On Fri, Feb 20, 2015 at 04:01:55PM -0600, Rob Herring wrote:
> [...]
>
> >>> += Data consumers =
> >>> +
> >>> +Required properties:
> >>> +
> >>> +eeproms: List of phandle and data cell specifier triplet, one triplet
> >>> + for each data cell the device might be interested in. The
> >>> + triplet consists of the phandle to the eeprom provider, then
> >>> + the offset in byte within that storage device, and the length
> >>> + in byte of the data we care about.
> >>
> >>
> >> The problem with this is it assumes you know who the consumer is and
> >> that it is a DT node. For example, how would you describe a serial
> >> number?
> >
> > Correct me if I miss understood.
> > Is serial number any different?
> > Am hoping that the eeprom consumer would be aware of offset and size of
> > serial number in the eeprom
> >
> > Cant the consumer do:
> >
> > eeprom-consumer {
> > eeproms = <&at24 0 4>;
> > eeprom-names = "device-serial-number";
>
> Yes, but who is "eeprom-consumer"?Any device that should lookup values in one of the EEPROM. > DT nodes generally describe a h/w block, but it this case, the > consumer depends on the OS, not the h/w. Not really, or at least, not more than any similar binding we currently have. The fact that a MAC-address for the first ethernet chip is stored at a given offset in a given eeprom has nothing to do with the OS. > I'm not saying you can't describe where things are, but I don't > think you should imply who is the consumer and doing so is > unnecessarily complicated. If you only take the case of a serial number, indeed. If you take other usage into account, you can't really do without it. > Also, the layout of EEPROM is likely very much platform specific. Indeed, which is why it should be in the DT. > Some could have a more complex structure perhaps with key ids and > linked list structure. Then just request the size of the whole list, and parse it afterwards in your driver? > I would do something more simple that is just a list of keys and their > location like this: > > device-serial-number = <start size>; > key1 = <start size>; > key2 = <start size>; I'm sorry, but what's the difference? Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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