linux-kernel - [PATCH v3 4/9] arm64: dts: qcom: sa8775p-ride: move the reset-gpios property of the PHY

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Message-Id: <20230810080909.6259-5-brgl@bgdev.pl>
Date:   Thu, 10 Aug 2023 10:09:04 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     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>,
        Andrew Halaney <ahalaney@...hat.com>
Cc:     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: [PATCH v3 4/9] arm64: dts: qcom: sa8775p-ride: move the reset-gpios property of the PHY

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 controls all
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 comprehensive solution for this problem in 2020 but it
never got upstream. We do however have workaround in place which allows
us to hard-code the PHY id in the compatible property, thus skipping the
ID scanning.

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>
Reviewed-by: Konrad Dybcio <konrad.dybcio@...aro.org>
---
 arch/arm64/boot/dts/qcom/sa8775p-ride.dts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sa8775p-ride.dts b/arch/arm64/boot/dts/qcom/sa8775p-ride.dts
index 09ae6e153282..a03a4c17c8f0 100644
--- a/arch/arm64/boot/dts/qcom/sa8775p-ride.dts
+++ b/arch/arm64/boot/dts/qcom/sa8775p-ride.dts
@@ -279,13 +279,13 @@ 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-assert-us = <11000>;
+			reset-deassert-us = <70000>;
 		};
 	};
 
-- 
2.39.2