cpufreq: brcmstb-avs-cpufreq: AVS CPUfreq driver for Broadcom STB SoCs

This driver supports voltage and frequency scaling on Broadcom STB SoCs
using AVS firmware with DFS and DVFS support.

Actual frequency or voltage scaling is done exclusively by the AVS
firmware. The driver merely provides a standard CPUfreq interface to
other kernel components and userland, and instructs the AVS firmware to
perform frequency or voltage changes on its behalf.
Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

MAINTAINERS

@@ -2744,6 +2744,7 @@ M:	bcm-kernel-feedback-list@broadcom.com
 L:	linux-pm@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/cpufreq/brcm,stb-avs-cpu-freq.txt
+F:	drivers/cpufreq/brcmstb*
 
 BROADCOM SPECIFIC AMBA DRIVER (BCMA)
 M:	Rafał Miłecki <zajec5@gmail.com>

drivers/cpufreq/Kconfig.arm

@@ -12,6 +12,17 @@ config ARM_BIG_LITTLE_CPUFREQ
 	help
 	  This enables the Generic CPUfreq driver for ARM big.LITTLE platforms.
 
+config ARM_BRCMSTB_AVS_CPUFREQ
+	tristate "Broadcom STB AVS CPUfreq driver"
+	depends on ARCH_BRCMSTB || COMPILE_TEST
+	default y
+	help
+	  Some Broadcom STB SoCs use a co-processor running proprietary firmware
+	  ("AVS") to handle voltage and frequency scaling. This driver provides
+	  a standard CPUfreq interface to to the firmware.
+
+	  Say Y, if you have a Broadcom SoC with AVS support for DFS or DVFS.
+
 config ARM_DT_BL_CPUFREQ
 	tristate "Generic probing via DT for ARM big LITTLE CPUfreq driver"
 	depends on ARM_BIG_LITTLE_CPUFREQ && OF

drivers/cpufreq/Makefile

@@ -51,6 +51,7 @@ obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ)	+= arm_big_little.o
 # LITTLE drivers, so that it is probed last.
 obj-$(CONFIG_ARM_DT_BL_CPUFREQ)		+= arm_big_little_dt.o
 
+obj-$(CONFIG_ARM_BRCMSTB_AVS_CPUFREQ)	+= brcmstb-avs-cpufreq.o
 obj-$(CONFIG_ARCH_DAVINCI)		+= davinci-cpufreq.o
 obj-$(CONFIG_UX500_SOC_DB8500)		+= dbx500-cpufreq.o
 obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ)	+= exynos5440-cpufreq.o