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

From: <[email-masked]>
Date: Sun, 20 Sep 2020 02:39:39 +0200

> -----Messaggio originale-----
> Da: Andrew Lunn <[email-masked]>
> Inviato: domenica 20 settembre 2020 02:31
> A: Ansuel Smith <[email-masked]>
> Cc: Miquel Raynal <[email-masked]>; Richard Weinberger
> <[email-masked]>; Vignesh Raghavendra <[email-masked]>; Rob Herring
> <[email-masked]>; David S. Miller <[email-masked]>; Jakub
> Kicinski <[email-masked]>; Heiner Kallweit <[email-masked]>;
> Russell King <[email-masked]>; Frank Rowand
> <[email-masked]>; Boris Brezillon <[email-masked]>; linux-
> [email-masked]; [email-masked]; linux-
> [email-masked]; [email-masked]
> Oggetto: Re: [PATCH v2 4/4] dt-bindings: net: Document use of mac-
> address-increment
> 
> > +  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

Honestly the mac-address-increment-byte is added to give user some control
but I
don't really have a use case for it. Should I limit it to 3 or just remove
the function?
Will address the other 2 comment in v3.
Thx for review.