From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 1/3] gpio: Add simple poweroff-gpio driver Date: Thu, 15 Nov 2012 11:00:06 -0700 Message-ID: <50A52DA6.3070409@wwwdotorg.org> References: <1352650891-18356-1-git-send-email-andrew@lunn.ch> <1352650891-18356-2-git-send-email-andrew@lunn.ch> <50A020C5.4070506@wwwdotorg.org> <20121112082546.GU22029@lunn.ch> <50A1212C.2080601@wwwdotorg.org> <20121112181947.GS24583@lunn.ch> <20121112184340.GA15643@lizard> <50A146E7.2040608@wwwdotorg.org> <20121115105954.GA17119@lizard> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20121115105954.GA17119@lizard> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Anton Vorontsov Cc: Andrew Lunn , Jason Cooper , devicetree-discuss@lists.ozlabs.org, Linus Walleij , Grant Likely , jm@lentin.co.uk, linux-arm-kernel@lists.infradead.org, gmbnomis@gmail.com List-Id: devicetree@vger.kernel.org On 11/15/2012 03:59 AM, Anton Vorontsov wrote: > On Thu, Nov 15, 2012 at 11:35:36AM +0100, Linus Walleij wrote: >> On Mon, Nov 12, 2012 at 7:58 PM, Stephen Warren wrote: >>> On 11/12/2012 11:43 AM, Anton Vorontsov wrote: >> >>>> Should the gpio driver fix its bindings then?.. Polarity is a quite >>>> generic concept of a GPIO, and flags are there for a reason. I'd rather >>>> prefer having >>> >>> There is no "GPIO driver" to fix; each GPIO driver has its own bindings, >>> and unfortunately, some of the GPIO binding authors chose not to include >>> any flags cell in the GPIO specifier (e.g. Samsung ARM SoCs IIRC, but >>> there are probably more). >> >> So can I read this something like we have been too liberal with the >> GPIO DT bindings and they are now a bit messy and need to be shaped >> up? I don't know how to achieve that :-( > > I guess there's really no reason to panic. :) > > 'git grep gpio-cells Documentation/' shows just mrvl-gpio.txt and > twl6040.txt having the wrong gpio-cells (i.e. 1). If there are too-few cells, the binding and driver can always be expanded to support more cells in a backwards-compatible way. > But even these can use one cells for both flags and pin number (unless you > really have 4294967295 GPIOs per controller). > > FWIW, current Samsung SOCs use 3 and even 4 cells for a GPIO specifier, > which is absolutely fine. Plus, the Samsung bindings do specify the > inversion flag. So, unless we have a lot of other [undocumented] bindings, > I don't see a big mess. And everything I currently see is fixable. Oh, I always thought that the Samsung bindings were one of the major issues here, but you're right - they do have the inversion flag already. So, perhaps there really isn't an issue, and we should revisit the GPIO-based regulator bindings and drivers, and allow them to (additionally) rely on the GPIO flags in the standard way.