i2c: i801: add helper i801_restore_regs

In few places relevant registers are reset to their initial value on
driver load. Factor this out to new helper i801_restore_regs to avoid
code duplication.
Even though no actual problems are known, this patch may contribute
to avoiding potential issues by:
- restoring register values also in the error path of i2c_add_adapter
- making restoring registers the last step (especially in i801_remove)

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Author: hkallweit

drivers/i2c/busses/i2c-i801.c

@@ -1629,6 +1629,12 @@ static void i801_setup_hstcfg(struct i801_priv *priv)
 	pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hstcfg);
 }
 
+static void i801_restore_regs(struct i801_priv *priv)
+{
+	outb_p(priv->original_hstcnt, SMBHSTCNT(priv));
+	pci_write_config_byte(priv->pci_dev, SMBHSTCFG, priv->original_hstcfg);
+}
+
 static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
 	int err, i;
@@ -1755,6 +1761,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if (err) {
 		platform_device_unregister(priv->tco_pdev);
 		i801_acpi_remove(priv);
+		i801_restore_regs(priv);
 		return err;
 	}
 
@@ -1779,19 +1786,19 @@ static void i801_remove(struct pci_dev *dev)
 {
 	struct i801_priv *priv = pci_get_drvdata(dev);
 
-	outb_p(priv->original_hstcnt, SMBHSTCNT(priv));
 	i801_disable_host_notify(priv);
 	i801_del_mux(priv);
 	i2c_del_adapter(&priv->adapter);
 	i801_acpi_remove(priv);
-	pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
 
 	platform_device_unregister(priv->tco_pdev);
 
 	/* if acpi_reserved is set then usage_count is incremented already */
 	if (!priv->acpi_reserved)
 		pm_runtime_get_noresume(&dev->dev);
 
+	i801_restore_regs(priv);
+
 	/*
 	 * do not call pci_disable_device(dev) since it can cause hard hangs on
 	 * some systems during power-off (eg. Fujitsu-Siemens Lifebook E8010)
@@ -1802,18 +1809,17 @@ static void i801_shutdown(struct pci_dev *dev)
 {
 	struct i801_priv *priv = pci_get_drvdata(dev);
 
-	/* Restore config registers to avoid hard hang on some systems */
-	outb_p(priv->original_hstcnt, SMBHSTCNT(priv));
 	i801_disable_host_notify(priv);
-	pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
+	/* Restore config registers to avoid hard hang on some systems */
+	i801_restore_regs(priv);
 }
 
 static int i801_suspend(struct device *dev)
 {
 	struct i801_priv *priv = dev_get_drvdata(dev);
 
-	outb_p(priv->original_hstcnt, SMBHSTCNT(priv));
-	pci_write_config_byte(priv->pci_dev, SMBHSTCFG, priv->original_hstcfg);
+	i801_restore_regs(priv);
+
 	return 0;
 }