fix Install `dtc` on your operating system. For Debian/Ubuntu, use `sudo apt install device-tree-compiler`. For other systems, consult your distribution's package manager or the official `dtc` documentation.

• fdt.FdtException: Error parsing DTB data: 'Invalid FDT magic'

  cause The input provided to the `FDT()` constructor is not valid binary Flattened Device Tree (DTB) data. This often happens if you pass a DTS string, malformed data, or an incorrect file format.
  fix Ensure the input to `FDT()` is valid binary DTB `bytes` data. If you intend to parse a DTS string, use `FDT.from_dts(your_dts_string)` instead (and ensure `dtc` is installed).

• fdt.FdtException: Error parsing DTS data: 'Command '['dtc', '-I', 'dts', '-O', 'dtb', '-o', ...

  cause While `dtc` was found, it failed to parse the provided DTS string. This indicates a syntax error or invalid structure within your DTS input.
  fix Carefully review your DTS string for syntax errors, missing semicolons, incorrect property formats, or malformed nodes. You can try running `dtc -I dts -O dtb -o /dev/null your_file.dts` directly in your terminal to get more specific error messages from `dtc`.

Warnings

• gotcha Parsing DTS (Device Tree Source) strings requires the `dtc` (Device Tree Compiler) utility to be installed on your system and available in the PATH. The `fdt` library executes `dtc` as a subprocess for this conversion.
  Fix: Install `dtc` via your system's package manager (e.g., `sudo apt install device-tree-compiler` on Debian/Ubuntu, or check your distribution's documentation).
• gotcha The `FDT` constructor directly accepts binary DTB data (`bytes`), while `FDT.from_dts()` is a class method specifically for parsing DTS string data (`str`). Mixing these can lead to parsing errors.
  Fix: Ensure you use `FDT(binary_dtb_data)` for DTB and `FDT.from_dts(dts_string_data)` for DTS. Do not pass DTS strings directly to the `FDT` constructor.

Install

• pip install fdt Install fdt

Imports

• FDT

  from fdt import FDT

Quickstart

Demonstrates loading Flattened Device Tree data from both a binary DTB blob and a DTS string. Note the requirement for the `dtc` utility for DTS parsing.

import os
from fdt import FDT

# Example 1: Parsing a binary DTB blob
# (Often read from a .dtb file)
dtb_blob = b'\xd0\x0d\xfe\xed\x00\x00\x00\x28\x00\x00\x00\x18\x00\x00\x00\x08\x00\x00\x00\x01\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00'

try:
    fdt_dtb = FDT(dtb_blob)
    print("\n--- Parsed DTB ---")
    print(fdt_dtb.get_dts()) # Convert to DTS string for display
except Exception as e:
    print(f"Error parsing DTB: {e}")

# Example 2: Parsing a DTS string
# Requires 'dtc' (Device Tree Compiler) to be installed on the system path.
# On Debian/Ubuntu: sudo apt install device-tree-compiler
dts_string = """
/dts-v1/;
/ {
    compatible = "example,device";
    prop1 = <0x12345678>;
    node1 {
        prop2 = "hello world";
    };
};
"""

try:
    fdt_dts = FDT.from_dts(dts_string)
    print("\n--- Parsed DTS ---")
    print(fdt_dts.get_dts()) # Display DTS string
    node = fdt_dts.get_node("/node1")
    if node:
        print(f"Value of prop2 in node1: {node.get_property('prop2').get_value()}")
except FileNotFoundError:
    print("\n--- WARNING: 'dtc' not found. Cannot parse DTS string. ---")
    print("Please install 'dtc' (Device Tree Compiler) on your system.")
except Exception as e:
    print(f"Error parsing DTS: {e}")