Re: [PATCH v3 1/3] dt-bindings: dmaengine: Document qcom,gpi dma binding

From: Vinod Koul
Date: Thu Oct 01 2020 - 07:15:02 EST


Hi Rob,

On 29-09-20, 13:44, Rob Herring wrote:

> > +description: |
> > + QCOM GPI DMA controller provides DMA capabilities for
> > + peripheral buses such as I2C, UART, and SPI.
> > +
> > +allOf:
> > + - $ref: "dma-controller.yaml#"
> > +
> > +properties:
> > + compatible:
> > + enum:
> > + - qcom,gpi-dma
>
> Should be SoC specific.

Okay, will add

> > +
> > + reg:
> > + maxItems: 1
> > +
> > + interrupts:
> > + description:
> > + Interrupt lines for each GPII instance
>
> GPII or GPI?

Hw uses GPII as "GPI Instance" :) so will update this

> > + maxItems: 13
> > +
> > + "#dma-cells":
> > + const: 3
> > + description: >
> > + DMA clients must use the format described in dma.txt, giving a phandle
> > + to the DMA controller plus the following 3 integer cells:
> > + - channel: if set to 0xffffffff, any available channel will be allocated
> > + for the client. Otherwise, the exact channel specified will be used.
> > + - seid: serial id of the client as defined in the SoC documentation.
> > + - client: type of the client as defined in dt-bindings/dma/qcom-gpi.h
> > +
> > + iommus:
> > + maxItems: 1
> > +
> > + dma-channels:
> > + maxItems: 1
>
> Not an array. Is there a maximum number of channels or 2^32 is valid?

I have not seen any max limit put, but we can be assured that it will
not go to 2^32, we can put a reasonable limit ..

Will add maximum :)

> > +
> > + dma-channel-mask:
> > + maxItems: 1
>
> So up to 32 channels?

yep!

--
~Vinod