i2c: i801: Fix resume bug

On suspend the original host configuration gets restored. The
resume routine has to undo this, otherwise the SMBus master
may be left in disabled state or in i2c mode.

[JD: Rebased on v5.8, moved the write into i801_setup_hstcfg.]
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Cc: stable@vger.kernel.org

drivers/i2c/busses/i2c-i801.c

@@ -1709,6 +1709,16 @@ static inline int i801_acpi_probe(struct i801_priv *priv) { return 0; }
 static inline void i801_acpi_remove(struct i801_priv *priv) { }
 #endif
 
+static unsigned char i801_setup_hstcfg(struct i801_priv *priv)
+{
+	unsigned char hstcfg = priv->original_hstcfg;
+
+	hstcfg &= ~SMBHSTCFG_I2C_EN;	/* SMBus timing */
+	hstcfg |= SMBHSTCFG_HST_EN;
+	pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hstcfg);
+	return hstcfg;
+}
+
 static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
 	unsigned char temp;
@@ -1830,14 +1840,10 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return err;
 	}
 
-	pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &temp);
-	priv->original_hstcfg = temp;
-	temp &= ~SMBHSTCFG_I2C_EN;	/* SMBus timing */
-	if (!(temp & SMBHSTCFG_HST_EN)) {
+	pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &priv->original_hstcfg);
+	temp = i801_setup_hstcfg(priv);
+	if (!(priv->original_hstcfg & SMBHSTCFG_HST_EN))
 		dev_info(&dev->dev, "Enabling SMBus device\n");
-		temp |= SMBHSTCFG_HST_EN;
-	}
-	pci_write_config_byte(priv->pci_dev, SMBHSTCFG, temp);
 
 	if (temp & SMBHSTCFG_SMB_SMI_EN) {
 		dev_dbg(&dev->dev, "SMBus using interrupt SMI#\n");
@@ -1963,6 +1969,7 @@ static int i801_resume(struct device *dev)
 {
 	struct i801_priv *priv = dev_get_drvdata(dev);
 
+	i801_setup_hstcfg(priv);
 	i801_enable_host_notify(&priv->adapter);
 
 	return 0;