2020-02-18 01:58:46

by Anson Huang

Subject: [PATCH] arm64: dts: imx8mn-ddr4-evk: Adjust 1.2GHz OPP voltage to OD mode

According to latest datasheet Rev.0, 10/2019, there is restriction
as below:

"If VDD_SOC/GPU/DDR = 0.95V, then VDD_ARM must be >= 0.95V."

As by default SoC is running at OD mode(VDD_SOC = 0.95V), so
VDD_ARM 1.2GHz OPP's voltage should be increased to 0.95V.

Signed-off-by: Anson Huang <[email protected]>
---
arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts b/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
index 2497eeb..7a61a1a 100644
--- a/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
@@ -13,6 +13,12 @@
compatible = "fsl,imx8mn-ddr4-evk", "fsl,imx8mn";
};

+&a53_opp_table {
+ opp-1200000000 {
+ opp-microvolt = <950000>;
+ };
+};
+
&A53_0 {
cpu-supply = <&buck2_reg>;
};
--
2.7.4

2020-02-24 01:48:22

by Shawn Guo

Subject: Re: [PATCH] arm64: dts: imx8mn-ddr4-evk: Adjust 1.2GHz OPP voltage to OD mode

On Tue, Feb 18, 2020 at 09:52:32AM +0800, Anson Huang wrote:
> According to latest datasheet Rev.0, 10/2019, there is restriction
> as below:
>
> "If VDD_SOC/GPU/DDR = 0.95V, then VDD_ARM must be >= 0.95V."
>
> As by default SoC is running at OD mode(VDD_SOC = 0.95V), so
> VDD_ARM 1.2GHz OPP's voltage should be increased to 0.95V.
>
> Signed-off-by: Anson Huang <[email protected]>
> ---
> arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts b/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
> index 2497eeb..7a61a1a 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
> +++ b/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
> @@ -13,6 +13,12 @@
> compatible = "fsl,imx8mn-ddr4-evk", "fsl,imx8mn";
> };
>
> +&a53_opp_table {
> + opp-1200000000 {
> + opp-microvolt = <950000>;
> + };
> +};
> +

The restriction applies to SoC rather than a particular board, right?
If so, the change should be made in imx8mn.dtsi?

Shawn

> &A53_0 {
> cpu-supply = <&buck2_reg>;
> };
> --
> 2.7.4
>

2020-02-24 02:03:13

by Anson Huang

Subject: RE: [PATCH] arm64: dts: imx8mn-ddr4-evk: Adjust 1.2GHz OPP voltage to OD mode

Hi, Shawn

> Subject: Re: [PATCH] arm64: dts: imx8mn-ddr4-evk: Adjust 1.2GHz OPP
> voltage to OD mode
>
> On Tue, Feb 18, 2020 at 09:52:32AM +0800, Anson Huang wrote:
> > According to latest datasheet Rev.0, 10/2019, there is restriction as
> > below:
> >
> > "If VDD_SOC/GPU/DDR = 0.95V, then VDD_ARM must be >= 0.95V."
> >
> > As by default SoC is running at OD mode(VDD_SOC = 0.95V), so VDD_ARM
> > 1.2GHz OPP's voltage should be increased to 0.95V.
> >
> > Signed-off-by: Anson Huang <[email protected]>
> > ---
> > arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
> > b/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
> > index 2497eeb..7a61a1a 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
> > +++ b/arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dts
> > @@ -13,6 +13,12 @@
> > compatible = "fsl,imx8mn-ddr4-evk", "fsl,imx8mn"; };
> >
> > +&a53_opp_table {
> > + opp-1200000000 {
> > + opp-microvolt = <950000>;
> > + };
> > +};
> > +
>
> The restriction applies to SoC rather than a particular board, right?
> If so, the change should be made in imx8mn.dtsi?

Yes, you are correct, for now, it is NOT related to board, I will do the change
in .dtsi in V2.

Anson