Getting Started Guide
This simple guide covers DTSh’s installation, configuration and basic usage.
Install DTSh
DTSh runs on Linux, macOS and Windows with Python 3.8 to 3.11.
It can be installed in some Zephyr development environment, or standalone in any Python environment.
Warning
On Windows, the readline API, on which DTSh relies for auto-completion and command history, is no longer distributed with the Python Standard Library: as a consequence, the user experience will be significantly degraded on this platform. This is known issue without workaround.
Prefer WSL if possible.
Requirements
Only prerequisite is the Python devicetree library, part of the Zephyr project. Other run-time requirements are simple external dependencies available from PyPI.
python-devicetree
To parse DTS and binding files into Devicetree models, DTSh relies on the
python-devicetree library (edtlib),
part of Zephyr’s DTS tooling.
Although this API may eventually become a standalone source code library, it is currently not a priority of the Zephyr project, and the PyPI package is no longer updated (the latest version is April 2022).
DTSh therefore re-distributes snapshots of this library along with its own implementation. This works but is not an ideal situation.
External Dependencies
Textualize’s rich library for beautiful formatting |
|
PyYAML, YAML parser for Python |
|
Stand-alone GNU readline module (macOS only) |
Installation
There are basically two types of installation:
alongside West, in a Python virtual environment you use for Zephyr development
standalone in any Python virtual environment
Install Alongside West
This method installs DTSh in a Python virtual environment that belongs to a West workspace, (where the west command itself is installed, with other dependencies).
Assuming you’ve followed Zephyr’s Getting Started Guide, the workspace should look like this:
zephyrproject/
├── .venv
├── .west
├── bootloader
├── modules
├── tools
└── zephyr
To install DTSh alongside West, activate this zephyrproject/.venv environment
before running pip:
# Active the Python virtual environment if not already done.
. zephyrproject/.venv/bin/activate
# Install latest version of DTSh from PyPI.
pip install -U dtsh
Tip
Or just run pip install -U dtsh from the same prompt where you usually enter west commands.
Standalone Installation
This method installs DTSh in a dedicated Python virtual environment: it’s a little less convenient but avoids installing anything in a development environment you actually depend on.
# Initialize Python virtual environment.
mkdir dtsh
cd dtsh
python -m venv .venv
# Activate and update system tools.
. .venv/bin/activate
pip install -U pip setuptools
# Install DTSh from PyPI.
pip install -U dtsh
Usage
Once installed, the Devicetree Shell is available as the dtsh command:
$ dtsh -h
usage: dtsh [-h] [-b DIR] [-u] [--preferences FILE] [--theme FILE] [-c CMD] [-f FILE] [-i] [DTS]
shell-like interface with Devicetree
options:
-h, --help show this help message and exit
open a DTS file:
-b DIR, --bindings DIR
directory to search for binding files
DTS path to the DTS file
user files:
-u, --user-files initialize per-user configuration files and exit
--preferences FILE load additional preferences file
--theme FILE load additional styles file
session control:
-c CMD execute CMD at startup (may be repeated)
-f FILE execute batch commands from FILE at startup
-i, --interactive enter interactive loop after batch commands
We’ll first confirm that the installation went well with a simple but typical usage, before tackling a few other scenarios.
Typical Use
Early at build-time, during the configuration phase, Zephyr assembles the final devicetree that will represent the system hardware during the actual build phase.
This devicetree is saved in Devicetree Source Format (DTS)
in build/zephyr/zephyr.dts for debugging purpose.
The typical DTSh’s use case is to open this DTS file generated at build-time, e.g.:
$ cd zephyr/samples/sensor/bme680
$ cmake -B build -DBOARD=nrf52840dk_nrf52840
$ dtsh build/zephyr/zephyr.dts
dtsh (0.2.2): A Devicetree Shell
How to exit: q, or quit, or exit, or press Ctrl-D
/
> ls -l
Name Labels Binding
───────────────────────────────────────────────────────
chosen
aliases
soc
pin-controller pinctrl nordic,nrf-pinctrl
entropy_bt_hci rng_hci zephyr,bt-hci-entropy
sw-pwm sw_pwm nordic,nrf-sw-pwm
cpus
leds gpio-leds
pwmleds pwm-leds
buttons gpio-keys
connector arduino_header arduino-header-r3
analog-connector arduino_adc arduino,uno-adc
The above example should always work:
regardless of the installation method,
cmakebeing sufficient for the configuration phaseregardless of whether
ZEPHYR_BASEis setregardless of whether you target a supported board or a custom board
Here, DTSh retrieves all it needs, and especially where to search for the bindings files,
from the CMake cache content in CMakeCache.txt:
build
├── CMakeCache.txt
└── zephyr
└── zephyr.dts
Tip
In this context, no need to pass the DTS file path to DTSh: by default it will try to open the devicetree at
build/zephyr/zephyr.dts;dtsh /path/to/project/build/zephyr/zephyr.dtswould also work, you don’t need to calldtshfrom the project’s rootTo open your devicetree:
cd <project> && cmake -B build -DBOARD=<board> && dtsh, or if using Westcd <project> && west build && dtsh
Other Uses
As we’ve seen, DTSh first tries to retrieve the bindings Zephyr has used at build-time, when the DTS file was generated, from the CMake cache. This is the most straight forward way to get a complete and legit bindings search path.
When this fails, DTSh will then try to work out the search path
Zephyr would use if it were to generate the DTS now
(Where Bindings Are Located): bindings found in
$ZEPHYR_BASE/dts/bindings and other default directories should still cover
the most simple use cases (e.g. Zephyr samples).
$ export ZEPHYR_BASE=/path/to/zephyrproject/zephyr
$ dtsh /path/to/zephyr.dts
This default behavior does not address all situations, though:
you may need additional bindings files from a custom location, or explicitly set the
DTS_ROOTCMake variableyou’re not working with Zephyr
For these use cases, the -b --bindings option permits to explicitly enumerate all the directories
to search in:
$ dtsh –bindings dir1 –bindings dir2 foobar.dts
Where:
dir1anddir1, and their sub-directories, shall contain all necessary YAML binding files in Zephyr’s Devicetree Binding Syntax, even if not working with Zephyrone of these directories shall contain a valid vendors file, e.g.
dir1/vendor-prefixes.txt
Batch Mode
For scripting and automation, DTSh can also be used non-interactively by passing:
a series of commands to execute at startup:
-c CMD1 -c CMD2or a file containing such commands:
-f FILE
The -i --interactive option then permits to enter the interactive loop after the batch commands have been executed.
For example, to list the contents of the root of the devicetree and then change to another directory, before entering the interactive loop, you can use the following command:
$ dtsh -c "ls -l" -c "cd &i2c0" -i
dtsh (0.2.2): A Devicetree Shell
How to exit: q, or quit, or exit, or press Ctrl-D
> Name Labels Binding
───────────────────────────────────────────────────────
chosen
aliases
soc
pin-controller pinctrl nordic,nrf-pinctrl
entropy_bt_hci rng_hci zephyr,bt-hci-entropy
sw-pwm sw_pwm nordic,nrf-sw-pwm
cpus
leds gpio-leds
pwmleds pwm-leds
buttons gpio-keys
connector arduino_header arduino-header-r3
analog-connector arduino_adc arduino,uno-adc
/soc/i2c@40003000
❭
Configuration
Users can tweak DTSh appearance and behavior by overriding its defaults in configuration files:
dtsh.ini: to override global preferences (see User Preferences)theme.ini: to override styles and colors (see User Themes)
These (optional) files must be located in a platform-dependent directory,
e.g. ~/.config/dtsh on GNU/Linux systems.
Running dtsh with the -u --user-files option will initialize configuration templates
in the expected location:
$ dtsh -u
User preferences: ~/.config/dtsh/dtsh.ini
User theme: ~/.config/dtsh/theme.ini
Tip
DTSh won’t override a user file that already exists: manually remove the file(s), and run the command again.
Eventually:
the
--preferences FILEoption permits to specify an additional preferences file to loadthe
--theme FILEoption permits to specify an additional theme file to load
First Steps
The few examples bellow introduce the basics of DTSh. Please refer to the handbook for complete documentation.
Navigate the devicetree like a file-system with cd:
/
> cd &i2c0
/soc/i2c@40003000
> cd ../flash-controller@4001e000
/soc/flash-controller@4001e000
> cd
/
❭
Print information about nodes with ls:
/
> ls
chosen
aliases
soc
pin-controller
entropy_bt_hci
sw-pwm
cpus
leds
pwmleds
buttons
connector
analog-connector
/
> ls &flash0 -l
Name Labels Binding
────────────────────────────────────
partitions fixed-partitions
/
> ls &flash0 -ld
Name Labels Binding
─────────────────────────────
flash@0 flash0 soc-nv-flash
/
> ls soc/flash-controller@4001e000/flash@0/partitions --format NKr
Name Also Known As Registers
─────────────────────────────────────────────────────────────
partition@0 mcuboot, boot_partition 0x0 (48 kB)
partition@c000 image-0, slot0_partition 0xc000 (472 kB)
partition@82000 image-1, slot1_partition 0x82000 (472 kB)
partition@f8000 storage, storage_partition 0xf8000 (32 kB)
Visualize the devicetree with, well, tree:
/soc
> tree --format Nc
Compatible
────────────────────────────────────────────────────────────
soc nordic,nrf52840-qiaa nordic,nrf52840 nordic,nrf52 simple-bus
├── interrupt-controller@e000e100 arm,v7m-nvic
├── timer@e000e010 arm,armv7m-systick
├── ficr@10000000 nordic,nrf-ficr
├── uicr@10001000 nordic,nrf-uicr
├── memory@20000000 mmio-sram
├── clock@40000000 nordic,nrf-clock
├── power@40000000 nordic,nrf-power
│ ├── gpregret1@4000051c nordic,nrf-gpregret
│ └── gpregret2@40000520 nordic,nrf-gpregret
├── radio@40001000 nordic,nrf-radio
│ └── ieee802154 nordic,nrf-ieee802154
├── uart@40002000 nordic,nrf-uarte
├── i2c@40003000 nordic,nrf-twi
│ └── bme680@76 bosch,bme680
Search the devicetree with find:
/
> find --with-description "2.4 GHz" -T --format NKCd
Also Known As Binding Description
────────────────────────────────────────────────────────────────────
/ … … …
└── soc … … …
└── radio@40001000 radio nordic,nrf-radio Nordic nRF family RADIO peripheral…
Export the devicetree to HTML by redirecting (>) commands output:
/
> ls -lR > board.html