drivers: soc: Add support for Exynos PMU driver

This patch moves Exynos PMU driver implementation from "arm/mach-exynos"
to "drivers/soc/samsung". This driver is mainly used for setting misc
bits of register from PMU IP of Exynos SoC which will be required to
configure before Suspend/Resume. Currently all these settings are done
in "arch/arm/mach-exynos/pmu.c" but moving ahead for ARM64 based SoC
support, there is a need of this PMU driver in driver/* folder.

This driver uses existing DT binding information and there should
be no functionality change in the supported platforms.

Signed-off-by: Amit Daniel Kachhap <[e-mail]>
[tested on Peach-Pi (Exynos5880)]
Signed-off-by: Pankaj Dubey <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
[for testing on Trats2 (Exynos4412) and Odroid XU3 (Exynos5422)]
Tested-by: Krzysztof Kozlowski <[e-mail]>
[k.kozlowski: Rebased, add necessary infrastructure for building and
selecting drivers/soc because original patchset was on top of movement
SROMc to drivers/soc]
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

arch/arm/mach-exynos/Kconfig

···
 	select ARM_GIC
 	select COMMON_CLK_SAMSUNG
 	select EXYNOS_THERMAL
+	select EXYNOS_PMU
 	select HAVE_ARM_SCU if SMP
 	select HAVE_S3C2410_I2C if I2C
 	select HAVE_S3C2410_WATCHDOG if WATCHDOG
···
 	select PINCTRL_EXYNOS
 	select PM_GENERIC_DOMAINS if PM
 	select S5P_DEV_MFC
+	select SOC_SAMSUNG
 	select SRAM
 	select THERMAL
 	select MFD_SYSCON

arch/arm/mach-exynos/Makefile

···
 
 # Core
 
-obj-$(CONFIG_ARCH_EXYNOS)	+= exynos.o pmu.o exynos-smc.o firmware.o \
-					exynos3250-pmu.o exynos4-pmu.o \
-					exynos5250-pmu.o exynos5420-pmu.o
+obj-$(CONFIG_ARCH_EXYNOS)	+= exynos.o exynos-smc.o firmware.o
 
 obj-$(CONFIG_EXYNOS_CPU_SUSPEND) += pm.o sleep.o
 obj-$(CONFIG_PM_SLEEP)		+= suspend.o

drivers/soc/Kconfig

···
 source "drivers/soc/mediatek/Kconfig"
 source "drivers/soc/qcom/Kconfig"
 source "drivers/soc/rockchip/Kconfig"
+source "drivers/soc/samsung/Kconfig"
 source "drivers/soc/sunxi/Kconfig"
 source "drivers/soc/tegra/Kconfig"
 source "drivers/soc/ti/Kconfig"

drivers/soc/Makefile

···
 obj-$(CONFIG_ARCH_MEDIATEK)	+= mediatek/
 obj-$(CONFIG_ARCH_QCOM)		+= qcom/
 obj-$(CONFIG_ARCH_ROCKCHIP)		+= rockchip/
+obj-$(CONFIG_SOC_SAMSUNG)	+= samsung/
 obj-$(CONFIG_ARCH_SUNXI)	+= sunxi/
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-$(CONFIG_SOC_TI)		+= ti/

drivers/soc/samsung/Kconfig

···
+#
+# SAMSUNG SoC drivers
+#
+menu "Samsung SOC driver support"
+
+config SOC_SAMSUNG
+	bool
+
+config EXYNOS_PMU
+	bool
+	depends on ARM && ARCH_EXYNOS
+
+endmenu

drivers/soc/samsung/Makefile

···
+obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o exynos3250-pmu.o exynos4-pmu.o \
+					exynos5250-pmu.o exynos5420-pmu.o