On 14/08/2020 11:03, Thomas Preston wrote:

I'm in the process of adding a device tree overlay for the PiFace
Digital Raspberry Pi daughter board [0]. It's an mcp23s17 SPI GPIO port
expander. In doing so, I noticed some errors with the mcp23s08 driver.

[snip]

They're quite trivial and backwards compatible, although I might be
wrong about "interrupt-controller". Can someone please confirm?

[snip]

[0] https://github.com/raspberrypi/linux/pull/3794

Actually I think I'm wrong about the interrupt-controller changes in 
patches 0002 and 0003.

I think Patch 0001 fixups are fine still.

Sorry for the noise!