[PATCH v2 2/7] dt-bindings: dmaengine: Add SpacemiT K3 DMA compatible string

[Troy Mitchell]

Hi Conor,

On Fri Mar 27, 2026 at 2:34 AM CST, Conor Dooley wrote:
> On Thu, Mar 26, 2026 at 04:17:17PM +0800, Troy Mitchell wrote:
>> From: Guodong Xu <guodong at riscstar.com>
>> 
>> Add k3 compatible string.
>
> That's obvious. What you need to explain is why it is not compatible with
> the existing k1.
>
Thanks for the review.

The SpacemiT K3 PDMA requires a new compatible string because it is not fully
backward compatible with the K1 implementation due to two main hardware differences:
- Variable extended DRCMR base: The DRCMR (DMA Request/Command Register) base
  address for extended DMA request numbers (>= 64) is different in the K3 hardware
  implementation.
- Memory addressing capabilities: Unlike the K1 SoC, where some DMA masters had
  memory addressing limitations (restricted to the 0-4GB space) and required a
  dedicated dma-bus, the K3 DMA masters have full memory addressing capabilities.

I will update the commit message in the v3 series.

                                              -Troy