Re: [linux-sunxi] [PATCH] ARM: dts: sun8i: a83t: Add CPU regulator supplies for A83T boards

[Chen-Yu Tsai <wens@xxxxxxxx>]

On Thu, Jun 28, 2018 at 2:45 AM, Ondřej Jirman
<doudahwezomiechahtah@xxxxxx> wrote:
> Hi,
>
> On Wed, Jun 27, 2018 at 10:27:09AM +0800, Chen-Yu Tsai wrote:
>> The OPPs for the A83T CPU cores were added in v4.17 in commit 2db639d8c166
>> ("ARM: dts: sun8i: a83t: add stable OPP tables and CPUfreq"), but board
>> level regulator supplies for the CPU clusters were only added for the
>> TBS-A711 tablet. This means the other A83T boards do not benefit from
>> voltage scaling, or worse, if the implementation does not scale the
>> frequency when the voltage is fixed, no benefit at all.
>>
>> Add board level CPU cluster power supplies to all the A83T development
>> boards, so they can have proper dynamic CPU voltage and frequency scaling.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
>> ---
>>  arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts | 8 ++++++++
>>  arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts           | 8 ++++++++
>>  arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts       | 8 ++++++++
>>  3 files changed, 24 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts b/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts
>> index 36ecebaff3c0..1c012a4def16 100644
>> --- a/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts
>> +++ b/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts
>> @@ -79,6 +79,14 @@
>>       };
>>  };
>>
>> +&cpu0 {
>> +     cpu-supply = <&reg_dcdc2>;
>> +};
>> +
>> +&cpu100 {
>> +     cpu-supply = <&reg_dcdc3>;
>> +};
>> +
>
> Shouldn't this be done for all CPU cores? Say you start the kernel with
> maxcpus=1 and then enable CPU5 later on, will the regulator get enabled,
> if it is not enabled by always-on setting?

As it stands, the cpufreq framework doesn't enable the regulator anyway.
There's nothing in the bindings that say how this should be set either.

ChenYu

>
> regards,
>   o.
>
>>  &ehci0 {
>>       status = "okay";
>>  };
>> diff --git a/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts b/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts
>> index 3b579d7567c8..c7ce4158d6c8 100644
>> --- a/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts
>> +++ b/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts
>> @@ -107,6 +107,14 @@
>>       };
>>  };
>>
>> +&cpu0 {
>> +     cpu-supply = <&reg_dcdc2>;
>> +};
>> +
>> +&cpu100 {
>> +     cpu-supply = <&reg_dcdc3>;
>> +};
>> +
>>  &de {
>>       status = "okay";
>>  };
>> diff --git a/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts b/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
>> index 88decb0747ac..e5f0645e53a7 100644
>> --- a/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
>> +++ b/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
>> @@ -145,6 +145,14 @@
>>       };
>>  };
>>
>> +&cpu0 {
>> +     cpu-supply = <&reg_dcdc2>;
>> +};
>> +
>> +&cpu100 {
>> +     cpu-supply = <&reg_dcdc3>;
>> +};
>> +
>>  &ehci0 {
>>       /* GL830 USB-to-SATA bridge here */
>>       status = "okay";
>> --
>> 2.18.0
>>
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