Messages in this thread | | | Date | Thu, 3 Sep 2015 10:18:54 +0100 | From | Peter Griffin <> | Subject | Re: [PATCH 1/7] dmaengine: st_fdma: Add STMicroelectronics FDMA DT binding documentation |
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Hi Lee,
On Wed, 26 Aug 2015, Lee Jones wrote:
> On Tue, 25 Aug 2015, Peter Griffin wrote: > > > Hi Vinod, > > > > Thanks for reviewing. > > > > On Wed, 19 Aug 2015, Vinod Koul wrote: > > > > > On Wed, Jul 08, 2015 at 05:11:22PM +0100, Peter Griffin wrote: > > > > This patch adds the DT binding documentation for the FDMA constroller > > > > found on STi based chipsets from STMicroelectronics. > > > > > > > > Signed-off-by: Ludovic Barre <ludovic.barre@st.com> > > > > Signed-off-by: Peter Griffin <peter.griffin@linaro.org> > > > > --- > > > > Documentation/devicetree/bindings/dma/st_fdma.txt | 76 +++++++++++++++++++++++ > > > > 1 file changed, 76 insertions(+) > > > > create mode 100644 Documentation/devicetree/bindings/dma/st_fdma.txt > > > > > > > > diff --git a/Documentation/devicetree/bindings/dma/st_fdma.txt b/Documentation/devicetree/bindings/dma/st_fdma.txt > > > > new file mode 100644 > > > > index 0000000..1ec7470 > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/dma/st_fdma.txt > > > > @@ -0,0 +1,76 @@ > > > > +* STMicroelectronics Flexible Direct Memory Access Device Tree bindings > > > > + > > > > +The FDMA is a general-purpose direct memory access controller capable of > > > > +supporting 16 independent DMA channels. It accepts up to 32 DMA requests. > > > > +The FDMA is based on a Slim processor which require a firmware. > > > > + > > > > +* FDMA Controller > > > > + > > > > +Required properties: > > > > +- compatible : Should be "st,fdma_mpe31" > > > > +- reg : Should contain DMA registers location and length > > > > +- interrupts : Should contain one interrupt shared by all channel > > > > > > s/channel/channels > > > > Will fix in v2. > > > > > > > > > +- dma-channels : Number of channels supported by the controller > > > > +- #dma-cells : Must be <3>. > > > > > > any reason three? > > > > Yes, it is documented further down in the file under DMA Client. > > > > To make it clearer in V2 I could change to > > > > "- #dma-cells : Must be <3>. See DMA client section below"? > > - #dma-cells : Must be <3> > 1st cell: Phandle to ... <blah> > 2nd cell: DMA channel ... <blah> > 3rd cell: Flags describing ... <blah>
I'd prefer not to document it twice in the same file as it is almost 20 lines long. IMHO it makes more sense to document it under the dma-client section like it is done presently, because when writing a dma-client node you need to know what these things mean.
When writing a controller node all you only need to know is "Must be <3>". A more avid reader now has a nice pointer to scroll down if they wish to find out more.
regards,
Peter.
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