i2c: pasemi: split driver into two separate modules

On powerpc, it is possible to compile test both the new apple (arm) and
old pasemi (powerpc) drivers for the i2c hardware at the same time,
which leads to a warning about linking the same object file twice:

scripts/Makefile.build:244: drivers/i2c/busses/Makefile: i2c-pasemi-core.o is added to multiple modules: i2c-apple i2c-pasemi

Rework the driver to have an explicit helper module, letting Kbuild
take care of whether this should be built-in or a loadable driver.

Fixes: 9bc5f4f6 ("i2c: pasemi: Split pci driver to its own file")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

drivers/i2c/busses/Makefile

@@ -90,10 +90,8 @@ obj-$(CONFIG_I2C_NPCM)		+= i2c-npcm7xx.o
 obj-$(CONFIG_I2C_OCORES)	+= i2c-ocores.o
 obj-$(CONFIG_I2C_OMAP)		+= i2c-omap.o
 obj-$(CONFIG_I2C_OWL)		+= i2c-owl.o
-i2c-pasemi-objs := i2c-pasemi-core.o i2c-pasemi-pci.o
-obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
-i2c-apple-objs := i2c-pasemi-core.o i2c-pasemi-platform.o
-obj-$(CONFIG_I2C_APPLE)	+= i2c-apple.o
+obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi-core.o i2c-pasemi-pci.o
+obj-$(CONFIG_I2C_APPLE)		+= i2c-pasemi-core.o i2c-pasemi-platform.o
 obj-$(CONFIG_I2C_PCA_PLATFORM)	+= i2c-pca-platform.o
 obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o

drivers/i2c/busses/i2c-pasemi-core.c

@@ -369,6 +369,7 @@ int pasemi_i2c_common_probe(struct pasemi_smbus *smbus)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(pasemi_i2c_common_probe);
 
 irqreturn_t pasemi_irq_handler(int irq, void *dev_id)
 {
@@ -378,3 +379,8 @@ irqreturn_t pasemi_irq_handler(int irq, void *dev_id)
 	complete(&smbus->irq_completion);
 	return IRQ_HANDLED;
 }
+EXPORT_SYMBOL_GPL(pasemi_irq_handler);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Olof Johansson <olof@lixom.net>");
+MODULE_DESCRIPTION("PA Semi PWRficient SMBus driver");