Re: [PATCH net-next v3] net: phy: at803x: add cable diagnostics support

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

On 5/13/2020 1:38 PM, Michael Walle wrote:
> The AR8031/AR8033 and the AR8035 support cable diagnostics. Adding
> driver support is straightforward, so lets add it.
> 
> The PHY just do one pair at a time, so we have to start the test four
> times. The cable_test_get_status() can block and therefore we can just
> busy poll the test completion and continue with the next pair until we
> are done.
> The time delta counter seems to run at 125MHz which just gives us a
> resolution of about 82.4cm per tick.
> 
> 100m cable, A/B/C/D open:
>   Cable test started for device eth0.
>   Cable test completed for device eth0.
>   Pair: Pair A, result: Open Circuit
>   Pair: Pair A, fault length: 107.94m
>   Pair: Pair B, result: Open Circuit
>   Pair: Pair B, fault length: 104.64m
>   Pair: Pair C, result: Open Circuit
>   Pair: Pair C, fault length: 105.47m
>   Pair: Pair D, result: Open Circuit
>   Pair: Pair D, fault length: 107.94m
> 
> 1m cable, A/B connected, C shorted, D open:
>   Cable test started for device eth0.
>   Cable test completed for device eth0.
>   Pair: Pair A, result: OK
>   Pair: Pair B, result: OK
>   Pair: Pair C, result: Short within Pair
>   Pair: Pair C, fault length: 0.82m
>   Pair: Pair D, result: Open Circuit
>   Pair: Pair D, fault length: 0.82m
> 
> Signed-off-by: Michael Walle <michael@walle.cc>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian