Re: [PATCH] thermal: rcar_gen3_thermal: Do not use interrupts for normal operation

[Daniel Lezcano <daniel.lezcano@linaro.org>]

On 30/11/2020 12:49, Niklas Söderlund wrote:
> Hi Daniel,
> 
> Thanks for your comments.
> 
> On 2020-11-30 09:15:00 +0100, Daniel Lezcano wrote:
>> On 26/11/2020 23:09, Niklas Söderlund wrote:
>>> Remove the usage of interrupts for the normal temperature operation and
>>> depend on the polling performed by the thermal core. This is done to
>>> prepare to use the interrupts as they are intended to trigger once
>>> specific trip points are passed and not to react to temperature changes
>>> in the normal operational range.
>>
>> I'm not sure to understand the change. Is it not more interesting to
>> have the polling mode disabled for PM reasons and let the interrupt to
>> fire at the first trip point so the mitigation happens then with the
>> polling passive ?
> 
> I agree and this is one of two goals I have with this change, in the 
> long run. The other is to be able support SoC models where the 
> interrupts may not be accessible.
> 
> The change in this patch is to stop using the interrupts to fire as soon 
> as the temp moves +/- 1 degree C, see rcar_gen3_thermal_update_range().  
> When I wrote that code I had misunderstood how things should be done and 
> thought I should use the interrupts as a substitute to the polling done 
> by the core and generate a THERMAL_EVENT_UNSPECIFIED as soon as the temp 
> changed, see rcar_gen3_thermal_irq().
> 
> The way I understand it today is that I should instead setup the 
> interrupts to fire if the temp moves over a trip point, in my case 
> described in DT to allow the system to be informed of this as you 
> describe above.
> 
> In this firs change I'm simply removing my incorrect usage of interrupts 
> that I in future changes will add back in an correct usage pattern while 
> at the same time making interrupts optional to support SoCs where the 
> may not be available.
> 
> Does this make sens or have I got the idea wrong?

Ah, ok. I understand better now, thanks for the clarification.

The interrupt mode implementation is wrong, so you remove it and switch
to the polling mode until the interrupt is re-implemented in the correct
way.



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