Re: [PATCH 1/3] ARM: dts: imx6: phycore-som: fix arm and soc minimum voltage

Marco Felsch
2019-12-02T12:42:13Z

Hi Stefan,

On 19-12-02 11:09, Stefan Riedmüller wrote:
> Hi Marco,
>
> your proposed setting is only valid for the LDO enabled case but not for the
> case where the LDO's are in bypass mode. Is that intended? In bypass mode it
> actually needs to be 0.925 V min for ARM and 1.15 V min for SOC.

The case is that the driver doesn't support the bypass mode currently so
yes it was intended.

> Did you experience an issue with the current settings or is this just a
> cosmetic change?

There is currently no issue because the internally LDO's don't try to
apply such a low voltage value. But I think it isn't a cosmetic change
because this value is wrong. We need to specify the valid voltage range.

Regards,
Marco

> Regards,
> Stefan
>
>
> On 29.11.19 17:48, Marco Felsch wrote:
> > The current set minimum voltage of 730000mV seems to be wrong. I don't
> > know the document which specifies that but the imx6qdl datasheets says
> > that the minimum voltage should be 1.05V for VDD_ARM (LDO enabled, lowest
> > opp) and 1.275V for VDD_SOC (LDO enabled, lowest opp).
> >
> > Fixes: ddec5d1c0047 ("ARM: dts: imx6: Add initial support for phyCORE-i.MX 6 SOM")
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > ---
> > arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi b/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi
> > index 6486df3e2942..46d4953c5588 100644
> > --- a/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi
> > +++ b/arch/arm/boot/dts/imx6qdl-phytec-phycore-som.dtsi
> > @@ -107,14 +107,14 @@
> > regulators {
> > vdd_arm: buck1 {
> > regulator-name = "vdd_arm";
> > - regulator-min-microvolt = <730000>;
> > + regulator-min-microvolt = <1050000>;
> > regulator-max-microvolt = <1380000>;
> > regulator-always-on;
> > };
> > vdd_soc: buck2 {
> > regulator-name = "vdd_soc";
> > - regulator-min-microvolt = <730000>;
> > + regulator-min-microvolt = <1275000>;
> > regulator-max-microvolt = <1380000>;
> > regulator-always-on;
> > };
> >
>

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