Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753123Ab2HBIZ5 (ORCPT ); Thu, 2 Aug 2012 04:25:57 -0400 Received: from hqemgate03.nvidia.com ([216.228.121.140]:7216 "EHLO hqemgate03.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752324Ab2HBIZx (ORCPT ); Thu, 2 Aug 2012 04:25:53 -0400 X-PGP-Universal: processed; by hqnvupgp05.nvidia.com on Thu, 02 Aug 2012 01:25:52 -0700 Message-ID: <501A3A00.7070207@nvidia.com> Date: Thu, 2 Aug 2012 17:27:44 +0900 From: Alex Courbot Organization: NVIDIA User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: Thierry Reding CC: Stephen Warren , Stephen Warren , Simon Glass , Grant Likely , Rob Herring , Greg Kroah-Hartman , Mark Brown , Arnd Bergmann , "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fbdev@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" Subject: Re: [RFC][PATCH v3 1/3] runtime interpreted power sequences References: <1343390750-3642-1-git-send-email-acourbot@nvidia.com> <1343390750-3642-2-git-send-email-acourbot@nvidia.com> <50170EA0.1010408@wwwdotorg.org> <501A338D.7080105@nvidia.com> <20120802082157.GA14866@avionic-0098.adnet.avionic-design.de> In-Reply-To: <20120802082157.GA14866@avionic-0098.adnet.avionic-design.de> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2408 Lines: 66 On Thu 02 Aug 2012 05:21:57 PM JST, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Thu, Aug 02, 2012 at 05:00:13PM +0900, Alex Courbot wrote: >> On 07/31/2012 07:45 AM, Stephen Warren wrote: >>> Oh I see. That's a little confusing. Why not just reference the relevant >>> resources directly in each step; something more like: >>> >>> gpio@1 { >>> action = "enable-gpio"; >>> gpio = <&gpio 1 0>; >>> }; >>> >>> I guess that might make parsing/building a little harder, since you'd >>> have to detect when you'd already done gpio_request() on a given GPIO >>> and not repeat it or something like that, but to me this makes the DT a >>> lot easier to comprehend. >> >> I tried to move towards having the phandles directly in the >> sequences themselves - that reminded me why I did not do that in the >> first place. Let's say we have a sequence like this (reg property >> omitted on purpose): >> >> power-on-sequence { >> step@0 { >> regulator = <&backlight_reg>; >> enable; >> }; >> step@1 { >> delay = <10000>; >> }; >> step@2 { >> pwm = <&pwm 2 5000000>; >> enable; >> }; >> step@3 { >> gpio = <&gpio 28 0>; >> enable; >> }; >> }; >> >> The problem is, how do we turn these phandles into the resource of >> interest. The type of the resource can be infered by the name of the >> property. The hard part is resolving the resource from the phandle - >> it seems like the API just does not allow to do this. GPIO has >> of_get_named_gpio, but AFAIK there are no equivalent for regulator >> consumer and PWM: the only way to use the DT with them is through >> get_regulator and get_pwm which work at the device level. >> >> Or is there a way that I overlooked? > > No, you are right. Perhaps we should add exported functions that do the > equivalent of of_pwm_request() or the regulator_dev_lookup() and > of_get_regulator() pair. How would that be looked with respect to "good DT practices"? I can somehow understand the wish to restrain DT access to these functions that integrate well with current workflows. Aren't we going to be frowned upon if we make more low-level functions public? Alex. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/