Re: [PATCH 3/5] dt-bindings: stm32-dma: Add property to handle STM32 DMAMUX

[Pierre Yves MORDRET]

On 03/20/2017 10:37 PM, Rob Herring wrote:
> On Mon, Mar 13, 2017 at 03:15:59PM +0100, M'boumba Cedric Madianga wrote:
>> This patch adds an optional property needed for STM32 DMA controller
>> addressed via STM32 DMAMUX.
>>
>> Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@xxxxxxxxx>
>> ---
>>  Documentation/devicetree/bindings/dma/stm32-dma.txt | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/dma/stm32-dma.txt b/Documentation/devicetree/bindings/dma/stm32-dma.txt
>> index 4408af6..7b5e91a 100644
>> --- a/Documentation/devicetree/bindings/dma/stm32-dma.txt
>> +++ b/Documentation/devicetree/bindings/dma/stm32-dma.txt
>> @@ -16,6 +16,9 @@ Optional properties:
>>  - resets: Reference to a reset controller asserting the DMA controller
>>  - st,mem2mem: boolean; if defined, it indicates that the controller supports
>>    memory-to-memory transfer
>> +- st,dmamux: boolean; if defined, it indicates that the controller is behind a
>> +  DMA multiplexer. In that case, using dma instances doesn't work for DMA
>> +  clients. They have to use dma-router instances.
>
> This should not be needed for the same reason we don't need anything
> like this for chained interrupt controllers.
>
> Also, the compatible string should be specific enough to provide this
> information.
>
> Rob

I don't understand what you're meant here. Our DMAs can work with or 
without DMAMUX driver. Driver uses this binding to use it or not.

Py

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