Messages in this thread | | | Subject | Re: [PATCH v2] arm64: dts: allwinner: h6: Use dummy regulator for Tanix TX6 | From | Robin Murphy <> | Date | Tue, 28 Apr 2020 16:21:28 +0100 |
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On 2020-04-28 3:26 pm, Clément Péron wrote: > Tanix TX6 has a fixed regulator. As DVFS is instructed to change > voltage to meet OPP table, the DVFS is not working as expected.
Hmm, isn't that really a bug in the DVFS code? I guess it's just blindly propagating -EINVAL from the fixed regulators not implementing set_voltage, but AFAICS it has no real excuse not to be cleverer and still allow switching frequency as long as the voltage *is* high enough for the given OPP. I wonder how well it works if the regulator is programmable but shared with other consumers... that case probably can't be hacked around in DT.
Robin.
> Avoid to introduce a new dedicated OPP Table where voltage are > equals to the fixed regulator as it will only duplicate all the OPPs. > Instead remove the fixed regulator so the DVFS framework will create > dummy regulator and will have the same behavior. > > Add some comments to explain this in the device-tree. > > Reported-by: Piotr Oniszczuk <warpme@o2.pl> > Fixes: add1e27fb703 ("arm64: dts: allwinner: h6: Enable CPU opp tables for Tanix TX6") > Signed-off-by: Clément Péron <peron.clem@gmail.com> > --- > .../boot/dts/allwinner/sun50i-h6-tanix-tx6.dts | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6-tanix-tx6.dts b/arch/arm64/boot/dts/allwinner/sun50i-h6-tanix-tx6.dts > index be81330db14f..3e96fcb317ea 100644 > --- a/arch/arm64/boot/dts/allwinner/sun50i-h6-tanix-tx6.dts > +++ b/arch/arm64/boot/dts/allwinner/sun50i-h6-tanix-tx6.dts > @@ -48,7 +48,15 @@ > }; > > &cpu0 { > - cpu-supply = <®_vdd_cpu_gpu>; > + /* > + * Don't specify the CPU regulator, as it's a fixed > + * regulator DVFS will not work as it is intructed > + * to reach a voltage which can't be reached. > + * Not specifying a regulator will create a dummy > + * regulator allowing all OPPs. > + * > + * cpu-supply = <®_vdd_cpu_gpu>; > + */ > }; > > &de { > @@ -68,7 +76,13 @@ > }; > > &gpu { > - mali-supply = <®_vdd_cpu_gpu>; > + /* > + * Don't specify the GPU regulator, see comment > + * above for the CPU supply. > + * > + * mali-supply = <®_vdd_cpu_gpu>; > + */ > + > status = "okay"; > }; > >
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