Hi Biju,
On 2021-11-17 08:55:15 +0000, Biju Das wrote:
> Another separate question, I have in my mind is how do we test trip
> points
> for negative temperature?
I think this is two different questions.
> This TSU doesn't have any interrupts and
> we need to use polling, The range is -40 to 125 degrees.
For tripping a trip-point polling or interrupt works. The only
difference is in the worst case polling will detect that i past the
trop-point <pollig-delay> later. For testing triggering of trippoints
(high or low) I don't think we need to care about this.
To actually test it we have two options.
1. Put the SoC in a good freezer and, alternately open an office branch
in the arctics :-)
2. Use the thermal emulation framework.
echo $temprature_in_mcelcius > /sys/class/thermal/$zone/emul_temp
If the temperature set using this is above/below a trippoint the
associated action will happen. A good demo of this is to try on Gen3
where you can observe the cooling device state changes as the
different trip points are triggerd in:
/sys/class/thermal/$cool/cur_state
And of course if you set a temperature that trips the critical point
the system will shutdown.
> If it goes below -40, I guess we need to shutdown the system.
> On device tree we normally specify only positive temperature.
> How do we handle this?
I have not tested it but would it not be as simple as adding a second
critical trippoint at -40 ?
--
Kind Regards,
Niklas Söderlund
