Re: [PATCH RFC net-next] net: phy: marvell10g: add downshift tunable support

On Tue, Jul 20, 2021 at 05:04:24PM +0200, Marek Behún wrote:

Hi Russell,

On Tue, 20 Jul 2021 14:38:20 +0100
Russell King [off-list ref] wrote:

quoted

Add support for the downshift tunable for the Marvell 88x3310 PHY.
Downshift is only usable with firmware 0.3.5.0 and later.

mv3310_{g,s}et_features are also used for 88E211x, but there is no such
register in the documentation for these PHYs. (Also firmware versions on
those are different, the newest is 8.3.0.0, but thats not important.)
My solution would be to rename the current methods prefix to mv211x_ and
and add new mv3310_{g,s}et_tunable methods.

There's more than just the tunables themselves - there's also
config_init().

We already need to reject downshift when old firmware is running,
as that fails to work correctly. So, we can just do that for
88E211x as well, adding a flag to struct mv3310_chip to indicate
whether downshift is present. Sound sensible?

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