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From: Vladimir Oltean <olteanv@gmail.com>
To: Shawn Guo <shawnguo@kernel.org>,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org
Cc: netdev@vger.kernel.org,
	Alex Marginean <alexandru.marginean@nxp.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	Michael Walle <michael@walle.cc>,
	Vladimir Oltean <vladimir.oltean@nxp.com>
Subject: [PATCH devicetree] arm64: dts: ls1028a: set up the real link speed for ENETC port 2
Date: Mon,  8 Mar 2021 15:08:34 +0200	[thread overview]
Message-ID: <20210308130834.2994658-1-olteanv@gmail.com> (raw)

From: Vladimir Oltean <vladimir.oltean@nxp.com>

In NXP LS1028A there is a MAC-to-MAC internal link between enetc_port2
and mscc_felix_port4. This link operates at 2.5Gbps and is described as
such for the mscc_felix_port4 node.

The reason for the discrepancy is a limitation in the PHY library
support for fixed-link nodes. Due to the fact that the PHY library
registers a software PHY which emulates the clause 22 register map, the
drivers/net/phy/fixed_phy.c driver only supports speeds up to 1Gbps.

The mscc_felix_port4 node is probed by DSA, which does not use the PHY
library directly, but phylink, and phylink has a different representation
for fixed-link nodes, one that does not have the limitation of not being
able to represent speeds > 1Gbps.

Since the enetc driver was converted to phylink too as of commit
71b77a7a27a3 ("enetc: Migrate to PHYLINK and PCS_LYNX"), the limitation
has been practically lifted there too, and we can describe the real link
speed in the device tree now.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
index 262fbad8f0ec..bf60f3858b0f 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
@@ -1027,7 +1027,7 @@ enetc_port2: ethernet@0,2 {
 				status = "disabled";
 
 				fixed-link {
-					speed = <1000>;
+					speed = <2500>;
 					full-duplex;
 				};
 			};
-- 
2.25.1


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             reply	other threads:[~2021-03-08 13:10 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-08 13:08 Vladimir Oltean [this message]
2021-03-15  6:01 ` [PATCH devicetree] arm64: dts: ls1028a: set up the real link speed for ENETC port 2 Shawn Guo

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