Re: [PATCH v9 1/2] ASoC: dt-bindings: realtek,rt5575: add support for ALC5575

[Rob Herring <robh@kernel.org>]

On Thu, Dec 11, 2025 at 07:01:29PM +0800, Oder Chiou wrote:
> Audio codec with I2S, I2C and SPI.
> 
> Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
> ---
>  .../bindings/sound/realtek,rt5575.yaml        | 44 +++++++++++++++++++
>  1 file changed, 44 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sound/realtek,rt5575.yaml
> 
> diff --git a/Documentation/devicetree/bindings/sound/realtek,rt5575.yaml b/Documentation/devicetree/bindings/sound/realtek,rt5575.yaml
> new file mode 100644
> index 000000000000..60f9af399dd2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sound/realtek,rt5575.yaml
> @@ -0,0 +1,44 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/sound/realtek,rt5575.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ALC5575 audio CODEC
> +
> +maintainers:
> +  - Oder Chiou <oder_chiou@realtek.com>
> +
> +description:
> +  The device supports both I2C and SPI. I2C is mandatory, while SPI is
> +  optional depending on the hardware configuration.
> +
> +allOf:
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> +  - $ref: dai-common.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - realtek,rt5575
> +      - realtek,rt5575-use-spi
> +
> +  reg:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        codec@57 {
> +            compatible = "realtek,rt5575";
> +            reg = <0x57>;
> +        };
> +    };

It is completely unclear what you are doing in the SPI case. I 
deciphered it studying the driver. I shouldn't have to do that, your 
binding should make that clear. 

So your DT must look like this:

i2c {
	codec@57 {
		compatible = "realtek,rt5575-use-spi";
		reg = <0x57>;
	};
};

spi {
	codec@1 {
		compatible = "realtek,rt5575";
		reg = <0x1>;
	};
};

First, there's no need for "-use-spi" because you can just check if 
there is a rt5575 SPI device and use it if there is. Why would you have 
the SPI device and not use it?

But really it is not ideal having 2 device nodes for a single device. It 
would be much simpler to just have something like this in the i2c node:

spi-parent = <&spi0 1>;

Where the cell is the chip-select #.

We have an 'i2c-parent' already for similar reasons when there are 2 
bus connections.

Rob