cpufreq: exynos: Convert exynos-cpufreq to platform driver

To make the driver multiplatform-friendly, unconditional initialization
in an initcall is replaced with a platform driver probed only if
respective platform device is registered.

Tested at: Exynos4210 (TRATS) and Exynos4412 (TRATS2)

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Sachin Kamat <sachin.kamat@linaro.org>
Tested-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/arch/arm/mach-exynos/common.c b/arch/arm/mach-exynos/common.c
index 61d2906..1510436 100644
--- a/arch/arm/mach-exynos/common.c
+++ b/arch/arm/mach-exynos/common.c
@@ -303,6 +303,11 @@
 	platform_device_register(&exynos_cpuidle);
 }
 
+void __init exynos_cpufreq_init(void)
+{
+	platform_device_register_simple("exynos-cpufreq", -1, NULL, 0);
+}
+
 void __init exynos_init_late(void)
 {
 	if (of_machine_is_compatible("samsung,exynos5440"))
diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h
index ff9b6a9..3f03334 100644
--- a/arch/arm/mach-exynos/common.h
+++ b/arch/arm/mach-exynos/common.h
@@ -22,6 +22,7 @@
 void exynos4_restart(enum reboot_mode mode, const char *cmd);
 void exynos5_restart(enum reboot_mode mode, const char *cmd);
 void exynos_cpuidle_init(void);
+void exynos_cpufreq_init(void);
 void exynos_init_late(void);
 
 void exynos_firmware_init(void);
diff --git a/arch/arm/mach-exynos/mach-exynos4-dt.c b/arch/arm/mach-exynos/mach-exynos4-dt.c
index 4603e6b..d3e54b7 100644
--- a/arch/arm/mach-exynos/mach-exynos4-dt.c
+++ b/arch/arm/mach-exynos/mach-exynos4-dt.c
@@ -22,6 +22,7 @@
 static void __init exynos4_dt_machine_init(void)
 {
 	exynos_cpuidle_init();
+	exynos_cpufreq_init();
 
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }
diff --git a/arch/arm/mach-exynos/mach-exynos5-dt.c b/arch/arm/mach-exynos/mach-exynos5-dt.c
index 1fe075a..602c5d7 100644
--- a/arch/arm/mach-exynos/mach-exynos5-dt.c
+++ b/arch/arm/mach-exynos/mach-exynos5-dt.c
@@ -44,6 +44,7 @@
 	}
 
 	exynos_cpuidle_init();
+	exynos_cpufreq_init();
 
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }