Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752026AbbKYRzH (ORCPT ); Wed, 25 Nov 2015 12:55:07 -0500 Received: from foss.arm.com ([217.140.101.70]:41436 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751114AbbKYRy4 (ORCPT ); Wed, 25 Nov 2015 12:54:56 -0500 Date: Wed, 25 Nov 2015 17:54:41 +0000 From: Mark Rutland To: Javi Merino Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, rui.zang@intel.com, edubezval@gmail.com, Zhang Rui , Rob Herring , Pawel Moll , Ian Campbell , Kumar Gala , devicetree@vger.kernel.org Subject: Re: [PATCH v3 2/4] devicetree: bindings: let thermal-sensor point to other thermal zones Message-ID: <20151125175441.GA32343@leverpostej> References: <1448464186-26289-1-git-send-email-javi.merino@arm.com> <1448464186-26289-3-git-send-email-javi.merino@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1448464186-26289-3-git-send-email-javi.merino@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7069 Lines: 225 On Wed, Nov 25, 2015 at 03:09:44PM +0000, Javi Merino wrote: > The thermal-sensor property of the thermal zone node accepts phandles to > thermal sensors. However, thermal zones can be created as an > aggregation of other thermal zones. Extend the thermal-sensors property > to allow phandles to other thermal zones. This patch also adds an > example that showcases how a board thermal zone can be created from the > aggregation of the cpu, gpu and lcd thermal zones. > > Cc: Zhang Rui > Cc: Eduardo Valentin > Cc: Rob Herring > Cc: Pawel Moll > Cc: Mark Rutland > Cc: Ian Campbell > Cc: Kumar Gala > Cc: devicetree@vger.kernel.org > Signed-off-by: Javi Merino > --- > > Notes: > Hi devicetree, > > Is it ok to extend the definition of the thermal-sensors property like > this? IOW are phandles strongly typed? I think it's OK so long as each thermal zone has #theremal-sensor-cells set explicitly, if used as a sensor, and we can agree on the semantics of what it means for a thermal zone to be a sensor. I don't really follow why you need the zone to be a sensor, and can't simply refer to the sensor from two zones. Are you trying to imply an ordering of trip points (e.g. that the sub-zones' trips should be taken into account first)? > > .../devicetree/bindings/thermal/thermal.txt | 154 ++++++++++++++++++++- > 1 file changed, 151 insertions(+), 3 deletions(-) > > diff --git a/Documentation/devicetree/bindings/thermal/thermal.txt b/Documentation/devicetree/bindings/thermal/thermal.txt > index 41b817f7b670..52b7e9ae3b4d 100644 > --- a/Documentation/devicetree/bindings/thermal/thermal.txt > +++ b/Documentation/devicetree/bindings/thermal/thermal.txt > @@ -145,9 +145,12 @@ Required properties: > Size: one cell > > - thermal-sensors: A list of thermal sensor phandles and sensor specifier > - Type: list of used while monitoring the thermal zone. > - phandles + sensor > - specifier > + Type: list of used while monitoring the thermal zone. The phandles > + phandles + sensor can point to thermal sensors or other thermal zone > + specifier nodes. If it points to other thermal zone > + nodes you should omit the sensor specifier > + and set #thermal-sensor-cells to 0 for the > + thermal zone. The example misses #thermal-sensor-cells = <0> for each of the zones. Can a zone normal have multiple sensors? If so, what is the aggregate value if a zone is used as a sensor? Max? Min? Scaled by contribution somehow? Thanks, Mark. > > - trips: A sub-node which is a container of only trip point nodes > Type: sub-node required to describe the thermal zone. > @@ -603,3 +606,148 @@ thermal-zones { > The above example is a mix of previous examples, a sensor IP with several internal > sensors used to monitor different zones, one of them is composed by several sensors and > with different cooling devices. > + > +(e) Board thermal with stacked thermal zones > + > +Instead of setting up one thermal zone combining multiple thermal > +zones and multiple trip points for each cooling device, we can create > +a hierarchy of thermal zones. > + > +#include > + > +&i2c1 { > + ... > + /* > + * An IC with several temperature sensor. > + */ > + adc_dummy: sensor@0x50 { > + ... > + #thermal-sensor-cells = <1>; /* sensor internal ID */ > + }; > +}; > + > +thermal-zones { > + > + cpu_thermal: cpu_thermal { > + polling-delay-passive = <1000>; /* milliseconds */ > + polling-delay = <2500>; /* milliseconds */ > + > + sustainable-power = <2500>; > + > + thermal-sensors = <&adc_dummy 0> > + > + trips { > + cpu_trip: cpu-trip { > + temperature = <60000>; /* millicelsius */ > + hysteresis = <2000>; /* millicelsius */ > + type = "passive"; > + }; > + }; > + > + cooling-maps { > + map0 { > + trip = <&cpu_trip>; > + cooling-device = <&cpu0 0 2>; > + }; > + }; > + }; > + > + gpu_thermal: gpu_thermal { > + polling-delay-passive = <1000>; /* milliseconds */ > + polling-delay = <2500>; /* milliseconds */ > + > + sustainable-power = <2500>; > + > + thermal-sensors = <&adc_dummy 2> > + > + trips { > + gpu_trip: gpu-trip { > + temperature = <55000>; /* millicelsius */ > + hysteresis = <2000>; /* millicelsius */ > + type = "passive"; > + } > + }; > + > + cooling-maps { > + map0 { > + trip = <&gpu_trip>; > + cooling-device = <&gpu0 0 2>; > + }; > + }; > + }; > + > + lcd_thermal: lcd_thermal { > + polling-delay-passive = <1000>; /* milliseconds */ > + polling-delay = <2500>; /* milliseconds */ > + > + sustainable-power = <2500>; > + > + thermal-sensors = <&adc_dummy 1> > + > + trips { > + lcd_trip: lcp-trip { > + temperature = <53000>; /* millicelsius */ > + hysteresis = <2000>; /* millicelsius */ > + type = "passive"; > + }; > + }; > + > + cooling-maps { > + map0 { > + trip = <&lcd_trip>; > + cooling-device = <&lcd0 5 10>; > + }; > + }; > + }; > + > + board_thermal: board-thermal { > + polling-delay-passive = <1000>; /* milliseconds */ > + polling-delay = <2500>; /* milliseconds */ > + > + thermal-sensors = <&cpu_thermal &gpu_thermal &lcd_thermal> > + > + sustainable-power = <2500>; > + > + trips { > + warm_trip: warm-trip { > + temperature = <62000>; /* millicelsius */ > + hysteresis = <2000>; /* millicelsius */ > + type = "passive"; > + }; > + crit_trip: crit-trip { > + temperature = <68000>; /* millicelsius */ > + hysteresis = <2000>; /* millicelsius */ > + type = "critical"; > + }; > + }; > + > + cooling-maps { > + map0 { > + trip = <&warm_trip>; > + cooling-device = <&cpu0 2 2>; > + contribution = <55>; > + }; > + map1 { > + trip = <&warm_trip>; > + cooling-device = <&gpu0 2 2>; > + contribution = <20>; > + }; > + map2 { > + trip = <&lcd_trip>; > + cooling-device = <&lcd0 7 10>; > + contribution = <15>; > + }; > + }; > + }; > +}; > + > +The above example is a different take at example (d). We create one > +thermal zone per sensor: cpu_thermal, gpu_thermal and lcd_thermal. > +Each of which has its own trip point for each own cooling device. We > +then define a board_thermal thermal zone that is a combination of all > +the other thermal zones. If the board hits its warm_trip, then all > +cooling devices are throttled. > + > +This example illustrates how we can throttle each device individually > +if its too hot and at the same time have some control over the whole > +system. > -- > 1.9.1 > -- 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/