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author | Lee Jones <lee.jones@linaro.org> | 2012-01-12 12:50:11 +0000 |
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committer | Lee Jones <lee.jones@linaro.org> | 2012-01-12 12:50:11 +0000 |
commit | 72108d578689febd3579bf16be470328ded6c6d9 (patch) | |
tree | cc36ad5306ce823f8e98956c8f048f48017be3cc /Documentation/hwmon/exynos4_tmu | |
parent | 330f78a83c1f47055427e10a68733af77b2cbac8 (diff) | |
parent | 2150f72fe35397cc6d6ce39866bd0462cfbcc916 (diff) |
Automatically merging tracking-igloo_kernel-other into merging-stable-linaro-ux500-3.1stable-linaro-ux500-3.1
Conflicting files:
Diffstat (limited to 'Documentation/hwmon/exynos4_tmu')
-rw-r--r-- | Documentation/hwmon/exynos4_tmu | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/Documentation/hwmon/exynos4_tmu b/Documentation/hwmon/exynos4_tmu new file mode 100644 index 00000000000..c3c6b41db60 --- /dev/null +++ b/Documentation/hwmon/exynos4_tmu @@ -0,0 +1,81 @@ +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 user space of +one of four threshold levels for the interrupt +through kobject_uevent_env and sysfs_notify functions. +Although an interrupt condition for level_0 can be set, +it is not notified to user space through sysfs_notify function. + +Sysfs Interface +--------------- +name name of the temperature sensor + RO + +temp1_input temperature + RO + +temp1_max temperature for level_1 interrupt + RO + +temp1_crit temperature for level_2 interrupt + RO + +temp1_emergency temperature for level_3 interrupt + RO + +temp1_max_alarm alarm for level_1 interrupt + RO + +temp1_crit_alarm + alarm for level_2 interrupt + RO + +temp1_emergency_alarm + alarm for level_3 interrupt + RO |