From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: Re: [PATCH v3 1/5] Documentation: add DT bindings for ARM SCPI sensors Date: Mon, 14 Sep 2015 16:15:40 +0100 Message-ID: <20150914151540.GI7002@leverpostej> References: <1442235619-4029-1-git-send-email-punit.agrawal@arm.com> <1442235619-4029-2-git-send-email-punit.agrawal@arm.com> <20150914131448.GC7002@leverpostej> <9hhh9mxf7lg.fsf@e105922-lin.cambridge.arm.com> <20150914134949.GE7002@leverpostej> <9hhk2rtdq1f.fsf@e105922-lin.cambridge.arm.com> <20150914144330.GH7002@leverpostej> <9hhfv2hdozu.fsf@e105922-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <9hhfv2hdozu.fsf@e105922-lin.cambridge.arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Punit Agrawal Cc: "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , Sudeep Holla , "linux-pm@vger.kernel.org" , "lm-sensors@lm-sensors.org" , Liviu Dudau , "edubezval@gmail.com" , "linux@roeck-us.net" , "linux-kernel@vger.kernel.org" , "robh+dt@kernel.org" List-Id: devicetree@vger.kernel.org On Mon, Sep 14, 2015 at 04:01:09PM +0100, Punit Agrawal wrote: > Mark Rutland writes: > > > On Mon, Sep 14, 2015 at 03:38:36PM +0100, Punit Agrawal wrote: > >> Mark Rutland writes: > >> > >> >> >> +Sensor bindings for the sensors based on SCPI Message Protocol > >> >> >> +-------------------------------------------------------------- > >> >> >> +SCPI provides an API to access the various sensors on the SoC. > >> >> >> + > >> >> >> +Required properties: > >> >> >> +- compatible : should be "arm,scpi-sensors". > >> >> >> +- #thermal-sensor-cells: should be set to 1. This property follows the > >> >> >> + thermal device tree bindings[2]. > >> >> > > >> >> > You need to specify what the valid values for this cell are. > >> >> > >> >> The enumeration depends on the number of sensors exported by SCP > >> >> firmware - which is platform dependent. I could add add something like > >> >> if you think that is helpful - > >> >> > >> >> "Valid cell value is a number between 0..n-1, where n is the number > >> >> of sensors exported by SCP firmware." > >> > > >> > Can the FW identifer space have holes? Or are they always contiguous? > >> > >> The way the SCP interface is defined, the sensor identifiers are > >> contiguous, but not all are temperature sensors. > > > > Ok. So how exactly are they enumerated for this binding? > > The sensor enumeration for r0 (which I've verified) and r1 can be found > at [0]. The valid cell values are identifiers for the temperature sensors. Ok. That's fine by me; I was confused and thought that there was some internal mapping. > >> > If this is the same as the raw FW identifer value, specify that. > >> > Otherwise, you need to specify the mapping. > >> > >> I'll update the patch to add mappings for Juno r0 (and r1 if I can get > >> my hands on one). > > > > If there's identical logic mapping the two, we might just be able to > > describe that rather than having to add tables all the time. > > > > After seeing the mapping already published, I am wondering if there is > any value in duplicating the information. If there are no objections, > I'll update this patch to add pointers instead. That's fine by me. The important part is that the value is a raw Sensor ID as the FW uses. So long as we state that, the IDs themselves can come from whatever documentation is valid for a particular instance. Thanks for the info! Thanks, Mark.