From mboxrd@z Thu Jan 1 00:00:00 1970 From: punit.agrawal@arm.com (Punit Agrawal) Date: Tue, 15 Sep 2015 10:37:39 +0100 Subject: [PATCH v3 1/5] Documentation: add DT bindings for ARM SCPI sensors In-Reply-To: <1442251092.2850.53.camel@linaro.org> (Jon Medhurst's message of "Mon, 14 Sep 2015 18:18:12 +0100") 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> <1442251092.2850.53.camel@linaro.org> Message-ID: <9hhy4g89g64.fsf@e105922-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org "Jon Medhurst (Tixy)" writes: > On Mon, 2015-09-14 at 15:38 +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, > > Is there any documentation other than DUI0922A? [1] From what I can seen > that just says it's a 16-bit value and doesn't put any particular > constraints on its value. Although not explicitly stated, if you look at the Get Sensor Capability [2] and Get Sensor Info [3] commands you can indirectly infer that the Sensor IDs are contiguous. Not the strongest guarantee I know. All platforms currently using SCP (Juno R0 and R1) do indeed expose contiguous identifiers. Maybe we can convince the authors to make it explicit. > > [1] http://community.arm.com/servlet/JiveServlet/download/8401-40-18262/DUI0922A_scp_message_interface.pdf [2] http://arminfo.emea.arm.com/help/index.jsp?topic=/com.arm.doc.dui0922b/ch03s02s21.html [3] http://arminfo.emea.arm.com/help/index.jsp?topic=/com.arm.doc.dui0922b/BABCCCJJ.html