Re: [PATCH v2] spi/drivers: Restrict COMPILE_TEST by HAS_DMA where needed

From: Mark Brown
Date: Sun Aug 31 2014 - 09:19:31 EST

On Sun, Aug 31, 2014 at 10:39:09AM +0200, Geert Uytterhoeven wrote:
> On Fri, Aug 29, 2014 at 9:13 PM, Geert Uytterhoeven

> >> I'm wondering if it isn't better to have the non-DMA platforms define
> >> stub (always error) DMA functions instead - it's less error prone and
> >> with SPI there's a bunch of drivers which can run perfectly usefully
> >> without DMA while optionally supporting DMA.

> > The SPI problem will sort itself out once all SPI master drivers have been
> > converted to use the SPI DMA core ;-)

> BTW, the dmaengine API has stubs, only the low-level dma-mapping API
> doesn't. That's why e.g. spi-rspi doesn't need a dependency on HAS_DMA.
> So it's indeed a good thing to handle the low-level DMA mapping in the
> subsystem's core, as only that part can be optional and depend on HAS_DMA.

Yeah, but I'd expect there's other subsystems which will be in a similar
boat here and with dmaengine having stubs it seems strange that the
mapping API doesn't.

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