From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932642Ab3BKVXt (ORCPT ); Mon, 11 Feb 2013 16:23:49 -0500 Received: from avon.wwwdotorg.org ([70.85.31.133]:40496 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932605Ab3BKVXs (ORCPT ); Mon, 11 Feb 2013 16:23:48 -0500 Message-ID: <51196161.7020901@wwwdotorg.org> Date: Mon, 11 Feb 2013 14:23:45 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Tony Lindgren CC: Linus Walleij , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Stephen Warren , Anmar Oueja , Laurent Meunier , Linus Walleij Subject: Re: [PATCH] pinctrl/pinconfig: add debug interface References: <1360527070-18430-1-git-send-email-linus.walleij@stericsson.com> <51195A63.7080706@wwwdotorg.org> <20130211210041.GW4801@atomide.com> <51195F00.4020309@wwwdotorg.org> <20130211212105.GX4801@atomide.com> In-Reply-To: <20130211212105.GX4801@atomide.com> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/11/2013 02:21 PM, Tony Lindgren wrote: > * Stephen Warren [130211 13:17]: >> On 02/11/2013 02:00 PM, Tony Lindgren wrote: >>> * Stephen Warren [130211 12:57]: >>>> On 02/10/2013 01:11 PM, Linus Walleij wrote: >>>>> From: Laurent Meunier >>>>> >>>>> This update adds a debugfs interface to modify a pin configuration >>>>> for a given state in the pinctrl map. This allows to modify the >>>>> configuration for a non-active state, typically sleep state. >>>>> This configuration is not applied right away, but only when the state >>>>> will be entered. >>>>> >>>>> This solution is mandated for us by HW validation: in order >>>>> to test and verify several pin configurations during sleep without >>>>> recompiling the software. >>>> >>>> I never understood why HW engineers can't just recompile the kernel. >>>> Besides, it's just a device tree change these days - no recompile even >>>> required, right? >>> >>> Typically when bringing up a new board you do not have the driver >>> specific mux settings verified. For developers, it's easiest to tweak >>> the muxing during runtime do the drivers as a loadable module, then >>> export the verified mux configuration into a .dts file. >> >> Well HW engineers typically just write to the HW registers directly >> rather than screwing around with the Linux pinctrl tables and >> unloading/reloading drivers. > > I've seen cases where most of the mux register configuration are > done correctly by HW engineers.. But there's always been some pieces > of the pin configuration wrong initially and that needs to be fixed by > the driver people to get things working. > > Being able to set the mux configuration via debugfs is also very > useful for the case of adding external devices to your proto boards > like beagle etc. This patch won't work for that, since it doesn't support adding new entries to the mux table, just editing existing entries. From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Mon, 11 Feb 2013 14:23:45 -0700 Subject: [PATCH] pinctrl/pinconfig: add debug interface In-Reply-To: <20130211212105.GX4801@atomide.com> References: <1360527070-18430-1-git-send-email-linus.walleij@stericsson.com> <51195A63.7080706@wwwdotorg.org> <20130211210041.GW4801@atomide.com> <51195F00.4020309@wwwdotorg.org> <20130211212105.GX4801@atomide.com> Message-ID: <51196161.7020901@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 02/11/2013 02:21 PM, Tony Lindgren wrote: > * Stephen Warren [130211 13:17]: >> On 02/11/2013 02:00 PM, Tony Lindgren wrote: >>> * Stephen Warren [130211 12:57]: >>>> On 02/10/2013 01:11 PM, Linus Walleij wrote: >>>>> From: Laurent Meunier >>>>> >>>>> This update adds a debugfs interface to modify a pin configuration >>>>> for a given state in the pinctrl map. This allows to modify the >>>>> configuration for a non-active state, typically sleep state. >>>>> This configuration is not applied right away, but only when the state >>>>> will be entered. >>>>> >>>>> This solution is mandated for us by HW validation: in order >>>>> to test and verify several pin configurations during sleep without >>>>> recompiling the software. >>>> >>>> I never understood why HW engineers can't just recompile the kernel. >>>> Besides, it's just a device tree change these days - no recompile even >>>> required, right? >>> >>> Typically when bringing up a new board you do not have the driver >>> specific mux settings verified. For developers, it's easiest to tweak >>> the muxing during runtime do the drivers as a loadable module, then >>> export the verified mux configuration into a .dts file. >> >> Well HW engineers typically just write to the HW registers directly >> rather than screwing around with the Linux pinctrl tables and >> unloading/reloading drivers. > > I've seen cases where most of the mux register configuration are > done correctly by HW engineers.. But there's always been some pieces > of the pin configuration wrong initially and that needs to be fixed by > the driver people to get things working. > > Being able to set the mux configuration via debugfs is also very > useful for the case of adding external devices to your proto boards > like beagle etc. This patch won't work for that, since it doesn't support adding new entries to the mux table, just editing existing entries.