Re: [PATCH v28 2/4] dt-bindings: i2c: ast2600-i2c.yaml: Add global-regs and enable-dma properties

[Krzysztof Kozlowski <krzk@kernel.org>]

On Mon, Mar 30, 2026 at 04:21:47PM +0800, Ryan Chen wrote:
> Add aspeed,enable-dma boolean property to indicate that DMA is
> available for transfers on this I2C bus.
> 
> Also add the aspeed,global-regs phandle to reference the AST2600
> global registers syscon node, containing the SoC-common I2C register
> set.
> 
> These properties apply only to the AST2600 binding. Legacy DTs remain
> unchanged.
> 
> Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
> ---
> Changes in v28:
> - update commit message correspond with aspeed,enable-dma.
> - remove aspeed,transfer-mode and add aspeed,enable-dma property and
>   description.
> - Fix aspeed,enable-dma description to reflect hardware capability rather
>   than software behavior
> Changes in v27:
> - change aspeed,transfer-mode to aspeed,enable-dma.
> ---
>  .../devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml          | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml b/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml
> index de2c359037da..67b23d1a4cec 100644
> --- a/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml
> +++ b/Documentation/devicetree/bindings/i2c/aspeed,ast2600-i2c.yaml
> @@ -37,6 +37,16 @@ properties:
>    resets:
>      maxItems: 1
>  
> +  aspeed,enable-dma:
> +    type: boolean
> +    description: Indicates this I2C controller instance has DMA capability.

Compatible implies that "I2C controller instance has DMA capability", no?

How two same devices, with exactly the same or compatible programming
model can have difference in the programming model for DMA (one lacks
it)?

Best regards,
Krzysztof