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

[Mark Brown]

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.

> 
> 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@xxxxxxxx>
> ---
> 
>  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
> 
> 
> Met vriendelijke groet / kind regards,
> 
> Mike Looijmans
> System Expert
> 
> 
> TOPIC Embedded Products B.V.
> Materiaalweg 4, 5681 RJ Best
> The Netherlands
> 
> T: +31 (0) 499 33 69 69
> E: mike.looijmans@xxxxxxxx
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> 
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