Re: [PATCH v4 4/9] ASoC: dt-bindings: wcd938x-sdw: add bindings for wcd938x-sdw

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 15/04/2021 17:39, Rob Herring wrote:
> On Wed, Apr 14, 2021 at 04:48:40PM +0100, Srinivas Kandagatla wrote:
>> Qualcomm WCD9380/WCD9385 Codec is a standalone Hi-Fi audio codec IC
>> connected over SoundWire. This device has two SoundWire devices RX and
>> TX respectively. This bindings is for those slave devices on WCD9380/WCD9385.
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> ---
>>   .../bindings/sound/qcom,wcd938x-sdw.yaml      | 61 +++++++++++++++++++
>>   1 file changed, 61 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/sound/qcom,wcd938x-sdw.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/sound/qcom,wcd938x-sdw.yaml b/Documentation/devicetree/bindings/sound/qcom,wcd938x-sdw.yaml
>> new file mode 100644
>> index 000000000000..fff33c65491b
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/sound/qcom,wcd938x-sdw.yaml
>> @@ -0,0 +1,61 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/sound/qcom,wcd938x-sdw.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Bindings for Qualcomm SoundWire Slave devices on WCD9380/WCD9385
>> +
>> +maintainers:
>> +  - Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> +
>> +description: |
>> +  Qualcomm WCD9380/WCD9385 Codec is a standalone Hi-Fi audio codec IC.
>> +  It has RX and TX Soundwire slave devices. This bindings is for the
>> +  slave devices.
>> +
>> +properties:
>> +  compatible:
>> +    const: sdw20217010d00
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  qcom,direction:
>> +    description: direction of the SoundWire device instance
>> +    enum:
>> +      - rx
>> +      - tx
> 
> Was thinking these were some established bus properties...
> 
> This would just be implied by the 'reg' property index. You could define
> 'reg-names' too I guess.
> 
>> +
>> +  qcom,port-mapping:
>> +    description: |
>> +      Specifies static port mapping between slave and master ports.
>> +      In the order of slave port index.
>> +    $ref: /schemas/types.yaml#/definitions/uint32-array
>> +    minItems: 4
>> +    maxItems: 5
> 
> qcom,rx-port-mapping and qcom,tx-port-mapping?
> 

If we have this property then "qcom,direction" becomes redundant.

> Or keep a single property and the driver knows how many slave ports for
> each direction. IOW, an array of 9 with first 4 entries for tx and last
> 5 for rx.

We can't have a single property with 9 entries as these are two separate 
devices, rx SoundWire Slave has 5 ports implemented where as tx SounWire 
slave has only 4 ports implemented in hw.

And the are on different SoundWire buses.

--srini
> 
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - qcom,direction
>> +  - qcom,port-mapping
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    soundwire@3230000 {
>> +        #address-cells = <2>;
>> +        #size-cells = <0>;
>> +        reg = <0x03230000 0x2000>;
>> +
>> +        codec@0,3 {
>> +            compatible = "sdw20217010d00";
>> +            reg  = <0 3>;
>> +            qcom,direction = "tx";
>> +            qcom,port-mapping = <2 3 4 5>;
>> +        };
>> +    };
>> +
>> +...
>> -- 
>> 2.21.0
>>