Hi Arnd,

thanks for looking into this, but I don't get your point yet.

> The slave_cb callback function is supposed to set the 'value'
> here,

Only if a master wants to READ from us.

> but it might return an error not assign the pointer,

An error is only returned if a WRITE from a master was not accepted by
the slave backend.

> It might be best to change the callback to return 'void' and not
> allow it to fail.

We need that because in case of an errno, the slave should send NACK to
the master instead of ACK.

> At least the eeprom slave cannot fail anyway, and it is the only
> implementation we have at the moment.

True. But giving a slave the possibility to NACK a write should be
present IMO.

> Alternatively, the  inline could return an error, and both bus
> drivers check for the error before using 'value'.

Hum, it does return an error?

	return client->slave_cb(client, event, val);

You probably mean something else?

Regards,

   Wolfram