From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8214DC4360F for ; Wed, 3 Apr 2019 20:06:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 545862084B for ; Wed, 3 Apr 2019 20:06:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726387AbfDCUGF (ORCPT ); Wed, 3 Apr 2019 16:06:05 -0400 Received: from muru.com ([72.249.23.125]:44172 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726099AbfDCUGF (ORCPT ); Wed, 3 Apr 2019 16:06:05 -0400 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 41585803A; Wed, 3 Apr 2019 20:06:18 +0000 (UTC) Date: Wed, 3 Apr 2019 13:06:00 -0700 From: Tony Lindgren To: Sebastian Reichel Cc: Dan Murphy , robh+dt@kernel.org, jacek.anaszewski@gmail.com, pavel@ucw.cz, lee.jones@linaro.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org Subject: Re: [PATCH 4/4] leds: lm3532: Introduce the lm3532 LED driver Message-ID: <20190403200600.GT49658@atomide.com> References: <20190321142838.22985-1-dmurphy@ti.com> <20190321142838.22985-4-dmurphy@ti.com> <20190322221654.GG19425@atomide.com> <20190325145444.GK19425@atomide.com> <044f67e7-e196-a5b9-728b-a7c5f283f56f@ti.com> <20190328210437.tcojjqynggk72zo2@earth.universe> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190328210437.tcojjqynggk72zo2@earth.universe> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Sebastian Reichel [190329 05:36]: > Hi, > > On Mon, Mar 25, 2019 at 11:01:18AM -0500, Dan Murphy wrote: > > On 3/25/19 9:54 AM, Tony Lindgren wrote: > > > * Dan Murphy [190325 12:36]: > > >> On 3/22/19 5:16 PM, Tony Lindgren wrote: > > >>> I can control the backlight brightness just fine via /sys, and > > >>> backlight shows up as the trigger in /sys/class/leds/lm3532:backlight, > > >>> but /sys/class/backlight is empty and looks like drm can't find it. > > >>> > > >>> Do I need to enable some additional driver(s) to get this to work > > >>> with the drm driver? > > >>> > > >> > > >> Can you dump or point to the defconfig? > > > > > > This is just with the omap2plus_defconfig as in the droid4-pending-v5.0 > > > test branch below [0]. That branch has Sebastian's drm patches. The > > > branch also has the older ti-lmu patches that I reverted for testing > > > before applying your new series and enabling it in .config. > > > > > > The drm driver (drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c) just > > > does: > > > > > > backlight = of_parse_phandle(node, "backlight", 0); > > > ... > > > > > > That should still work the same, right? > > > > Yes it should still work the same. > > I did not change the node name. > > So the DRM driver should find the node. > > This will not work, since the next line tries to get it as a > backlight device, but it's an LED device instead: > > of_find_backlight_by_node(backlight); > > I suppose the backlight device could be instantiated on top > of the LED device somehow. Hmm yeah I thought setting the ledtrig-backlight for it would do the trick. But after thinking about it there might be some backlight lifecycle issues with that where everything would need to be torn down for the panel to change the backlight trigger. I think the panel driver(s) assume the backlight to always be there at probe time. Well this is just based on just guessing.. I might be wrong. I have no issues using of_find_backlight_by_node() like other panels. > (sorry for slow responses; I'm quite busy right now) No problem. Regards, Tony