Messages in this thread | | | Date | Tue, 21 Aug 2018 07:59:48 +0200 | From | Boris Brezillon <> | Subject | Re: [LINUX PATCH v10 1/2] dt-bindings: mtd: arasan: Add device tree binding documentation |
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On Tue, 21 Aug 2018 05:47:18 +0000 Naga Sureshkumar Relli <nagasure@xilinx.com> wrote:
> > > +Required properties: > > > +- compatible: Should be "xlnx,zynqmp-nand" or "arasan,nfc-v3p10" > > > > In your example it's not an "or" since both are defined. > In our previous discussion (https://lore.kernel.org/patchwork/patch/748901/) > We decided to have compatible strings like " compatible = "<soc-vendor>,<ip-revision>", "arasan,<ip-revision>";" > So it should be either of these. > so I will write something like below > "Possible values are "xlnx,zynqmp-nand" > "arasan,nfc-v3p10" > And in example I will mention any one compatible. > Is it ok?
Hm, why do you need arasan,nfc-v3p10 at all if it's supposed to be overloaded by a soc specific compat?
> > > + > > > +Optional properties: > > > +- arasan,has-mdma: Enables DMA support > > > > Can't you detect that based on the compatible (or thanks to a register). If it's something you > > choose when configuring the IP and can't detect at runtime I guess it's fine. > There is no way to select DMA when configuring the IP. > But it has internal DMA and there is a register to select PIO or DMA while starting a transfer. > So if user really don't want DMA, then we will never set DMA in the code based on DT property.
If it's a purely SW choice, then is shouldn't be described in the DT. You can use a module param, but I'm not even sure why one would want to disable DMA.
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