RE: [PATCH v4 2/4] hwmon: (pmbus/max20830): add VOUT feedback resistor scaling support

> >> +	switch (reg) {
> >> +	case PMBUS_READ_VOUT:
> >> +		ret = pmbus_read_word_data(client, page, phase, reg);
> >> +		if (ret < 0)
> >> +			return ret;
> >> +
> >> +		/* Apply voltage divider scaling if resistors are non-zero */
> >> +		if (data->vout_rfb1 && data->vout_rfb2) {
> >> +			temp = (u64)data->vout_rfb1 + (u64)data->vout_rfb2;
> >> +			temp = DIV_ROUND_CLOSEST_ULL((u64)ret * temp,
> data->vout_rfb2);
> >> +			ret = clamp_val(temp, 0, 0xFFFF);
> >> +		}
> >> +		return ret;
> >> +	default:
> >> +		return -ENODATA;
> >> +	}
> >> +}
> >
> > [Severity: High]
> > Does this code introduce a UAPI inconsistency by only scaling
> PMBUS_READ_VOUT?
> >
> > When in1_input is read, it returns the scaled output voltage.
> >
> > However, because this switch returns -ENODATA for limits (like
> > PMBUS_VOUT_OV_WARN_LIMIT or PMBUS_VOUT_OV_FAULT_LIMIT),
> reading limits
> > like in1_max will return the unscaled feedback voltage directly from the chip.
> >
> 
> I would suggest to add a comment explaining that this series does not support
> any limit registers. That should "address" the issues raised by Sashiko, and also
> help future readers understand why the limit registers are not scaled.
> 

Will try adding this, thanks.
- Alexis