On Tue, Dec 13, 2016 at 03:33:30PM +0100, Quentin Schulz wrote: > This enables CONFIG_THERMAL_OF by default for sunxi_defconfig. It is > required to get Allwinner SoCs' temperature from the GPADC driver. > > The Allwinner SoCs all have an ADC that can also act as a touchscreen > controller and a thermal sensor. The first four channels can be used > either for the ADC or the touchscreen and the fifth channel is used for > the thermal sensor. > > The thermal sensor requires the IP to be in touchscreen mode to return > correct values. Therefore, if the user is continuously reading the ADC > channel(s), the thermal framework in which the thermal sensor is > registered will switch the IP in touchscreen mode to get a temperature > value and requires a delay of 100ms (because of the mode switching), > then the ADC will switch back to ADC mode and requires also a delay of > 100ms. If the ADC readings are critical to user and the SoC temperature > is not, the GPADC driver is capable of not registering the thermal > sensor in the thermal framework and thus, "quicken" the ADC readings. In > most use cases, the SoC temperature is more critical (for cpu throttling > for example or activating cooling devices) than ADC readings, thus it is > now enabled by default. > > Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx> Applied, thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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