clk: samsung: Allow modular build of the Audio Subsystem CLKCON driver

Any clock dependencies can be properly handled with deferred probing
so we can remove core_initcall and switch to a proper loadable platform
driver module.
This change has been tested on Exynos4412 Odroid U3 based board.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/1467987300-31450-1-git-send-email-s.nawrocki@samsung.com

drivers/clk/samsung/Kconfig

@@ -9,6 +9,15 @@ config EXYNOS_ARM64_COMMON_CLK
 	bool "Samsung Exynos ARMv8-family clock controller support" if COMPILE_TEST
 	depends on COMMON_CLK_SAMSUNG
 
+config EXYNOS_AUDSS_CLK_CON
+	tristate "Samsung Exynos AUDSS clock controller support"
+	depends on COMMON_CLK_SAMSUNG
+	default y if ARCH_EXYNOS
+	help
+	  Support for the Audio Subsystem CLKCON clock controller present
+	  on some Exynos SoC variants. Choose M or Y here if you want to
+	  use audio devices such as I2S, PCM, etc.
+
 # For S3C24XX platforms, select following symbols:
 config S3C2410_COMMON_CLK
 	bool "Samsung S3C2410 clock controller support" if COMPILE_TEST

drivers/clk/samsung/Makefile

@@ -12,7 +12,7 @@ obj-$(CONFIG_SOC_EXYNOS5410)	+= clk-exynos5410.o
 obj-$(CONFIG_SOC_EXYNOS5420)	+= clk-exynos5420.o
 obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK)	+= clk-exynos5433.o
 obj-$(CONFIG_SOC_EXYNOS5440)	+= clk-exynos5440.o
-obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-audss.o
+obj-$(CONFIG_EXYNOS_AUDSS_CLK_CON) += clk-exynos-audss.o
 obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-clkout.o
 obj-$(CONFIG_EXYNOS_ARM64_COMMON_CLK)	+= clk-exynos7.o
 obj-$(CONFIG_S3C2410_COMMON_CLK)+= clk-s3c2410.o

drivers/clk/samsung/clk-exynos-audss.c

@@ -273,17 +273,7 @@ static struct platform_driver exynos_audss_clk_driver = {
 	.remove = exynos_audss_clk_remove,
 };
 
-static int __init exynos_audss_clk_init(void)
-{
-	return platform_driver_register(&exynos_audss_clk_driver);
-}
-core_initcall(exynos_audss_clk_init);
-
-static void __exit exynos_audss_clk_exit(void)
-{
-	platform_driver_unregister(&exynos_audss_clk_driver);
-}
-module_exit(exynos_audss_clk_exit);
+module_platform_driver(exynos_audss_clk_driver);
 
 MODULE_AUTHOR("Padmavathi Venna <padma.v@samsung.com>");
 MODULE_DESCRIPTION("Exynos Audio Subsystem Clock Controller");