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

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On Wed, Apr 15, 2020 at 10:50 AM Bibby Hsieh <bibby.hsieh@xxxxxxxxxxxx> wrote:
>
> 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?

Sounds good to me.

Best regards,
Tomasz



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