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

Andrew Davis
2024-01-09T16:53:41Z

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@ti.com>
>> ---
>> .../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
>