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>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 85d69f3e624f..924e84a53488 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -39,6 +39,7 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/dmi.h>
+#include <linux/acpi.h>
 #include <asm/io.h>
 
 
@@ -168,6 +169,9 @@ static int __devinit piix4_setup(struct pci_dev *PIIX4_dev,
                 }
         }
 
+        if (acpi_check_region(piix4_smba, SMBIOSIZE, piix4_driver.name))
+                return -EBUSY;
+
         if (!request_region(piix4_smba, SMBIOSIZE, piix4_driver.name)) {
                 dev_err(&PIIX4_dev->dev, "SMBus region 0x%x already in use!\n",
                         piix4_smba);