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SubjectRe: [PATCH RFT 1/2] phylib: add device reset GPIO support
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Hello.

On 05/14/2016 10:50 PM, Andrew Lunn wrote:

>>>>>>> Another issue is that on some boards we have one reset line tied to
>>>>>>> multiple PHYs.How do we prevent multiple resets being taking place when each of
>>>>>>> the PHYs are registered?
>>>>>>
>>>>>> My patch just doesn't address this case -- it's about the
>>>>>> individual resets only.
>>>>>
>>>>> This actually needs to be addresses a layer above. What you have is a
>>>>> bus reset, not a device reset.
>>>>
>>>> No.
>>>> There's simply no such thing as a bus reset for the xMII/MDIO
>>>> busses, there's simply no reset signaling on them. Every device has
>>>> its own reset signal and its own timing requirements.
>>>
>>> Except in the case above, where two phys are sharing the same reset
>>> signal. So although it is not part of the mdio standard to have a bus
>>> reset, this is in effect what the gpio line is doing, resetting all
>>> devices on the bus. If you don't model that as a bus reset, how do you
>>> model it?
>>
>> I'm not suggesting that the shared reset should be handled by my
>> patch. Contrariwise, I suggested to use the mii_bus::reset() method
>
> I think we miss understood each other somewhere.
>
> Your code is great for one gpio reset line for one phy.
>
> I think there could be similar code one layer above to handle one gpio
> line for multiple phys.

Ah, you want me to recognize some MAC/MDIO bound prop (e.g.
"mdio-reset-gpios") in of_mdiobus_register()? I'll think about it now that my
patch needs fixing anyway...

> Andrew

MBR, Sergei

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