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authorMartin Blumenstingl <martin.blumenstingl@googlemail.com>2017-01-22 17:41:32 +0100
committerDavid S. Miller <davem@davemloft.net>2017-01-24 13:31:02 -0500
commit7630ea4bda18df2ee1c64dfdca1724a9cc32f920 (patch)
treeebb096b59a04490bf57ee7af007cb41af8a5fbab /Documentation
parentf39aac7e839368e3895dff952f3bfa0a22e20060 (diff)
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 <martin.blumenstingl@googlemail.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Acked-by: Rob Herring <robh@kernel.org> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/net/phy.txt5
1 files changed, 3 insertions, 2 deletions
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