2022-10-16 18:06:42

by Caleb Connolly

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Subject: [PATCH 1/5] arm64: dts: qcom: pmi8998: add rradc node

Add a DT node for the Round Robin ADC found in the PMI8998 PMIC.

Signed-off-by: Caleb Connolly <[email protected]>
---
arch/arm64/boot/dts/qcom/pmi8998.dtsi | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/pmi8998.dtsi b/arch/arm64/boot/dts/qcom/pmi8998.dtsi
index 6d3d212560c1..5a479259c041 100644
--- a/arch/arm64/boot/dts/qcom/pmi8998.dtsi
+++ b/arch/arm64/boot/dts/qcom/pmi8998.dtsi
@@ -18,6 +18,14 @@ pmi8998_gpio: gpios@c000 {
interrupt-controller;
#interrupt-cells = <2>;
};
+
+ pmi8998_rradc: adc@4500 {
+ compatible = "qcom,pmi8998-rradc";
+ reg = <0x4500>;
+ #io-channel-cells = <1>;
+
+ status = "disabled";
+ };
};

pmi8998_lsid1: pmic@3 {
--
2.38.0


2022-10-17 01:49:33

by Krzysztof Kozlowski

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Subject: Re: [PATCH 1/5] arm64: dts: qcom: pmi8998: add rradc node

On 16/10/2022 14:03, Caleb Connolly wrote:
> Add a DT node for the Round Robin ADC found in the PMI8998 PMIC.
>
> Signed-off-by: Caleb Connolly <[email protected]>
> ---
> arch/arm64/boot/dts/qcom/pmi8998.dtsi | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/qcom/pmi8998.dtsi b/arch/arm64/boot/dts/qcom/pmi8998.dtsi
> index 6d3d212560c1..5a479259c041 100644
> --- a/arch/arm64/boot/dts/qcom/pmi8998.dtsi
> +++ b/arch/arm64/boot/dts/qcom/pmi8998.dtsi
> @@ -18,6 +18,14 @@ pmi8998_gpio: gpios@c000 {
> interrupt-controller;
> #interrupt-cells = <2>;
> };
> +
> + pmi8998_rradc: adc@4500 {
> + compatible = "qcom,pmi8998-rradc";
> + reg = <0x4500>;
> + #io-channel-cells = <1>;
> +
> + status = "disabled";

Why disabling it? It does not need any external/board resources, so
maybe it should be just like other adcs - enabled by default? What does
it measure? What is its input?

Best regards,
Krzysztof

2022-10-17 16:04:30

by Caleb Connolly

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Subject: Re: [PATCH 1/5] arm64: dts: qcom: pmi8998: add rradc node



On 17/10/2022 02:10, Krzysztof Kozlowski wrote:
> On 16/10/2022 14:03, Caleb Connolly wrote:
>> Add a DT node for the Round Robin ADC found in the PMI8998 PMIC.
>>
>> Signed-off-by: Caleb Connolly <[email protected]>
>> ---
>> arch/arm64/boot/dts/qcom/pmi8998.dtsi | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/pmi8998.dtsi b/arch/arm64/boot/dts/qcom/pmi8998.dtsi
>> index 6d3d212560c1..5a479259c041 100644
>> --- a/arch/arm64/boot/dts/qcom/pmi8998.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/pmi8998.dtsi
>> @@ -18,6 +18,14 @@ pmi8998_gpio: gpios@c000 {
>> interrupt-controller;
>> #interrupt-cells = <2>;
>> };
>> +
>> + pmi8998_rradc: adc@4500 {
>> + compatible = "qcom,pmi8998-rradc";
>> + reg = <0x4500>;
>> + #io-channel-cells = <1>;
>> +
>> + status = "disabled";
>
> Why disabling it? It does not need any external/board resources, so
> maybe it should be just like other adcs - enabled by default? What does
> it measure? What is its input?

The RRADC mostly reports values which only make sense on mobile devices, battery
ID and temperature, USB and DC input voltage/current as well as a (duplicate?)
die temperature of the PMIC - I guess closer to the SMB/FG block.

When I last tested the DC input readings didn't work on db845c, as it just
produces the 4.2v you'd get from a battery.

Enabling it by default should be fine (and would certainly simplify this series :P).
>
> Best regards,
> Krzysztof
>

--
Kind Regards,
Caleb (they/them)

2022-10-17 17:44:43

by Krzysztof Kozlowski

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Subject: Re: [PATCH 1/5] arm64: dts: qcom: pmi8998: add rradc node

On 17/10/2022 11:29, Caleb Connolly wrote:

>>> + pmi8998_rradc: adc@4500 {
>>> + compatible = "qcom,pmi8998-rradc";
>>> + reg = <0x4500>;
>>> + #io-channel-cells = <1>;
>>> +
>>> + status = "disabled";
>>
>> Why disabling it? It does not need any external/board resources, so
>> maybe it should be just like other adcs - enabled by default? What does
>> it measure? What is its input?
>
> The RRADC mostly reports values which only make sense on mobile devices, battery
> ID and temperature, USB and DC input voltage/current as well as a (duplicate?)
> die temperature of the PMIC - I guess closer to the SMB/FG block.
>
> When I last tested the DC input readings didn't work on db845c, as it just
> produces the 4.2v you'd get from a battery.

If it is connected to some line - e.g. to the battery - then it is
operational and there is no reason to disable it.


Best regards,
Krzysztof