From: Rob Herring <robh@kernel.org>
To: Laxman Dewangan <ldewangan@nvidia.com>
Cc: broonie@kernel.org, mark.rutland@arm.com,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
Douglas Anderson <dianders@chromium.org>,
Aleksandr Frid <afrid@nvidia.com>
Subject: Re: [PATCH V2 1/2] regulator: pwm: DT: Add ramp delay for exponential voltage transition
Date: Mon, 21 Nov 2016 10:17:27 -0600 [thread overview]
Message-ID: <20161121161727.y6pvydowiyeyy7qs@rob-hp-laptop> (raw)
In-Reply-To: <1479479756-10755-1-git-send-email-ldewangan@nvidia.com>
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@nvidia.com>
> CC: Douglas Anderson <dianders@chromium.org>
> CC: Aleksandr Frid <afrid@nvidia.com>
>
> ---
> This patch is continuation of discussion on patch
> regulator: pwm: Fix regulator ramp delay for continuous mode
> https://patchwork.kernel.org/patch/9216857/
> 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 a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
> 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 regulator
>
> +- voltage-ramp-exponential: Boolean, Some of PWM regulator has the exponential
> + transition in voltage ramp as opposite to fixed
> + slew-rate linear transition on other regulators.
> + For such PWM regulator, presence of this property will
> + tell that value of the regulator ramp delay provided by
> + DT property "regulator-ramp-delay" is exponential and
> + fixed delay for any voltage level change.
> + If PWM regulator supports the fixed linear slew rate
> + then this property should be absent from DT node and
> + property "regulator-ramp-delay" is used as linear slew
> + 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.
Rob
next prev parent reply other threads:[~2016-11-21 16:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-18 14:35 [PATCH V2 1/2] regulator: pwm: DT: Add ramp delay for exponential voltage transition Laxman Dewangan
2016-11-18 14:35 ` [PATCH V2 2/2] regulator: pwm: " Laxman Dewangan
2016-11-21 16:17 ` Rob Herring [this message]
2016-11-22 8:50 ` [PATCH V2 1/2] regulator: pwm: DT: " Laxman Dewangan
2016-11-22 21:13 ` Rob Herring
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