On Mon, Nov 09, 2020 at 08:47:10AM -0500, Sean Anderson wrote:
> On 11/9/20 8:29 AM, Mark Brown wrote:

> > In this case it also looks like the controller hardware requires
> > transmit data and therefore should be setting SPI_MUST_TX and just
> > removing the in driver default anyway, though that will have no effect
> > one way or anther on the issue you're seeing.

> There is a recieve-only mode, but it is not used by this driver. Perhaps
> it should be.

I'd expect it'd perform better, especially on systems that are
apparently struggling for CPU bandwidth like yours seems to.

> > Please also try to avoid the use of master/slave terminology where
> > reasonable, controller and device tend to work for SPI (though MOSI/MISO
> > are going to be harder to shift).

> Here I use it to draw distinction between the SPI master and the SPI
> slave, which are both devices in different contexts. 

If you find the use of device to refer to the device being controlled
confusing consider also using something like client device instead,
there's a number of ways to do it (there's a list in Documentation IIRC).