[PATCH v10 2/3] DMA: Freescale: Add new 8-channel DMA engine device tree nodes
Hongbo Zhang
hongbo.zhang at freescale.com
Tue Sep 24 20:30:59 EST 2013
On 09/24/2013 01:04 AM, Stephen Warren wrote:
> On 09/18/2013 04:15 AM, hongbo.zhang at freescale.com wrote:
>> From: Hongbo Zhang <hongbo.zhang at freescale.com>
>>
>> Freescale QorIQ T4 and B4 introduce new 8-channel DMA engines, this patch adds
>> the device tree nodes for them.
>> diff --git a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt
>> +Required properties:
>> +
>> +- compatible : must include "fsl,elo3-dma"
>> +- reg : DMA General Status Registers, i.e. DGSR0 which contains
>> + status for channel 1~4, and DGSR1 for channel 5~8
> Is that a single entry, which is large enough to cover both registers,
> or a pair of entries, one per register? Reading the text, I might assume
> the former, but looking at the examples, it's the latter.
My impression is that I cannot tell it is one larger entry or two
entries by reading the description text, but the example gives the answer.
Is it so important to specify it is only one entry or entries list?
I prefer language as concise as possible, especially for the common
properties such as reg and interrupt (eg the reg is implicitly offset
and length of registers, can be continuous or not), it is difficult or
unnecessary or impossible to describe much details, the example can also
work as a complementary description, otherwise no need to put an example
in the binding document.
> ...
> +Example:
>> +dma at 100300 {
>> + #address-cells = <1>;
>> + #size-cells = <1>;
>> + compatible = "fsl,elo3-dma";
>> + reg = <0x100300 0x4>,
>> + <0x100600 0x4>;
>
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