RE: [PATCH v27 2/4] dt-bindings: i2c: ast2600-i2c.yaml: Add global-regs and transfer-mode properties

Ryan Chen
2026-03-26T02:19:49Z

> Subject: Re: [PATCH v27 2/4] dt-bindings: i2c: ast2600-i2c.yaml: Add global-regs
> and transfer-mode properties
>
> On Wed, Mar 25, 2026 at 08:11:54AM +0000, Ryan Chen wrote:
> > Hello Jeremy,
> > Thanks the review.
> >
> > > Subject: Re: [PATCH v27 2/4] dt-bindings: i2c: ast2600-i2c.yaml: Add
> > > global-regs and transfer-mode properties
> > >
> > > Hi Ryan,
> > >
> > > > The AST2600 I2C controller supports three transfer modes (byte,
> > > > buffer, DMA). Add "aspeed,transfer-mode" so DT can select the
> > > > preferred transfer method per controller instance.
> > >
> > > This patch does not add an aspeed,transfer-mode property.
> > Will update use aspeed,enable-dma
>
> [...]
>
> > > > +  aspeed,enable-dma:
> > > > +    type: boolean
> > > > +    description: |
> > > > +      I2C bus enable dma mode transfer.
> > > > +
> > > > +      ASPEED ast2600 platform equipped with 16 I2C controllers
> > > > +that share a
> > > > +      single DMA engine. DTS files can specify the data transfer
> > > > +mode to/from
> > > > +      the device, either DMA or programmed I/O.
> > >
> > > As we had discussed: this does not define the transfer mode, only
> > > whether DMA is available to the peripheral.
> > >
> > > Why mention the 16 i2c controllers here?
> > >
> > > Please keep this description simple and relevant to the specific
> > > purpose of the property.
> >
> > Will update with following.
> > description: Enable DMA for transfers on this I2C bus.
>
> You still don't understand the distinction. It's not enable, but that the h/w
> instance *has* DMA capability or not. It is still up to the OS what to do with
> that information.
>
Thanks
Will update
description: Indicates this I2C controller instance has DMA capability.