From: Martin Blumenstingl Date: Sun, 22 Jan 2017 16:41:32 +0000 (+0100) Subject: Documentation: net: phy: improve explanation when to specify the PHY ID X-Git-Tag: v4.10-rc6~8^2~29 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7630ea4bda18df2ee1c64dfdca1724a9cc32f920;p=platform%2Fkernel%2Flinux-exynos.git Documentation: net: phy: improve explanation when to specify the PHY ID The old description basically read like "ethernet-phy-idAAAA.BBBB" can be specified when you know the actual PHY ID. However, specifying this has a side-effect: it forces Linux to bind to a certain PHY driver (the one that matches the ID given in the compatible string), ignoring the ID which is reported by the actual PHY. Whenever a device is shipped with (multiple) different PHYs during it's production lifetime then explicitly specifying "ethernet-phy-idAAAA.BBBB" could break certain revisions of that device. Signed-off-by: Martin Blumenstingl Reviewed-by: Andrew Lunn Acked-by: Rob Herring Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt index ff1bc4b1bb3b..fb5056b22685 100644 --- a/Documentation/devicetree/bindings/net/phy.txt +++ b/Documentation/devicetree/bindings/net/phy.txt @@ -19,8 +19,9 @@ Optional Properties: specifications. If neither of these are specified, the default is to assume clause 22. - If the phy's identifier is known then the list may contain an entry - of the form: "ethernet-phy-idAAAA.BBBB" where + If the PHY reports an incorrect ID (or none at all) then the + "compatible" list may contain an entry with the correct PHY ID in the + form: "ethernet-phy-idAAAA.BBBB" where AAAA - The value of the 16 bit Phy Identifier 1 register as 4 hex digits. This is the chip vendor OUI bits 3:18 BBBB - The value of the 16 bit Phy Identifier 2 register as