Re: create drivers/net/mdio and move mdio drivers into it

[Florian Fainelli <f.fainelli@gmail.com>]

On 02/19/2017 10:10 PM, YUAN Linyu wrote:
> 
> 
>> -----Original Message-----
>> From: Florian Fainelli [mailto:f.fainelli@gmail.com]
>> Sent: Monday, February 20, 2017 1:42 PM
>> To: YUAN Linyu; David S . Miller; Andrew Lunn
>> Cc: netdev@vger.kernel.org; cugyly@163.com
>> Subject: Re: create drivers/net/mdio and move mdio drivers into it
>>> 3. another idea is bind mdio device to network device
>>
>> You would have to be more specific about what you want to do here. If
>> the MDIO device is e.g: a switch, what we recommend doing is provide a
>> fixed-link node that describes how the Ethernet MAC and the switch's
>> CPU/management ports are connected (that way the MAC always "sees" the
>> link as UP, running with a specific speed and duplex).
>>
> Yes, some system will configured the phy to fixed speed/duplex at boot time,
> no phy driver used in kernel at all.

There is always a PHY driver used, either is a dedicated one, or its the
generic PHY driver in drivers/net/phy/phy_device.c, even when fixed
PHYs/link are used.

> If network device know mdio device it used, we can do phy dump through this 
> mdio device driver.

We are not going to accept MDIO device drivers whose only purpose is to
allow PHY devices register dumps. Implement a proper PHY driver for
these devices, if nothing needs to be done, you just need to call into
genphy_* functions, and just override how to do register dumps.

> 
>> If this is a different kind of MDIO device, e.g: an USB/PCIe/SATA PHY,
>> there is no network device associated with those.
>>
> mdio under drivers/net/, it will not cover these devices.
> 

-- 
Florian