Re: [PATCH] thermal: ti-soc-thermal: Fix bogus thermal shutdowns for omap4430

From: Pavel Machek
Date: Sun Aug 23 2020 - 17:12:20 EST


Hi!

> We can sometimes get bogus thermal shutdowns on omap4430 at least with
> droid4 running idle with a battery charger connected:
>
> thermal thermal_zone0: critical temperature reached (143 C), shutting down
>
> Dumping out the register values shows we can occasionally get a 0x7f value
> that is outside the TRM listed values in the ADC conversion table. And then
> we get a normal value when reading again after that. Reading the register
> multiple times does not seem help avoiding the bogus values as they stay
> until the next sample is ready.
>
> Looking at the TRM chapter "18.4.10.2.3 ADC Codes Versus Temperature", we
> should have values from 13 to 107 listed with a total of 95 values. But
> looking at the omap4430_adc_to_temp array, the values are off, and the
> end values are missing. And it seems that the 4430 ADC table is similar
> to omap3630 rather than omap4460.
>
> Let's fix the issue by using values based on the omap3630 table and just
> ignoring invalid values. Compared to the 4430 TRM, the omap3630 table has
> the missing values added while the TRM table only shows every second
> value.
>
> Note that sometimes the ADC register values within the valid table can
> also be way off for about 1 out of 10 values. But it seems that those
> just show about 25 C too low values rather than too high values. So those
> do not cause a bogus thermal shutdown.

This does not seem to be in recent -next. Ping?

Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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