On 25/06/2025 16:18, Michal Wilczynski wrote: > > > On 6/25/25 15:55, Krzysztof Kozlowski wrote: >> On 25/06/2025 14:45, Michal Wilczynski wrote: >>> >>> >>> On 6/24/25 15:53, Matt Coster wrote: >>>> On 23/06/2025 12:42, Michal Wilczynski wrote: >>>>> Update the img,powervr-rogue.yaml to include the T-HEAD TH1520 SoC's >>>>> specific GPU compatible string. >>>>> >>>>> The thead,th1520-gpu compatible, along with its full chain >>>>> img,img-bxm-4-64, and img,img-rogue, is added to the >>>>> list of recognized GPU types. >>>>> >>>>> The power-domains property requirement for img,img-bxm-4-64 is also >>>>> ensured by adding it to the relevant allOf condition. >>>>> >>>>> Acked-by: Krzysztof Kozlowski <krzysztof.kozlow...@linaro.org> >>>>> Reviewed-by: Ulf Hansson <ulf.hans...@linaro.org> >>>>> Reviewed-by: Bartosz Golaszewski <bartosz.golaszew...@linaro.org> >>>>> Signed-off-by: Michal Wilczynski <m.wilczyn...@samsung.com> >>>>> --- >>>>> Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml | 9 >>>>> ++++++++- >>>>> 1 file changed, 8 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml >>>>> b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml >>>>> index >>>>> 4450e2e73b3ccf74d29f0e31e2e6687d7cbe5d65..9b241a0c1f5941dc58a1e23970f6d3773d427c22 >>>>> 100644 >>>>> --- a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml >>>>> +++ b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml >>>>> @@ -21,6 +21,11 @@ properties: >>>>> # work with newer dts. >>>>> - const: img,img-axe >>>>> - const: img,img-rogue >>>>> + - items: >>>>> + - enum: >>>>> + - thead,th1520-gpu >>>>> + - const: img,img-bxm-4-64 >>>>> + - const: img,img-rogue >>>>> - items: >>>>> - enum: >>>>> - ti,j721s2-gpu >>>>> @@ -93,7 +98,9 @@ allOf: >>>>> properties: >>>>> compatible: >>>>> contains: >>>>> - const: img,img-axe-1-16m >>>>> + enum: >>>>> + - img,img-axe-1-16m >>>>> + - img,img-bxm-4-64 >>>> >>>> This isn't right – BXM-4-64 has two power domains like BXS-4-64. I don't >>>> really know what the right way to handle that in devicetree is given the >>>> TH1520 appears to expose only a top-level domain for the entire GPU, but >>>> there are definitely two separate domains underneath that as far as the >>>> GPU is concerned (see the attached snippet from integration guide). >>>> >>>> Since power nodes are ref-counted anyway, do we just use the same node >>>> for both domains and let the driver up/down-count it twice? >>> >>> Hi Matt, >>> >>> Thanks for the very helpful insight. That's a great point, it seems the >>> SoC's design presents a tricky case for the bindings. >>> >>> I see what you mean about potentially using the same power domain node >>> twice. My only hesitation is that it might be a bit unclear for someone >>> reading the devicetree later. Perhaps another option could be to relax >>> the constraint for this compatible? >>> >>> Krzysztof, we'd be grateful for your thoughts on how to best model this >>> situation. >> >> >> It's your hardware, you should tell us, not me. I don't know how many >> power domains you have there, but for sure it is not one AND two domains >> the same time. It is either one or two, because power domains are not >> the same as regulator supplies. > > Hi Krzysztof, Matt, > > The img,bxm-4-64 GPU IP itself is designed with two separate power > domains. The TH1520 SoC, which integrates this GPU, wires both of these > to a single OS controllable power gate (controlled via mailbox and E902 > co-processor).
This helps... and also sounds a lot like regulator supplies, not power domains. :/ > > This means a devicetree for the TH1520 can only ever provide one power > domain for the GPU. However, a generic binding for img,bxm-4-64 should If this was a supply, you would have two supplies. Anyway internal wirings of GPU do not matter in such case and more important what the SoC has wired. And it has one power domain. > account for a future SoC that might implement both power domains. > > That's why I proposed to relax the constraints on the img,bmx-4-64 GPU. This should be constrained per each device, so 1 for you and 2 for everyone else. Best regards, Krzysztof
