Re: [PATCH 1/2] dt-bindings: hwmon: pmbus: ti,lm25066: add current limit properties

[Guenter Roeck]

On 6/12/26 09:12, Conor Dooley wrote:
> On Fri, Jun 12, 2026 at 05:10:38PM +0800, Potin Lai wrote:
> > On Fri, Jun 12, 2026 at 1:27 AM Conor Dooley <conor@xxxxxxxxxx> wrote:
> > > On Thu, Jun 11, 2026 at 05:58:44PM +0800, Potin Lai wrote:
> > > > Add mutually exclusive 'ti,cl-smbus-high' and 'ti,cl-smbus-low' boolean
> > > > properties to configure the device's Current Limit (CL) behavior using
> > > > SMBus settings instead of physical pins.
> > > >
> > > > Signed-off-by: Potin Lai <potin.lai.pt@xxxxxxxxx>
> > > > ---
> > > >   .../devicetree/bindings/hwmon/pmbus/ti,lm25066.yaml  | 20 ++++++++++++++++++++
> > > >   1 file changed, 20 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/ti,lm25066.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/ti,lm25066.yaml
> > > > index a20f140dc79a..95ea7c26dec2 100644
> > > > --- a/Documentation/devicetree/bindings/hwmon/pmbus/ti,lm25066.yaml
> > > > +++ b/Documentation/devicetree/bindings/hwmon/pmbus/ti,lm25066.yaml
> > > > @@ -46,6 +46,26 @@ properties:
> > > >
> > > >       additionalProperties: false
> > > >
> > > > +  ti,cl-smbus-high:
> > > > +    description: |
> > > > +      Configure the Current Limit (CL) to use the SMBus high setting.
> > > > +    type: boolean
> > > > +
> > > > +  ti,cl-smbus-low:
> > > > +    description: |
> > > > +      Configure the Current Limit (CL) to use the SMBus low setting.
> > > > +    type: boolean
> > >
> > > What's smbus specific about this? If the pin was connected to a GPIO,
> > > you'd then need to have different properties or use these ones with an
> > > inaccurate name.
> >
> > The "smbus" in the property name was originally meant to indicate
> > that the setting is configured via the internal register over the SMBus (I2C)
> > interface, rather than physical pins.
>
> Right, but if you do it via the physical pins using a gpio, you still
> need a way to say what limit is. The status quo only works if the limit
> pin is tied high or low.

The physical pin is supposed to be connected to ground or left floating.
It seems unlikely that anyone would ever have the idea of connecting it
to a GPIO pin, and doing so would for sure mess up the driver because
its state is only read in the probe function. The configuration here
is for setting the limit range (scale) with a configuration register
to override the configuration obtained from the external pin.

Either case, even _if_ the CL pin is connected to a GPIO pin, the status
of that pin would be read from the configuration register. A devicetree
property is not needed for that. The properties are to _override_ the pin
configuration, not to reflect it.

Thanks,
Guenter