Re: [PATCH v2 01/19] dt-bindings: spi: dw: Add Tx/Rx DMA properties

[Serge Semin]

On Fri, May 15, 2020 at 01:27:15PM +0100, Mark Brown wrote:
> On Fri, May 15, 2020 at 02:51:51PM +0300, Andy Shevchenko wrote:
> > On Fri, May 15, 2020 at 01:47:40PM +0300, Serge Semin wrote:
> 
> > > Since commit 22d48ad7bfac ("spi: dw: Add Elkhart Lake PSE DMA support")
> > > the spi-dw-mid.c module supports a platform DMA engine handling the DW APB
> > > SSI controller requests. Lets alter the DW SPI bindings file to accept the
> > > Rx and Tx DMA line specifiers.
> 
> > I'm wondering if these properties are implied by the SPI generic one?
> > (forgive me if I'm not understanding all DT schema relations)
> 
> Which SPI generic DMA bindings are you thinking of here?  There aren't
> any in spi-controller.yaml.

There are default schemas in the dt-core, which defines the dmas and dma-names
type, but the exact naming and number of phandler+identifiers are implementation
specific. So it's either supposed to be implemented on the generic SPI controller
basis (like in someplace of spi-controller.yaml) or in individual controllers DT
schema. As Mark said we don't have any DMA properties definition in the generic
SPI controller schema (spi-controller.yaml), so the particular SPI controllers
DT schemas have got their own DMA properties declared. Most of them BTW use the
same naming as we do here: "rx" and "tx", but some alas don't.

-Sergey