PM / devfreq: tegra: add devfreq driver for Tegra Activity Monitor

The ACTMON block can monitor several counters, providing averaging and firing
interrupts based on watermarking configuration. This implementation monitors
the MCALL and MCCPU counters to choose an appropriate frequency for the
external memory clock.

This patch is based on work by Alex Frid <afrid@nvidia.com> and Mikko
Perttunen <mikko.perttunen@kapsi.fi>.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/Kconfig

@@ -87,4 +87,14 @@ config ARM_EXYNOS5_BUS_DEVFREQ
 	  It reads PPMU counters of memory controllers and adjusts the
 	  operating frequencies and voltages with OPP support.
 
+config ARM_TEGRA_DEVFREQ
+       tristate "Tegra DEVFREQ Driver"
+       depends on ARCH_TEGRA_124_SOC
+       select DEVFREQ_GOV_SIMPLE_ONDEMAND
+       select PM_OPP
+       help
+         This adds the DEVFREQ driver for the Tegra family of SoCs.
+         It reads ACTMON counters of memory controllers and adjusts the
+         operating frequencies and voltages with OPP support.
+
 endif # PM_DEVFREQ

drivers/devfreq/Makefile

@@ -7,3 +7,4 @@ obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
 # DEVFREQ Drivers
 obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos/
 obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ)	+= exynos/
+obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra-devfreq.o