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

[Vladimir Oltean]

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