On Wed, Oct 10, 2018 at 10:21:51PM +0000, Trent Piepho wrote:

> So that's the problem!  I, like everyone else I suspect, switched to
> using GPIO chip selects with this driver because of this.  I narrowed

That's generally a good idea.

> it down to a CS de-assert when the bus switched from TX to RX, which of
> course makes a SPI register read fail on most devices.  The TX FIFO
> would empty at this point, so that would explain it.

> Did the designers of this IP ever read a SPI device datasheet???

> Got to agree with Mark Brown, why would anyone ever want to NOT have it
> work properly?  The previous behavior is not "alternate correct", it's
> Broken.

This isn't even that unusual an innovation for hardware to have, for
some reason automatic chip select management is *really* popular and
rarely helpful.  It's far from the most entertaining thing I've seen
hardware do.