Re: [PATCH v10 2/3] DMA: Freescale: Add new 8-channel DMA enginedevice tree nodes

From: Hongbo Zhang
Date: Tue Sep 24 2013 - 06:31:31 EST

On 09/24/2013 01:04 AM, Stephen Warren wrote:
On 09/18/2013 04:15 AM, hongbo.zhang@xxxxxxxxxxxxx wrote:
From: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>

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.

+dma@100300 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ compatible = "fsl,elo3-dma";
+ reg = <0x100300 0x4>,
+ <0x100600 0x4>;

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at