Detect and configure pi-top hubs and accessories
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README.md

pi-top Device Management

Python-based daemon for detecting, configuring and communicating with pi-top hardware/peripherals

Table of Contents

What is in this repository?

How do I install pi-top hardware support?

The code in this repository forms the basis of the pt-device-manager software package, available for install on both pi-topOS and Raspbian. On the latest versions of pi-topOS, this package is pre-installed. On other platforms such as Raspbian, it is NOT recommended to install this package directly.

Dependency tree for pi-top device software

As demonstrated in the software tree above, pt-devices installs all of the relevant software for full pi-top device support, and is therefore the best solution for ensuring full pi-top hardware support:

sudo apt install pt-devices

However, this design also allows for specific hardware requirements to only install what is needed. For example, to add pi-topHUB and pi-topSPEAKER support:

sudo apt install pt-hub pt-speaker

As both the packages pt-hub and pt-pulse have dependencies on the pt-device-manager, the pt-device-manager package will also be installed and enabled. It is not recommended to install any of the Python 3 libraries directly if you require plug-and-play functionality.

Summary

pt-device-manager is a Python 3 program that when installed and run on a pi-top device enables detection, configuration and management of pi-top hardware. This includes hubs (e.g. pi-top or pi-topCEED) as well as peripherals (pi-topPULSE, pi-topSPEAKER). The actual work of communicating with each hardware device is handled by software equivalent to 'device drivers' in separate repositories. However the pt-device-manager takes care of loading and initialising these drivers in a pattern akin to a plugin architecture.

The responsibilities of the device manager include:

  • Detecting whether the operating system is running on pi-top hardware, and if so initialising communication with the hub.
  • Communicating with pi-top hubs to detect hardware changes and notifications, such as battery status, hardware-initiated shutdown, etc.
  • Detecting connection/disconnection of pi-top peripherals, such as a pi-topSPEAKER, and initialising peripheral such that whenever possible it will work in a 'plug & play' manner.
  • Opening a request-reponse messaging server and responding to requests from clients, e.g. responding to a request for the current screen brightness.
  • Opening a publishing messaging server and broadcasting to connected client when hardware changes take place.
  • Monitoring user input in order to dim the screen backlight when the user has been inactive for a configurable period.
  • Shutting down the OS when required.

Extra required configuration

Dependencies - pt-device-manager
  • python3-pt-common
    • Common class of Python operations (see this repo)
  • python3-pip
    • Used to install pyserial (see config directory), which is not available to install using apt-get.
  • python3-systemd
    • Used to write to the journal
  • libzmq3-dev, python3-zmq
    • Used to broadcast messages to OS about device changes
  • wiringpi
    • Used by poweroff-v1
  • xprintidle, x11-xserver-utils, lightdm
    • Used for user idle time. Requires additional configuration (see below)
Recommends - pt-device-manager
  • pt-desktop

    • Used, if available, for providing GUI-based instructions/information to the user, particularly to notify if a system reconfiguration is required
  • python3-pt-pulse, python3-pt-speaker, python3-pt-hub-v1, python3-pt-hub-v2, python3-pt-proto-plus

    • Modules that the device manager will use if the device is detected to ensure that it is configured correctly
Dependencies - python3-pt-common
  • raspi-config
    • Used to determine if I2C is enabled, so that devices and peripherals can be detected
  • python3-systemd
    • Used to write to the syslog as a system process
  • i2c-tools
    • Used to handle I2C interaction
  • alsa-utils
    • Used to configure sound settings
User Input

User input for dimming the screen backlight when the user has been inactive for a configurable period is monitored using xprintidle. xprintidle requires extra configuration to work with the root user with admin privileges. This is needed in this case because the device manager needs to run as the root user:

/usr/bin/xhost local:root

To set this up yourself, run xhost-setup.

If you would like to do this manually, you will need to have this run on every boot. Find this line in /etc/lightdm/lightdm.conf:

#display-setup-script=

and modify as follows:

display-setup-script=/usr/bin/xhost local:root

NOTE: pt-device-manager does this automatically for you during the installation process.

Supported device drivers and repositories

The following is a summary of relevant device details:

Device I2C Address SPI Bus
pi-topHUB v1 (pi-top) 0x0b 1
pi-topHUB v1 (pi-topCEED) - 1
pi-topHUB v2 0x10 -
Peripheral I2C Address
pi-topPROTO+ 0x2a
pi-topPULSE 0x24
pi-topSPEAKER v1 (Left) 0x71
pi-topSPEAKER v1 (Right) 0x72
pi-topSPEAKER v1 (Mono) 0x73
pi-topSPEAKER v2 0x43

Contents

Directory: pt-device-manager

pt-device-manager

This Python script is the brain of the pi-top device management on pi-topOS. See How it works for more information.

ptdm_*

These Python modules are used by pt-device-manager.

Directory: library/ptcommon

All files

These files are shared by multiple components in pi-top device management. python3-pt-common installs these files to /usr/lib/python3/dist-packages/, where they can be imported and used by the components that require them.

ptdm_*

These Python modules are used by pt-device-manager.

Directory: tools

pt-brightness, pt-battery

These Python scripts are pt-device-manager messaging clients. They send messages to the device management service to adjust the screen settings or query the battery status on a pi-top device.

pt-i2s

Used by pt-device-manager to switch I2S on/off on the Raspberry Pi, specifically when targeting pi-topSPEAKER/pi-topPULSE. This is only used in conjunction with pi-topHUB v1, as I2S is handled automatically on pi-topHUB v2. To configure for I2S, a custom asound.conf file is used to enable mixing multiple audio sources. As well as this, some settings in /boot/config.txt are altered:

  • dtoverlay=hifiberry-dac - enables I2S audio on subsequent boots
  • #dtparam=audio=on - disables default sound driver
  • dtoverlay=i2s-mmap - allows multiple audio sources to be mixed together

Disabling I2S reverses these changes.

Directory: assets

hifiberry-alsactl.restore

Found in assets subdirectory. This file exposes a soundcard device configuration to the operating system, enabling volume control. It is used by pt-device-manager when it detects that I2S has been enabled via the daemon for the first time, whereby it reboots to enable. This operation is only required once, so a 'breadcrumb' file is created to indicate that this has been completed. This is only used in conjunction with pi-topHUB v1, as I2S is handled automatically on pi-topHUB v2.

Directory: poweroff

poweroff-v1(.c), poweroff-v2

These programs (written in C and Python respectively) are used to send a message directly to the relevant pi-topHUB to trigger a full system hardware shutdown.

poweroff-v{1,2}.service

These are systemd services for the poweroff programs, which ensure that they are always run when the OS is shutting down. These are typically put in /lib/system/systemd/, and enabled by running sudo systemctl enable poweroff-v1.service and sudo systemctl enable poweroff-v1.service in the terminal. These services require the poweroff-v1 and poweroff-v2 files to be executable and put in /usr/lib/pt-device-manager, although this can be easily changed as desired.

Directory: tests

pt-device-manager-req-test

This Python script tests that the device manager is able to respond to requests for information such as the getting current device and brightness level as well as pinging, setting brightness and blanking/unblanking the screen.

pt-device-manager-resp-test

This Python script tests that the device manager is able to emit all of its publishing events, that reflect a system state change, such as battery level, brightness, lid opened/closed and peripheral connection state.

Controlling the device manager

pt-device-manager is intended to be a systemd service which starts with the OS and stops on shutdown. However for diagnostic or debugging purposes it can be useful to start and stop it, or to run it standalone.

Checking the current status of the device manager (with example output):

sudo systemctl status pt-device-manager

 pt-device-manager.service - pi-top device auto-detection and configuration daemon
     Loaded: loaded (/lib/systemd/system/pt-device-manager.service; enabled)
     Active: active (running) since Tue 2017-10-17 15:55:43 UTC; 1s ago
 Main PID: 15974 (pt-device-manag)
     CGroup: /system.slice/pt-device-manager.service
                     └─15974 /usr/bin/python3 /usr/lib/pt-device-manager/pt-device-manager

Starting/stopping the device manager:

sudo systemctl start pt-device-manager
sudo systemctl stop pt-device-manager

Stopping and disabling the service, and then running standalone:

sudo systemctl stop pt-device-manager
sudo systemctl disable pt-device-manager
cd /usr/lib/pt-device-manager
sudo ./pt-device-manager --no-journal --log-level 20

Note when running the device manager standalone, the above two command line parameters are useful:

  • --no-journal forces the device manager to log to stdout rather than the systemd journal
  • --log-level X sets the logging levels where 10 is the lowest (debug) and 40 is the highest (serious errors only)

Logging

As the pt-device-manager runs as a systemd service, it logs to the system journal. This can be viewed using commands such as:

sudo journalctl -u pt-device-manager
sudo journalctl -u pt-device-manager --no-pager
sudo journalctl -u pt-device-manager -b

Support

Links

Troubleshooting

Why is my pi-top device/peripheral not working?

  • Please see the corresponding repository for your device. Repositories are listed at the top of this README.

Why is my pi-top v1 reporting itself to be a pi-topCEED?