From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752153Ab2IQGgf (ORCPT ); Mon, 17 Sep 2012 02:36:35 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:55309 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751302Ab2IQGge (ORCPT ); Mon, 17 Sep 2012 02:36:34 -0400 Message-ID: <5056C4EC.1030305@gmail.com> Date: Mon, 17 Sep 2012 08:36:28 +0200 From: Sebastian Hesselbarth User-Agent: Mozilla/5.0 (X11; Linux i686; rv:10.0.5) Gecko/20120624 Icedove/10.0.5 MIME-Version: 1.0 To: Nicolas Pitre CC: Jason Cooper , Andrew Lunn , Thomas Petazzoni , Lior Amsalem , Russell King , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Rob Herring , Ben Dooks , devicetree-discuss@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4 03/10] pinctrl: mvebu: kirkwood pinctrl driver References: <1344689809-6223-1-git-send-email-sebastian.hesselbarth@gmail.com> <1347550912-18021-1-git-send-email-sebastian.hesselbarth@gmail.com> <1347550912-18021-4-git-send-email-sebastian.hesselbarth@gmail.com> <20120916074652.GM28177@lunn.ch> <20120916124015.GI5469@titan.lakedaemon.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/17/2012 03:55 AM, Nicolas Pitre wrote: > On Sun, 16 Sep 2012, Jason Cooper wrote: >> On Sun, Sep 16, 2012 at 09:46:52AM +0200, Andrew Lunn wrote: >>>> +++ b/Documentation/devicetree/bindings/pinctrl/marvell,kirkwood-pinctrl.txt >>>> @@ -0,0 +1,279 @@ >>>> +* Marvell Kirkwood SoC pinctrl driver for mpp >>>> + >>>> +Please refer to marvell,mvebu-pinctrl.txt in this directory for common binding >>>> +part and usage. >>>> + >>>> +Required properties: >>>> +- compatible: "marvell,88f6180-pinctrl", >>>> + "marvell,88f6190-pinctrl", "marvell,88f6192-pinctrl", >>>> + "marvell,88f6281-pinctrl", "marvell,88f6282-pinctrl" >>>> + >>>> +This driver supports all kirkwood variants, i.e. 88f6180, 88f619x, and 88f628 >>> ... >>> If i wanted to mass convert all existing kirkwood DT boards over to >>> use pinctrl, im stuck at the very first step. I've no idea what chip >>> they use, it was not relevant before. >> >> Let's try to do the DT correctly, and create a migration path for >> kirkwood to work first, then migrate to using the DT fully. > > Beware beware. > > The DT should of course describe the hardware as accurately as possible. > That doesn't necessarily mean it should describe the hardware as > _extensively_ as possible. > > And that doesn't mean that all the information found in the DT has to be > consumed by the kernel either. > > Any information that can be *probed* at run time has no benefit being > stuffed in a DT. That's true whether it is Linux or another operating > system. The more that can be probed at run time the better. I had a closer look at how kirkwood probes its id. I mentionend kirkwood_id() earlier but in fact it is kirkwood_pcie_id(). I assume pcie registers are shut down with pcie clk gated? That would require to have pcie running at least at boot-time on all boards. While it is still possible to grab the id and power down pcie later, I still think that using five different compatible strings is better here. Of course, there is some effort to obtain the kirkwood SoC variant for all boards. Sebastian