Re: [PATCH v3 00/16] thermal: exynos: Thermal code rework to use device tree

Eduardo Valentin
2015-01-21T09:08:04Z

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On Thu, Jan 22, 2015 at 02:06:10AM +0100, Tobias Jakobi wrote:
> Hello!
>
>
> Lukasz Majewski wrote:
> >> The point is that I'm still working with a rather old version of the
> >> cpufreq series, a version which still had the Exynos4x12 code in it
> >> (this was removed later, if I remember correctly because of problems
> >> with how to properly describe boost configuration in DT).
> >
> > Is your board Odroid-U3/Trats2 ?
> It's an Odroid-X2, so pretty similar to the U3, except that it doesn't
> have any active cooling device.
>
>
> >> Anyway, to not get completly off-topic here, I noticed some small
> >> issue with v3 of the thermal series. I've enabled
> >> CONFIG_THERMAL_HWMON so that I can use lm_sensors to query
> >> temperature of the board. However while the thermal_zone is created,
> >> there is no hwmon node to be found.
> >
> > I'm not surprised, that some use cases (about which I wasn't even
> > aware) show up.
> > I've already fixed issues reported by Abhilash (with v5 and a following
> > patch) and look closer into the THERMAL_HWMON.
> The problem seems to be that of_parse_thermal_zones always sets
> 'no_hwmon' to true, so that thermal_zone_device_register never registers
> a hwmon device when the underlaying thermal zone is setup through DT. I
> don't understand the rationale behind this, even with the comment ('No
> hwmon because there might be hwmon drivers registering').
>

The reason is that hwmon sensor device drivers also register via of-thermal.
So, adding hwmon interface by default will create a cyclic problem.

Cheers,

>
> > I've also done some work regarding FAN controlled by hwmon for Odroid
> > U3.
> > Could you look on following series:
> > http://www.spinics.net/lists/linux-samsung-soc/msg40471.html
> >
> > I can only guess that your board might need similar entries for your
> > DTS file(s).
>
> Like I said, the X2 only has a passive heatsink, so no fan controlling here.
>
>
> With best wishes,
> Tobias
>

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