Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754485Ab3JDOJS (ORCPT ); Fri, 4 Oct 2013 10:09:18 -0400 Received: from top.free-electrons.com ([176.31.233.9]:47328 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754114Ab3JDOJQ (ORCPT ); Fri, 4 Oct 2013 10:09:16 -0400 Date: Fri, 4 Oct 2013 11:09:26 -0300 From: Ezequiel Garcia To: Mark Rutland Cc: Ezequiel Garcia , "linux-kernel@vger.kernel.org" , "linux-input@vger.kernel.org" , Daniel Mack , Dmitry Torokhov , "rob.herring@calxeda.com" , devicetree@vger.kernel.org Subject: Re: [PATCH v2 2/2] input: rotary-encoder: Add 'on-each-step' to binding documentation Message-ID: <20131004140925.GA27809@localhost> References: <1380891203-17617-1-git-send-email-ezequiel@vanguardiasur.com.ar> <1380891203-17617-3-git-send-email-ezequiel@vanguardiasur.com.ar> <20131004131956.GE6999@e106331-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20131004131956.GE6999@e106331-lin.cambridge.arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3713 Lines: 86 On Fri, Oct 04, 2013 at 02:19:56PM +0100, Mark Rutland wrote: > On Fri, Oct 04, 2013 at 01:53:23PM +0100, Ezequiel Garcia wrote: > > The driver now supports a new mode to handle the interruptions generated > > by the device: on this new mode an input event is generated on each step > > (i.e. on each IRQ). Therefore, add a new DT property, to select the > > mode: 'rotary-encoder,on-each-step'. > > > > Cc: Daniel Mack > > Cc: Dmitry Torokhov > > Cc: Rob Herring > > Cc: devicetree@vger.kernel.org > > Signed-off-by: Ezequiel Garcia > > --- > > I'm not at all happy with this DT binding as it's way to customized > > for the current driver. For instance, if we want to support mapping > > key events (or better arbitrary linux-input event types) it seems > > there's no easy way to fix the binding. > > > > Maybe a better way of handling the different 'modes' is through > > compatible strings? > > I'd prefer not to have more pseudo-devices in DT, and would prefer not > to have compatible strings that boil down to driver options. We end up > just embedding a tonne of Linux-specific driver configuration in the DT > rather than describing hardware. > > That said, I'm not sure what the best solution is here. > > > > > I'm not really sure, so I hope the DT guys have some comment on this. > > > > Documentation/devicetree/bindings/input/rotary-encoder.txt | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/Documentation/devicetree/bindings/input/rotary-encoder.txt b/Documentation/devicetree/bindings/input/rotary-encoder.txt > > index 3315495..b89e38d 100644 > > --- a/Documentation/devicetree/bindings/input/rotary-encoder.txt > > +++ b/Documentation/devicetree/bindings/input/rotary-encoder.txt > > @@ -15,6 +15,7 @@ Optional properties: > > - rotary-encoder,rollover: Automatic rollove when the rotary value becomes > > greater than the specified steps or smaller than 0. For absolute axis only. > > - rotary-encoder,half-period: Makes the driver work on half-period mode. > > +- rotary-encoder,on-each-step: Makes the driver send an event on each step. > > Could this not be something requested at runtime? > Sure. The different modes: * default (no option) * rotary-encoder,half-period * rotary-encoder,on-each-step Just map to different interruption handlers. I don't have any other rotary-encoder device, so I'm not at all sure what's the use of the other two cases. My particular device is detented, and produces a 'stable' event on each step (i.e on each IRQ). Regarding the runtime specification: you mean as a module parameter? That should be trivial to add, no? > Could you explain what you want to achieve with this? -- what events do > you want to occur when, to be handled in what way? > Hm.. maybe I should have added the binding to the 1/2 patch and CCed everybody involved for better context. Anyway, I hope the above is clearer, I'm not really sure how to specify the details in the DT binding, since it's a specific interruption handler for this class of encoder devices (stable on each step). That said, I really hope I'm crafting a generic solution and not some tailor-made implementation that just happens to match my use case. The input maintainer's opinion on this would be valuable. -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- 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/