[PATCH V2 19/20] Documentation: thermal: Explain the exynos thermal driver model

Amit Daniel Kachhap
2013-04-26T10:39:40Z

This patch updates the documentation to explain the driver model
and file layout.

Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
---
Documentation/thermal/exynos_thermal | 43 ++++++++++++++++++++++++++-------
1 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/Documentation/thermal/exynos_thermal b/Documentation/thermal/exynos_thermal
index 2b46f67..9010c44 100644
--- a/Documentation/thermal/exynos_thermal
+++ b/Documentation/thermal/exynos_thermal
@@ -1,17 +1,17 @@
-Kernel driver exynos4_tmu
+Kernel driver exynos_tmu
=================

Supported chips:
-* ARM SAMSUNG EXYNOS4 series of SoC
- Prefix: 'exynos4-tmu'
+* ARM SAMSUNG EXYNOS4, EXYNOS5 series of SoC
Datasheet: Not publicly available

Authors: Donggeun Kim <dg77.kim@samsung.com>
+Authors: Amit Daniel <amit.daniel@samsung.com>

-Description
------------
+TMU controller Description:
+---------------------------

-This driver allows to read temperature inside SAMSUNG EXYNOS4 series of SoC.
+This driver allows to read temperature inside SAMSUNG EXYNOS4/5 series of SoC.

The chip only exposes the measured 8-bit temperature code value
through a register.
@@ -34,9 +34,9 @@ The three equations are:
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
+TMU(Thermal Management Unit) in EXYNOS4/5 generates interrupt
when temperature exceeds pre-defined levels.
-The maximum number of configurable threshold is four.
+The maximum number of configurable threshold is five.
The threshold levels are defined as follows:
Level_0: current temperature > trigger_level_0 + threshold
Level_1: current temperature > trigger_level_1 + threshold
@@ -47,6 +47,31 @@ The threshold levels are defined as follows:
through the corresponding registers.

When an interrupt occurs, this driver notify kernel thermal framework
-with the function exynos4_report_trigger.
+with the function exynos_report_trigger.
Although an interrupt condition for level_0 can be set,
it can be used to synchronize the cooling action.
+
+TMU driver description:
+-----------------------
+
+The exynos thermal driver is structured as,
+
+ Kernel Core thermal framework
+ (thermal_core.c, step_wise.c, cpu_cooling.c)
+ ^
+ |
+ |
+TMU configuration data -------> TMU Driver <------> Exynos Core thermal wrapper
+(exynos_tmu_data.c) (exynos_tmu.c) (exynos_thermal_common.c)
+(exynos_tmu_data.h) (exynos_tmu.h) (exynos_thermal_common.h)
+
+a) TMU configuration data: This consist of TMU register offsets/bitfields
+ described through structure exynos_tmu_registers. Also several
+ other platform data (struct exynos_tmu_platform_data) members
+ are used to configure the TMU.
+b) TMU driver: This component initialises the TMU controller and sets different
+ thresholds. It invokes core thermal implementation with the call
+ exynos_report_trigger.
+c) Exynos Core thermal wrapper: This provides 3 wrapper function to use the
+ Kernel core thermal framework. They are exynos_unregister_thermal,
+ exynos_register_thermal and exynos_report_trigger.
--
1.7.1