netdev - Re: [net-next,PATCH 3/3] net: phy: realtek: Add property to enable SSC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <c52624fb-9d5f-4eb7-af3f-e2cef872a2ba@mailbox.org>
Date: Wed, 3 Dec 2025 20:21:00 +0100
From: Marek Vasut <marek.vasut@...lbox.org>
To: "Russell King (Oracle)" <linux@...linux.org.uk>,
 Vladimir Oltean <vladimir.oltean@....com>
Cc: netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
 Aleksander Jan Bajkowski <olek2@...pl>, Andrew Lunn <andrew@...n.ch>,
 Conor Dooley <conor+dt@...nel.org>, Eric Dumazet <edumazet@...gle.com>,
 Florian Fainelli <f.fainelli@...il.com>,
 Heiner Kallweit <hkallweit1@...il.com>, Jakub Kicinski <kuba@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Michael Klein <michael@...sekall.de>, Paolo Abeni <pabeni@...hat.com>,
 Rob Herring <robh@...nel.org>, devicetree@...r.kernel.org
Subject: Re: [net-next,PATCH 3/3] net: phy: realtek: Add property to enable
 SSC

On 12/3/25 6:35 PM, Russell King (Oracle) wrote:
> On Wed, Dec 03, 2025 at 02:34:30PM +0200, Vladimir Oltean wrote:
>> On Wed, Dec 03, 2025 at 10:18:35AM +0000, Russell King (Oracle) wrote:
>>> On Sun, Nov 30, 2025 at 01:58:34AM +0100, Marek Vasut wrote:
>>>> Add support for spread spectrum clocking (SSC) on RTL8211F(D)(I)-CG,
>>>> RTL8211FS(I)(-VS)-CG, RTL8211FG(I)(-VS)-CG PHYs. The implementation
>>>> follows EMI improvement application note Rev. 1.2 for these PHYs.
>>>>
>>>> The current implementation enables SSC for both RXC and SYSCLK clock
>>>> signals. Introduce new DT property 'realtek,ssc-enable' to enable the
>>>> SSC mode.
>>>
>>> Should there be separate properties for CLKOUT SSC enable and RXC SSC
>>> enable?
>>
>> That's what we're trying to work out. I was going to try and give an
>> example (based on stmmac) why you wouldn't want RXC SSC but you'd still
>> want CLKOUT SSC, but it doesn't seem to hold water based on your feedback.
>> Having one device tree property to control both clocks is a bit simpler.
> 
> The problem I see is that if we introduce a single property for both,
> we then need to maintain this single property ad infinitum. If we
> later find that we need separate control, we could end up with three
> properties - the combined one, and two for individual controls.
> 
> If we are to go with a single property, then I think we should have at
> least discussed what we would do if we need separate control.
> 
> If we go with two properties now, then we don't have to consider this,
> and we will only ever have the two properties rather than three.
It seems the CLKOUT and RXC SSC can be enabled entirely separately, so I 
think two properties are the way to go ?