soc: samsung: exynos-chipid: convert to a module

Exynos ChipID and ASV (Adaptive Supply Voltage) driver is not essential
to system boot and it can successfully be built and loaded as module.

This makes core kernel image smaller and reduces the memory footprint
when multi-platform kernel is booted on non-Exynos board.  Usually it is
also distro-friendly.

Add multiple authors of the driver since its conversion from
mach-exynos, ordered alphabetically by first name.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Sylwester Nawrocki <snawrocki@kernel.org>
Tested-by: Sylwester Nawrocki <snawrocki@kernel.org>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Tested-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20210919093114.35987-3-krzysztof.kozlowski@canonical.com

drivers/soc/samsung/Kconfig

@@ -13,13 +13,14 @@ config EXYNOS_ASV_ARM
 	depends on EXYNOS_CHIPID
 
 config EXYNOS_CHIPID
-	bool "Exynos ChipID controller and ASV driver" if COMPILE_TEST
+	tristate "Exynos ChipID controller and ASV driver" if COMPILE_TEST
 	depends on ARCH_EXYNOS || COMPILE_TEST
 	select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
 	select MFD_SYSCON
 	select SOC_BUS
 	help
 	  Support for Samsung Exynos SoC ChipID and Adaptive Supply Voltage.
+	  This driver can also be built as module (exynos_chipid).
 
 config EXYNOS_PMU
 	bool "Exynos PMU controller driver" if COMPILE_TEST

drivers/soc/samsung/Makefile

 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_EXYNOS_ASV_ARM)	+= exynos5422-asv.o
+obj-$(CONFIG_EXYNOS_CHIPID)	+= exynos_chipid.o
+exynos_chipid-y			+= exynos-chipid.o exynos-asv.o
 
-obj-$(CONFIG_EXYNOS_CHIPID)	+= exynos-chipid.o exynos-asv.o
 obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o
 
 obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)	+= exynos3250-pmu.o exynos4-pmu.o \

drivers/soc/samsung/exynos-chipid.c

@@ -15,6 +15,7 @@
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/mfd/syscon.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
@@ -128,6 +129,7 @@ static const struct of_device_id exynos_chipid_of_device_ids[] = {
 	{ .compatible = "samsung,exynos4210-chipid" },
 	{}
 };
+MODULE_DEVICE_TABLE(of, exynos_chipid_of_device_ids);
 
 static struct platform_driver exynos_chipid_driver = {
 	.driver = {
@@ -137,4 +139,11 @@ static struct platform_driver exynos_chipid_driver = {
 	.probe	= exynos_chipid_probe,
 	.remove	= exynos_chipid_remove,
 };
-builtin_platform_driver(exynos_chipid_driver);
+module_platform_driver(exynos_chipid_driver);
+
+MODULE_DESCRIPTION("Samsung Exynos ChipID controller and ASV driver");
+MODULE_AUTHOR("Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>");
+MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>");
+MODULE_AUTHOR("Pankaj Dubey <pankaj.dubey@samsung.com>");
+MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
+MODULE_LICENSE("GPL");

drivers/soc/samsung/exynos5422-asv.c

@@ -503,3 +503,4 @@ int exynos5422_asv_init(struct exynos_asv *asv)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(exynos5422_asv_init);