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

[ansuelsmth]

> -----Messaggio originale-----
> Da: Andrew Lunn <andrew@xxxxxxx>
> Inviato: domenica 20 settembre 2020 02:31
> A: Ansuel Smith <ansuelsmth@xxxxxxxxx>
> Cc: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>; Richard Weinberger
> <richard@xxxxxx>; Vignesh Raghavendra <vigneshr@xxxxxx>; Rob Herring
> <robh+dt@xxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Jakub
> Kicinski <kuba@xxxxxxxxxx>; Heiner Kallweit <hkallweit1@xxxxxxxxx>;
> Russell King <linux@xxxxxxxxxxxxxxx>; Frank Rowand
> <frowand.list@xxxxxxxxx>; Boris Brezillon <bbrezillon@xxxxxxxxxx>; linux-
> mtd@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx
> 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.