Re: [PATCH] net: phy: Add driver for Motorcomm Quad 2.5GbE phy

[Andrew Lunn]

On Wed, Jul 15, 2026 at 07:59:55PM +0800, Kyle Switch wrote:
> 
> 
> On 7/15/26 05:46, Andrew Lunn wrote:
> >> +static inline int ytphy_top_write(struct phy_device *phydev, u32 regnum,
> >> +				  u16 val)
> >> +{
> >> +	struct yt8521_priv *priv = phydev->priv;
> >> +	struct mii_bus *bus = phydev->mdio.bus;
> >> +
> >> +	return bus->write(bus, priv->top_phy_addr, regnum, val);
> >> +}
> > 
> > Please could you explain the architecture in detail. It seems like you
> > are accessing registers of some other device on the bus.
> > 
> > Maybe you need to use the code in phy_package.c?
> 
> Ans: YT8824 contains top extend reg space, and the addr is fixed, for 
> internal phy8824 the value is 9, and external phy8824 is (baseaddr + 4).

Does the "top extend reg space" have values in the ID registers, 2 and
3? Is Linux trying to probe this address space?

Anyway, it does sound like you need to use phy_package. That will give
you a better API for accessing the registers in the other address
space.

	Andrew