Re: [PATCH 5/9] dt-bindings: gpu: mali-bifrost: Add a compatible for MediaTek MT8186

[AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>]

Il 09/02/23 10:45, Chen-Yu Tsai ha scritto:
> On Thu, Feb 9, 2023 at 5:20 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@collabora.com> wrote:
>>
>> Il 09/02/23 09:49, Chen-Yu Tsai ha scritto:
>>> On Wed, Feb 8, 2023 at 6:37 PM AngeloGioacchino Del Regno
>>> <angelogioacchino.delregno@collabora.com> wrote:
>>>>
>>>> Get GPU support on MT8186 by adding its compatible.
>>>
>>> I'd skip MT8186 for now. We have to work out some binning details for the
>>> OPP, in particular how to deal with both Panfrost (or Mali) and SVS adding
>>> the OPP table. We were just looking at the Mali driver today.
>>>
>>
>> Dealing with binning is fairly easy... I have something already done for
>> that one, but I'm not sure that it would be the best option.
>> My solution makes use of opp-supported-hw by "standard means", but perhaps
>> let's have a separated conversation about it?
>>
>> I don't think that skipping this would give any benefit though, because
>> that is only adding a compatible and whatever binning support would have
>> to be generic and 99% not bound to any mediatek specific compatible.
> 
> The binning is related to voltage range, not maximum OPP. So it's more
> like fast/slow example in Documentation/devicetree/bindings/opp/opp-v2.yaml
> or the opp/allwinner,sun50i-h6-operating-points.yaml, minus the efuse node.
> 
> The downstream DT currently looks like this:
> 
> opp-950000000 {
>          opp-hz = /bits/ 64 <950000000>;
> 
> /* This is Mali specific; ignore
>          opp-hz-real = /bits/ 64 <950000000>,
>                        /bits/ 64 <950000000>;
> */
>          opp-microvolt = <900000>, <1000000>;
>          opp-microvolt-bin4 = <875000>, <975000>;
>          opp-microvolt-bin5 = <850000>, <950000>;
> };
> 

Yes, my option is, in short:

	opp-900000000 {
		opp-hz = /bits/ 64 <900000000>;
		opp-microvolt = <850000>;
		opp-supported-hw = <0xcf>;
	};

	opp-900000000-bin4 {
		opp-hz = /bits/ 64 <900000000>;
		opp-microvolt = <837500>;
		opp-supported-hw = <0x10>;
	};

	opp-900000000-bin5 {
		opp-hz = /bits/ 64 <900000000>;
		opp-microvolt = <825000>;
		opp-supported-hw = <0x20>;
	};



> 
> ChenYu