Re: [PATCH] ARM: dts: exynos: Use thermal fuse value for thermal zone 0 on Exynos5420

Krzysztof Kozlowski
2017-02-13T11:59:53Z

On Mon, Feb 13, 2017 at 1:38 PM, Anand Moon <linux.amoon@gmail.com> wrote:
> Hi Krzysztof,
>
>
>
> On 12 February 2017 at 01:44, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>> In Odroid XU3 Lite board, the temperature levels reported for thermal
>> zone 0 were weird. In warm room:
>> /sys/class/thermal/thermal_zone0/temp:32000
>> /sys/class/thermal/thermal_zone1/temp:51000
>> /sys/class/thermal/thermal_zone2/temp:55000
>> /sys/class/thermal/thermal_zone3/temp:54000
>> /sys/class/thermal/thermal_zone4/temp:51000
>>
>> Sometimes after booting the value was even equal to ambient temperature
>> which is highly unlikely to be a real temperature of sensor in SoC.
>>
>> The thermal sensor's calibration (trimming) is based on fused values.
>> In case of the board above, the fused values are: 35, 52, 43, 58 and 43
>> (corresponding to each TMU device). However driver defined a minimum value
>> for fused data as 40 and for smaller values it was using a hard-coded 55
>> instead. This lead to mapping data from sensor to wrong temperatures
>> for thermal zone 0.
>>
>> Various vendor 3.10 trees (Hardkernel's based on Samsung LSI, Artik 10)
>> do not impose any limits on fused values. Since we do not have any
>> knowledge about these limits, use 0 as a minimum accepted fused value.
>> This should essentially allow accepting any reasonable fused value thus
>> behaving like vendor driver.
>>
>
> On HK following values are define in drivers/thermal/exynos_thermal.c
>
> #define EFUSE_MIN_VALUE 40
> #define EFUSE_MAX_VALUE 100

Are they being used?

Best regards,
Krzysztof