Re: [PATCH v2 5/6] Documentation: DT: vdma: update binding doc for AXI CDMA

[Rob Herring]

On Mon, Mar 28, 2016 at 05:27:01AM +0000, Appana Durga Kedareswara Rao wrote:
> Hi Soren,
> 
> > -----Original Message-----
> > From: Sören Brinkmann [mailto:soren.brinkmann@xxxxxxxxxx]
> > Sent: Monday, March 28, 2016 12:58 AM
> > To: Appana Durga Kedareswara Rao
> > Cc: robh+dt@xxxxxxxxxx; pawel.moll@xxxxxxx; mark.rutland@xxxxxxx;
> > ijc+devicetree@xxxxxxxxxxxxxx; galak@xxxxxxxxxxxxxx; Michal Simek;
> > vinod.koul@xxxxxxxxx; dan.j.williams@xxxxxxxxx; Anurag Kumar Vulisha; Appana
> > Durga Kedareswara Rao; moritz.fischer@xxxxxxxxx;
> > laurent.pinchart@xxxxxxxxxxxxxxxx; luis@xxxxxxxxxxxxxxxxx; Srikanth
> > Vemula; Anirudha Sarangi; devicetree@xxxxxxxxxxxxxxx; linux-arm-
> > kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > dmaengine@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH v2 5/6] Documentation: DT: vdma: update binding doc for
> > AXI CDMA
> > 
> > On Sun, 2016-03-27 at 23:36:06 +0530, Kedareswara rao Appana wrote:
> > > This patch updates the device-tree binding doc for adding support for
> > > AXI CDMA.
> > >
> > > Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx>
> > > ---
> > > ---> Modified commit message as suggested by Vinod.
> > > ---> Moved the patch to forward in the series as suggested by vinod.
> > >
> > >  .../devicetree/bindings/dma/xilinx/xilinx_vdma.txt     | 18
> > +++++++++++++++++-
> > >  1 file changed, 17 insertions(+), 1 deletion(-)
> > >
> > > diff --git
> > > a/Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
> > > b/Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
> > > index 5841421..2b0c12b 100644
> > > --- a/Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
> > > +++ b/Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
> > > @@ -8,8 +8,12 @@ target devices. It can be configured to have one channel
> > or two channels.
> > >  If configured as two channels, one is to transmit to the device and
> > > another  is to receive from the device.
> > >
> > > +Xilinx AXI CDMA engine, it does transfers between memory-mapped
> > > +source address and a memory-mapped destination address.
> > > +
> > >  Required properties:
> > > -- compatible: Should be "xlnx,axi-vdma-1.00.a" or "xlnx,axi-dma-1.00.a"
> > > +- compatible: Should be "xlnx,axi-vdma-1.00.a" or "xlnx,axi-dma-1.00.a" or
> > > +	      "xlnx,axi-cdma-1.00.a""
> > >  - #dma-cells: Should be <1>, see "dmas" property below
> > >  - reg: Should contain VDMA registers location and length.
> > >  - xlnx,num-fstores: Should be the number of framebuffers as configured in
> > h/w.
> > > @@ -80,6 +84,18 @@ axi_dma_0: axidma@40400000 {
> > >  	} ;
> > >  } ;
> > >
> > > +axi_cdma_0: axicdma@7e200000 {
> > > +       compatible = "xlnx,axi-cdma-1.00.a";
> > > +       #dma-cells = <1>;
> > > +       reg = < 0x7e200000 0x10000 >;
> > > +       xlnx,addrwidth = <0x20>;
> > > +       dma-channel@7e200000 {
> > > +               compatible = "xlnx,axi-dma-mm2s-channel";
> > > +               interrupts = < 0 55 4 >;
> > > +               xlnx,datawidth = <0x40>;
> > > +       } ;
> > > +} ;
> > 
> > As in the other patch, the node name should be 'dma-controller@...' and the
> > inconsistend spacing could be fixed.
> 
> Ok will fix...
> 
> > 
> > Also, it seems this adds pretty much identical examples that just differ in the
> > compat string. Is that really needed?
> 
> Most of the properties are same across the three DMA's
> For AXI VDMA there are few required properties that are not required for AXI DMA/CDMA.
> That's why added example for the other IP's as well I mean for AXI DMA and CDMA.

It needs to be clear what properties are required/valid for each 
compatible string rather than relying on examples. I should be able to 
write or validate the examples based on the rest of the text.

Rob