Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754137AbaAFNvw (ORCPT ); Mon, 6 Jan 2014 08:51:52 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:62471 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752708AbaAFNvv (ORCPT ); Mon, 6 Jan 2014 08:51:51 -0500 Date: Mon, 6 Jan 2014 13:51:45 +0000 From: Mark Rutland To: Matthew Longnecker Cc: Wei Ni , Eduardo Valentin , "swarren@wwwdotorg.org" , Pawel Moll , "ian.campbell@citrix.com" , "rob.herring@calxeda.com" , "linux@roeck-us.net" , "rui.zhang@intel.com" , "grant.likely@linaro.org" , "durgadoss.r@intel.com" , "linux-pm@vger.kernel.org" , "devicetree@vger.kernel.org" , "lm-sensors@lm-sensors.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCHv9 02/20] thermal: introduce device tree parser Message-ID: <20140106135145.GD21906@e106331-lin.cambridge.arm.com> References: <1384285582-16933-1-git-send-email-eduardo.valentin@ti.com> <1384285582-16933-3-git-send-email-eduardo.valentin@ti.com> <52C4D612.2090808@nvidia.com> <52C5A6CE.5060904@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52C5A6CE.5060904@nvidia.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 02, 2014 at 05:50:06PM +0000, Matthew Longnecker wrote: > > > I think the platform driver may set governor for the thermal zone, > > so how about to add a property named as "governor", > > and parse it to tzp->governor_name, > > something like: > > ret = of_property_read_string(child, "governor", &str); > > if (ret == 0) > > if (strlen(str) < THERMAL_NAME_LENGTH) > > strcpy(tzp->governor_name, str); > > > > Thanks. > > Wei. > > DT is supposed to describe the hardware, right? The governor isn't > hardware -- it's a software control policy. On the other hand, that > control policy must be tuned according to the behaviors of the platform > hardware otherwise the system will be unstable. > > Is it appropriate to be naming the governor in DT? If so, is it equally > appropriate to describe any governor-specific parameters in DT (even > though they are pure software constructs)? The dt should be relatively static -- if the hardware doesn't change the dt shouldn't have to. The governers are not static. We can introduce new ones and throw away old ones at any time. Tuning parameters can also change at any time. I'd prefer to not have governer details described in the dt, and the choice of governer and configuration of its tuning parameters should be made at runtime somehow. Thanks, Mark. -- 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/