Re: [PATCH] dma-mapping: remove an unnecessary NULL check

[Christoph Hellwig]

On Thu, Apr 25, 2019 at 03:13:49PM +0100, Ian Abbott wrote:
> So for comedi_isadma, we can just replace the NULL with a pointer to a 
> static dummy device with a 24-bit coherent mask?

It should be converted to a proper isa_driver, so that it gets a real
struct device.