Re: [PATCH v12 1/2] dt-binding: i2c: add bus-supply property

[Bibby Hsieh <bibby.hsieh@mediatek.com>]

On Tue, 2020-03-24 at 11:34 +0100, Wolfram Sang wrote:
> > > > +- bus-supply
> > > > +     phandle to the regulator that provides power to i2c.
> > >
> > > I think this is not clear enough. I assume it means the regulator for
> > > driving SCL/SDA? In the coverletter you mention also an EEPROM. In your
> > > case, this is driven by the same regulator? I am skeptical we can
> > > abstract it like this because I2C devices could be driven by various
> > > regulators in the system, so there couldn't be one "bus regulator". The
> > > regulator for the EEPROM should be described in the EEPROM node. So,
> > > this "bus supply" is only for driving SCL/SDA?
> > 
> > In our case the bus-supply regulator drives the voltage rail to which
> > SCL/SDA are pulled up and there is an EEPROM on the bus, powered by
> > yet another rail. There is also another slave on the bus which uses
> > the same regulator as the bus-supply for its own power.
> > 
> > In other words, bus-supply only ensures that SCL and SDA are in a
> > usable state. Other consumers need to refer to the regulator in their
> > own supplies if they need it for their own power.
> > 
> > Does this answer your questions?
> 
> Yes, this was exactly what I was assuming.
> 
> So, I think the above documentation should be changed: s|i2c|SCL/SDA|
> 
> D'accord?
> 
Yes, I think SCL/SDA is better than i2c

Tomasz, How about it?

Thanks

Bibby