Re: [PATCH v2 1/8] dt-bindings: PCI: Add binding for qps615

Krishna Chaitanya Chundru
2024-08-05T05:27:09Z

On 8/5/2024 10:44 AM, Krzysztof Kozlowski wrote:
> On 05/08/2024 06:11, Krishna Chaitanya Chundru wrote:
>
>
>>>> +
>>>> + qcom,nfts:
>>>> + $ref: /schemas/types.yaml#/definitions/uint8
>>>> + description:
>>>> + Fast Training Sequence (FTS) is the mechanism that
>>>> + is used for bit and Symbol lock.
>>>
>>> What are the values? Why this is uint8?
>>>
>> These represents number of fast training sequence and doesn't have
>> any units and the maximum value for this is 0xFF only so we used
>> uint8.
>>> You described the desired Linux feature or behavior, not the actual
>>> hardware. The bindings are about the latter, so instead you need to
>>> rephrase the property and its description to match actual hardware
>>> capabilities/features/configuration etc.
>> ack.
>>>
>>>> +
>>>> +allOf:
>>>> + - $ref: /schemas/pci/pci-bus-common.yaml#
>>>> + - if:
>>>> + properties:
>>>> + compatible:
>>>> + contains:
>>>> + const: pci1179,0623
>>>> + required:
>>>> + - compatible
>>>
>>> Why do you have entire if? You do not have multiple variants, drop.
>>>
>> The child nodes also referencing the qcom,qps615.yaml# node, I tried
>> to use this way to say "the below properties are for the required for
>> parent and optional for child".
>
> I don't understand how child device can be exactly the same as parent
> device. How does it look in terms of hardware? Pins and supplies?
>
>>>> + then:
>>>> + required:
>>>> + - vdd18-supply
>>>> + - vdd09-supply
>>>> + - vddc-supply
>>>> + - vddio1-supply
>>>> + - vddio2-supply
>>>> + - vddio18-supply
>>>> + - qcom,qps615-controller
>>>> + - reset-gpios
>>>> +
>>>> +patternProperties:
>>>> + "@1?[0-9a-f](,[0-7])?$":
>>>> + type: object
>>>> + $ref: qcom,qps615.yaml#
>>>> + additionalProperties: true
>>>
>>> Nope, drop pattern Properties or explain what is this.
>>>
>> the child nodes represent the downstream ports of the PCIe
>> switch which wants to use same properties that is why
>> I tried to use this pattern properties.
>
> Downstream port is not the same as device. Why downstream port has the
> same supplies? To which pins are they connected?
>
>
Hi Krzysztof,

Downstream ports dosen't have pins or supplies to power on.

But there are properties like qcom,l0s-entry-delay-ns,
qcom,l1-entry-delay-ns, qcom,tx-amplitude-millivolt etc which
applicable for child nodes also. Instead of re-declaring the
these properties again I tried to use pattern properties.

- krishna Chaitanya.
>
>
> Best regards,
> Krzysztof
>