[PATCH v5 01/11] i2c: Enhance i2c_new_ancillary_device API

[Wolfram Sang]

Hi Geert,

> > Would this binding allow to not use the RTC if the second reg is
> > missing? What are the advantages of not enabling RTC? Saving power?
> 
> It doesn't work if there is no clock?

Maybe I am confusing something now, but if the RTC _needs_ to be
enabled, then why we don't do it unconditionally?

> > Thinking more about this: DT is hardware description, so the RTC should
> > always be described in DT. If the RTC is actually activated is more a
> > configuration thing, or? Brainstorming: maybe the PMIC driver could try
> > to find the node with reg == 0x6f and see if firmware has enabled it or
> > not?
> 
> I guess the RTC part would acknowledge anyway?
> It is always present, it is just part of the RAA215300.

I mean the driver should scan for the DT node. Not on the bus. But a
phandle is probably safer.

> Sure, you can put that in DT.  But it's a pity you have to do that,
> as the device (the PMIC part) does know the revision...
> That's why I suggested to let the PMIC part instantiate an i2c ancillary
> device...

I see. I'll let it sink in some more.

Happy hacking,

   Wolfram

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