I am running a Raspberry Pi 3 Model B Plus Rev 1.3, Raspbian Buster, and Linux version 5.10.52-v7+. My CAN Shield is the [RS485&CAN Module](http://wiki.inno-maker.com/display/HOMEPAGE/rs485-can) . How I can use interruptions for knowing when a new frame is received by the CAN-bus ? I can see in your code that the function: `static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)` do that. but how I can access it?