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

[Mike Looijmans <mike.looijmans@topic.nl>]

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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