Re: [PATCH RFC v2 02/11] dt-bindings: gpu: Add PowerVR Series5 SGX GPUs

[Andrew Davis]

On 1/9/24 5:32 AM, Krzysztof Kozlowski wrote:
> On 08/01/2024 19:32, Andrew Davis wrote:
> > The Imagination PowerVR Series5 "SGX" GPU is part of several SoCs from
> > multiple vendors. Describe how the SGX GPU is integrated in these SoC,
> > including register space and interrupts. Clocks, reset, and power domain
> > information is SoC specific.
> >
> > Signed-off-by: Andrew Davis <afd@xxxxxx>
> > ---
> >   .../bindings/gpu/img,powervr-sgx.yaml         | 124 ++++++++++++++++++
> >   MAINTAINERS                                   |   1 +
> >   2 files changed, 125 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/gpu/img,powervr-sgx.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/gpu/img,powervr-sgx.yaml b/Documentation/devicetree/bindings/gpu/img,powervr-sgx.yaml
> > new file mode 100644
> > index 0000000000000..bb821e1184de9
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/gpu/img,powervr-sgx.yaml
> > @@ -0,0 +1,124 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +# Copyright (c) 2023 Imagination Technologies Ltd.
>
> Your email has @TI domain, are you sure you attribute your copyrights to
> Imagination?

The file started as a copy/paste from a IMG copyrighted file, even
though it is now almost completely re-written I've left their (c)
for good measure. I'll add an additional TI (c).

> ...
>
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  clocks: true
>
> Missing min/maxItems

These are set in the allOf/if/then blocks below, seems
if I don't set them to at least something here then I get
a warning:

   'clock-names', 'clocks' do not match any of the regexes: 'pinctrl-[0-9]+'

even if I define them in the allOf block below. I don't
know what the min/max should be until I check the compatible
in the allOf block.

> > +
> > +  clock-names:
> > +    minItems: 1
> > +    items:
> > +      - const: core
> > +      - const: mem
> > +      - const: sys
> > +
> > +  power-domains:
> > +    maxItems: 1
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +
> > +additionalProperties: false
>
> This goes after allOf: block.

ACK

> > +
> > +allOf:
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: ti,am6548-gpu
> > +    then:
> > +      required:
> > +        - power-domains
> > +    else:
> > +      properties:
> > +        power-domains: false
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - allwinner,sun6i-a31-gpu
> > +              - ingenic,jz4780-gpu
> > +    then:
> > +      allOf:
> > +        - if:
>
> I don't understand why do you need to embed allOf inside another allOf.
> The upper (outer) if:then: looks entirely useless.

It is so that both compatibles falls through to having
clock being required.

Logic in YAML always seems messy to me, here it is in pseudo C:

if (compatible == allwinner,sun6i-a31-gpu ||
    compatible == ingenic,jz4780-gpu) {
	if (compatible == allwinner,sun6i-a31-gpu)
		clocks: ...
	if (compatible == ingenic,jz4780-gpu)
		clocks: ...
	required:
		- clocks
		- clock-names
} else { /* disallow for all others */
	properties:
		clocks: false
		clock-names: false
}

Now if I had an "else if" that didn't force the indention to keep
growing I would have used that. (does one exist?) I also cannot
simply add the clock properties only for the two compats need
them for the reasons above and so must add them unconditionally
before then explicitly disable them in a catch-all else path.

Andrew

> > +            properties:
> > +              compatible:
> > +                contains:
> > +                  const: allwinner,sun6i-a31-gpu
> > +          then:
> > +            properties:
> > +              clocks:
> > +                minItems: 2
> > +                maxItems: 2
> > +              clock-names:
> > +                minItems: 2
> > +                maxItems: 2
>
>
> Best regards,
> Krzysztof