Re: [PATCH 2/9] dt-bindings: i2c: qcom-cci: add description of a vbus-supply property

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Fri 04 Feb 10:42 PST 2022, Mark Brown wrote:

> On Fri, Feb 04, 2022 at 10:05:47AM -0800, Bjorn Andersson wrote:
> > On Thu 03 Feb 08:46 PST 2022, Vladimir Zapolskiy wrote:
> 
> > > +- vbus-supply:
> 
> > I don't think "vbus" is an appropriate name for his. Perhaps "vddio" or
> > something like that would be better.
> 
> > But there's a bigger question here, this is not a supply for the
> > i2c master, it's simply a supply for pulling up the bus. So it's not
> > entirely correct to specify it as a supply for the CCI node (which is
> > also the reason why the name isn't obvious).
> 
> Does the device (controller?) not have a supply that the I2C bus is
> referenced to?  If so that supply should be named.
> 

No, for some reason the regulator in question is not connected to either
the master or the client devices, it's only used for pull up of a few
of the i2c busses.

> > Typically we don't don't mention the bus-supply because it happens to be
> > pulled up either by io-supply for the block, or by some always-on
> > regulator in the system.
> 
> If the bus is being pulled up to some supply other than the supply that
> the bus is referenced to that doesn't sound like the greatest electrical
> engineering ever...  without any context it's hard to comment about this
> particular system.

That's what the schematics says...

Regards,
Bjorn