[PATCH v3 4/4] dt-bindings: net: Document use of mac-address-increment

[Ansuel Smith]

Two new bindings are now supported by the of_net driver to increase (or
decrease) a mac-address. This can be very useful in case where the
system extract the mac-address for the device from a dedicated partition
and have a generic mac-address that needs to be incremented based on the
device number.
- mac-address-increment-byte is used to tell what byte must be
  incremented (if not set the last byte is increased)
- mac-address-increment is used to tell how much to increment of the
  extracted mac-address decided byte.

Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx>
---
 .../bindings/net/ethernet-controller.yaml     | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
index fa2baca8c726..8174f64e79bd 100644
--- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
@@ -32,6 +32,27 @@ properties:
       - minItems: 6
         maxItems: 6
 
+  mac-address-increment:
+    description:
+      The MAC address can optionally be increased (or decreased using
+      negative values) from the original value read (from a nvmem cell
+      for example). This can be used if the mac is read from a dedicated
+      partition and must be increased based on the number of device
+      present in the system. The increment will not overflow/underflow to
+      the other bytes if it's over 255 or 0.
+      (example 00:01:02:03:04:ff + 1 == 00:01:02:03:04:00)
+    minimum: -255
+    maximum: 255
+
+  mac-address-increment-byte:
+    description:
+      If 'mac-address-increment' is defined, this will tell what byte of
+      the mac-address will be increased. If 'mac-address-increment' is
+      not defined, this option will do nothing.
+    default: 5
+    minimum: 3
+    maximum: 5
+
   max-frame-size:
     $ref: /schemas/types.yaml#definitions/uint32
     description:
-- 
2.27.0