[PATCH 1/2] net: ti: am65-cpsw-nuss: Workaround for buggy PHY/Board

[Siddharth Vadapalli]

Roger,

On 25/08/23 00:39, Roger Quadros wrote:
> 
> 
> On 24/08/2023 21:24, Tom Rini wrote:
>> On Thu, Aug 24, 2023 at 11:34:29PM +0530, Siddharth Vadapalli wrote:
>>> Hello Roger,
>>>
>>> On 22-08-2023 17:43, Roger Quadros wrote:

...

> 
> Even a single "PHY not found" print is not OK. It looks like an
> error while it should not.
> 
> The correct solution is to use the MDIO uclass framework and add
> some generic handling in the class driver. drivers/net/eth-phy-uclass.c
> 
> We could provide the delay time in the 'reset-deassert-us' property.
> Although I'm not sure if this is the correct property for this case
> as there is no RESET GPIO on the board. What we really want is delay
> from power-on-reset. Which means we might have to introduce a new property
> and use time from boot to determine if PHY is ready or not?
> 
> NOTE: PHY ready time is different for hardware reset and power-on-reset.
> 50ms vs 150ms

Another alternative could be that of implementing the for-loop within
phy_connect() along with the delay, by updating the function with a new
parameter "tries" which indicates the number of retries before finally printing
"PHY not found" in case of an error. Optionally, another parameter "delay" can
be added, which indicates the delay within the for-loop.

This implementation will require updating all drivers in drivers/net which use
phy_connect(), with the "tries" parameter set to 1 for them. The am65-cpsw-nuss
driver can set "tries" to 5 as done in the current patch.

The idea behind moving the for-loop within phy_connect() is that it will help
solve the issue for other drivers as well, if they potentially encounter such
buggy PHYs in future boards.

> 

-- 
Regards,
Siddharth.