From 69226896ad636b94f6d2e55d75ff21a29c4de83b Mon Sep 17 00:00:00 2001 From: Roger Quadros Date: Fri, 21 Apr 2017 16:15:38 +0300 Subject: mdio_bus: Issue GPIO RESET to PHYs. Some boards [1] leave the PHYs at an invalid state during system power-up or reset thus causing unreliability issues with the PHY which manifests as PHY not being detected or link not functional. To fix this, these PHYs need to be RESET via a GPIO connected to the PHY's RESET pin. Some boards have a single GPIO controlling the PHY RESET pin of all PHYs on the bus whereas some others have separate GPIOs controlling individual PHY RESETs. In both cases, the RESET de-assertion cannot be done in the PHY driver as the PHY will not probe till its reset is de-asserted. So do the RESET de-assertion in the MDIO bus driver. [1] - am572x-idk, am571x-idk, a437x-idk Signed-off-by: Roger Quadros Signed-off-by: David S. Miller --- Documentation/devicetree/bindings/net/mdio.txt | 33 ++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 Documentation/devicetree/bindings/net/mdio.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/net/mdio.txt b/Documentation/devicetree/bindings/net/mdio.txt new file mode 100644 index 000000000000..4ffbbacebda1 --- /dev/null +++ b/Documentation/devicetree/bindings/net/mdio.txt @@ -0,0 +1,33 @@ +Common MDIO bus properties. + +These are generic properties that can apply to any MDIO bus. + +Optional properties: +- reset-gpios: List of one or more GPIOs that control the RESET lines + of the PHYs on that MDIO bus. +- reset-delay-us: RESET pulse width in microseconds as per PHY datasheet. + +A list of child nodes, one per device on the bus is expected. These +should follow the generic phy.txt, or a device specific binding document. + +Example : +This example shows these optional properties, plus other properties +required for the TI Davinci MDIO driver. + + davinci_mdio: ethernet@0x5c030000 { + compatible = "ti,davinci_mdio"; + reg = <0x5c030000 0x1000>; + #address-cells = <1>; + #size-cells = <0>; + + reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>; + reset-delay-us = <2>; /* PHY datasheet states 1us min */ + + ethphy0: ethernet-phy@1 { + reg = <1>; + }; + + ethphy1: ethernet-phy@3 { + reg = <3>; + }; + }; -- cgit v1.2.3