On 2/16/2021 5:06 AM, Andrew Lunn wrote:
> On Mon, Feb 15, 2021 at 07:02:18AM +0000, Nathan Rossi wrote:
>> From: Nathan Rossi <nathan.ro...@digi.com>
>>
>> The documentation for MDIO bindings describes the "broken-turn-around",
>> "reset-assert-us", and "reset-deassert-us" properties such that any MDIO
>> device can define them. Other MDIO devices may require these properties
>> in order to correctly function on the MDIO bus.
>>
>> Enable the parsing and configuration associated with these properties by
>> moving the associated OF parsing to a common function
>> of_mdiobus_child_parse and use it to apply these properties for both
>> PHYs and other MDIO devices.
>
> Hi Nathan
>
> What device are you using this with?
>
> The Marvell Switch driver does its own GPIO reset handling. It has a
> better idea when a hardware reset should be applied than what the
> phylib core has. It will also poll the EEPROM busy bit after a
> reset. How long a pause you need after the reset depends on how full
> the EEPROM is.
>
> And i've never had problems with broken-turn-around with Marvell
> switches.
The patch does make sense though, Broadcom 53125 switches have a broken
turn around and are mdio_device instances, the broken behavior may not
show up with all MDIO controllers used to interface though. For the
reset, I would agree with you this is better delegated to the switch
driver, given that unlike PHY devices, we have no need to know the
mdio_device ID prior to binding the device and the driver together.
>
> Given the complexity of an Ethernet switch, it is probably better if
> it handles its own reset.
>
> Andrew
>
--
Florian
