Re: [PATCH net-next v8 15/15] ax88796b: Add support for AX88772D, AX88179A and AX88279

[Birger Koblitz <mail@birger-koblitz.de>]

On 31/08/2026 4:38 pm, Andrew Lunn wrote:
>> +/* AX88179A-based PHYs cannot access MMD registers via MII_MMD_CTRL/MII_MMD_DATA
>> + * Make sure to use c45 access instead.
>> + */
>> +static int asix_read_mmd(struct phy_device *phydev, int devnum, u16 reg)
>> +{
>> +	struct mii_bus *bus = phydev->mdio.bus;
>> +	int addr = phydev->mdio.addr;
>> +
>> +	return __mdiobus_c45_read(bus, addr, devnum, reg);
>> +}
>> +
>> +static int asix_write_mmd(struct phy_device *phydev, int devnum, u16 reg, u16 val)
>> +{
>> +	struct mii_bus *bus = phydev->mdio.bus;
>> +	int addr = phydev->mdio.addr;
>> +
>> +	return __mdiobus_c45_write(bus, addr, devnum, reg, val);
>> +}
> 
> Please see aa63217916e1818a28b711384a9340d965ad073f
> 
>      net: phy: add generic helpers for direct C45 MMD access
>      
>      Some PHYs support direct C45 register access but not C22 indirect MMD
>      access (registers 0xD and 0xE). When discovered via C22, phylib routes
>      MMD access through the indirect path, which won't work on these
>      devices.
>      
>      Add genphy_read_mmd_c45() and genphy_write_mmd_c45() as read_mmd/
>      write_mmd callbacks that bypass the C22 indirect path and use the bus
>      C45 accessors directly.
Thanks for pointing this out, Andrew. Will use that helper function
instead in the next round.

Birger