Re: [PATCH 1/2] regulator: pwm-regulator: Revert "Calculate the output voltage for disabled PWMs"

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

On 06-11-2026 14:36, Mark Brown wrote:
> On Fri, Nov 06, 2026 at 01:59:55PM +0100, Mike Looijmans wrote:
>> This reverts commit 6a7d11efd691 ("regulator: pwm-regulator: Calculate the
>> output voltage for disabled PWMs")
> Adding Martin who wrote that patch - please CC people if you're directly
> updating their patches.

Sorry, that wasn't intentional. I was just used to get_maintainer.pl and 
patman "doing the right thing" that I didn't consider checking that. I 
promise to do better next time.


>
>> A disabled PWM is not the same as "set to 0%". If the PWM is disabled,
>> this could also mean that its output pin is tristated for example.
>>
>> If the PWM range is limited to something else than 0..100% this causes the
>> probe function to fail 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
>>
>> The reason is that regulator_register() calls get_voltage(). The PWM is
>> disabled at this point, and then the validity check triggers.
>>
>> Anything that calls get_voltage() while the PWM is disabled would get an
>> -ENOTRECOVERABLE return value for a pwm-regulator that doesn't allow 0%.
>>
>> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
>> ---
>>
>>   drivers/regulator/pwm-regulator.c | 7 -------
>>   1 file changed, 7 deletions(-)
>>
>> diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
>> index 7434b6b22d325..f50530c77d92f 100644
>> --- a/drivers/regulator/pwm-regulator.c
>> +++ b/drivers/regulator/pwm-regulator.c
>> @@ -157,13 +157,6 @@ static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
>>   
>>   	pwm_get_state(drvdata->pwm, &pstate);
>>   
>> -	if (!pstate.enabled) {
>> -		if (pstate.polarity == PWM_POLARITY_INVERSED)
>> -			pstate.duty_cycle = pstate.period;
>> -		else
>> -			pstate.duty_cycle = 0;
>> -	}
>> -
>>   	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))
>> ---
>> base-commit: f66469d9905b39d2c260a15d7d6db450f4db67c1
>> branch: linux-master-pwm-regulator
>>
>> -- 
>> 2.43.0
>>
>>

-- 
Mike Looijmans