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

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Message-ID: <d359b309-7fa2-5089-df14-e27eafed96d1@linaro.org>
Date:   Mon, 24 Aug 2020 12:45:44 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Pavel Machek <pavel@....cz>, Tony Lindgren <tony@...mide.com>
Cc:     Eduardo Valentin <edubezval@...il.com>, Keerthy <j-keerthy@...com>,
        Zhang Rui <rui.zhang@...el.com>,
        Amit Kucheria <amit.kucheria@...durent.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-omap@...r.kernel.org, Merlijn Wajer <merlijn@...zup.org>,
        Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH] thermal: ti-soc-thermal: Fix bogus thermal shutdowns for
 omap4430

On 23/08/2020 23:12, Pavel Machek wrote:
> 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?

Pong.

Going back from vacation. Will be in next very soon.


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