Re: [PATCH net-next v5] net: phy: Add driver for Motorcomm Quad 2.5GbE phy

[Kyle Switch]

On 7/25/26 06:18, Andrew Lunn wrote:
> On Fri, Jul 24, 2026 at 03:18:47PM +0200, Andrew Lunn wrote:
> 1;4000;47c> > Ans: It is different from the m88e1111 PHY, which may support UTP, fiber, 
>>>      or combo mode. However, the PHY8824 is only used with UTPs, and 
>>>      its structure is as follows, which includes UTP0, UTP1,UTP2,UTP3 and USXGMII.
>>>
>>>      RJ45 <----> UTP0 <------>
>>>      RJ45 <----> UTP1 <------>   USXGMII  <----->  USXGMII(the side of MAC)
>>>      RJ45 <----> UTP2 <------>
>>>      RJ45 <----> UTP3 <------>
>>>
>>>      It is similar to phy8821 driver in motorcomm.c, with the difference 
>>>      being that one has one UTP port and phy8824 has four UTP ports.
>>>      YT8824_RSSR_FIBER_SPACE is used to access USXGMII reg space, Perhaps it 
>>>      would be more accurate to call it YT8824_RSSR_USXGMII_SPACE or 
>>>      YT8824_RSSR_SERDES_SPACE.
>>
>> O.K, that completely changes my understanding of this device. Yes,
>> YT8824_RSSR_FIBER_SPACE should change name. And i would include this
>> diagram in the driver, and indicate how YT8824_RSSR_*_SPACE map to
>> this.
>>
>> For the locking, look thought all the code which is touching the
>> USXGMII side and see if it can be moved into probe().
> 
> So thinking about locking:
> 
> +static int yt8824_config_aneg(struct phy_device *phydev)
> +{
> +	int phy_ctrl = 0;
> +	int ret = 0;
> +
> +	ret = phy8824_page_write_lock(phydev, YT8824_RSSR_UTP_SPACE);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (linkmode_test_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
> +			      phydev->advertising))
> +		phy_ctrl = MDIO_AN_10GBT_CTRL_ADV2_5G;
> +
> +	ret = phy_modify_mmd_changed(phydev, MDIO_MMD_AN,
> +				     MDIO_AN_10GBT_CTRL,
> +				     MDIO_AN_10GBT_CTRL_ADV2_5G,
> +				     phy_ctrl);
> +	if (ret)
> +		return ret;
> +
> +	return genphy_config_aneg(phydev);
> +
> 
> This is only touching the UTP side of things. What a PHY advertises
> should not affect the USXGMII side. Why does it need
> YT8824_RSSR_UTP_SPACE? What would happen if YT8824_RSSR_USXGMII_SPACE
> has selected?
> 

Ans: i have updated PATCH v6 in 
https://patchwork.kernel.org/project/netdevbpf/patch/20260723102112.1155723-1-kyle.switch@xxxxxxxxxxxxxx/.
     The log of this patch failure is as "Patch does not apply to net-next-0". 
     The patch v7 will be rebased and updated. Could you provide some comments based on patch v6 included
     refactor the usage of USXGMII, add helper in phy-c45? The definition of YT8824_RSSR_FIBER_SPACE was 
     modified in patch v7.
     
  
>     Andrew