Re: [PATCH v7 01/12] dt-bindings: add img,pvrsgx.yaml for Imagination GPUs

[H. Nikolaus Schaller]

Hi Tony,

> Am 03.05.2020 um 17:01 schrieb Tony Lindgren <tony@xxxxxxxxxxx>:
> 
> * Paul Cercueil <paul@xxxxxxxxxxxxxxx> [200503 14:19]:
>> You have a new SoC with a SGX, and you only need to enable one clock to get
>> it to work. So you create a devicetree node which receives only one clock.
>> 
>> Turns out, that the bootloader was enabling the other 3 clocks, and since
>> the last release, it doesn't anymore. You're left with having to support a
>> broken devicetree.
>> 
>> That's the kind of problem that can be easily avoided by enforcing the
>> number of clocks that have to be provided.
> 
> The number of clocks depends on how it's wired for the SoC.
> 
> On omaps, there's are no controls for additinoal SGX clocks. Sure some
> of the clocks may be routed to multple places internally by the wrapper
> module. But we have no control over that.
> 
> If we wanted to specify just the "fck" clock on omaps, then we can
> do it with something like this:
> 
> allOf:
>  - if:
>    properites:
>      compatible:
>        enum:
> 	  - "ti,omap4-sgx544-112"
> 	  - "ti,omap5-sgx544-116"
> 	  - "ti,dra7-sgx544-116"
>    then:
>      properties:
>        clocks:
> 	  minItems: 1
> 	  maxItems: 1
> 
>        clock-names:
> 	  const: fck
> 
>    required:
>      - clocks
>      - clock-names

will add to v8 of this series as a separate patch on top of the
general one. This should make it easier to have a focussed discussion
and revert/bisect if something goes wrong.

BR and thanks,
Nikolaus