linux-kernel - Re: [PATCH 03/15] arm64: dts: imx8mp-evk: fix BUCK/LDO voltage

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Date:   Fri, 21 Oct 2022 17:13:47 +0800
From:   Peng Fan <peng.fan@....nxp.com>
To:     Marco Felsch <m.felsch@...gutronix.de>
Cc:     robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de,
        devicetree@...r.kernel.org, Peng Fan <peng.fan@....com>,
        linux-kernel@...r.kernel.org, linux-imx@....com,
        kernel@...gutronix.de, festevam@...il.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 03/15] arm64: dts: imx8mp-evk: fix BUCK/LDO voltage

Hi Marco

On 10/20/2022 7:02 PM, Marco Felsch wrote:
> Hi Peng,
> 
> On 22-10-20, Peng Fan (OSS) wrote:
>> From: Peng Fan <peng.fan@....com>
>>
>> Per PCA9450C datasheet, the voltage range as below:
>> BUCK1 0.6 - 2.1875
>> BUCK2 0.6 - 2.1875
>> BUCK4 0.6 - 3.4
>> BUCK5 0.6 - 3.4
>> BUCK6 0.6 - 3.4
>>
>> LDO1 1.6-1.9, 3.0-3.3
>> LDO2 0.8 – 1.15
>> LDO3 0.8 - 3.3
>> LDO4 0.8 - 3.3
>> LDO5 1.8 - 3.3
>>
>> So correct them, and also add LDO[2,4]
> 
> In the DTS you specify voltage constraints for a specific hardware and
> not the one supported by the PMIC. What the PMIC supports (min/max) is
> specified within the driver.

Technically we could set board voltage to PMIC voltage range, it not
damage the board from hardware level.
but I am not sure whether Linux could work proper.
Saying set VDD_SOC/DDR to pmic min voltage, system will crash,
because it could not support higher freq.

I am not sure how to proceed on this, just update commit log
to say that the board voltage range could be set to pmic voltage range?

Thanks,
Peng.

> 
> Regards,
>    Marco
> 
>>
>> Fixes: 5497bc2a2bff ("arm64: dts: imx8mp-evk: Add PMIC device")
>> Signed-off-by: Peng Fan <peng.fan@....com>
>> ---
>>   arch/arm64/boot/dts/freescale/imx8mp-evk.dts | 44 +++++++++++++-------
>>   1 file changed, 30 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
>> index b4c1ef2559f2..a4cddc5a8620 100644
>> --- a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
>> +++ b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
>> @@ -248,8 +248,8 @@ pmic@25 {
>>   		regulators {
>>   			BUCK1 {
>>   				regulator-name = "BUCK1";
>> -				regulator-min-microvolt = <720000>;
>> -				regulator-max-microvolt = <1000000>;
>> +				regulator-min-microvolt = <600000>;
>> +				regulator-max-microvolt = <2187500>;
>>   				regulator-boot-on;
>>   				regulator-always-on;
>>   				regulator-ramp-delay = <3125>;
>> @@ -257,8 +257,8 @@ BUCK1 {
>>   
>>   			reg_arm: BUCK2 {
>>   				regulator-name = "BUCK2";
>> -				regulator-min-microvolt = <720000>;
>> -				regulator-max-microvolt = <1025000>;
>> +				regulator-min-microvolt = <600000>;
>> +				regulator-max-microvolt = <2187500>;
>>   				regulator-boot-on;
>>   				regulator-always-on;
>>   				regulator-ramp-delay = <3125>;
>> @@ -268,40 +268,56 @@ reg_arm: BUCK2 {
>>   
>>   			BUCK4 {
>>   				regulator-name = "BUCK4";
>> -				regulator-min-microvolt = <3000000>;
>> -				regulator-max-microvolt = <3600000>;
>> +				regulator-min-microvolt = <600000>;
>> +				regulator-max-microvolt = <3400000>;
>>   				regulator-boot-on;
>>   				regulator-always-on;
>>   			};
>>   
>>   			BUCK5 {
>>   				regulator-name = "BUCK5";
>> -				regulator-min-microvolt = <1650000>;
>> -				regulator-max-microvolt = <1950000>;
>> +				regulator-min-microvolt = <600000>;
>> +				regulator-max-microvolt = <3400000>;
>>   				regulator-boot-on;
>>   				regulator-always-on;
>>   			};
>>   
>>   			BUCK6 {
>>   				regulator-name = "BUCK6";
>> -				regulator-min-microvolt = <1045000>;
>> -				regulator-max-microvolt = <1155000>;
>> +				regulator-min-microvolt = <600000>;
>> +				regulator-max-microvolt = <3400000>;
>>   				regulator-boot-on;
>>   				regulator-always-on;
>>   			};
>>   
>>   			LDO1 {
>>   				regulator-name = "LDO1";
>> -				regulator-min-microvolt = <1650000>;
>> -				regulator-max-microvolt = <1950000>;
>> +				regulator-min-microvolt = <1600000>;
>> +				regulator-max-microvolt = <3300000>;
>> +				regulator-boot-on;
>> +				regulator-always-on;
>> +			};
>> +
>> +			LDO2 {
>> +				regulator-name = "LDO2";
>> +				regulator-min-microvolt = <800000>;
>> +				regulator-max-microvolt = <1150000>;
>>   				regulator-boot-on;
>>   				regulator-always-on;
>>   			};
>>   
>>   			LDO3 {
>>   				regulator-name = "LDO3";
>> -				regulator-min-microvolt = <1710000>;
>> -				regulator-max-microvolt = <1890000>;
>> +				regulator-min-microvolt = <800000>;
>> +				regulator-max-microvolt = <3300000>;
>> +				regulator-boot-on;
>> +				regulator-always-on;
>> +			};
>> +
>> +			ldo4: LDO4 {
>> +				regulator-name = "LDO4";
>> +				regulator-min-microvolt = <800000>;
>> +				regulator-max-microvolt = <3300000>;
>>   				regulator-boot-on;
>>   				regulator-always-on;
>>   			};
>> -- 
>> 2.37.1
>>
>>
>>