[BPI-R3] [OpenWRT] Support for SPI communication in OpenWRT

Given that the BPI-R3 (or R4) seem to have a GPIO header that looks to have SPI pins - Is there any support for SPI communications in OpenWRT.

If there is some latent support for SPI in OpenWRT, but not supported on the BPI-R3 - I might start looking into the OpenWRT kernel to see what’s involved in adding support. Any pointers would be appreciated.

SPI is fully supported, and the bus on pins 19, 21 and 23 of the 26-pin header is also enabled by default. However, nothing is connected to it. Linux doesn’t enabled access to SPI from userspace by default but rather only for specific peripherals if defined in device tree:

So to either have access to /dev/spi* or assign an in-kernel driver you have to add those to the device tree of the R3. The usual way to do so would be by creating a device tree overlay describing the peripheral board you are attaching and it’s connections (SPI I know now, but maybe also other input or output pins for reset, interrupt, …).