meta-raspberrypi

If your use case requires a single image to be compatible across a wider range of Raspberry Pi hardware rather than a specific board, use the multi-board machine targets. These machines pull in firmware, kernel images, and modules for all relevant boards in their respective architecture class.

• raspberrypi-armv7: Targets all ARMv7-based Raspberry Pi boards.
• raspberrypi-armv8: Targets all ARMv8-based Raspberry Pi boards.

Standard linux-firmware from OE-Core (poky) does not include the necessary WiFi and Bluetooth firmware for Raspberry Pi boards.

This layer resolves this by using .bbappends to add files from Raspbian repositories to the linux-firmware recipe. All machines in this layer automatically include the required wireless firmware via the MACHINE_EXTRA_RRECOMMENDS variable. For example, raspberrypi3 includes multiple firmware packages to support 3, 3B, and 3B+ models.

To support WM8960-based sound cards (e.g., Waveshare Hi-Fi HAT or Seeed Studio ReSpeaker), add wm8960 to MACHINE_FEATURES. You may need to use amixer to configure volume and toggle mixer settings manually.

MACHINE_FEATURES += "wm8960"

# Example amixer configuration
amixer -c1 sset 'Headphone',0 80%,80%
amixer -c1 sset 'Speaker',0 80%,80%
amixer -c1 sset 'Left Input Mixer Boost' toggle
amixer -c1 sset 'Left Output Mixer PCM' toggle
amixer -c1 sset 'Right Input Mixer Boost' toggle
amixer -c1 sset 'Right Output Mixer PCM' toggle

To enable the one-wire communication bus (typically for sensors), set ENABLE_W1 = "1" in local.conf. The default GPIO pin is 4. After discovery, you can list connected devices using:

ls /sys/bus/w1/devices/

To use CAN with MCP2515-based modules, enable the SPI bus and the CAN interface. For dual CAN modules (like PiCAN2 Duo), use the ENABLE_DUAL_CAN variable instead. You can also configure the crystal oscillator frequency and the interrupt pins for can0 and can1.

# For MCP2515-based modules
ENABLE_SPI_BUS = "1"
ENABLE_CAN = "1"

# For dual CAN modules (e.g. PiCAN2 Duo)
ENABLE_SPI_BUS = "1"
ENABLE_DUAL_CAN = "1"

# Configure oscillator frequency (default is 16MHz, e.g., to set 8MHz)
CAN_OSCILLATOR="8000000"

# Configure interrupt pins (defaults: can0=25, can1=24)
CAN0_INTERRUPT_PIN = "12"
CAN1_INTERRUPT_PIN = "16"

# For 2-Channel CAN-BUS(FD) Shield (MCP2518FD)
ENABLE_DUAL_CAN_SEED_FD_HAT_V2 = "1"

There are two primary ways to contribute to meta-raspberrypi:

1. GitHub Pull Requests (Preferred): Submit pull requests directly to the GitHub mirror at https://github.com/agherzan/meta-raspberrypi.
2. Mailing List: Send patches to the Yocto Project mailing list. If using this method, you must use specific git formatting for the subject line and use git send-email to deliver them.

When sending to the mailing list, the maintainer will periodically include your patches in a GitHub pull request to trigger CI workflows.

# Generate patches with the correct subject prefix
git format-patch -s --subject-prefix='meta-raspberrypi][PATCH' origin

# Send the generated patch to the mailing list
git send-email --to yocto@lists.yoctoproject.org <generated patch>

To build a Raspberry Pi image using standard Yocto/OpenEmbedded workflows, follow these steps:

1. Initialize the build environment:

   source openembedded-core/oe-init-build-env rpi-build

2. Configure bblayers.conf to include meta-raspberrypi and its required dependencies (bitbake, openembedded-core, and meta-yocto).
3. Configure local.conf by setting the MACHINE variable to one of the supported Raspberry Pi boards.
4. Execute the build:

   bitbake core-image-base

5. Flash the resulting .wic.bz2 file to an SD card using bmaptool.
6. Boot the Raspberry Pi.

Camera modules are not enabled by default. You must explicitly enable them in local.conf to add the correct device tree overlays and memory allocations.

• Camera Module V2: Uses imx219 overlay. Set RASPBERRYPI_CAMERA_V2 = "1".
• Camera Module V3: Uses imx708 overlay. Set RASPBERRYPI_CAMERA_V3 = "1".

To enable a hardware shutdown button using device tree kernels, set ENABLE_GPIO_SHUTDOWN = "1". This includes the gpio-keys kernel module.

Note: The default pin is GPIO 3, which conflicts with the I2C bus. If you are using I2C or PiTFT, you must assign a different pin using GPIO_SHUTDOWN_PIN.

ENABLE_GPIO_SHUTDOWN = "1"
GPIO_SHUTDOWN_PIN = "25"

If you prefer using the kas build tool, follow these steps:

1. Install kas via PyPi:

   sudo pip3 install kas

2. Edit the `kas-poky-rpi.yml` file and set the `machine:` key to one of the supported boards (refer to `conf/machine/*.conf` for available options).
3. Run the build using `kas`:
   ```bash
   kas build meta-raspberrypi/kas-poky-rpi.yml

4. Flash the generated .wic.bz2 file to an SD card using bmaptool.
5. Boot the Raspberry Pi.