From 66d402e2e9455cf0213c42b97f22a0493372d7cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Volker=20R=C3=BCmelin?= <vr_qemu@t-online.de>
Date: Tue, 1 Sep 2020 15:22:21 +0200
Subject: [PATCH] i2c: i801: Fix resume bug
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Git-commit: 66d402e2e9455cf0213c42b97f22a0493372d7cc
Patch-mainline: v5.9-rc6
References: git-fixes

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
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/i2c/busses/i2c-i801.c |   21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1487,6 +1487,16 @@ static inline int i801_acpi_probe(struct
 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;
@@ -1592,14 +1602,10 @@ static int i801_probe(struct pci_dev *de
 		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");
@@ -1726,6 +1732,7 @@ static int i801_resume(struct device *de
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct i801_priv *priv = pci_get_drvdata(pci_dev);
 
+	i801_setup_hstcfg(priv);
 	i801_enable_host_notify(&priv->adapter);
 
 	return 0;