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SubjectRe: [PATCH 02/14] dmaengine: dma-jz4780: Separate chan/ctrl registers
On 10-07-18, 17:36, Paul Cercueil wrote:

> > > @@ -3,7 +3,8 @@
> > > Required properties:
> > >
> > > - compatible: Should be "ingenic,jz4780-dma"
> > > -- reg: Should contain the DMA controller registers location and
> > > length.
> > > +- reg: Should contain the DMA channel registers location and
> > > length, followed
> > > + by the DMA controller registers location and length.
> > > - interrupts: Should contain the interrupt specifier of the DMA
> > > controller.
> > > - interrupt-parent: Should be the phandle of the interrupt
> > > controller that
> > > - clocks: Should contain a clock specifier for the JZ4780 PDMA
> > > clock.
> > > @@ -22,7 +23,8 @@ Example:
> > >
> > > dma: dma@13420000 {
> > > compatible = "ingenic,jz4780-dma";
> > > - reg = <0x13420000 0x10000>;
> > > + reg = <0x13420000 0x400
> > > + 0x13421000 0x40>;
> >
> > Second should be optional or we break platform which may not have
> > updated DT..
>
> See comment below.
>
> > > - jzdma->base = devm_ioremap_resource(dev, res);
> > > - if (IS_ERR(jzdma->base))
> > > - return PTR_ERR(jzdma->base);
> > > + jzdma->chn_base = devm_ioremap_resource(dev, res);
> > > + if (IS_ERR(jzdma->chn_base))
> > > + return PTR_ERR(jzdma->chn_base);
> > > +
> > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> > > + if (!res) {
> > > + dev_err(dev, "failed to get I/O memory\n");
> > > + return -EINVAL;
> > > + }
> >
> > okay and this breaks if you happen to get probed on older DT. I think DT
> > is treated as ABI so you need to continue support older method while
> > finding if DT has split resources
>
> See my response to PrasannaKumar. All the Ingenic-based boards do compile
> the devicetree within the kernel, so I think it's still fine to add breaking
> changes. I'll wait on @Rob to give his point of view on this, though.
>
> (It's not something hard to change, but I'd like to know what's the policy
> in that case. I have other DT-breaking patches to submit)

The policy is that DT is an ABI and should not break :)

Who maintains Ingenic arch. MAINTAINERS doesn't tell me.

--
~Vinod

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