From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinay Simha Subject: Re: [RESEND] [PATCH v2 2/4] dt-bindings: Add jdi lt070me05000 panel bindings Date: Wed, 24 Aug 2016 17:53:00 +0530 Message-ID: References: <1469978126-925-1-git-send-email-simhavcs@gmail.com> <1469978126-925-2-git-send-email-simhavcs@gmail.com> <20160824115639.GC3169@ulmo.ba.sec> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <20160824115639.GC3169@ulmo.ba.sec> Sender: linux-kernel-owner@vger.kernel.org To: Thierry Reding Cc: Archit Taneja , John Stultz , Sumit Semwal , David Airlie , Rob Herring , Mark Rutland , "open list:DRM PANEL DRIVERS" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list List-Id: devicetree@vger.kernel.org if we do not set the polarity to 8mA, panel will have gibberish display. (information to set 8mA is available only in nexus7-msm-flo-3.4-lollipop-release_dsi kernel nx7 release) i will add this reset-gpios = <&tlmm_pinmux 54 GPIO_ACTIVE_LOW>; On Wed, Aug 24, 2016 at 5:26 PM, Thierry Reding wrote: > On Sun, Jul 31, 2016 at 08:45:21PM +0530, Vinay Simha BN wrote: > [...] >> diff --git a/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt b/Documentation/devicetree/bindings/display/panel/jdi,lt070me05000.txt > [...] >> +- reset-gpios: phandle of gpio for reset line >> + This should be 8mA, gpio can be configured using mux, pinctrl, pinctrl-names >> + XRES, Reset, Low active >> +- enable-gpios: phandle of gpio for enable line >> + LED_EN, LED backlight enable, High active > > This is a little confusing. Shouldn't we rather completely omit any > mention of the polarity of these and let the board design handle this? > > If the reset is low active, then I'd expect that to be reflected in the > GPIO specifier of the reset-gpios property, like so: > > panel@0 { > ... > reset-gpios = <&tlmm_pinmux 54 GPIO_ACTIVE_LOW>; > ... > }; > > With that a driver can simply deal with a high active reset, which it > currently doesn't. The problem with the current description is that it > is unclear who's to deal with the polarity. In order for this to work > properly with the current driver you'll have to specify the GPIO as > GPIO_ACTIVE_HIGH, which is not what the binding says it should be. > > Thierry -- regards, vinaysimha