net: phy: dp83867: Add documentation for optional impedance control

Add documention of ti,min-output-impedance and ti,max-output-impedance
which can be used to correct MAC impedance mismatch using phy extended
registers.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/devicetree/bindings/net/ti,dp83867.txt b/Documentation/devicetree/bindings/net/ti,dp83867.txt
index 5d21141a68b547104d5f152da0214dc847f4a3e9..85bf945b898f0d156702f16d76be315c9108e1aa 100644 (file)
--- a/Documentation/devicetree/bindings/net/ti,dp83867.txt
+++ b/Documentation/devicetree/bindings/net/ti,dp83867.txt
@@ -9,6 +9,18 @@ Required properties:
        - ti,fifo-depth - Transmitt FIFO depth- see dt-bindings/net/ti-dp83867.h
                for applicable values
 
+Optional property:
+       - ti,min-output-impedance - MAC Interface Impedance control to set
+                                   the programmable output impedance to
+                                   minimum value (35 ohms).
+       - ti,max-output-impedance - MAC Interface Impedance control to set
+                                   the programmable output impedance to
+                                   maximum value (70 ohms).
+
+Note: ti,min-output-impedance and ti,max-output-impedance are mutually
+      exclusive. When both properties are present ti,max-output-impedance
+      takes precedence.
+
 Default child nodes are standard Ethernet PHY device
 nodes as described in Documentation/devicetree/bindings/net/phy.txt