Latest kernels include experimental fbttf modules. I connect cheapest oled screen(128x64px) via SPI to orange pi pc.
Connections:
data - spi0 mosi (PC0 pin 19)
clk - spi0 clk (PC2 pin 23)
cs - spi0 cs (PC3 pin 24)
d/c - PC7 (pin 18)
vcc - 3.3v (pin 1)
gnd - gnd (pin 6)
dts overlay:
/*
* adafruit13m-overlay.dts
*
* based on overlay for RPi https://github.com/kenrestivo/linux/blob/3d61a22b05cbf7ac2f6b620dcd45c2fb49fb9442/arch/arm/boot/dts/overlays/adafruit13m-overlay.dts
*/
/dts-v1/ /plugin/;
/ {
compatible = "allwinner,sun8i-h3";
fragment@0 {
target-path = "/aliases";
__overlay__ {
spi0 = "/soc/spi@01c68000";
};
};
fragment@1 {
target = <&pio>;
__overlay__ {
adafruit13m_pins: adafruit13m_pins {
allwinner,pins = "PC7";
allwinner,function = "gpio_out";
};
};
};
fragment@2 {
target = <&spi0>;
__overlay__ {
/* needed to avoid dtc warning */
#address-cells = <1>;
#size-cells = <0>;
status = "okay";
adafruit13m: adafruit13m@0{
compatible = "solomon,ssd1306";
reg = <0>;
pinctrl-names = "default";
pinctrl-0 = <&adafruit13m_pins>;
spi-max-frequency = <6000000>;
buswidth = <8>;
fps = <20>;
dc-gpios = <&pio 2 7 0>;
#debug = <3>;
rotate = <0>;
};
};
};
__overrides__ {
#speed = <&adafruit13m>,"spi-max-frequency:0";
#rotate = <&adafruit13m>,"rotate:0";
fps = <&adafruit13m>,"fps:0";
#debug = <&adafruit13m>,"debug:0";
};
};
build:
/usr/src/linux-headers-4.10.0-sun8i/scripts/dtc/dtc -@ -I dts -O dtb -o /boot/dtb-4.10.0-sun8i/overlay/adafruit13m-overlay.dtbo adafruit13m-overlay.dts
added to /boot/armbianEnv.txt:
overlays=adafruit13m-overlay #overlay loading
extraargs=fbcon=map:1 #remove fbcon attachement
after reboot new framebuffer device found (/dev/fb0 on my headless configuration)
