Enabling Rpi3 Interfaces using Device Tree

Photon OS RPI3 images from Photon 3.0 rev2 has Device Tree Overlay support. And these images have compiled Overlays to enable/disable Rpi3 Interface. Perform the following:

SPI Interface: Execute following commands to enable SPI Interface:

mkdir /sys/kernel/config/device-tree/overlays/
cat /boot/broadcom/overlays/bcm2837-rpi-enable-spi0.dtbo > /sys/kernel/config/device-tree/overlays/spi/dtbo

Audio Interface: Execute following commands to enable Audio Interface:

mkdir  /sys/kernel/config/device-tree/overlays/audio
cat /boot/broadcom/overlays/bcm2837-rpi-enable-audio.dtbo >  /sys/kernel/config/device-tree/overlays/audio/dtbo

Note: Ensure that the linux-drivers-sound rpm is installed.

I2C Interface: Execute following command to enable I2C Interface:

modprobe i2c-dev

#Customizing Device Tree Overlay

Photon OS also provides Device Tree Compilers (i.e. dtc), to compile Customised Device Tree Overlays. Execute following command to install dtc on Photon OS:

tdnf install dtc

Execute following command to compile the overlay:

dtc -@ -O dtb -o my_overlay_dt.dtbo my_overlay_dt.dts

For more information about format of Device Tree Overlay, see https://www.kernel.org/doc/Documentation/devicetree/overlay-notes.txt