Re: [PATCH v2 6/6] dt-bindings: dma: Convert Qualcomm BAM DMA binding to json format

From: Krzysztof Kozlowski
Date: Tue Apr 12 2022 - 03:06:18 EST


On 12/04/2022 08:19, Kuldeep Singh wrote:
> On Mon, Apr 11, 2022 at 01:38:41PM +0200, Krzysztof Kozlowski wrote:
>> On 11/04/2022 12:58, Kuldeep Singh wrote:
>>>> This is something new and it seems only one SoC defines it (not even one
>>>> BAM version). I wonder whether this is actually correct or this
>>>> particular version of BAM is slightly different. Maybe someone could
>>>> clarify it, but if no - looks ok.
>>>
>>> Yes, sdm845.dtsi uses 4 entries and rest 1.
>>
>> Yes, I know. This does not solve my wonder.
>>
>>>
>>>>
>>>>> +
>>>>> + num-channels:
>>>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>>>> + description:
>>>>> + Indicates supported number of DMA channels in a remotely controlled bam.
>>>>> +
>>>>> + qcom,controlled-remotely:
>>>>> + $ref: /schemas/types.yaml#/definitions/flag
>>>>
>>>> type: boolean
>>>
>>> Boolean comes under flag in types.yaml
>>>
>>> definitions:
>>> flag:
>>> oneOf:
>>> - type: boolean
>>> const: true
>>> - type: 'null'
>>>
>>> I have seen other boolean properties(spi-cpol, spi-cpha and bunch of
>>> others) using type flag. I think we should keep flag here.
>>
>> type:boolean is just shorter and example-schema recommends it. If you
>> want to base on something (as a template, pattern) then the
>> example-schema is the source, the preferred one.
>
> I had seen other spec using flag and that's why kept same here.

I understand, you mentioned it before. However other spec is not the
example-schema...

> Which example schema are you talking about?

There is only one example-schema.
$ find ./linux -name 'example-schema*'

>>>> clocks, clock-names, qcom-ee - these are required according to old bindings.
>>>
>>> I missed qcom,ee. Will add in v3.
>>>
>>> For clocks and clock-names , there are two platforms(msm8996.dtsi,
>>> sdm845.dtsi) where these properties are missing. And I don't want to add
>>> some random values. Shall I skip them here? and let board owners add
>>> them later.
>>
>> These are required, so the SoC DTSI should be fixed. Not with random
>> clocks but something proper. :)
>
> Yes absolutely :-)
> I have kept Srinivas in copy, who sent initial support for both the
> dtsi. Probably he can confirm provided his email doesn't bounce.
>
> Anyway Krzysztof, can you confirm the same as you have been actively
> contributing to Qcom peripherals. I will add credit in follow-up
> submission.

Honestly not now, because I don't have access to related datasheets (I
am working on this). You can though try to look at original (vendor)
sources:
https://git.codelinaro.org/clo/la/kernel/msm-4.19 (sdm845)
https://git.codelinaro.org/clo/la/kernel/msm-3.18 (msm8996)


Best regards,
Krzysztof