Re: [PATCH 4/4] Update device tree Synopsys DW DMAC documentation

[Andy Shevchenko]

On Wed, 2016-11-16 at 16:56 +0300, Eugeniy Paltsev wrote:
> Â* Rename is_private to is-private as ordered by DT policy.
> ÂThe change leaves the support for the old format.
> 
> Â* Add is-memcpu property, so it is possible to
> Âenable memory-to-memory transfers support via DT.
> 
> Â* Add hw-llp property, so it is possible to enable
> Âhardware multi block transfers support via DT.
> 
> ÂFix white spaces.
> 
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
> ---
> ÂDocumentation/devicetree/bindings/dma/snps-dma.txt | 10 ++++++++--
> Â1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt
> b/Documentation/devicetree/bindings/dma/snps-dma.txt
> index 0f55832..d41d960 100644
> --- a/Documentation/devicetree/bindings/dma/snps-dma.txt
> +++ b/Documentation/devicetree/bindings/dma/snps-dma.txt
> @@ -20,13 +20,19 @@ Required properties:
> ÂDeprecated properties:
> Â- data_width: Maximum data width supported by hardware per AHB master
> ÂÂÂ(0 - 8bits, 1 - 16bits, ..., 5 - 256bits)

> +- is_private: The device channels should be marked as private and not
> for by the
> +ÂÂgeneral purpose DMA channel allocator. False if not passed.

This...

> Â
> Â
> ÂOptional properties:
> Â- interrupt-parent: Should be the phandle for the interrupt
> controller
> ÂÂÂthat services interrupts for this device

> -- is_private: The device channels should be marked as private and not
> for by the
> +- is-private: The device channels should be marked as private and not
> for by the
> ÂÂÂgeneral purpose DMA channel allocator. False if not passed.

...and this is a part of patch 1.

> +- is-memcpu: The device channels do support memory-to-memory 

memcpy

> transfers. 

> False
> +ÂÂif not passed.
> +- hw-llp: Multi block transfers supported by hardware per AHB master.
> +ÂÂ0 (default): not supported, 1: supported.

Overall, since we are going to expose some properties to the Device Tree
I would really think twice about naming. Better if we reuse something
existing already.

So, what I can see is

dmacap,private
dmacap,memcpy

Here is a selling point as well, i.e. standardization.

'hw-llp' sounds too tricky, perhaps 'multi-block' is better and could be
re-used.

> Â
> ÂExample:
> Â
> @@ -56,7 +62,7 @@ The four cells in order are:
> Â4. Peripheral master for transfers on allocated channel
> Â

> ÂExample:
> -	
> +

No, no need to touch this.

-- 
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy