i2c-sis5595: Resolve resource conflict with sis5595

Let the i2c-sis5595 driver release its PCI device after registering.
This is to allow the sis5595 hardware monitoring driver to also
access this PCI device. The same trick is already used in the
i2c-viapro and via686a drivers to let them both load.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/busses/i2c-sis5595.c

@@ -129,6 +129,7 @@ MODULE_PARM_DESC(force_addr, "Initialize the base address of the i2c controller"
 
 static struct pci_driver sis5595_driver;
 static unsigned short sis5595_base;
+static struct pci_dev *sis5595_pdev;
 
 static u8 sis5595_read(u8 reg)
 {
@@ -379,6 +380,8 @@ MODULE_DEVICE_TABLE (pci, sis5595_ids);
 
 static int __devinit sis5595_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
+	int err;
+
 	if (sis5595_setup(dev)) {
 		dev_err(&dev->dev, "SIS5595 not detected, module not inserted.\n");
 		return -ENODEV;
@@ -389,20 +392,24 @@ static int __devinit sis5595_probe(struct pci_dev *dev, const struct pci_device_
 
 	sprintf(sis5595_adapter.name, "SMBus SIS5595 adapter at %04x",
 		sis5595_base + SMB_INDEX);
-	return i2c_add_adapter(&sis5595_adapter);
-}
+	err = i2c_add_adapter(&sis5595_adapter);
+	if (err) {
+		release_region(sis5595_base + SMB_INDEX, 2);
+		return err;
+	}
 
-static void __devexit sis5595_remove(struct pci_dev *dev)
-{
-	i2c_del_adapter(&sis5595_adapter);
-	release_region(sis5595_base + SMB_INDEX, 2);
+	/* Always return failure here.  This is to allow other drivers to bind
+	 * to this pci device.  We don't really want to have control over the
+	 * pci device, we only wanted to read as few register values from it.
+	 */
+	sis5595_pdev =  pci_dev_get(dev);
+	return -ENODEV;
 }
 
 static struct pci_driver sis5595_driver = {
 	.name		= "sis5595_smbus",
 	.id_table	= sis5595_ids,
 	.probe		= sis5595_probe,
-	.remove		= __devexit_p(sis5595_remove),
 };
 
 static int __init i2c_sis5595_init(void)
@@ -413,6 +420,12 @@ static int __init i2c_sis5595_init(void)
 static void __exit i2c_sis5595_exit(void)
 {
 	pci_unregister_driver(&sis5595_driver);
+	if (sis5595_pdev) {
+		i2c_del_adapter(&sis5595_adapter);
+		release_region(sis5595_base + SMB_INDEX, 2);
+		pci_dev_put(sis5595_pdev);
+		sis5595_pdev = NULL;
+	}
 }
 
 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");