Re: [PATCH v2 0/2] Add a generic virtual thermal sensor

[Alexandre Bailon]

On 9/17/21 4:03 PM, Daniel Lezcano wrote:
> On 17/09/2021 15:33, Alexandre Bailon wrote:
> > Hi Daniel,
> >
> > On 9/17/21 2:41 PM, Daniel Lezcano wrote:
> > > On 17/09/2021 09:27, Alexandre Bailon wrote:
> > > > This series add a virtual thermal sensor.
> > > > It could be used to get a temperature using some thermal sensors.
> > > > Currently, the supported operations are max, min and avg.
> > > > The virtual sensor could be easily extended to support others
> > > > operations.
> > > >
> > > > Note:
> > > > Currently, thermal drivers must explicitly register their sensors to
> > > > make them
> > > > available to the virtual sensor.
> > > > This doesn't seem a good solution to me and I think it would be
> > > > preferable to
> > > > update the framework to register the list of each available sensors.
> > > Why must the drivers do that ?
> > Because there are no central place where thermal sensor are registered.
> > The only other way I found was to update thermal_of.c,
> > to register the thermal sensors and make them available later to the
> > virtual thermal sensor.
> >
> > To work, the virtual thermal need to get the sensor_data the ops from
> > the thermal sensor.
> > And as far I know, this is only registered in thermal_of.c, in the
> > thermal zone data
> > but I can't access it directly from the virtual thermal sensor.
> >
> > How would you do it ?
> Via the phandles when registering the virtual sensor ?
As far I know, we can't get the ops or the sensor_data from the phandle 
of a thermal sensor.
The closest solution I found so far would be to aggregate the thermal 
zones instead of thermal sensors.
thermal_zone_device has the data needed and a thermal zone could be find 
easily using its name.

But, using a thermal_zone_device, I don't see how to handle module 
unloading.

Thanks,
Alexandre
> Or is the problem you are mentioning related to the sensor module
> loading after the virtual sensor ?