Re: [PATCH v2] lan743x: correctly handle chips with internal PHY

From: Andrew Lunn
Date: Sat Nov 07 2020 - 23:15:04 EST


On Fri, Nov 06, 2020 at 08:43:24AM -0500, Sven Van Asbroeck wrote:
> From: Sven Van Asbroeck <thesven73@xxxxxxxxx>
>
> Commit 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
> assumes that chips with an internal PHY will never have a devicetree
> entry. This is incorrect: even for these chips, a devicetree entry
> can be useful e.g. to pass the mac address from bootloader to chip:
>
> &pcie {
> status = "okay";
>
> host@0 {
> reg = <0 0 0 0 0>;
>
> #address-cells = <3>;
> #size-cells = <2>;
>
> lan7430: ethernet@0 {
> /* LAN7430 with internal PHY */
> compatible = "microchip,lan743x";
> status = "okay";
> reg = <0 0 0 0 0>;
> /* filled in by bootloader */
> local-mac-address = [00 00 00 00 00 00];
> };
> };
> };
>
> If a devicetree entry is present, the driver will not attach the chip
> to its internal phy, and the chip will be non-operational.
>
> Fix by tweaking the phy connection algorithm:
> - first try to connect to a phy specified in the devicetree
> (could be 'real' phy, or just a 'fixed-link')
> - if that doesn't succeed, try to connect to an internal phy, even
> if the chip has a devnode
>
> Tested on a LAN7430 with internal PHY. I cannot test a device using
> fixed-link, as I do not have access to one.
>
> Fixes: 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
> Tested-by: Sven Van Asbroeck <thesven73@xxxxxxxxx> # lan7430
> Signed-off-by: Sven Van Asbroeck <thesven73@xxxxxxxxx>
> ---
>
> v1 -> v2:
> Andrew Lunn: keep patch minimal and correct, so keep open-coded version
> of of_phy_get_and_connect().

Hi Sven

Why is it required to remove adapter->phy_mode? It is not clear to me
what this change has to do with not looking for an internal PHY.

> @@ -1063,6 +1065,7 @@ static int lan743x_phy_open(struct lan743x_adapter *adapter)
>
> phy_start(phydev);
> phy_start_aneg(phydev);
> + phy_attached_info(phydev);

This also has nothing to do with the problem you are fixing. It is a
sensible thing to do, but it should be a separate patch, and target
net-next, since it is not a fix.

Andrew