On 24.07.2020 20:40, Florian Fainelli wrote:
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>
> On 7/24/20 3:50 AM, Codrin Ciubotariu wrote:
>> The MACB embeds an MDIO bus controller. For this reason, the PHY nodes
>> were represented as sub-nodes in the MACB node. Generally, the
>> Ethernet controller is different than the MDIO controller, so the PHYs
>> are probed by a separate MDIO driver. Since adding the PHY nodes directly
>> under the ETH node became deprecated, we adjust the MACB driver to look
>> for an MDIO node and register the subnode MDIO devices.
>>
>> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@xxxxxxxxxxxxx>
>> ---
>>
>> Changes in v3:
>> - moved the check for the mdio node at the beginnging of
>> macb_mdiobus_register(). This way, the mdio devices will be probed even
>> if macb is a fixed-link
>>
>> Changes in v2:
>> - readded newline removed by mistake;
>>
>> drivers/net/ethernet/cadence/macb_main.c | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
>> index 89fe7af5e408..cb0b3637651c 100644
>> --- a/drivers/net/ethernet/cadence/macb_main.c
>> +++ b/drivers/net/ethernet/cadence/macb_main.c
>> @@ -740,6 +740,16 @@ static int macb_mii_probe(struct net_device *dev)
>> static int macb_mdiobus_register(struct macb *bp)
>> {
>> struct device_node *child, *np = bp->pdev->dev.of_node;
>> + struct device_node *mdio_node;
>> + int ret;
>> +
>> + /* if an MDIO node is present, it should contain the PHY nodes */
>> + mdio_node = of_get_child_by_name(np, "mdio");
>> + if (mdio_node) {
>> + ret = of_mdiobus_register(bp->mii_bus, mdio_node);
>> + of_node_put(mdio_node);
>> + return ret;
>> + }
>
> This does take care of registering the MDIO bus controller when present
> as a sub-node, however if you also plan on making use of fixed-link, we
> will have already returned.
>
>>
>> if (of_phy_is_fixed_link(np))
>> return mdiobus_register(bp->mii_bus);
>>
>
> Really not sure what this is achieving, because we start off assuming
> that we have an OF driven configuration, but later on we register the
> MDIO bus with mdiobus_register() (and not of_mdiobus_register()), so no
> scanning of the MDIO bus will happen.
I agree that returning mdiobus_register() here makes no sense since
there are no other PHY devices to scan for and probe. I can replace this
with NULL.
The reason for fixed-link check here is to skip the following loop:
for_each_available_child_of_node(np, child)
if (of_mdiobus_child_is_phy(child)) {
of_node_put(child);
return of_mdiobus_register(bp->mii_bus, np);
}
of_mdiobus_child_is_phy() returns true when it finds the fixed-link
node, because it has no compatible.
>
> How does the driver currently support being provided a fixed-link
> property? Should not we at least have this pattern:
>
> */
> if (of_phy_is_fixed_link(dn)) {
> ret = of_phy_register_fixed_link(dn);
> if (ret)
> return ret;
>
> priv->phy_dn = dn;
> }
>
> It does not look like you are breaking anything here, because it does
> not look like this works at all.
From what I understand, the new phylink(_create) handles the fixed-link
case, so there is not reason to explicitly register the fixed-link.
Best regards,
Codrin
> --
> Florian
>
