Re: [PATCH V2 1/2] regulator: pwm: DT: Add ramp delay for exponential voltage transition
From: Rob Herring
Date: Tue Nov 22 2016 - 16:14:29 EST
On Tue, Nov 22, 2016 at 2:50 AM, Laxman Dewangan <ldewangan@xxxxxxxxxx> wrote:
> On Monday 21 November 2016 09:47 PM, Rob Herring wrote:
>> On Fri, Nov 18, 2016 at 08:05:55PM +0530, Laxman Dewangan wrote:
>>> Some PWM regulator has the exponential transition in voltage change as
>>> opposite to fixed slew-rate linear transition on other regulators.
>>> For such PWM regulators, add the property to tell that voltage change
>>> is exponential and having fixed delay for any level of change.
>>> Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
>>> CC: Douglas Anderson <dianders@xxxxxxxxxxxx>
>>> CC: Aleksandr Frid <afrid@xxxxxxxxxx>
>>> This patch is continuation of discussion on patch
>>> regulator: pwm: Fix regulator ramp delay for continuous mode
>>> where is it discussed to have separate property for PWM which has
>>> exponential voltage transition.
>>> Changes from V1:
>>> - Pass the flag to tell that voltage ramp is exponential instead of
>>> providing delay.
>>> .../devicetree/bindings/regulator/pwm-regulator.txt | 12
>>> 1 file changed, 12 insertions(+)
>>> diff --git
>>> index 3aeba9f..2d9ef3a 100644
>>> --- a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>>> +++ b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>>> @@ -54,6 +54,18 @@ Optional properties:
>>> - enable-gpios: GPIO to use to enable/disable the
>>> +- voltage-ramp-exponential: Boolean, Some of PWM regulator has the
>>> + transition in voltage ramp as opposite to fixed
>>> + slew-rate linear transition on other regulators.
>>> + For such PWM regulator, presence of this property
>>> + tell that value of the regulator ramp delay
>>> provided by
>>> + DT property "regulator-ramp-delay" is exponential
>>> + fixed delay for any voltage level change.
>>> + If PWM regulator supports the fixed linear slew
>>> + then this property should be absent from DT node
>>> + property "regulator-ramp-delay" is used as linear
>>> + rate.
>> Sorry, but on further thought, I don't think we should mix different
>> units for the same property. Also, the fact that the ramp is exponential
>> is irrelevant. You just want an absolute delay time rather than a rate,
>> right? So instead, how about just "regulator-ramp-time-us". Roughly what
>> you had in v1, but not PWM specific.
> Can we say "regulator-settling-time-us" and make it generic i.e. part of the
> regulator core instead of PWM regulator specific?