linux-kernel - Re: [PATCH 3/4] ARM: dts: da850-evm: enable cpufreq

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Message-ID: <CAMpxmJUT7Rc5noOAKZsoaN--hu14wQTujnH_6v8TWiO=KufNhg@mail.gmail.com>
Date:   Thu, 21 Mar 2019 17:43:55 +0100
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     David Lechner <david@...hnology.com>
Cc:     Bartosz Golaszewski <brgl@...ev.pl>, Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        arm-soc <linux-arm-kernel@...ts.infradead.org>,
        linux-devicetree <devicetree@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Adam Ford <adam.ford@...icpd.com>
Subject: Re: [PATCH 3/4] ARM: dts: da850-evm: enable cpufreq

czw., 21 mar 2019 o 17:36 Bartosz Golaszewski
<bgolaszewski@...libre.com> napisał(a):
>
> czw., 21 mar 2019 o 16:53 David Lechner <david@...hnology.com> napisał(a):
> >
> > On 3/21/19 9:10 AM, Bartosz Golaszewski wrote:
> > > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > >
> > > Enable cpufreq-dt support for da850-evm. The cvdd regulator is fixed
> > > at 1.2V on this board so disable the lower operating points and enable
> > > the 375MHz opp.
> >
> >
> > The board-da850-evm.c file seems to indicate that this regulator is
> > variable and comes from the tps65070. This regulator seems to be missing
> > from the device tree though, even though it has device tree bindings.
> >
>
> Oh snap, you're right. I glanced over the 1.2V comment and thought
> it's the same as other boards, but actually it specifies: .min_uV =
> 950000, .max_uV = 1350000, so all the operating points should work on
> that one.
>

It seems this pmic is defined here[1] and a skeleton included here[2]
and then the regulator constraints follow.

Bart

[1] https://elixir.bootlin.com/linux/latest/source/arch/arm/boot/dts/da850-evm.dts#L224
[2] https://elixir.bootlin.com/linux/latest/source/arch/arm/boot/dts/da850-evm.dts#L326

> Bart
>
> > Cc: Adam Ford
> >
> >
> > >
> > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > > ---
> > >   arch/arm/boot/dts/da850-evm.dts | 30 ++++++++++++++++++++++++++++++
> > >   1 file changed, 30 insertions(+)
> > >
> > > diff --git a/arch/arm/boot/dts/da850-evm.dts b/arch/arm/boot/dts/da850-evm.dts
> > > index f04bc3e15332..f63867692da4 100644
> > > --- a/arch/arm/boot/dts/da850-evm.dts
> > > +++ b/arch/arm/boot/dts/da850-evm.dts
> > > @@ -151,6 +151,15 @@
> > >                       system-clock-frequency = <24576000>;
> > >               };
> > >       };
> > > +
> > > +     cvdd: regulator0 {
> > > +             compatible = "regulator-fixed";
> > > +             regulator-name = "cvdd";
> > > +             regulator-min-microvolt = <1200000>;
> > > +             regulator-max-microvolt = <1200000>;
> > > +             regulator-always-on;
> > > +             regulator-boot-on;
> > > +     };
> > >   };
> > >
> > >   &ecap2 {
> > > @@ -191,6 +200,27 @@
> > >       };
> > >   };
> > >
> > > +&cpu {
> > > +     cpu-supply = <&cvdd>;
> > > +};
> > > +
> > > +/*
> > > + * DA850-EVM has a fixed CVDD of 1.2V - we cannot go below 300MHz or
> > > + * above 375MHz.
> > > + */
> > > +
> > > +&opp_100 {
> > > +     status = "disabled";
> > > +};
> > > +
> > > +&opp_200 {
> > > +     status = "disabled";
> > > +};
> > > +
> > > +&opp_375 {
> > > +     status = "okay";
> > > +};
> > > +
> > >   &sata {
> > >       status = "okay";
> > >   };
> > >
> >