Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH 1/2] dma: of: Remove restriction that #dma-cells can't be 0 | Date | Mon, 22 Apr 2013 16:54:37 +0200 |
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On Monday 22 April 2013, Lars-Peter Clausen wrote: > > On 04/22/2013 02:38 PM, Arnd Bergmann wrote: > > On Monday 22 April 2013, Lars-Peter Clausen wrote: > >> > >> There is no sensible reason why #dma-cells shouldn't be allowed to be 0. It is > >> completely up to the DMA controller how many additional parameters, besides the > >> phandle, it needs to identify a channel. E.g. for DMA controller with only one > >> channel or for DMA controllers which don't have a restriction on which channel > >> can be used for which peripheral it completely legitimate to not require any > >> additional parameters. > >> > >> Also fixes the following warning: > >> drivers/dma/of-dma.c: In function 'of_dma_controller_register': > >> drivers/dma/of-dma.c:67:7: warning: 'nbcells' may be used uninitialized in this function > >> > >> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> > > > > Do you have an example for this? If a dma engine has only one request line, > > why would you even use the dmaengine subsystem for it, rather than including > > the code to program it in the slave driver? > > Why wouldn't I use the dmaengine subsystem for a DMA controller? In my > particular case different instances of the same DMA core will be used with > different DMA slaves. And the DMA slaves can also have different DMA master > cores, depending on the system.
Right, that makes sense.
Acked-by: Arnd Bergmann <arnd@arndb.de>
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