Re: [PATCH v1 1/2] dt-bindings: ASoC: Add Cadence I2S controller for StarFive JH8100 SoC

[Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>]

On 2023/12/21 21:53, Conor Dooley wrote:
> Xingyu, Mark,
> 
> On Thu, Dec 21, 2023 at 11:32:22AM +0800, Xingyu Wu wrote:
>> Add bindings for the Multi-Channel I2S controller of Cadence
>> on the StarFive JH8100 SoC.
>> 
>> Signed-off-by: Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>
>> ---
>>  .../bindings/sound/cdns,jh8100-i2s.yaml       | 100 ++++++++++++++++++
>>  1 file changed, 100 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/sound/cdns,jh8100-i2s.yaml
>> 
>> diff --git a/Documentation/devicetree/bindings/sound/cdns,jh8100-i2s.yaml b/Documentation/devicetree/bindings/sound/cdns,jh8100-i2s.yaml
>> new file mode 100644
>> index 000000000000..5d95d9ab3e45
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/sound/cdns,jh8100-i2s.yaml
>> @@ -0,0 +1,100 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/sound/cdns,jh8100-i2s.yaml#
> 
> Filename matching the compatible please.

Noted.

> 
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Cadence multi-channel I2S controller for StarFive JH8100 SoC
>> +
>> +description: |
> 
> You only need the | if there is formatting to preserve.

Will drop.

> 
>> +  The Cadence I2S Controller implements a function of the multi-channel
>> +  (up to 8-channel) bus. It combines functions of a transmitter and a receiver.
>> +  It is used in the StarFive JH8100 SoC.
>> +
>> +maintainers:
>> +  - Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>
>> +  - Walker Chen <walker.chen@xxxxxxxxxxxxxxxx>
>> +
>> +properties:
>> +  compatible:
>> +    const: starfive,jh8100-i2s
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    description: |
>> +      The interrupt line number for the I2S controller. Add this
>> +      parameter if the I2S controller that you are using does not
>> +      support DMA.
> 
> You've got one i2s controller here, you should know if it supports DMA
> or not.

The I2S already supports interrupt handler, but if the SoC supports DMA controller to be use, it can optionally use DMA.

> 
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    items:
>> +      - description: Bit clock
>> +      - description: Main ICG clock
>> +      - description: Inner master clock
>> +
>> +  clock-names:
>> +    items:
>> +      - const: bclk
>> +      - const: icg
>> +      - const: mclk_inner
>> +
>> +  resets:
>> +    maxItems: 1
>> +
>> +  dmas:
>> +    items:
>> +      - description: TX DMA Channel
>> +      - description: RX DMA Channel
>> +    minItems: 1
>> +
>> +  dma-names:
>> +    items:
>> +      - const: tx
>> +      - const: rx
>> +    minItems: 1
>> +
>> +  cdns,i2s-max-channels:
>> +    description: |
>> +      Number of I2S max stereo channels supported by the hardware.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    minimum: 1
>> +    maximum: 8
> 
> Mark, is there no common property for this kind of thing? That said,
> there's one device here so the number is known at present.
> Another note, this property is not required, so it should have a
> default.
> 
> It's kinda hard to know with this binding - it is touted as being for a
> particular Cadence IP, and some aspects are pretty generic, but at the
> same time there's only one device here so it's hard to tell what is
> variable between implementations and what is not.
> Are there no other implementations of this controller? Unless it is
> brand new, I find that hard to believe.
> 
> Cheers,
> Conor.
> 
 
Sorry, It does not seem to be common property. The Cadence I2S supports 8 channels. There are four I2S controllers on the JH8100 SoC, and two of them just provide 4 channels to use, one of them just provide 2 channels.
It seems to depend on the SoC.

Thanks,
Xingyu Wu

>> +
>> +  "#sound-dai-cells":
>> +    const: 0
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - clocks
>> +  - clock-names
>> +  - resets
>> +
>> +oneOf:
>> +  - required:
>> +      - dmas
>> +      - dma-names
>> +  - required:
>> +      - interrupts
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    i2s@122b0000 {
>> +      compatible = "starfive,jh8100-i2s";
>> +      reg = <0x122b0000 0x1000>;
>> +      clocks = <&syscrg_ne 133>,
>> +               <&syscrg_ne 170>,
>> +               <&syscrg 50>;
>> +      clock-names = "bclk", "icg",
>> +                    "mclk_inner";
>> +      resets = <&syscrg_ne 43>;
>> +      dmas = <&dma 7>, <&dma 6>;
>> +      dma-names = "tx", "rx";
>> +      cdns,i2s-max-channels = <2>;
>> +      #sound-dai-cells = <0>;
>> +    };
>> -- 
>> 2.25.1
>> 
>>