From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH 2/3] hwmon: Driver for OMAP3 temperature sensor Date: Tue, 30 Dec 2014 19:00:02 +0100 Message-ID: <20141230180002.GC23142@amd> References: <20141226102933.GA28778@amd> <1419597294-21487-1-git-send-email-sre@kernel.org> <1419597294-21487-3-git-send-email-sre@kernel.org> <20141229181556.GA26926@amd> <54A1BB2B.9060204@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <54A1BB2B.9060204-l0cyMroinI0@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Nishanth Menon Cc: Grazvydas Ignotas , Sebastian Reichel , Mark Rutland , dt list , Pawel Moll , Ian Campbell , Tony Lindgren , Kumar Gala , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , lm-sensors-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org, Rob Herring , Jean Delvare , =?iso-8859-1?Q?Beno=EEt?= Cousson , Pali Rohar , "linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Guenter Roeck , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org On Mon 2014-12-29 14:35:55, Nishanth Menon wrote: > On 12/29/2014 12:15 PM, Pavel Machek wrote: > > On Mon 2014-12-29 12:01:03, Nishanth Menon wrote: > >> On Mon, Dec 29, 2014 at 11:52 AM, Grazvydas Ignotas wrote: > >>> On Fri, Dec 26, 2014 at 2:34 PM, Sebastian Reichel wrote: > >>>> OMAP34xx and OMAP36xx processors contain a register in the syscon area, > >>>> which can be used to determine the SoCs temperature. This patch provides > >>>> a DT based driver for the temperature sensor based on an older driver > >>>> written by Peter De Schrijver for the Nokia N900 and N9. > >>> > >>> The sensor looks like an earlier iteration of sensors used in newer > >>> OMAPs, which are already supported by maybe > >>> drivers/thermal/ti-soc-thermal/ , maybe it would make sense to update > >>> that driver instead? > >> > >> Just to be clear - OMAP4 is the first time that the sensors were > >> reliable enough to be used. > > > > When testing initial version of the patch, they seem to work very well > > in the omap3 case. > > Just be careful when you try to make thermal policy like decisions > based on this sensor. Placement of the sensor w.r.t the actual logic I guess we won't do that, certainly not anytime soon. > Also notice http://www.ti.com/lit/er/sprz278f/sprz278f.pdf "Advisory > 3.1.1.186 MMC OCP Clock Not Gated When Thermal Sensor Is Used" I think > there were accuracy issues at certain values etc.. So remember to do a > off mode type PM tests as well before you consider requesting these to > be merged. Thanks a lot for a pointer. 3x 100uA power draw when you enable temperature sensor, because it also errorneously enables MMC. I wonder how the solution would look in the device tree... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html