Messages in this thread | | | Date | Tue, 19 Oct 2021 16:12:40 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH] net: fec: defer probe if PHY on external MDIO bus is not available |
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On Thu, Oct 14, 2021 at 01:30:43PM +0200, Matthias Schiffer wrote: > On some SoCs like i.MX6UL it is common to use the same MDIO bus for PHYs > on both Ethernet controllers. Currently device trees for such setups > have to make assumptions regarding the probe order of the controllers: > > For example in imx6ul-14x14-evk.dtsi, the MDIO bus of fec2 is used for > the PHYs of both fec1 and fec2. The reason is that fec2 has a lower > address than fec1 and is thus loaded first, so the bus is already > available when fec1 is probed. > > Besides being confusing, this limitation also makes it impossible to use > the same device tree for variants of the i.MX6UL with one Ethernet > controller (which have to use the MDIO of fec1, as fec2 does not exist) > and variants with two controllers (which have to use fec2 because of the > load order). > > To fix this, defer the probe of the Ethernet controller when the PHY is > not on our own MDIO bus and not available. > > Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com> > --- > drivers/net/ethernet/freescale/fec_main.c | 23 ++++++++++++++++++++++- > 1 file changed, 22 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c > index 47a6fc702ac7..dc070dd216e8 100644 > --- a/drivers/net/ethernet/freescale/fec_main.c > +++ b/drivers/net/ethernet/freescale/fec_main.c > @@ -3820,7 +3820,28 @@ fec_probe(struct platform_device *pdev) > goto failed_stop_mode; > > phy_node = of_parse_phandle(np, "phy-handle", 0); > - if (!phy_node && of_phy_is_fixed_link(np)) { > + if (phy_node) { > + struct device_node *mdio_parent = > + of_get_next_parent(of_get_parent(phy_node)); > + > + ret = 0; > + > + /* Skip PHY availability check for our own MDIO bus to avoid > + * cyclic dependency > + */ > + if (mdio_parent != np) { > + struct phy_device *phy = of_phy_find_device(phy_node); > + > + if (phy) > + put_device(&phy->mdio.dev); > + else > + ret = -EPROBE_DEFER; > + }
I've not looked at the details yet, just back from vacation. But this seems wrong. I would of expected phylib to of returned -EPRODE_DEFER at some point, when asked for a PHY which does not exist yet. All the driver should need to do is make sure it returns the -EPRODE_DEFER.
Andrew
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