From: Jean Delvare <jdelvare@suse.de>
Date: Wed, 12 Nov 2014 09:25:37 +0000 (+0100)
Subject: i2c: i801: Check if interrupts are disabled
X-Git-Tag: v3.19-rc1~84^2~43
X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=aeb8a3d16ae0faceeae77adde2d3f9f2b199f4d9

i2c: i801: Check if interrupts are disabled

There is a control bit in the PCI configuration space which disables
interrupts. If this bit is set, the driver should not try to make use
of interrupts, it won't receive any.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index a6f3bc38fbe5..3f1f30313cd7 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -109,12 +109,16 @@
 
 /* PCI Address Constants */
 #define SMBBAR		4
+#define SMBPCICTL	0x004
 #define SMBPCISTS	0x006
 #define SMBHSTCFG	0x040
 
 /* Host status bits for SMBPCISTS */
 #define SMBPCISTS_INTS		0x08
 
+/* Control bits for SMBPCICTL */
+#define SMBPCICTL_INTDIS	0x0400
+
 /* Host configuration bits for SMBHSTCFG */
 #define SMBHSTCFG_HST_EN	1
 #define SMBHSTCFG_SMB_SMI_EN	2
@@ -1231,6 +1235,22 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	/* Default timeout in interrupt mode: 200 ms */
 	priv->adapter.timeout = HZ / 5;
 
+	if (priv->features & FEATURE_IRQ) {
+		u16 pcictl, pcists;
+
+		/* Complain if an interrupt is already pending */
+		pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists);
+		if (pcists & SMBPCISTS_INTS)
+			dev_warn(&dev->dev, "An interrupt is pending!\n");
+
+		/* Check if interrupts have been disabled */
+		pci_read_config_word(priv->pci_dev, SMBPCICTL, &pcictl);
+		if (pcictl & SMBPCICTL_INTDIS) {
+			dev_info(&dev->dev, "Interrupts are disabled\n");
+			priv->features &= ~FEATURE_IRQ;
+		}
+	}
+
 	if (priv->features & FEATURE_IRQ) {
 		init_waitqueue_head(&priv->waitq);