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From:   Leonard Crestez <leonard.crestez@nxp.com>
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Subject: Re: [PATCH 1/2] arm64: dts: imx8mq: Correct OPP table according to
 latest datasheet
Thread-Topic: [PATCH 1/2] arm64: dts: imx8mq: Correct OPP table according to
 latest datasheet
Thread-Index: AQHVLWLGEgwa/2nQ4E+GYs5uFNg8hw==
Date:   Fri, 28 Jun 2019 05:58:42 +0000
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On 28.06.2019 06:37, Anson.Huang@nxp.com wrote:=0A=
> From: Anson Huang <Anson.Huang@nxp.com>=0A=
> =0A=
> According to latest datasheet (Rev.1, 10/2018) from below links,=0A=
> in the consumer datasheet, 1.5GHz is mentioned as highest opp but=0A=
> depends on speed grading fuse, and in the industrial datasheet,=0A=
> 1.3GHz is mentioned as highest opp but depends on speed grading=0A=
> fuse. 1.5GHz and 1.3GHz opp use same voltage, so no need for=0A=
> consumer part to support 1.3GHz opp, with same voltage, CPU should=0A=
> run at highest frequency in order to go into idle as quick as=0A=
> possible, this can save power.=0A=
=0A=
I looked at the same datasheets and it's not clear to me that 1.3 Ghz =0A=
should be disallowed for consumer parts. Power consumption increases =0A=
with both voltage and frequency so having two OPPs with same voltage =0A=
does make sense.=0A=
=0A=
>   			opp-hz =3D /bits/ 64 <1300000000>;=0A=
>   			opp-microvolt =3D <1000000>;=0A=
> -			opp-supported-hw =3D <0xc>, <0x7>;=0A=
> +			/* Industrial only but rely on speed grading */=0A=
> +			opp-supported-hw =3D <0xc>, <0x4>;=0A=
=0A=
Comment is false, you're explicitly excluding consumer parts via the =0A=
second element.=0A=
=0A=
>   			opp-hz =3D /bits/ 64 <1500000000>;=0A=
>   			opp-microvolt =3D <1000000>;=0A=
>   			/* Consumer only but rely on speed grading */=0A=
> -			opp-supported-hw =3D <0x8>, <0x7>;=0A=
> +			opp-supported-hw =3D <0x8>, <0x3>;=0A=
=0A=
If you don't want to rely on the fact that only consumer parts should be =
=0A=
fused for 1.5 Ghz then please delete the comment.=0A=