netdev - Initialize ethernet phy in low power mode before ndo

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Message-ID: <4t7npxg4jxxoeemcat3besmrfn6sbgsgoolpxbw5asfxfj7xxl@inac2mylgpzl>
Date: Tue, 12 Nov 2024 13:36:37 +0100
From: Sean Nyekjaer <sean@...nix.com>
To: Wei Fang <wei.fang@....com>, Andrew Lunn <andrew+netdev@...n.ch>, 
	imx@...ts.linux.dev, netdev@...r.kernel.org
Subject: Initialize ethernet phy in low power mode before ndo_open

Hi,

I'm using a imx6ull, we have an unused ethernet on our board. We would
like it to use as little power as possible as it's battery operated.
During probe I would expect the ethernet driver to probe the phy
deivce and set it in low power mode (BMCR_PDOWN).
The bit is correcly set if I up/down the interface, is that prefered
behavior?

I can see it's the same stmmac driver for stm32mp1 etc.

I can also set the phy in low power mode in the bootloader, but then the
fec driver would reset phy and we end up where we started.

Br,
/Sean