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development kernel and soc temperture sensor


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I know one should't ask or complain here regarding the dev kernel branch, but maybe somebody of you stumbled upon this and knows where to point me:

I successfully build and used the "dev" kernel several times for the BananaPi (Allwinner A20 Soc) and it works just fine. The patch regarding the axp209 sysfs interface can simply be taken over from the from the "next" kernel branch and you get a working temperture reading from the axp209 pmu.

I still haven't managed to get the internal soc's temperature sensor working in dev kernel, though. I know it has something to do with the touchscreen driver but couldn't find out what exactly is required to make it work. Can anybody please point me in the right direction? Right now I am pretty much lost and dont know where to look in the sources.



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6 minutes ago, martinayotte said:

Euuhh ??? temp sensor as nothing to do with touchscreen driver, especially that most boards don't have them ...

On A20 TSADC is used as a temperature sensor, and, in fact, on newer SoCs GPADC can be used for resistive touchscreens too.




 * The Allwinner SoCs all have an ADC that can also act as a touchscreen
 * controller and a thermal sensor.
 * The thermal sensor works only when the ADC acts as a touchscreen controller
 * and is configured to throw an interrupt every fixed periods of time (let say
 * every X seconds).



Regarding the dev kernel - its configuration is not maintained so it's probably broken due to thermal sensor migration from touch screen driver to the IIO subsystem.

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Thanks, at least I know now where to look. Will let you know when I make substantial progress.


Edit: Yeah, it was that easy. I simply had to select the corresponding option in kernel config. It can be found under /DeviceDrivers/IndustrialIO/ADC/sun4i-gpadc-iio.


Everything is running just fine under 4.14-rc3! Thanks a lot, Zador!

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