Re: [PATCH 2/2] regulator: pwm-regulator: Revert "Add validity checks in continuous .get_voltage"

[Mike Looijmans]

On 08-11-2026 16:13, Mark Brown wrote:
> On Fri, Nov 06, 2026 at 01:59:56PM +0100, Mike Looijmans wrote:
> > This reverts commit c92688cac239 ("regulator: pwm-regulator: Add validity
> > checks in continuous .get_voltage").
> > The core, and in particular the machine_constraints_voltage() method,
> > expects the regulator to report what the current setting is, even if that
> > is outside the allowed range. The core will then bring the voltage into
> > that range. It cannot do that if the regulator refuses to return its
> > setting, and causes probe() to fail for a pwm-regulator when it has
> > restrictions to the PWM range with messages like:
> >    dsp7-pwm: failed to get the current voltage: -ENOTRECOVERABLE
> >    pwm-regulator dsp7-supply-pwm: error -ENOTRECOVERABLE: Failed to register
> >      regulator pwm-regulator
> >    pwm-regulator dsp7-supply-pwm: probe with driver pwm-regulator failed
> >      with error -131
> Are you sure?  We have specific handling for -ENOTRECOVERABLE which just
> blindly writes in the range specified in the constraints if the current
> voltage is unreadable.  If that mechanism isn't working we should fix it
> rather than changing drivers.

In core.c:

        if (current_uV == -ENOTRECOVERABLE) {
            /* This regulator can't be read and must be initialized */
            rdev_info(rdev, "Setting %d-%duV\n",
                  rdev->constraints->min_uV,
                  rdev->constraints->max_uV);
            _regulator_do_set_voltage(rdev,
                          rdev->constraints->min_uV,
                          rdev->constraints->max_uV);
            current_uV = regulator_get_voltage_rdev(rdev);
        }

        if (current_uV < 0) {
            if (current_uV != -EPROBE_DEFER)
                rdev_err(rdev,
                     "failed to get the current voltage: %pe\n",
                     ERR_PTR(current_uV));
            return current_uV;
        }

After _regulator_do_set_voltage() it calls regulator_get_voltage_rdev() 
again, which keeps returning -ENOTRECOVERABLE, and thus the error path 
kicks in.


> > Besides that, regulator_get_voltage() is not supposed to return any
> > state information, as is mentioned in the API documentation.
> >   	voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
> > -	if (voltage < min(max_uV_duty, min_uV_duty) ||
> > -	    voltage > max(max_uV_duty, min_uV_duty))
> > -		return -ENOTRECOVERABLE;
> The rest of the function relies on this to avoid having to deal with
> wrapping when things are out of range.

It's core.c that will handle that. It expects regulator_get_voltage() to 
return something out of range, and will correct that situation.



--
Mike Looijmans
System Expert

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