On Tue, Mar 12, 2019 at 12:56:22PM +0100, Krzysztof Kozlowski wrote:
commit 28928a3ce142b2e4e5a7a0f067cefb41a3d2c3f9 upstream.
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 exynos4412 with one change - the samsung,tmu_min_efuse_value.
Signed-off-by: Krzysztof Kozlowski krzk@kernel.org Acked-by: Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com Acked-by: Eduardo Valentin edubezval@gmail.com Reviewed-by: Javier Martinez Canillas javier@osg.samsung.com Tested-by: Javier Martinez Canillas javier@osg.samsung.com Reviewed-by: Anand Moon linux.amoon@gmail.com Tested-by: Anand Moon linux.amoon@gmail.com
arch/arm/boot/dts/exynos5420-tmu-sensor-conf.dtsi | 25 +++++++++++++++++++++++ arch/arm/boot/dts/exynos5420.dtsi | 10 ++++----- 2 files changed, 30 insertions(+), 5 deletions(-) create mode 100644 arch/arm/boot/dts/exynos5420-tmu-sensor-conf.dtsi
this backport does not apply to 4.9.y, but only 4.4.y. Can you also send a 4.9.y backport so that someone moving from 4.4.y to 4.9.y does not get a regression?
thanks,
greg k-h