Re: [PATCH v3 3/4] thermal: add more description for thermal-zones

[Eduardo Valentin <edubezval-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Tue, Aug 26, 2014 at 10:17:29AM +0800, Wei Ni wrote:
> On 08/25/2014 07:07 PM, Eduardo Valentin wrote:
> > Hello Wei Ni,
> > 
> > On Mon, Aug 25, 2014 at 02:29:47PM +0800, Wei Ni wrote:
> >> Add more description for the "polling-delay" property.
> >> Set "trips" and "cooling maps" as optional property, because
> >> if missing these two sub-nodes, the thermal zone device still
> >> work properly.
> >>
> >> Signed-off-by: Wei Ni <wni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> >> ---
> >>  Documentation/devicetree/bindings/thermal/thermal.txt | 10 ++++++----
> >>  1 file changed, 6 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/thermal/thermal.txt b/Documentation/devicetree/bindings/thermal/thermal.txt
> >> index f5db6b7..e3d3ed9 100644
> >> --- a/Documentation/devicetree/bindings/thermal/thermal.txt
> >> +++ b/Documentation/devicetree/bindings/thermal/thermal.txt
> >> @@ -136,8 +136,8 @@ containing trip nodes and one sub-node containing all the zone cooling maps.
> >>  
> >>  Required properties:
> >>  - polling-delay:	The maximum number of milliseconds to wait between polls
> >> -  Type: unsigned	when checking this thermal zone.
> >> -  Size: one cell
> >> +  Type: unsigned	when checking this thermal zone. If this value is 0, the
> >> +  Size: one cell	driver will not run polling queue, but just cancel it.
> >>  
> > 
> > The description above is specific to Linux kernel implementation
> > nomenclature. DT description needs to be OS agnostic.
> > 
> >>  - polling-delay-passive: The maximum number of milliseconds to wait
> >>    Type: unsigned	between polls when performing passive cooling.
> >> @@ -148,14 +148,16 @@ Required properties:
> >>    phandles + sensor
> >>    specifier
> >>  
> >> +Optional property:
> >>  - trips:		A sub-node which is a container of only trip point nodes
> >>    Type: sub-node	required to describe the thermal zone.
> >>  
> >>  - cooling-maps:		A sub-node which is a container of only cooling device
> >>    Type: sub-node	map nodes, used to describe the relation between trips
> >> -			and cooling devices.
> >> +			and cooling devices. If missing the "trips" property,
> >> +			This sub-node will not be parsed, because no trips can
> >> +			be bound to cooling devices.
> > 
> > Do you mean if the thermal zone misses the "trips" property? Actually,
> > the binding describes both, cooling-maps and trips, as required
> > properties. Thus, both needs to be in place to consider the thermal zone
> > as a proper described zone.
> 
> I moved the "trips" and "cooling-maps" to optional property, because if
> missing these two properties, the thermal zone devices still can be
> registered, and the driver can work properly, it has the basic function,
> can read temperature from thermal sysfs, although it doesn't have trips
> and bind with cooling devices.


If a thermal zone is used only for monitoring, then I believe it lost
its purpose. As  Maybe a different framework shall be used, such as hwmon,
for instance?

The purpose of a thermal zone is to describe thermal behavior of a
hardware. As it is mentioned in the thermal.txt file.


> 
> Thanks.
> Wei.
> 
> > 
> >>  
> >> -Optional property:
> >>  - coefficients:		An array of integers (one signed cell) containing
> >>    Type: array		coefficients to compose a linear relation between
> >>    Elem size: one cell	the sensors listed in the thermal-sensors property.
> >> -- 
> >> 1.8.1.5
> >>
>