Re: [PATCH v3 2/5] dt-bindings: clocks: atmel,at91rm9200-pmc: convert to yaml

[Claudiu.Beznea]

On 09.05.2023 09:25, Krzysztof Kozlowski wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 09/05/2023 07:27, Claudiu Beznea wrote:
>> Convert Atmel PMC documentation to yaml. Along with it clock names
>> were adapted according to the current available device trees as
>> different controller versions accept different clocks (some of them
>> have 3 clocks as input, some has 2 clocks as inputs and some with 2
>> input clocks uses different clock names).
>>
> 
> Thank you for your patch. There is something to discuss/improve.
> 
>> +title: Atmel Power Management Controller (PMC)
>> +
>> +maintainers:
>> +  - Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
>> +
>> +description:
>> +  The power management controller optimizes power consumption by controlling all
>> +  system and user peripheral clocks. The PMC enables/disables the clock inputs
>> +  to many of the peripherals and to the processor.
>> +
>> +properties:
>> +  compatible:
>> +    oneOf:
>> +      - items:
>> +          - enum:
>> +              - atmel,at91sam9g15-pmc
>> +              - atmel,at91sam9g20-pmc
>> +              - atmel,at91sam9g25-pmc
>> +              - atmel,at91sam9g35-pmc
>> +              - atmel,at91sam9x25-pmc
>> +              - atmel,at91sam9x35-pmc
>> +          - enum:
>> +              - atmel,at91sam9260-pmc
>> +              - atmel,at91sam9x5-pmc
> 
> I missed it last time - why you have two enums? We never talked about
> this. It's usually wrong... are you sure this is real hardware:
> atmel,at91sam9g20-pmc, atmel,at91sam9260-pmc
> ?

I have 2 enums because there are some hardware covered by:
"vendor-name,hardware-v1-pmc", "syscon" and some covered by:
"vendor-name,hardware-v2-pmc", "vendor-name,hardware-v1-pmc", "syscon".

Many AT91 device trees compatibles were written in this way. Thus when new
versions of the same IP has been introduced the drivers were not
necessarily updated but the compatibles in device trees were updated e.g.
with "vendor-name,hardware-v2-pmc" (the full compatible becoming
"vendor-name,hardware-v2-pmc", "vendor-name,hardware-v1-pmc", "syscon") and
let the drivers fall back to already in driver supported compatible
"vendor-name,hardware-v1-pmc", "syscon". In general v2 comes with new
features in addition to v1.

That way they AT91 ensures the ABI properties of DT and thus when the
drivers were finally updated with the new features of the
"vendor-name,hardware-v2-pmc" DT remained in place.

Please let me know if these could be handled better in YAML.

Thank you,
Claudiu

> 
> 
>> +          - const: syscon
>> +      - items:
>> +          - enum:
>> +              - atmel,at91rm9200-pmc
>> +              - atmel,at91sam9260-pmc
>> +              - atmel,at91sam9g45-pmc
>> +              - atmel,at91sam9n12-pmc
>> +              - atmel,at91sam9rl-pmc
>> +              - atmel,sama5d2-pmc
>> +              - atmel,sama5d3-pmc
>> +              - atmel,sama5d4-pmc
>> +              - microchip,sam9x60-pmc
>> +              - microchip,sama7g5-pmc
>> +          - const: syscon
>> +
> 
> 
> Best regards,
> Krzysztof
>