Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751209AbdGMHtU (ORCPT ); Thu, 13 Jul 2017 03:49:20 -0400 Received: from mail-it0-f68.google.com ([209.85.214.68]:35589 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750854AbdGMHtS (ORCPT ); Thu, 13 Jul 2017 03:49:18 -0400 MIME-Version: 1.0 In-Reply-To: <20170713073954.GA1363@amd> References: <20170630112109.13785-1-enric.balletbo@collabora.com> <20170713073954.GA1363@amd> From: Enric Balletbo Serra Date: Thu, 13 Jul 2017 09:49:16 +0200 Message-ID: Subject: Re: [PATCH v2 1/4] dt-bindings: pwm-backlight: add pwm-delay-us property To: Pavel Machek Cc: Rob Herring , Enric Balletbo i Serra , Thierry Reding , Lee Jones , Daniel Thompson , Jingoo Han , Bartlomiej Zolnierkiewicz , Richard Purdie , Jacek Anaszewski , Heiko Stuebner , Linux PWM List , "linux-fbdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Guenter Roeck , "open list:ARM/Rockchip SoC..." , huang lin 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: 3333 Lines: 79 2017-07-13 9:39 GMT+02:00 Pavel Machek : > On Thu 2017-07-13 09:22:15, Enric Balletbo Serra wrote: >> Rob, >> >> 2017-07-06 20:23 GMT+02:00 Enric Balletbo Serra : >> > Hi Rob, >> > >> > 2017-07-06 19:07 GMT+02:00 Rob Herring : >> >> On Fri, Jun 30, 2017 at 6:21 AM, Enric Balletbo i Serra >> >> wrote: >> >>> From: huang lin >> >>> >> >>> Add a pwm-delay-us property to specify the delay between setting an >> >>> initial (non-zero) PWM value and enabling the backlight, and also the >> >>> delay between disabling the backlight and setting PWM value to 0. >> >>> >> >>> Signed-off-by: huang lin >> >>> Signed-off-by: Enric Balletbo i Serra >> >>> --- >> >>> Changes since v1: >> >>> - As suggested by Daniel Thompson >> >>> - Do not assume power-on delay and power-off delay will be the same >> >>> >> >>> v1: https://lkml.org/lkml/2017/6/28/219 >> >>> >> >>> Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt | 6 ++++++ >> >>> 1 file changed, 6 insertions(+) >> >>> >> >>> diff --git a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt >> >>> index 764db86..49b037e 100644 >> >>> --- a/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt >> >>> +++ b/Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt >> >>> @@ -17,6 +17,11 @@ Optional properties: >> >>> "pwms" property (see PWM binding[0]) >> >>> - enable-gpios: contains a single GPIO specifier for the GPIO which enables >> >>> and disables the backlight (see GPIO binding[1]) >> >>> + - pwm-delay-us: delay between setting an initial (non-zero) PWM value and >> >>> + enabling the backlight, and also the delay between disabling >> >>> + the backlight and setting PWM value to 0. >> >>> + The 1st cell is the pre-delay in micro seconds. >> >>> + The 2nd cell is the post-delay in micro seconds. >> >> >> >> pre and post imply a time before and after a certain event, but these >> >> are for 2 different events. These are more like an enable/on delay and >> >> disable/off delay which probably should be separate properties. What >> >> happens when we need the opposite sequence or a different sequence? >> >> Maybe some panel requires the PWM to be 0 until some time after >> >> enabling. >> >> >> >> A second proposal, what do you think? >> >> - post-pwm-on-delay-us: Delay in us after setting an initial (non-zero) PWM >> and enabling the backlight using GPIO. > > This says "PWM on", "enable GPIO", "delay". Which is not what you > want. > Ok, seems I need to improve a bit more my English skills. :) after -> between ? Then, if I understand correctly, this (found in another binding that I used as reference) - post-power-on-delay-ms : Delay in ms after powering the card and de-asserting the reset-gpios (if any) means, Power the card, de-asserting reset, delay ? Regards, Enric. > -- > (english) http://www.livejournal.com/~pavelmachek > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html