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From: Andrew Lunn <andrew@lunn•ch>
To: "Marek Behún" <kabel@kernel•org>
Cc: Vladimir Oltean <olteanv@gmail•com>,
	Holger Brunck <holger.brunck@hitachienergy•com>,
	"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
	Jakub Kicinski <kuba@kernel•org>
Subject: Re: [v3 2/2] dsa: mv88e6xxx: make serdes SGMII/Fiber output amplitude configurable
Date: Wed, 8 Dec 2021 18:55:48 +0100	[thread overview]
Message-ID: <YbDxpJH3GgPDge+O@lunn.ch> (raw)
In-Reply-To: <20211208183626.4e475b0d@thinkpad>

On Wed, Dec 08, 2021 at 06:36:26PM +0100, Marek Behún wrote:
> On Wed, 8 Dec 2021 19:19:09 +0200
> Vladimir Oltean <olteanv@gmail•com> wrote:
> 
> > On Wed, Dec 08, 2021 at 06:00:57PM +0100, Marek Behún wrote:
> > > > Also, maybe drop the "serdes-" prefix? The property will sit under a
> > > > SERDES lane node, so it would be a bit redundant?  
> > > 
> > > Hmm. Holger's proposal adds the property into the port node, not SerDes
> > > lane node. mv88e6xxx does not define bindings for SerDes lane nodes
> > > (yet).  
> > 
> > We need to be careful about that. You're saying that there chances of
> > there being a separate SERDES driver for mv88e6xxx in the future?
> 
> I don't think so. Although Russell is working on rewriting the SerDes
> code to new Phylink API, the SerDes code will always be a part of
> mv88e6xxx driver, I think.

In theory, the 6352 family uses standard c22 layout for its SERDES. It
might be possible to use generic code for that. But given the
architecture, i expect such a change would have the mv88e6xxx
instantiate such generic code, not use an external device.

For the 6390 family the SERDES and the MAC are pretty intertwined, and
it is not a 1:1 mapping. It might be possible to make use of shared
code, but i've much doubt it will be a separate device.

I would put the properties in the port nodes, next to phy-mode,
phy-handle, etc.

Where it might get interesting is the 10G modes, where there are 4
lanes. Is it possible to configure the voltage for each lane? Or is it
one setting for all 4 lanes? I've not looked at the data sheet, so i
cannot answer this.
y
    Andrew

  reply	other threads:[~2021-12-08 17:55 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-07 19:07 [v3 1/2] Docs/devicetree: add serdes.yaml Holger Brunck
2021-12-07 19:07 ` [v3 2/2] dsa: mv88e6xxx: make serdes SGMII/Fiber output amplitude configurable Holger Brunck
2021-12-07 19:27   ` Marek Behún
2021-12-08 12:29     ` Holger Brunck
2021-12-08 15:28       ` Marek Behún
2021-12-08 15:49         ` Holger Brunck
2021-12-08 16:17           ` Marek Behún
2021-12-08 16:21             ` Marek Behún
2021-12-08 16:41               ` Vladimir Oltean
2021-12-08 16:49                 ` Vladimir Oltean
2021-12-08 17:00                   ` Marek Behún
2021-12-08 17:19                     ` Vladimir Oltean
2021-12-08 17:36                       ` Marek Behún
2021-12-08 17:55                         ` Andrew Lunn [this message]
2021-12-08 18:15                           ` Marek Behún
2021-12-08 16:51                 ` Marek Behún
2021-12-08 16:59                   ` Vladimir Oltean
2021-12-08 17:10                     ` Marek Behún
2021-12-08 17:12                       ` Marek Behún
2021-12-08 17:20                       ` Vladimir Oltean
2021-12-08 17:00             ` Andrew Lunn
2021-12-08 17:16               ` Marek Behún
2021-12-15 10:27                 ` Holger Brunck
2021-12-15 20:53                   ` Marek Behún
2022-01-20  7:52                     ` Holger Brunck
2022-01-20 17:57                       ` Marek Behún

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