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From: Rob Herring <robh@kernel.org>
To: Dimitri Fedrau <dimitri.fedrau@liebherr.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Florian Fainelli <f.fainelli@gmail.com>,
	netdev@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Dimitri Fedrau <dima.fedrau@gmail.com>
Subject: Re: [PATCH net-next 1/3] dt-bindings: net: ethernet-phy: add property mac-series-termination-ohms
Date: Tue, 11 Mar 2025 12:33:44 -0500	[thread overview]
Message-ID: <20250311173344.GA3802548-robh@kernel.org> (raw)
In-Reply-To: <20250307-dp83822-mac-impedance-v1-1-bdd85a759b45@liebherr.com>

On Fri, Mar 07, 2025 at 11:30:01AM +0100, Dimitri Fedrau wrote:
> Add property mac-series-termination-ohms in the device tree bindings for
> selecting the resistance value of the builtin series termination resistors
> of the PHY. Changing the resistance to an appropriate value can reduce
> signal reflections and therefore improve signal quality.
> 
> Signed-off-by: Dimitri Fedrau <dimitri.fedrau@liebherr.com>
> ---
>  Documentation/devicetree/bindings/net/ethernet-phy.yaml | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> index 824bbe4333b7ed95cc39737d3c334a20aa890f01..4a710315a83ccf15bfc210ae432ae988cf31e04c 100644
> --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> @@ -238,6 +238,11 @@ properties:
>        peak-to-peak specified in ANSI X3.263. When omitted, the PHYs default
>        will be left as is.
>  
> +  mac-series-termination-ohms:

A property of the MAC (or associated with it) should be in the MAC's 
node. Also, sounds like either either end could have a property. We 
already have similar properties in other cases: 'termination-ohms' for 
example. That appears to be for series term as well given a value of 
120ohms. 

Rob

  reply	other threads:[~2025-03-11 17:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-07 10:30 [PATCH net-next 0/3] net: phy: dp83822: Add support for changing the MAC series termination Dimitri Fedrau via B4 Relay
2025-03-07 10:30 ` [PATCH net-next 1/3] dt-bindings: net: ethernet-phy: add property mac-series-termination-ohms Dimitri Fedrau via B4 Relay
2025-03-11 17:33   ` Rob Herring [this message]
2025-03-11 18:06     ` Andrew Lunn
2025-03-07 10:30 ` [PATCH net-next 2/3] net: phy: Add helper for getting MAC series termination resistance Dimitri Fedrau via B4 Relay
2025-03-07 10:30 ` [PATCH net-next 3/3] net: phy: dp83822: Add support for changing the MAC series termination Dimitri Fedrau via B4 Relay
2025-03-07 13:39 ` [PATCH net-next 0/3] " Andrew Lunn
2025-03-07 14:22   ` Dimitri Fedrau
2025-03-07 15:34     ` Andrew Lunn
2025-03-07 19:23       ` Dimitri Fedrau

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