Re: [PATCH v4 3/7] dt-bindings: dmaengine: xilinx_dma: add optional xlnx,sg-length-width property

[Rob Herring <robh@kernel.org>]

On Thu, Aug 02, 2018 at 04:10:08PM +0200, Andrea Merello wrote:
> The width of the "length register" cannot be autodetected, and it is now
> specified with a DT property. Add DOC for it.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: devicetree@vger.kernel.org
> Cc: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
> Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
> ---
> Changes in v2:
> 	- change property name
> 	- property is now optional
> 	- cc DT maintainer
> Changes in v3:
> 	- reword
> 	- cc DT maintainerS and ML
> Changes in v4:
> 	- specify the unit, the valid range and the default value
> ---
>  Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt b/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt
> index a2b8bfaec43c..aec4a41a03ae 100644
> --- a/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt
> +++ b/Documentation/devicetree/bindings/dma/xilinx/xilinx_dma.txt
> @@ -41,6 +41,10 @@ Optional properties:
>  - xlnx,include-sg: Tells configured for Scatter-mode in
>  	the hardware.
>  Optional properties for AXI DMA:
> +- xlnx,sg-length-width: Should be set to the width in bits of the length
> +  	register as configured in h/w. Takes values {8...26}. If the property
> +	is missing or invalid then the default value 23 is used. This is the
> +	maximum value that is supported by all IP versions.

If 23 is the max, then why is the range 8-26?