Re: [PATCH v4 4/4] net: mdio: Add RTL9300 MDIO driver

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Jan 22, 2025 at 11:02:14PM +0000, Chris Packham wrote:
> Hi Andrew,
> 
> On 23/01/2025 10:47, Andrew Lunn wrote:
> >> I believe the POLL_SEL configuration actually affects an internal port
> >> polling unit. From the datasheets I have it seems pretty configurable, you
> >> can tell it which phy registers to poll and what values indicate link
> >> up/down (the defaults are conveniently setup to match the Realtek PHYs).
> > You need to disable this. The linux PHY driver is driving the PHY, and
> > the hardware has no idea what Linux is doing. Say the driver has
> > changed the page to read a temperature sensor, when the switch does a
> > poll. Rather than reading the link status, it gets some random value
> > from the page containing the temperature sensor.
> 
> There's a mask that can be set via a register that can disable polling 
> for a port. The trick will be deciding when to do so.

On probe. And leave is disabled. phylink will provide you with all the
information you need about link up, what the link speed is etc. There
is no need for PPU.

	Andrew