Meta-raspberrypi - how to configure device tree for MCP251x


Chris Tapp
 

I am having trouble getting the Waveshare 2-CH CAN HAT working with an RPI4. Channel 0 does not come up, channel 1 does, but it will only send one message (eventually reporting "write: No buffer space available”) and not receive anything.

Looking at the mcp2515-can0-overlay.dts and mcp2515-can1-overlay.dts device tree files in /tmp/work-shared/raspberrypi4/kernel-source/arch/arm/boot/dts/overlays/, it looks as if the interrupts are not mapped as required for the board.

      DTS               HAT
CAN0  brcm,pins = <25>  PIN23
CAN1  brcm,pins = <25>  PIN25

This doesn’t look right, and seems consistent with the behaviour I am seeing.

I would also like to check the device chip select signals, but I can't see how (if) they are mapped in the dts files.

How can I override these settings when I build the image?

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Chris Tapp
opensource@...
www.keylevel.com

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