mx6sabresd: Trying to use qca,clk-out-frequency

[Vladimir Oltean]

On Wed, 17 Jun 2020 at 22:01, Vladimir Oltean <olteanv at gmail.com> wrote:
>
> Hi Fabio,
>
> On Wed, 17 Jun 2020 at 21:30, Fabio Estevam <festevam at gmail.com> wrote:
> >
> > Hi,
> >
> > Now that mx6sabresd board has Ethernet working again with this fix:
> > https://lists.denx.de/pipermail/u-boot/2020-June/416623.html
> >
> > ,I would like to remove the ar8031_phy_fixup() from
> > board/freescale/mx6sabresd/mx6sabresd.c.
> >
> > Here is what I tested so far: https://pastebin.com/raw/cQW5RmXW
> >
> > However, I see that in drivers/net/phy/atheros.c the
> >
> > if (!ofnode_read_u32(node, "qca,clk-out-frequency", &freq)) {
> >
> > condition is never executed, so qca,clk-out-frequency configuration
> > does not take effect.
> >
> > Any ideas why this happens?
> >
> > Thanks
>
> I just tried it out on a board I have.
> This:
>     printf("%s: found PHY node: %s\n", __func__, ofnode_get_name(node));
> prints this:
> ar803x_of_init: found PHY node: ethernet at 2d10000
>
> which is very odd, because it's not the ethernet-phy node, but the
> node of the parent.
> It happens because ofnode_valid() is false here:
>
> static inline ofnode phy_get_ofnode(struct phy_device *phydev)
> {
>     if (ofnode_valid(phydev->node))
>         return phydev->node;
>     else
>         return dev_ofnode(phydev->dev);
> }
>
> which again seems to be caused by this commit:
>
> commit eef0b8a930d1a8799b8ebd26e67e27401df6a9f7
> Author: Grygorii Strashko <grygorii.strashko at ti.com>
> Date:   Thu Jul 5 12:02:48 2018 -0500
>
>     net: phy: add ofnode node to struct phy_device
>
>     Now the UCLASS_ETH device "node" field is owerwritten by some
> network drivers in
>     case of Ethernet PHYs which are linked to UCLASS_ETH device using
>     "phy-handle" DT property and when Ethernet PHY driver needs to read some
>     additional information from DT. In such cases following happens (in
>     general):
>
>     - network drivers
>             priv->phydev = phy_connect(priv->bus, priv->phyaddr, dev,
>                                        priv->interface);
>             <-- phydev is connected to dev which is UCLASS_ETH device
>
>             if (priv->phy_of_handle > 0)
>                     dev_set_of_offset(priv->phydev->dev, priv->phy_of_handle);
>             <-- phydev->dev->node is overwritten by phy-handle DT node
>
>     - PHY driver in .config() callback
>             int node = dev_of_offset(dev);
>             <-- PHY driver uses overwritten dev->node
>             const void *fdt = gd->fdt_blob;
>
>              if (fdtdec_get_bool(fdt, node, "property"))
>                     ...
>
>     As result, UCLASS_ETH device can't be used any more for DT accessing.
>
>     This patch adds additional ofnode node field to struct phy_device which can
>     be set explicitly by network drivers and used by PHY drivers, so
>     overwriting can be avoided. Also add helper function phy_get_ofnode()
>     which will check and return phy_device->node or dev_ofnode(phydev->dev) for
>     backward compatibility with existing drivers.
>
>     Signed-off-by: Grygorii Strashko <grygorii.strashko at ti.com>
>     Acked-by: Joe Hershberger <joe.hershberger at ni.com>
>
> Didn't yet figure out what to do, though.
>
> -Vladimir

Update:
I upgraded tsec to DM_MDIO:
https://patchwork.ozlabs.org/project/uboot/patch/20200612151735.49048-4-Zhiqiang.Hou@nxp.com/
and it now prints the correct phy node:
ar803x_of_init: found PHY node: ethernet-phy at 2

Pretty sure that DM_MDIO is also how Michael tested this.
What I'm pretty fuzzy about is: do we _need_ DM_MDIO for this to work?
Who's more knowledgeable about this stuff around here?

-Vladimir