Re: [PATCH 1/4] dt-bindings: thermal: mediatek: Add AP domain to LVTS thermal controllers for mt8195

[Daniel Lezcano]

Hi Rob,

On 16/03/2023 23:35, Rob Herring wrote:
> On Thu, Mar 09, 2023 at 11:39:13AM +0100, Daniel Lezcano wrote:
> > On 09/03/2023 05:40, Chen-Yu Tsai wrote:
> > > On Wed, Mar 8, 2023 at 12:46 AM <bchihi@xxxxxxxxxxxx> wrote:
> > > > From: Balsam CHIHI <bchihi@xxxxxxxxxxxx>
> > > >
> > > > Add AP Domain to LVTS thermal controllers dt-binding definition for mt8195.
> > > >
> > > > Signed-off-by: Balsam CHIHI <bchihi@xxxxxxxxxxxx>
> > > > ---
> > > >    include/dt-bindings/thermal/mediatek,lvts-thermal.h | 10 ++++++++++
> > > >    1 file changed, 10 insertions(+)
> > > >
> > > > diff --git a/include/dt-bindings/thermal/mediatek,lvts-thermal.h b/include/dt-bindings/thermal/mediatek,lvts-thermal.h
> > > > index c09398920468..8fa5a46675c4 100644
> > > > --- a/include/dt-bindings/thermal/mediatek,lvts-thermal.h
> > > > +++ b/include/dt-bindings/thermal/mediatek,lvts-thermal.h
> > > > @@ -16,4 +16,14 @@
> > > >    #define MT8195_MCU_LITTLE_CPU2  6
> > > >    #define MT8195_MCU_LITTLE_CPU3  7
> > > >
> > > > +#define MT8195_AP_VPU0  8
> > >
> > > Can't this start from 0? This is a different hardware block. The index
> > > namespace is separate. Same question for MT8192.
> >
> > The ID is used to differentiate the thermal zone identifier in the device
> > tree from the driver.
> >
> > +		vpu0-thermal {
> > +			polling-delay = <0>;
> > +			polling-delay-passive = <0>;
> > +			thermal-sensors = <&lvts_ap MT8195_AP_VPU0>;
> > +
> > +			trips {
> > +				vpu0_crit: trip-crit {
> > +					temperature = <100000>;
> > +					hysteresis = <2000>;
> > +					type = "critical";
> > +				};
> > +			};
> > +		};
> >
> > If MT8195_AP_VPU0 is 0, then the code won't be able to differentiate
> > MT8195_AP_VPU0 and MT8195_MCU_BIG_CPU0
> >
> > The LVTS driver will call devm_thermal_of_zone_register() with the sensor
> > id. If MT8195_MCU_BIG_CPU0 and MT8195_AP_VPU0 have the same id, then at the
> > moment of registering the MT8195_AP_VPU0, the underlying OF thermal
> > framework code will use MT8195_MCU_BIG_CPU0 description instead because it
> > will be the first to be find in the DT.
> >
> > If MT8195_AP_VPU0 is described in DT before, then the same will happen when
> > registering MT8195_MCU_BIG_CPU0, MT8195_AP_VPU0 will be registered instead.
> >
> > IOW all ids must be different.
>
> That's broken for how producer/consumer phandle+args bindings work.

Do you mean this is broken for thermal zone description in the DT in 
general ?

What would be the correct approach ?



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