@DumTux Two avenues to pursue here:
1) SPI issue
The Omega2 family does not support full-duplex SPI transmissions because of a hardware bug in the underlying MT7688 SoC used in the Omega2. More details in this FAQ post.
The MT7688 is intended to support full-duplex, so it will have all of the full-duplex flags. I'm not sure how that will impact your driver.
An alternative would be to setup software based SPI and instantiate your mcp2515 driver on the software SPI. We have information on how to setup a sw SPI bus from userspace, but we don't have experience with sw SPI using the DTS file.
2) IRQ GPIO in DTS
If I'm reading the DTS file correctly, these lines mean that GPIO11 being is used for the interrupt line?
interrupt-parent = <&gpio>;
interrupts = <11 IRQ_TYPE_EDGE_FALLING>;
Using GPIO11 might be causing the issue. From our GPIO documentation article:
Is there any way you can use a different GPIO for the interrupt line? Even if it's temporary, just to confirm this is causing the issue.
Any GPIO not listed as a special pin will do fine.