Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933231AbcKVVOV (ORCPT ); Tue, 22 Nov 2016 16:14:21 -0500 Received: from mail.kernel.org ([198.145.29.136]:59086 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932545AbcKVVOT (ORCPT ); Tue, 22 Nov 2016 16:14:19 -0500 MIME-Version: 1.0 In-Reply-To: <583406CC.9080306@nvidia.com> References: <1479479756-10755-1-git-send-email-ldewangan@nvidia.com> <20161121161727.y6pvydowiyeyy7qs@rob-hp-laptop> <583406CC.9080306@nvidia.com> From: Rob Herring Date: Tue, 22 Nov 2016 15:13:49 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH V2 1/2] regulator: pwm: DT: Add ramp delay for exponential voltage transition To: Laxman Dewangan Cc: Mark Brown , Mark Rutland , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , Douglas Anderson , Aleksandr Frid Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3046 Lines: 72 On Tue, Nov 22, 2016 at 2:50 AM, Laxman Dewangan 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 >>> CC: Douglas Anderson >>> CC: Aleksandr Frid >>> >>> --- >>> 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. > > > Can we say "regulator-settling-time-us" and make it generic i.e. part of the > regulator core instead of PWM regulator specific? Sure. Rob