linux-kernel - Re: [PATCH 3/3] arm64: dts: qcom: qcs615: add pcie phy max current property

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Message-ID: <hughcvp6indpkjadvx3z3s3umkgqkbnqfp3wvle4jm4xdzkniy@e2oqjinaaa65>
Date: Wed, 25 Dec 2024 23:09:01 -0600
From: Bjorn Andersson <andersson@...nel.org>
To: Ziyue Zhang <quic_ziyuzhan@...cinc.com>
Cc: vkoul@...nel.org, kishon@...nel.org, dmitry.baryshkov@...aro.org, 
	abel.vesa@...aro.org, neil.armstrong@...aro.org, manivannan.sadhasivam@...aro.org, 
	konradybcio@...nel.org, robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org, 
	linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	devicetree@...r.kernel.org
Subject: Re: [PATCH 3/3] arm64: dts: qcom: qcs615: add pcie phy max current
 property

On Wed, Dec 04, 2024 at 06:52:49PM +0800, Ziyue Zhang wrote:
> Add vdda-pll-max-microamp for vdda-pll-supply. The value of this property
> is from the power grid guide. It is the maximum current the regulator can
> provide. The property will be parsed by PCIe PHY driver to set the current
> load.
> 
> Signed-off-by: Ziyue Zhang <quic_ziyuzhan@...cinc.com>
> ---
>  arch/arm64/boot/dts/qcom/qcs615-ride.dts | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/qcs615-ride.dts b/arch/arm64/boot/dts/qcom/qcs615-ride.dts
> index 18f131ae9e07..6d93ef0d886b 100644
> --- a/arch/arm64/boot/dts/qcom/qcs615-ride.dts
> +++ b/arch/arm64/boot/dts/qcom/qcs615-ride.dts
> @@ -215,6 +215,7 @@ &pcie {
>  &pcie_phy {
>  	vdda-phy-supply = <&vreg_l5a>;
>  	vdda-pll-supply = <&vreg_l12a>;
> +	vdda-pll-max-microamp = <165000>;

It seems from the driver patch (patch 2/3) that you will apply this
load-request at init and release it at exit, which I believe will hold
the regulator at HPM always.

If that's the case, why is vreg_l12a declared with
regulator-allow-set-load and support LPM on this board?

If the regulator needs to be in HPM on this board, remove
regulator-allow-set-load and the LPM mode from the regulator.


In fact, you (all of you) should remove all regulator-allow-set-load and
LPM modes from the DT until you know what that implies - and then
provide specific patches with clear description of the impact when you
add it back.

Regards,
Bjorn

>  
>  	status = "okay";
>  };
> -- 
> 2.34.1
>