Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752865AbaGVEkO (ORCPT ); Tue, 22 Jul 2014 00:40:14 -0400 Received: from mail-vc0-f179.google.com ([209.85.220.179]:64666 "EHLO mail-vc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750821AbaGVEkM (ORCPT ); Tue, 22 Jul 2014 00:40:12 -0400 MIME-Version: 1.0 In-Reply-To: <20140721225153.GJ17528@sirena.org.uk> References: <1404303560-32209-1-git-send-email-acourbot@nvidia.com> <1404303560-32209-5-git-send-email-acourbot@nvidia.com> <53B42B60.1000600@wwwdotorg.org> <53B4C9C0.4000605@nvidia.com> <53CD333F.2070805@wwwdotorg.org> <20140721211630.GA12076@mithrandir> <20140721225153.GJ17528@sirena.org.uk> From: Alexandre Courbot Date: Tue, 22 Jul 2014 13:39:51 +0900 Message-ID: Subject: Re: [PATCH 4/4] ARM: tegra: roth: add display DT node To: Mark Brown Cc: Thierry Reding , Stephen Warren , Alexandre Courbot , Terje Bergstrom , "linux-tegra@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 22, 2014 at 7:51 AM, Mark Brown wrote: > On Mon, Jul 21, 2014 at 11:16:32PM +0200, Thierry Reding wrote: >> On Mon, Jul 21, 2014 at 09:35:27AM -0600, Stephen Warren wrote: > >> > > vdd-2v8-display needs to remain always-on however. Here we may hit a >> > > limitation of the simple-panel driver, where only one power supply can >> > > be provided. > >> > Can't we fix the simple-panel driver to allow a list of regulators in >> > the property? > >> I have no objection to allowing that. But I don't think there's a way to >> do that with the current regulator API. You can use the bulk API, but >> that requires separate properties, not multiple regulators in one >> property. > >> Perhaps one idea to solve this would be to make the regulator API return >> a regulator handle that in fact controls an array of regulators? Adding >> Mark. > > I'm really not comfortable with that idea, it seems like most of the > users would be abusing it - one of the biggest issues is always getting > people to understand that their driver may be used in other systems with > the supplies mapped differently. If you were going to do something > along those lines you'd need to do something that enumerated all the > supply properties on the device. I also don't think that would do it - for many displays the power-on sequence is not as simple as "switch all the regulators on". Maybe what we would want is to have panel-simple allow panels to provide a "probe" callback so they can request and manage any extra resource they need. This would of course imply that custom enable/disable and suspend/resume callbacks. Then the driver might not be "simple" anymore, but IMHO it would not be that bad. -- 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/