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From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Heiko Stuebner <heiko@sntech.de>, Andrew Lunn <andrew@lunn.ch>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	kernel@collabora.com
Subject: Re: [PATCH] arm64: dts: rockchip: use MAC TX delay for ROCK 4D
Date: Thu, 24 Jul 2025 19:16:53 +0100	[thread overview]
Message-ID: <aIJ4lZgfTiNmHaXF@shell.armlinux.org.uk> (raw)
In-Reply-To: <20250724-rk3576-rock4d-phy-timings-v1-1-1cdce2b4aca4@kernel.org>

On Thu, Jul 24, 2025 at 04:31:25PM +0200, Sebastian Reichel wrote:
> According to the Ethernet controller device tree binding "rgmii-id"
> means, that the PCB does not have extra long lines to add the required
> delays. This is indeed the case for the ROCK 4D.
> 
> The problem is, that the Rockchip MAC Linux driver interprets the
> interface type differently and abuses the information to configure
> RX and TX delays in the MAC using (vendor) properties 'rx_delay' and
> 'tx_delay'.
> 
> When Detlev Casanova upstreamed the ROCK 4D device tree, he used the
> correct description for the board ("rgmii-id"). This results in no delays
> being configured in the MAC. At the same time the PHY will provide
> some delays.

So why can't the MAC be fixed to conform to the requirements that are
well documented for RGMII?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!


WARNING: multiple messages have this Message-ID (diff)
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Heiko Stuebner <heiko@sntech.de>, Andrew Lunn <andrew@lunn.ch>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	kernel@collabora.com
Subject: Re: [PATCH] arm64: dts: rockchip: use MAC TX delay for ROCK 4D
Date: Thu, 24 Jul 2025 19:16:53 +0100	[thread overview]
Message-ID: <aIJ4lZgfTiNmHaXF@shell.armlinux.org.uk> (raw)
In-Reply-To: <20250724-rk3576-rock4d-phy-timings-v1-1-1cdce2b4aca4@kernel.org>

On Thu, Jul 24, 2025 at 04:31:25PM +0200, Sebastian Reichel wrote:
> According to the Ethernet controller device tree binding "rgmii-id"
> means, that the PCB does not have extra long lines to add the required
> delays. This is indeed the case for the ROCK 4D.
> 
> The problem is, that the Rockchip MAC Linux driver interprets the
> interface type differently and abuses the information to configure
> RX and TX delays in the MAC using (vendor) properties 'rx_delay' and
> 'tx_delay'.
> 
> When Detlev Casanova upstreamed the ROCK 4D device tree, he used the
> correct description for the board ("rgmii-id"). This results in no delays
> being configured in the MAC. At the same time the PHY will provide
> some delays.

So why can't the MAC be fixed to conform to the requirements that are
well documented for RGMII?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

  parent reply	other threads:[~2025-07-24 18:36 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-24 14:31 [PATCH] arm64: dts: rockchip: use MAC TX delay for ROCK 4D Sebastian Reichel
2025-07-24 14:31 ` Sebastian Reichel
2025-07-24 15:51 ` Andrew Lunn
2025-07-24 15:51   ` Andrew Lunn
2025-07-25  5:24   ` Sebastian Reichel
2025-07-25  5:24     ` Sebastian Reichel
2025-07-25 12:21     ` Andrew Lunn
2025-07-25 12:21       ` Andrew Lunn
2025-07-24 18:16 ` Russell King (Oracle) [this message]
2025-07-24 18:16   ` Russell King (Oracle)
2025-07-25  5:42   ` Sebastian Reichel
2025-07-25  5:42     ` Sebastian Reichel

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