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

Ryan Chen
2026-03-31T07:10:14Z

> Subject: Re: [PATCH v28 2/4] dt-bindings: i2c: ast2600-i2c.yaml: Add global-regs
> and enable-dma properties
>
> Hi Ryan,
>
> > All AST2600 I2C controller instances have DMA hardware.
> > I will remove the aspeed,enable-dma property and instead expose sysfs
> > attribute in driver to allow users to enable dma/buffer/byte.
>
> Sounds reasonable, but before you do so, how are you planning to manage the
> allocation of DMA channels across multiple i2c peripherals?
>
The AST2600 I2C hardware has only one can use DMA at a time.
To avoid the complexity of managing DMA channel contention,
I plan to use buffer mode by default for all controllers, which still provides
better performance than byte mode without requiring DMA channel allocation.