From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Subject: Re: [PATCH] ARM: dts: imx6qdl: Adjust the brightness setting for LVDS panel Date: Thu, 22 Jan 2015 16:38:04 +0100 Message-ID: <1421941084.3084.45.camel@pengutronix.de> References: <1421749355-23050-1-git-send-email-r63905@freescale.com> <20150120113837.GC2766@dragon> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:38500 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750754AbbAVPiK (ORCPT ); Thu, 22 Jan 2015 10:38:10 -0500 In-Reply-To: <20150120113837.GC2766@dragon> Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Shawn Guo Cc: Robby Cai , linux-pwm@vger.kernel.org, Eric Nelson , Tim Harvey , jg1.han@samsung.com, Troy Kisky , thierry.reding@gmail.com, kernel@pengutronix.de, lee.jones@linaro.org, linux-arm-kernel@lists.infradead.org Am Dienstag, den 20.01.2015, 19:38 +0800 schrieb Shawn Guo: > Add LAKML and a few interested people. > > Shawn > > On Tue, Jan 20, 2015 at 06:22:35PM +0800, Robby Cai wrote: > > Hannstar XGA panel is used by default on i.MX6QDL Sabre Auto/Lite/SD > > or derived board. > > > > According to its data sheet [1], > > a) the dimming duty cycle is 20% - 100%. > > This patch changes the brightness-level from 20 to 100 with step 10 to > > make it straight-forward. > > b) the typical dimming frequency is 20KHz. > > The previous setting is 200Hz. This patch corrects it. > > > > [1] > > http://boundarydevices.com/wp-content/uploads/2013/06/HSD100PXN1-A00-C11-1.0.pdf > > > > Signed-off-by: Robby Cai > > --- > > arch/arm/boot/dts/imx6qdl-gw52xx.dtsi | 6 +++--- > > arch/arm/boot/dts/imx6qdl-gw53xx.dtsi | 6 +++--- > > arch/arm/boot/dts/imx6qdl-gw54xx.dtsi | 6 +++--- > > arch/arm/boot/dts/imx6qdl-nitrogen6x.dtsi | 6 +++--- > > arch/arm/boot/dts/imx6qdl-sabreauto.dtsi | 6 +++--- > > arch/arm/boot/dts/imx6qdl-sabrelite.dtsi | 6 +++--- > > arch/arm/boot/dts/imx6qdl-sabresd.dtsi | 6 +++--- > > 7 files changed, 21 insertions(+), 21 deletions(-) > > > > diff --git a/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi b/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi > > index b5756c2..33484d8 100644 > > --- a/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi > > +++ b/arch/arm/boot/dts/imx6qdl-gw52xx.dtsi > > @@ -29,9 +29,9 @@ > > > > backlight { > > compatible = "pwm-backlight"; > > - pwms = <&pwm4 0 5000000>; > > - brightness-levels = <0 4 8 16 32 64 128 255>; > > - default-brightness-level = <7>; > > + pwms = <&pwm4 0 50000>; > > + brightness-levels = <0 20 30 40 50 60 70 80 90 100>; > > + default-brightness-level = <9>; I notice that the intervals are changed from exponential to linear. Is this really wanted here? I expect that the new settings result in huge steps in perceived brightness at low levels and a nearly imperceptible change at the last step. regards Philipp