i2c: Check for ACPI resource conflicts

Check for ACPI resource conflicts in i2c bus drivers. I've included
all recent SMBus master drivers for PC hardware.

I've voluntarily left out:
* Drivers that don't run on PCs: they can't conflict with ACPI.
* Bit-banged bus device drivers: it's very unlikely that ACPI would
  deal with such buses.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
diff --git a/drivers/i2c/busses/i2c-sis630.c b/drivers/i2c/busses/i2c-sis630.c
index eb2b218..72c29a6 100644
--- a/drivers/i2c/busses/i2c-sis630.c
+++ b/drivers/i2c/busses/i2c-sis630.c
@@ -55,6 +55,7 @@
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
+#include <linux/acpi.h>
 #include <asm/io.h>
 
 /* SIS630 SMBus registers */
@@ -437,6 +438,11 @@
 
 	dev_dbg(&sis630_dev->dev, "ACPI base at 0x%04x\n", acpi_base);
 
+	retval = acpi_check_region(acpi_base + SMB_STS, SIS630_SMB_IOREGION,
+				   sis630_driver.name);
+	if (retval)
+		goto exit;
+
 	/* Everything is happy, let's grab the memory and set things up. */
 	if (!request_region(acpi_base + SMB_STS, SIS630_SMB_IOREGION,
 			    sis630_driver.name)) {