Re: [PATCH v2 4/4] dt-bindings: net: Document use of mac-address-increment

From: Andrew Lunn
Date: Sat Sep 19 2020 - 20:31:53 EST


> + mac-address-increment:
> + description:
> + The MAC address can optionally be increased (or decreased using
> + negative values) from the original value readed (from a nvmem cell

Read is irregular, there is no readed, just read.

> + for example). This can be used if the mac is readed from a dedicated
> + partition and must be increased based on the number of device
> + present in the system.

You should probably add there is no underflow/overflow to other bytes
of the MAC address. 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: 0
> + maximum: 5

Is there a real need for this? A value of 0 seems like a bad idea,
since a unicast address could easily become a multicast address, which
is not valid for an interface address. It also does not seem like a
good idea to allow the OUI to be changed. So i think only bytes 3-5
should be allowed, but even then, i don't think this is needed, unless
you do have a clear use case.

Andrew