mfd: sec-core: Allow building as module

The main MFD driver for Samsung PMICs (S2MPSXX, S5M876X) used with
Exynos SoCs can be compiled and used as a module.  The dependent clock,
regulator and RTC drivers already can be built as a module.

Building entire set of drivers as modules might require using initial
ramdisk and can make booting process longer (due to probe deferrals).
However adding such option is useful for testing and for multi-platform
configurations.

This also add required module authors to sec-irq.c file based on recent
main contributors.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -1032,17 +1032,24 @@ config MFD_RN5T618
 	  functionality of the device.
 
 config MFD_SEC_CORE
-	bool "SAMSUNG Electronics PMIC Series Support"
+	tristate "SAMSUNG Electronics PMIC Series Support"
 	depends on I2C=y
 	select MFD_CORE
 	select REGMAP_I2C
 	select REGMAP_IRQ
 	help
-	  Support for the Samsung Electronics MFD series.
+	  Support for the Samsung Electronics PMIC devices coming
+	  usually along with Samsung Exynos SoC chipset.
 	  This driver provides common support for accessing the device,
 	  additional drivers must be enabled in order to use the functionality
 	  of the device
 
+	  To compile this driver as a module, choose M here: the
+	  module will be called sec-core.
+	  Have in mind that important core drivers (like regulators) depend
+	  on this driver so building this as a module might require proper
+	  initial ramdisk or might not boot up as well in certain scenarios.
+
 config MFD_SI476X_CORE
 	tristate "Silicon Laboratories 4761/64/68 AM/FM radio."
 	depends on I2C

drivers/mfd/sec-irq.c

@@ -6,6 +6,7 @@
 #include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
+#include <linux/module.h>
 #include <linux/regmap.h>
 
 #include <linux/mfd/samsung/core.h>
@@ -493,3 +494,10 @@ int sec_irq_init(struct sec_pmic_dev *sec_pmic)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(sec_irq_init);
+
+MODULE_AUTHOR("Sangbeom Kim <sbkim73@samsung.com>");
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_AUTHOR("Krzysztof Kozlowski <krzk@kernel.org>");
+MODULE_DESCRIPTION("Interrupt support for the S5M MFD");
+MODULE_LICENSE("GPL");