linux-kernel - Re: [PATCH 5/9] arm64: dts: qcom: sa8775p-ride: move the reset-gpios property of the PHY

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Message-ID: <siqiyihftz3musfjulpcqunhgi7npftumrfwfyh2pqnlx6zeb7@rrpwmkvjshfb>
Date:   Mon, 7 Aug 2023 16:32:38 -0500
From:   Andrew Halaney <ahalaney@...hat.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Alex Elder <elder@...aro.org>,
        Srini Kandagatla <srinivas.kandagatla@...aro.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 5/9] arm64: dts: qcom: sa8775p-ride: move the reset-gpios
 property of the PHY

On Mon, Aug 07, 2023 at 09:35:03PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> Device-tree bindings for MDIO define per-PHY reset-gpios as well as a
> global reset-gpios property at the MDIO node level which controlls all

s/controlls/controls/

> devices on the bus. The latter is most likely a workaround for the
> chicken-and-egg problem where we cannot read the ID of the PHY before
> bringing it out of reset but we cannot bring it out of reset until we've
> read its ID.
> 
> I have proposed a solution for this problem in 2020 but it never got
> upstream. Now we have a workaround in place which allows us to hard-code
> the PHY id in the compatible property, thus skipping the ID scanning).

nitpicky, but I think that already existed at that time :D

> 
> Let's make the device-tree for sa8775p-ride slightly more correct by
> moving the reset-gpios property to the PHY node with its ID put into the
> PHY node's compatible.
> 
> Link: https://lore.kernel.org/all/20200622093744.13685-1-brgl@bgdev.pl/
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---
>  arch/arm64/boot/dts/qcom/sa8775p-ride.dts | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sa8775p-ride.dts b/arch/arm64/boot/dts/qcom/sa8775p-ride.dts
> index 38327aff18b0..1c471278d441 100644
> --- a/arch/arm64/boot/dts/qcom/sa8775p-ride.dts
> +++ b/arch/arm64/boot/dts/qcom/sa8775p-ride.dts
> @@ -279,13 +279,12 @@ mdio {
>  		#address-cells = <1>;
>  		#size-cells = <0>;
>  
> -		reset-gpios = <&pmm8654au_2_gpios 8 GPIO_ACTIVE_LOW>;
> -		reset-delay-us = <11000>;
> -		reset-post-delay-us = <70000>;
> -
>  		sgmii_phy: phy@8 {
> +			compatible = "ethernet-phy-id0141.0dd4";
>  			reg = <0x8>;
>  			device_type = "ethernet-phy";
> +			reset-gpios = <&pmm8654au_2_gpios 8 GPIO_ACTIVE_LOW>;
> +			reset-deassert-us = <70000>;

Doesn't this need reset-assert-us?