Subject: [PATCH V4 1/2] of: Add generic device tree DMA helpers

From: [email-masked] (Jon Hunter)
Date: Fri, 14 Sep 2012 12:19:04 -0500

On 09/14/2012 11:28 AM, Stephen Warren wrote:
> On 09/13/2012 04:00 PM, Jon Hunter wrote:
>> This is based upon the work by Benoit Cousson [1] and Nicolas Ferre [2]
>> to add some basic helpers to retrieve a DMA controller device_node and the
>> DMA request/channel information.
> 
>> diff --git a/Documentation/devicetree/bindings/dma/dma.txt b/Documentation/devicetree/bindings/dma/dma.txt
> 
>> +* Generic DMA Controller and DMA request bindings
>> +
>> +Generic binding to provide a way for a driver using DMA Engine to retrieve the
>> +DMA request or channel information that goes from a hardware device to a DMA
>> +controller.
>> +
>> +
>> +* DMA controller
>> +
>> +Required property:
>> +- #dma-cells: 		Must be at least 1. Used to provide DMA controller
>> +			specific information. See DMA client binding below for
> ...
>> +* DMA client
>> +
>> +Client drivers should specify the DMA property using a phandle to the controller
>> +followed by DMA controller specific data.
>> +
>> +Required property:
>> +- dmas:			List of one or more DMA specifiers, each consisting of
>> +			- A phandle pointing to DMA controller node
>> +			- A single integer cell containing DMA controller
>> +			  specific information. This typically contains a dma
>> +			  request line number or a channel number, but can
>> +			  contain any data that is used required for configuring
>> +			  a channel.
> 
> "A single integer cell" doesn't sound correct; shouldn't this be
> something like "a number of integer cells, as determined by the
> #dma-cells property in the node referenced by phandle"?

Thanks for catching that. I had been re-working this a few times and
must have forgotten to update that.

Cheers
Jon