From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f170.google.com ([209.85.192.170]:40186 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751629Ab3HTAGc convert rfc822-to-8bit (ORCPT ); Mon, 19 Aug 2013 20:06:32 -0400 Received: by mail-pd0-f170.google.com with SMTP id x10so5941493pdj.1 for ; Mon, 19 Aug 2013 17:06:32 -0700 (PDT) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT From: Mike Turquette In-Reply-To: <20130819093543.GF3719@e106331-lin.cambridge.arm.com> References: <2805432.jMVhHxhr1m@flatron> <20130817145316.GT26614@pengutronix.de> <8770601.066pCcRnTh@flatron> <20130819093543.GF3719@e106331-lin.cambridge.arm.com> Message-ID: <20130820000625.4443.23018@quantum> Subject: Re: [PATCH v5 1/2] ASoC: fsl: Add S/PDIF CPU DAI driver Date: Mon, 19 Aug 2013 17:06:25 -0700 Sender: devicetree-owner@vger.kernel.org To: Mark Rutland , Tomasz Figa Cc: Sascha Hauer , Nicolin Chen , "ian.campbell@citrix.com" , Pawel Moll , "galak@codeaurora.org" , "broonie@kernel.org" , "lars@metafoo.de" , "p.zabel@pengutronix.de" , "linuxppc-dev@lists.ozlabs.org" , "alsa-devel@alsa-project.org" , "devicetree@vger.kernel.org" , "timur@tabi.org" , "rob.herring@calxeda.com" , "shawn.guo@linaro.org" , "festevam@gmail.com" , "swarren@wwwdotorg.org" List-ID: Quoting Mark Rutland (2013-08-19 02:35:43) > On Sat, Aug 17, 2013 at 04:17:18PM +0100, Tomasz Figa wrote: > > On Saturday 17 of August 2013 16:53:16 Sascha Hauer wrote: > > > On Sat, Aug 17, 2013 at 02:28:04PM +0200, Tomasz Figa wrote: > > > > > > > Also I would make this option required. Use a dummy clock for > > > > > > > mux > > > > > > > inputs that are grounded for a specific SoC. > > > > > > > > > > > > Some clocks are not from CCM and we haven't defined in > > > > > > imx6q-clk.txt, > > > > > > so in most cases we can't provide a phandle for them, eg: > > > > > > spdif_ext. > > > > > > I think it's a bit hard to force it to be 'required'. An > > > > > > 'optional' > > > > > > looks more flexible to me and a default one is ensured even if > > > > > > it's > > > > > > missing. > > > > > > > > > > <&clks 0> is the dummy clock. This can be used for all input clocks > > > > > not > > > > > defined by the SoC. > > > > > > > > Where does this assumption come from? Is it documented anywhere? > > > > > > This is how all i.MX clock bindings currently are. See > > > Documentation/devicetree/bindings/clock/imx*-clock.txt > > > > OK, thanks. > > > > I guess we need some discussion on dummy clocks vs skipped clocks. I think > > we want some consistency on this, don't we? > > > > If we really need a dummy clock, then we might also want a generic way to > > specify it. > > What do we actually mean by a "dummy clock"? We already have bindings > for "fixed-clock" and co friends describe relatively simple > preconfigured clocks. Some platforms have a fake clock which defines noops callbacks and basically doesn't do anything. This is analogous to the dummy regulator implementation. A central one could be registered by the clock core, as is done by the regulator core. I'll add this to the todo list. Regards, Mike > > If a clock isn't actually wired, we shouldn't describe it at all, or > we're describing what Linux wants to think rather than what the hardware > actually is. That can easily be handled with clock-names. > > Thanks, > Mark.