cpufreq / boost: Kconfig: Support for software-managed BOOST

Add CONFIG_CPU_FREQ_BOOST_SW Kconfig option such that software-managed
boost is enabled only after selecting "EXYNOS Frequency Overclocking -
Software".  It also depends on the thermal subsystem to be compiled in,
which is necessary for disabling boost and cooling down the device when
overheating is detected.

Software-managed boost _MUST_ _NOT_ be enabled without thermal subsystem
with properly defined overheating temperature thresholds.

This option doesn't affect the x86's hardware-driven boost support
in the acpi-cpufreq driver.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/Kconfig

@@ -20,6 +20,10 @@ if CPU_FREQ
 config CPU_FREQ_GOV_COMMON
 	bool
 
+config CPU_FREQ_BOOST_SW
+	bool
+	depends on THERMAL
+
 config CPU_FREQ_STAT
 	tristate "CPU frequency translation statistics"
 	default y

drivers/cpufreq/Kconfig.arm

@@ -66,6 +66,21 @@ config ARM_EXYNOS5440_CPUFREQ
 
 	  If in doubt, say N.
 
+config ARM_EXYNOS_CPU_FREQ_BOOST_SW
+	bool "EXYNOS Frequency Overclocking - Software"
+	depends on ARM_EXYNOS_CPUFREQ
+	select CPU_FREQ_BOOST_SW
+	select EXYNOS_THERMAL
+	help
+	  This driver supports software managed overclocking (BOOST).
+	  It allows usage of special frequencies for Samsung Exynos
+	  processors if thermal conditions are appropriate.
+
+	  It reguires, for safe operation, thermal framework with properly
+	  defined trip points.
+
+	  If in doubt, say N.
+
 config ARM_HIGHBANK_CPUFREQ
 	tristate "Calxeda Highbank-based"
 	depends on ARCH_HIGHBANK