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From: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
To: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	devicetree@vger.kernel.org, robh+dt@kernel.org
Cc: palmer@dabbelt.com, paul.walmsley@sifive.com,
	atish.patra@wdc.com,
	Sagar Shrikant Kadam <sagar.kadam@sifive.com>
Subject: [PATCH v1 1/3] dts: phy: fix missing mdio device and probe failure of vsc8541-01 device
Date: Wed, 13 May 2020 06:56:59 -0700	[thread overview]
Message-ID: <1589378222-15238-2-git-send-email-sagar.kadam@sifive.com> (raw)
In-Reply-To: <1589378222-15238-1-git-send-email-sagar.kadam@sifive.com>

HiFive unleashed A00 board has VSC8541-01 ethernet phy, this device is
identified as a Revision B device as described in device identification
registers. In order to use this phy in the unmanaged mode, it requires
a specific reset sequence of logical 0-1-0-1 transition on the NRESET pin
as documented here [1].

Currently, the bootloader (fsbl) takes care of the phy reset. If due to
some reason the phy device hasn't received the reset by the prior stages
before the linux macb driver comes into the picture, the MACB mii bus gets
probed but the mdio scan fails and is not even able to read the phy ID
registers. It gives an error message:

"libphy: MACB_mii_bus: probed
mdio_bus 10090000.ethernet-ffffffff: MDIO device at address 0 is missing."

Thus adding the device OUI (Organizationally Unique Identifier) to the phy
device node helps to probe the phy device.

[1]: VSC8541-01 datasheet:
https://www.mouser.com/ds/2/523/Microsemi_VSC8541-01_Datasheet_10496_V40-1148034.pdf

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
---
 arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
index 4a2729f..60846e8 100644
--- a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
+++ b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
@@ -88,6 +88,7 @@
 	phy-mode = "gmii";
 	phy-handle = <&phy0>;
 	phy0: ethernet-phy@0 {
+		compatible = "ethernet-phy-id0007.0771";
 		reg = <0>;
 	};
 };
-- 
2.7.4


WARNING: multiple messages have this Message-ID (diff)
From: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
To: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	devicetree@vger.kernel.org, robh+dt@kernel.org
Cc: atish.patra@wdc.com, palmer@dabbelt.com,
	Sagar Shrikant Kadam <sagar.kadam@sifive.com>,
	paul.walmsley@sifive.com
Subject: [PATCH v1 1/3] dts: phy: fix missing mdio device and probe failure of vsc8541-01 device
Date: Wed, 13 May 2020 06:56:59 -0700	[thread overview]
Message-ID: <1589378222-15238-2-git-send-email-sagar.kadam@sifive.com> (raw)
In-Reply-To: <1589378222-15238-1-git-send-email-sagar.kadam@sifive.com>

HiFive unleashed A00 board has VSC8541-01 ethernet phy, this device is
identified as a Revision B device as described in device identification
registers. In order to use this phy in the unmanaged mode, it requires
a specific reset sequence of logical 0-1-0-1 transition on the NRESET pin
as documented here [1].

Currently, the bootloader (fsbl) takes care of the phy reset. If due to
some reason the phy device hasn't received the reset by the prior stages
before the linux macb driver comes into the picture, the MACB mii bus gets
probed but the mdio scan fails and is not even able to read the phy ID
registers. It gives an error message:

"libphy: MACB_mii_bus: probed
mdio_bus 10090000.ethernet-ffffffff: MDIO device at address 0 is missing."

Thus adding the device OUI (Organizationally Unique Identifier) to the phy
device node helps to probe the phy device.

[1]: VSC8541-01 datasheet:
https://www.mouser.com/ds/2/523/Microsemi_VSC8541-01_Datasheet_10496_V40-1148034.pdf

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
---
 arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
index 4a2729f..60846e8 100644
--- a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
+++ b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
@@ -88,6 +88,7 @@
 	phy-mode = "gmii";
 	phy-handle = <&phy0>;
 	phy0: ethernet-phy@0 {
+		compatible = "ethernet-phy-id0007.0771";
 		reg = <0>;
 	};
 };
-- 
2.7.4



  reply	other threads:[~2020-05-13 13:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-13 13:56 [PATCH v1 0/3] fix macb phy probe failure if phy-reset is not handled Sagar Shrikant Kadam
2020-05-13 13:56 ` Sagar Shrikant Kadam
2020-05-13 13:56 ` Sagar Shrikant Kadam [this message]
2020-05-13 13:56   ` [PATCH v1 1/3] dts: phy: fix missing mdio device and probe failure of vsc8541-01 device Sagar Shrikant Kadam
2020-05-13 13:57 ` [PATCH v1 2/3] dts: phy: add GPIO number and active state used for phy reset Sagar Shrikant Kadam
2020-05-13 13:57   ` Sagar Shrikant Kadam
2020-05-13 13:57 ` [PATCH v1 3/3] riscv: defconfig: enable gpio support for HiFive Unleashed Sagar Shrikant Kadam
2020-05-13 13:57   ` Sagar Shrikant Kadam
2020-05-23  5:44 ` [PATCH v1 0/3] fix macb phy probe failure if phy-reset is not handled Sagar Kadam
2020-05-23  5:44   ` Sagar Kadam

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