i2c-designware: Fix build error if CONFIG_I2C_DESIGNWARE_PLATFORM=y && CONFIG_I2C_DESIGNWARE_PCI=y

This patch adds config I2C_DESIGNWARE_CORE in Kconfig, and let
I2C_DESIGNWARE_PLATFORM and I2C_DESIGNWARE_PCI select I2C_DESIGNWARE_CORE.

Because both I2C_DESIGNWARE_PLATFORM and I2C_DESIGNWARE_PCI can be built as
built-in or module, we also need to export the functions in i2c-designware-core.

This fixes below build error when CONFIG_I2C_DESIGNWARE_PLATFORM=y &&
CONFIG_I2C_DESIGNWARE_PCI=y:

  LD      drivers/i2c/busses/built-in.o
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_clear_int':
i2c-designware-core.c:(.text+0xa10): multiple definition of `i2c_dw_clear_int'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x928): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_init':
i2c-designware-core.c:(.text+0x178): multiple definition of `i2c_dw_init'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x90): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `dw_readl':
i2c-designware-core.c:(.text+0xe8): multiple definition of `dw_readl'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x0): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_isr':
i2c-designware-core.c:(.text+0x724): multiple definition of `i2c_dw_isr'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x63c): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_xfer':
i2c-designware-core.c:(.text+0x4b0): multiple definition of `i2c_dw_xfer'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x3c8): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_is_enabled':
i2c-designware-core.c:(.text+0x9d4): multiple definition of `i2c_dw_is_enabled'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x8ec): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `dw_writel':
i2c-designware-core.c:(.text+0x124): multiple definition of `dw_writel'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x3c): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_xfer_msg':
i2c-designware-core.c:(.text+0x2e8): multiple definition of `i2c_dw_xfer_msg'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x200): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_enable':
i2c-designware-core.c:(.text+0x9c8): multiple definition of `i2c_dw_enable'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x8e0): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_read_comp_param':
i2c-designware-core.c:(.text+0xa24): multiple definition of `i2c_dw_read_comp_param'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x93c): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_disable':
i2c-designware-core.c:(.text+0x9dc): multiple definition of `i2c_dw_disable'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x8f4): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_func':
i2c-designware-core.c:(.text+0x710): multiple definition of `i2c_dw_func'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x628): first defined here
drivers/i2c/busses/i2c-designware-pci.o: In function `i2c_dw_disable_int':
i2c-designware-core.c:(.text+0xa18): multiple definition of `i2c_dw_disable_int'
drivers/i2c/busses/i2c-designware-platform.o:i2c-designware-platdrv.c:(.text+0x930): first defined here
make[3]: *** [drivers/i2c/busses/built-in.o] Error 1
make[2]: *** [drivers/i2c/busses] Error 2
make[1]: *** [drivers/i2c] Error 2
make: *** [drivers] Error 2

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable@vger.kernel.org [3.2+]

drivers/i2c/busses/Kconfig

@@ -355,9 +355,13 @@ config I2C_DAVINCI
 	  devices such as DaVinci NIC.
 	  For details please see http://www.ti.com/davinci
 
+config I2C_DESIGNWARE_CORE
+	tristate
+
 config I2C_DESIGNWARE_PLATFORM
 	tristate "Synopsys DesignWare Platform"
 	depends on HAVE_CLK
+	select I2C_DESIGNWARE_CORE
 	help
 	  If you say yes to this option, support will be included for the
 	  Synopsys DesignWare I2C adapter. Only master mode is supported.
@@ -368,6 +372,7 @@ config I2C_DESIGNWARE_PLATFORM
 config I2C_DESIGNWARE_PCI
 	tristate "Synopsys DesignWare PCI"
 	depends on PCI
+	select I2C_DESIGNWARE_CORE
 	help
 	  If you say yes to this option, support will be included for the
 	  Synopsys DesignWare I2C adapter. Only master mode is supported.

drivers/i2c/busses/Makefile

@@ -33,10 +33,11 @@ obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
 obj-$(CONFIG_I2C_BLACKFIN_TWI)	+= i2c-bfin-twi.o
 obj-$(CONFIG_I2C_CPM)		+= i2c-cpm.o
 obj-$(CONFIG_I2C_DAVINCI)	+= i2c-davinci.o
+obj-$(CONFIG_I2C_DESIGNWARE_CORE)	+= i2c-designware-core.o
 obj-$(CONFIG_I2C_DESIGNWARE_PLATFORM)	+= i2c-designware-platform.o
-i2c-designware-platform-objs := i2c-designware-platdrv.o i2c-designware-core.o
+i2c-designware-platform-objs := i2c-designware-platdrv.o
 obj-$(CONFIG_I2C_DESIGNWARE_PCI)	+= i2c-designware-pci.o
-i2c-designware-pci-objs := i2c-designware-pcidrv.o i2c-designware-core.o
+i2c-designware-pci-objs := i2c-designware-pcidrv.o
 obj-$(CONFIG_I2C_EG20T)		+= i2c-eg20t.o
 obj-$(CONFIG_I2C_GPIO)		+= i2c-gpio.o
 obj-$(CONFIG_I2C_HIGHLANDER)	+= i2c-highlander.o

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

@@ -25,6 +25,7 @@
  * ----------------------------------------------------------------------------
  *
  */
+#include <linux/export.h>
 #include <linux/clk.h>
 #include <linux/errno.h>
 #include <linux/err.h>
@@ -316,6 +317,7 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	dw_writel(dev, dev->master_cfg , DW_IC_CON);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(i2c_dw_init);
 
 /*
  * Waiting for bus not busy
@@ -568,12 +570,14 @@ done:
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(i2c_dw_xfer);
 
 u32 i2c_dw_func(struct i2c_adapter *adap)
 {
 	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
 	return dev->functionality;
 }
+EXPORT_SYMBOL_GPL(i2c_dw_func);
 
 static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
 {
@@ -678,17 +682,20 @@ tx_aborted:
 
 	return IRQ_HANDLED;
 }
+EXPORT_SYMBOL_GPL(i2c_dw_isr);
 
 void i2c_dw_enable(struct dw_i2c_dev *dev)
 {
        /* Enable the adapter */
 	dw_writel(dev, 1, DW_IC_ENABLE);
 }
+EXPORT_SYMBOL_GPL(i2c_dw_enable);
 
 u32 i2c_dw_is_enabled(struct dw_i2c_dev *dev)
 {
 	return dw_readl(dev, DW_IC_ENABLE);
 }
+EXPORT_SYMBOL_GPL(i2c_dw_is_enabled);
 
 void i2c_dw_disable(struct dw_i2c_dev *dev)
 {
@@ -699,18 +706,22 @@ void i2c_dw_disable(struct dw_i2c_dev *dev)
 	dw_writel(dev, 0, DW_IC_INTR_MASK);
 	dw_readl(dev, DW_IC_CLR_INTR);
 }
+EXPORT_SYMBOL_GPL(i2c_dw_disable);
 
 void i2c_dw_clear_int(struct dw_i2c_dev *dev)
 {
 	dw_readl(dev, DW_IC_CLR_INTR);
 }
+EXPORT_SYMBOL_GPL(i2c_dw_clear_int);
 
 void i2c_dw_disable_int(struct dw_i2c_dev *dev)
 {
 	dw_writel(dev, 0, DW_IC_INTR_MASK);
 }
+EXPORT_SYMBOL_GPL(i2c_dw_disable_int);
 
 u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev)
 {
 	return dw_readl(dev, DW_IC_COMP_PARAM_1);
 }
+EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param);