Messages in this thread | | | Date | Thu, 30 Aug 2018 05:04:20 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH net-next 1/3] net: nixge: Add support for fixed-link subnodes |
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On Wed, Aug 29, 2018 at 05:40:44PM -0700, Moritz Fischer wrote: > Add support for fixed-link cases where no MDIO is > actually required to run the device. > In that case no MDIO bus is instantiated since the > actual registers are not available in hardware.
Hi Moritz
There are a few different use cases here:
The hardware is missing MDIO - You need fixed-link.
The hardware has MDIO, but you don't have a PHY connected on it, and use fixed link.
The hardware has MDIO, and it is used e.g. for an Ethernet switch, or a PHY for another Ethernet interface. Plus you need fixed link.
The binding typically looks like:
&fec1 { phy-mode = "rmii"; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_fec1>; status = "okay";
fixed-link { speed = <100>; full-duplex; };
mdio1: mdio { #address-cells = <1>; #size-cells = <0>; status = "okay";
switch0: switch0@0 { compatible = "marvell,mv88e6085"; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_switch>; reg = <0>; eeprom-length = <512>; interrupt-parent = <&gpio3>;
It is important you have the mdio subnode, with PHYs and switches as children. The driver currently gets this wrong, it uses pdev->dev.of_node.
So the first patch should be to extend this behaviour. Look for a child node called mdio. If it exists, call nixge_mdio_setup() passing that child. Otherwise continue using pdev->dev.of_node, so you don't break backwards compatibility.
Then a patch adding support for fixed-link. If the mdio child node exists, you still need to register the MDIO bus. If there is no child node, but there is a fixed-link, skip registering the mdio bus with pdev->dev.of_node.
Andrew
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