Hello Krzysztof, On 02/11/2017 05:14 PM, Krzysztof Kozlowski 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. > > The exynos5420-tmu-sensor-conf.dtsi is copied directly from existing > exynso4412 with one change - the samsung,tmu_min_efuse_value. > > Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx> > > --- > > Testing on other Exynos542x boards is much appreciated. Especially I > wonder what efuse values are there. I tested on both Exynos5422 Odroid XU4 and Exynos5800 Peach Pi boards. The temperatures levels reported for these two boards on a warm room are: Odroid XU4 # cat /sys/class/thermal/thermal_zone*/temp 50000 50000 54000 51000 48000 Peach Pi # cat /sys/class/thermal/thermal_zone*/temp 42000 44000 27000 <-- weird value for thermal zone 2 like zone 0 in your XU3 lite 45000 45000 And the efuse values for the TMU devices are: Odroid XU4 TMU0 = 45 TMU1 = 44 TMU2 = 44 TMU3 = 46 TMU3 = 46 Peach Pi TMU0 = 44 TMU1 = 46 TMU2 = 36 TMU3 = 53 TMU3 = 46 The fused value for TMU2 is < 40 so that explains the weird temperature level for thermal zone 2 in Peach. So after your patch, makes more sense: # cat /sys/class/thermal/thermal_zone*/temp 41000 42000 45000 43000 43000 I wonder though if 0 is the best value or if we should just lower more to cover the used e-fuse values in Exynos5 boards. But as you said, we have no knowledge about these limits... Reviewed-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx> Tested-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx> Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
