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| author | Len Brown <len.brown@intel.com> | 2012-10-09 07:35:52 +0200 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2012-10-09 07:35:52 +0200 |
| commit | 29b19e250434c6193c8b8e4c34c9c6284dd4f101 (patch) | |
| tree | 8a1c8e308c9ae964f7fb612e921e10cf4c30ba15 /Documentation/thermal/exynos_thermal | |
| parent | idr: rename MAX_LEVEL to MAX_IDR_LEVEL (diff) | |
| parent | thermal: Exynos: Fix NULL pointer dereference in exynos_unregister_thermal() (diff) | |
| download | linux-29b19e250434c6193c8b8e4c34c9c6284dd4f101.tar.xz linux-29b19e250434c6193c8b8e4c34c9c6284dd4f101.zip | |
Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux into thermal
Conflicts:
drivers/staging/omap-thermal/omap-thermal-common.
OMAP supplied dummy TC1 and TC2,
at the same time that the thermal tree removed them
from thermal_zone_device_register()
drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
propogate the upstream MAX_IDR_LEVEL re-name
to prevent a build failure
Previously-fixed-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'Documentation/thermal/exynos_thermal')
| -rw-r--r-- | Documentation/thermal/exynos_thermal | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/Documentation/thermal/exynos_thermal b/Documentation/thermal/exynos_thermal new file mode 100644 index 000000000000..2b46f67b1ccb --- /dev/null +++ b/Documentation/thermal/exynos_thermal @@ -0,0 +1,52 @@ +Kernel driver exynos4_tmu +================= + +Supported chips: +* ARM SAMSUNG EXYNOS4 series of SoC + Prefix: 'exynos4-tmu' + Datasheet: Not publicly available + +Authors: Donggeun Kim <dg77.kim@samsung.com> + +Description +----------- + +This driver allows to read temperature inside SAMSUNG EXYNOS4 series of SoC. + +The chip only exposes the measured 8-bit temperature code value +through a register. +Temperature can be taken from the temperature code. +There are three equations converting from temperature to temperature code. + +The three equations are: + 1. Two point trimming + Tc = (T - 25) * (TI2 - TI1) / (85 - 25) + TI1 + + 2. One point trimming + Tc = T + TI1 - 25 + + 3. No trimming + Tc = T + 50 + + Tc: Temperature code, T: Temperature, + TI1: Trimming info for 25 degree Celsius (stored at TRIMINFO register) + Temperature code measured at 25 degree Celsius which is unchanged + TI2: Trimming info for 85 degree Celsius (stored at TRIMINFO register) + Temperature code measured at 85 degree Celsius which is unchanged + +TMU(Thermal Management Unit) in EXYNOS4 generates interrupt +when temperature exceeds pre-defined levels. +The maximum number of configurable threshold is four. +The threshold levels are defined as follows: + Level_0: current temperature > trigger_level_0 + threshold + Level_1: current temperature > trigger_level_1 + threshold + Level_2: current temperature > trigger_level_2 + threshold + Level_3: current temperature > trigger_level_3 + threshold + + The threshold and each trigger_level are set + through the corresponding registers. + +When an interrupt occurs, this driver notify kernel thermal framework +with the function exynos4_report_trigger. +Although an interrupt condition for level_0 can be set, +it can be used to synchronize the cooling action. |