[U-Boot] [PATCH] drivers: net: phy: Ignore PHY ID 0 during PHY probing

[Joe Hershberger]

On Wed, Jun 19, 2019 at 4:07 AM Alexandru Marginean
<alexandru.marginean at nxp.com> wrote:
>
> Current code fails to probe some C45 PHYs that also respond to C22 reads.
> This is the case for PHYs like Aquantia AQR112, Marvell 88X2242 (as
> previously posted on the u-boot list).
> If the PHY ID reads all 0s just ignore it and try the next devad.
>
> Signed-off-by: Alex Marginean <alexm.osslist at gmail.com>
> ---
>  drivers/net/phy/phy.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index c1c1af9abd..7ccbc4d9da 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -727,6 +727,15 @@ static struct phy_device *create_phy_by_mask(struct mii_dev *bus,
>         while (phy_mask) {
>                 int addr = ffs(phy_mask) - 1;
>                 int r = get_phy_id(bus, addr, devad, &phy_id);
> +
> +               /* If the PHY ID is flat 0 we ignore it.  There are C45 PHYs

Agreed on the format.

> +                * that return all 0s for C22 reads (like Aquantia AQR112) and
> +                * there are C22 PHYs that return all 0s for C45 reads (like
> +                * Atheros AR8035).
> +                */
> +               if (phy_id == 0)
> +                       return NULL;

As for continue or return, this should probably check that phy_id == 0
and r == 0, right?

> +
>                 /* If the PHY ID is mostly f's, we didn't find anything */
>                 if (r == 0 && (phy_id & 0x1fffffff) != 0x1fffffff) {
>                         is_c45 = (devad == MDIO_DEVAD_NONE) ? false : true;
> --
> 2.17.1
>
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