Re: [PATCH net-next v3 03/13] ax88179_178a: Use MMD accessor functions for AX88179A

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

On 7/24/26 18:44, Andrew Lunn wrote:
> On Fri, Jul 24, 2026 at 09:36:46AM +0200, Birger Koblitz wrote:
>> The AX88179A uses a much simpler Clause-45 MMD access interface,
>> which are made available through ax_read_mmd() and ax_write_mmd(),
>> which in turn call the chips' respective implementation.
>>
>> Make use of these functions for stract MMD read/write operations.
>>
>> Signed-off-by: Birger Koblitz <mail@birger-koblitz.de>
>> ---
>>   drivers/net/usb/ax88179_178a.c | 39 +++++++++++----------------------------
>>   1 file changed, 11 insertions(+), 28 deletions(-)
>>
>> diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
>> index b90a75a11024c58192bdb4a9436636bc9312148c..b7837c7a89f9b5ee520ef1ae91bbc7619d1a12bd 100644
>> --- a/drivers/net/usb/ax88179_178a.c
>> +++ b/drivers/net/usb/ax88179_178a.c
>> @@ -985,22 +985,19 @@ ax88179_ethtool_get_eee(struct usbnet *dev, struct ethtool_keee *data)
>>   	int val;
>>   
>>   	/* Get Supported EEE */
>> -	val = ax88179_phy_read_mmd_indirect(dev, MDIO_PCS_EEE_ABLE,
>> -					    MDIO_MMD_PCS);
>> +	val = ax_read_mmd(dev, MDIO_MMD_PCS, MDIO_PCS_EEE_ABLE);
> 
> All these look to be standard EEE registers. phylib should be handling
> this for you. Put a printk in genphy_c45_read_eee_cap1() and make sure
> it is being called.
> 
> Basically, anything which is part of 802.3 clause 22 or clause 45
> should have helpers in phylib, and in most cases, phylib itself will
> take care of it. A MAC driver touching the PHY is generally a bad
> design, a layer violation. So any driver using phylink or phylib, all
> direct access to the PHY needs to be removed.
> 
This is again the existing code targeting the AX179, I just used the
new MMD accessor functions that target both architectures. I cannot convert
that with any confidence that it will work without having those devices.
One would need to write PHY drivers and use phylink to make the mess
go away.

Birger