On Wed, Sep 24, 2014 at 01:32:27PM +0300, Andy Shevchenko wrote:
> On Wed, 2014-09-24 at 09:44 +0100, Mark Brown wrote:
> > On Thu, Sep 18, 2014 at 08:08:52PM +0300, Andy Shevchenko wrote:

> > > In case of DMA we never got things done until we enable both channels. In case
> > > of receive only or send only mode the user has to provide a dummy buffer.

> > The driver must never impose such requirements on clients, they
> > shouldn't need to know about the quirks of the controller.  There's
> > support in the core providing dummy buffers for transmit and receive,
> > you should use that (possibly extending it so the dummies are only
> > provided for DMA).

> Currently driver in case of receiving or sending only will never call
> the xfer_done from DMA callback since we never will have counter equal
> to 2. So, the driver already relies on duplex mode. Am I missing
> something?

Please re-read what I wrote above, especially the first phrase.  You
can't require that we rewrite essentialy every SPI driver on the off
chance that it's used with this controller.